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Yamada D, Bushey D, Li F, Hibbard KL, Sammons M, Funke J, Litwin-Kumar A, Hige T, Aso Y. Hierarchical architecture of dopaminergic circuits enables second-order conditioning in Drosophila. eLife 2023; 12:e79042. [PMID: 36692262 PMCID: PMC9937650 DOI: 10.7554/elife.79042] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 01/23/2023] [Indexed: 01/25/2023] Open
Abstract
Dopaminergic neurons with distinct projection patterns and physiological properties compose memory subsystems in a brain. However, it is poorly understood whether or how they interact during complex learning. Here, we identify a feedforward circuit formed between dopamine subsystems and show that it is essential for second-order conditioning, an ethologically important form of higher-order associative learning. The Drosophila mushroom body comprises a series of dopaminergic compartments, each of which exhibits distinct memory dynamics. We find that a slow and stable memory compartment can serve as an effective 'teacher' by instructing other faster and transient memory compartments via a single key interneuron, which we identify by connectome analysis and neurotransmitter prediction. This excitatory interneuron acquires enhanced response to reward-predicting odor after first-order conditioning and, upon activation, evokes dopamine release in the 'student' compartments. These hierarchical connections between dopamine subsystems explain distinct properties of first- and second-order memory long known by behavioral psychologists.
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Affiliation(s)
- Daichi Yamada
- Department of Biology, University of North Carolina at Chapel HillChapel HillUnited States
| | - Daniel Bushey
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Feng Li
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Karen L Hibbard
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Megan Sammons
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Jan Funke
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | | | - Toshihide Hige
- Department of Biology, University of North Carolina at Chapel HillChapel HillUnited States
- Department of Cell Biology and Physiology, University of North Carolina at Chapel HillChapel HillUnited States
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel HillChapel HillUnited States
| | - Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
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52
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Marquand K, Roselli C, Cervantes-Sandoval I, Boto T. Sleep benefits different stages of memory in Drosophila. Front Physiol 2023; 14:1087025. [PMID: 36744027 PMCID: PMC9892949 DOI: 10.3389/fphys.2023.1087025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/06/2023] [Indexed: 01/20/2023] Open
Abstract
Understanding the physiological mechanisms that modulate memory acquisition and consolidation remains among the most ambitious questions in neuroscience. Massive efforts have been dedicated to deciphering how experience affects behavior, and how different physiological and sensory phenomena modulate memory. Our ability to encode, consolidate and retrieve memories depends on internal drives, and sleep stands out among the physiological processes that affect memory: one of the most relatable benefits of sleep is the aiding of memory that occurs in order to both prepare the brain to learn new information, and after a learning task, to consolidate those new memories. Drosophila lends itself to the study of the interactions between memory and sleep. The fruit fly provides incomparable genetic resources, a mapped connectome, and an existing framework of knowledge on the molecular, cellular, and circuit mechanisms of memory and sleep, making the fruit fly a remarkable model to decipher the sophisticated regulation of learning and memory by the quantity and quality of sleep. Research in Drosophila has stablished not only that sleep facilitates learning in wild-type and memory-impaired animals, but that sleep deprivation interferes with the acquisition of new memories. In addition, it is well-accepted that sleep is paramount in memory consolidation processes. Finally, studies in Drosophila have shown that that learning itself can promote sleep drive. Nevertheless, the molecular and network mechanisms underlying this intertwined relationship are still evasive. Recent remarkable work has shed light on the neural substrates that mediate sleep-dependent memory consolidation. In a similar way, the mechanistic insights of the neural switch control between sleep-dependent and sleep-independent consolidation strategies were recently described. This review will discuss the regulation of memory by sleep in Drosophila, focusing on the most recent advances in the field and pointing out questions awaiting to be investigated.
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Affiliation(s)
- Katie Marquand
- Department of Physiology, School of Medicine, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Camilla Roselli
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Isaac Cervantes-Sandoval
- Department of Biology, Georgetown University, Washington, DC, United States
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, United States
| | - Tamara Boto
- Department of Physiology, School of Medicine, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
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53
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Marquis M, Wilson RI. Locomotor and olfactory responses in dopamine neurons of the Drosophila superior-lateral brain. Curr Biol 2022; 32:5406-5414.e5. [PMID: 36450284 DOI: 10.1016/j.cub.2022.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/17/2022] [Accepted: 11/03/2022] [Indexed: 12/03/2022]
Abstract
The Drosophila brain contains about 50 distinct morphological types of dopamine neurons.1,2,3,4 Physiological studies of Drosophila dopamine neurons have been largely limited to one brain region, the mushroom body,5,6,7,8,9,10,11,12,13 where they are implicated in learning.14,15,16,17,18 By comparison, we know little about the physiology of other Drosophila dopamine neurons. Interestingly, a recent whole-brain imaging study found that dopamine neuron activity in several fly brain regions is correlated with locomotion.19 This is notable because many dopamine neurons in the rodent brain are also correlated with locomotion or other movements20,21,22,23,24,25,26,27,28,29,30; however, most rodent studies have focused on learned and rewarded behaviors, and few have investigated dopamine neuron activity during spontaneous (self-timed) movements. In this study, we monitored dopamine neurons in the Drosophila brain during self-timed locomotor movements, focusing on several previously uncharacterized cell types that arborize in the superior-lateral brain, specifically the lateral horn and superior-lateral protocerebrum. We found that activity of all of these dopamine neurons correlated with spontaneous fluctuations in walking speed, with different cell types showing different speed correlations. Some dopamine neurons also responded to odors, but these responses were suppressed by repeated odor encounters. Finally, we found that the same identifiable dopamine neuron can encode different combinations of locomotion and odor in different individuals. If these dopamine neurons promote synaptic plasticity-like the dopamine neurons of the mushroom body-then, their tuning profiles would imply that plasticity depends on a flexible integration of sensory signals, motor signals, and recent experience.
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Affiliation(s)
- Michael Marquis
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Rachel I Wilson
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
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Fisher YE, Marquis M, D'Alessandro I, Wilson RI. Dopamine promotes head direction plasticity during orienting movements. Nature 2022; 612:316-322. [PMID: 36450986 PMCID: PMC9729112 DOI: 10.1038/s41586-022-05485-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 10/25/2022] [Indexed: 12/05/2022]
Abstract
In neural networks that store information in their connection weights, there is a tradeoff between sensitivity and stability1,2. Connections must be plastic to incorporate new information, but if they are too plastic, stored information can be corrupted. A potential solution is to allow plasticity only during epochs when task-specific information is rich, on the basis of a 'when-to-learn' signal3. We reasoned that dopamine provides a when-to-learn signal that allows the brain's spatial maps to update when new spatial information is available-that is, when an animal is moving. Here we show that the dopamine neurons innervating the Drosophila head direction network are specifically active when the fly turns to change its head direction. Moreover, their activity scales with moment-to-moment fluctuations in rotational speed. Pairing dopamine release with a visual cue persistently strengthens the cue's influence on head direction cells. Conversely, inhibiting these dopamine neurons decreases the influence of the cue. This mechanism should accelerate learning during moments when orienting movements are providing a rich stream of head direction information, allowing learning rates to be low at other times to protect stored information. Our results show how spatial learning in the brain can be compressed into discrete epochs in which high learning rates are matched to high rates of information intake.
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Affiliation(s)
- Yvette E Fisher
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Department of Molecular and Cellular Biology, University of California Berkeley, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Michael Marquis
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | | | - Rachel I Wilson
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.
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55
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Turrel O, Ramesh N, Escher MJF, Pooryasin A, Sigrist SJ. Transient active zone remodeling in the Drosophila mushroom body supports memory. Curr Biol 2022; 32:4900-4913.e4. [PMID: 36327980 DOI: 10.1016/j.cub.2022.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 08/15/2022] [Accepted: 10/06/2022] [Indexed: 11/22/2022]
Abstract
Elucidating how the distinct components of synaptic plasticity dynamically orchestrate the distinct stages of memory acquisition and maintenance within neuronal networks remains a major challenge. Specifically, plasticity processes tuning the functional and also structural state of presynaptic active zone (AZ) release sites are widely observed in vertebrates and invertebrates, but their behavioral relevance remains mostly unclear. We here provide evidence that a transient upregulation of presynaptic AZ release site proteins supports aversive olfactory mid-term memory in the Drosophila mushroom body (MB). Upon paired aversive olfactory conditioning, AZ protein levels (ELKS-family BRP/(m)unc13-family release factor Unc13A) increased for a few hours with MB-lobe-specific dynamics. Kenyon cell (KC, intrinsic MB neurons)-specific knockdown (KD) of BRP did not affect aversive olfactory short-term memory (STM) but strongly suppressed aversive mid-term memory (MTM). Different proteins crucial for the transport of AZ biosynthetic precursors (transport adaptor Aplip1/Jip-1; kinesin motor IMAC/Unc104; small GTPase Arl8) were also specifically required for the formation of aversive olfactory MTM. Consistent with the merely transitory increase of AZ proteins, BRP KD did not interfere with the formation of aversive olfactory long-term memory (LTM; i.e., 1 day). Our data suggest that the remodeling of presynaptic AZ refines the MB circuitry after paired aversive conditioning, over a time window of a few hours, to display aversive olfactory memories.
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Affiliation(s)
- Oriane Turrel
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Niraja Ramesh
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Marc J F Escher
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Atefeh Pooryasin
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany.
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56
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Qiao J, Yang S, Geng H, Yung WH, Ke Y. Input-timing-dependent plasticity at incoming synapses of the mushroom body facilitates olfactory learning in Drosophila. Curr Biol 2022; 32:4869-4880.e4. [PMID: 36265490 DOI: 10.1016/j.cub.2022.09.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 08/15/2022] [Accepted: 09/27/2022] [Indexed: 11/06/2022]
Abstract
Aversive olfactory conditioning in Drosophila is a valuable model for elucidating the mechanism of associative learning. Much effort has centered around the role of neuroplasticity at the mushroom body (MB)-mushroom body output neuron (MBON) synapses in mapping odors to specific behaviors. By electrophysiological recordings from MB neurons, we discovered a form of input-timing-dependent plasticity at the incoming synapses from projection neurons that controls the efficacy of aversive olfactory memory formation. Importantly, this plasticity is facilitated by the neural activity of PPL1, the neuronal cluster that also modulates MB-MBON connections at the output stage of MB. Unlike the MB-MBON synapses that probably utilize dopamine D1-like receptors, this neuroplasticity is dependent on D2-like receptors that are expressed mainly by γ Kenyon cells noticeably in their somato-dendritic region. The D2-like receptors recruit voltage-gated calcium channels, leading to calcium influx in the soma and dendrites of γ neurons. Together, our results reveal a previously unrecognized synaptic component of the MB circuit architecture that not only could increase the salience of a conditioning odor but also couples the process of memory encoding and valency mapping to drive-associative learning.
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Affiliation(s)
- Jingda Qiao
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Shengxi Yang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Hongyan Geng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Wing-Ho Yung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
| | - Ya Ke
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
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57
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Manoim JE, Davidson AM, Weiss S, Hige T, Parnas M. Lateral axonal modulation is required for stimulus-specific olfactory conditioning in Drosophila. Curr Biol 2022; 32:4438-4450.e5. [PMID: 36130601 PMCID: PMC9613607 DOI: 10.1016/j.cub.2022.09.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 08/15/2022] [Accepted: 09/04/2022] [Indexed: 11/26/2022]
Abstract
Effective and stimulus-specific learning is essential for animals' survival. Two major mechanisms are known to aid stimulus specificity of associative learning. One is accurate stimulus-specific representations in neurons. The second is a limited effective temporal window for the reinforcing signals to induce neuromodulation after sensory stimuli. However, these mechanisms are often imperfect in preventing unspecific associations; different sensory stimuli can be represented by overlapping populations of neurons, and more importantly, the reinforcing signals alone can induce neuromodulation even without coincident sensory-evoked neuronal activity. Here, we report a crucial neuromodulatory mechanism that counteracts both limitations and is thereby essential for stimulus specificity of learning. In Drosophila, olfactory signals are sparsely represented by cholinergic Kenyon cells (KCs), which receive dopaminergic reinforcing input. We find that KCs have numerous axo-axonic connections mediated by the muscarinic type-B receptor (mAChR-B). By using functional imaging and optogenetic approaches, we show that these axo-axonic connections suppress both odor-evoked calcium responses and dopamine-evoked cAMP signals in neighboring KCs. Strikingly, behavior experiments demonstrate that mAChR-B knockdown in KCs impairs olfactory learning by inducing undesired changes to the valence of an odor that was not associated with the reinforcer. Thus, this local neuromodulation acts in concert with sparse sensory representations and global dopaminergic modulation to achieve effective and accurate memory formation.
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Affiliation(s)
- Julia E Manoim
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Andrew M Davidson
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Shirley Weiss
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Toshihide Hige
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Moshe Parnas
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
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58
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Dasgupta S, Hattori D, Navlakha S. A neural theory for counting memories. Nat Commun 2022; 13:5961. [PMID: 36217003 PMCID: PMC9551066 DOI: 10.1038/s41467-022-33577-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/22/2022] [Indexed: 11/09/2022] Open
Abstract
Keeping track of the number of times different stimuli have been experienced is a critical computation for behavior. Here, we propose a theoretical two-layer neural circuit that stores counts of stimulus occurrence frequencies. This circuit implements a data structure, called a count sketch, that is commonly used in computer science to maintain item frequencies in streaming data. Our first model implements a count sketch using Hebbian synapses and outputs stimulus-specific frequencies. Our second model uses anti-Hebbian plasticity and only tracks frequencies within four count categories ("1-2-3-many"), which trades-off the number of categories that need to be distinguished with the potential ethological value of those categories. We show how both models can robustly track stimulus occurrence frequencies, thus expanding the traditional novelty-familiarity memory axis from binary to discrete with more than two possible values. Finally, we show that an implementation of the "1-2-3-many" count sketch exists in the insect mushroom body.
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Affiliation(s)
- Sanjoy Dasgupta
- Computer Science and Engineering Department, University of California San Diego, La Jolla, CA, 92037, USA
| | - Daisuke Hattori
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA.
| | - Saket Navlakha
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.
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59
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Martinez-Cervantes J, Shah P, Phan A, Cervantes-Sandoval I. Higher-order unimodal olfactory sensory preconditioning in Drosophila. eLife 2022; 11:e79107. [PMID: 36129180 PMCID: PMC9566850 DOI: 10.7554/elife.79107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 09/18/2022] [Indexed: 11/22/2022] Open
Abstract
Learning and memory storage is a complex process that has proven challenging to tackle. It is likely that, in nature, the instructive value of reinforcing experiences is acquired rather than innate. The association between seemingly neutral stimuli increases the gamut of possibilities to create meaningful associations and the predictive power of moment-by-moment experiences. Here, we report physiological and behavioral evidence of olfactory unimodal sensory preconditioning in fruit flies. We show that the presentation of a pair of odors (S1 and S2) before one of them (S1) is associated with electric shocks elicits a conditional response not only to the trained odor (S1) but to the odor previously paired with it (S2). This occurs even if the S2 odor was never presented in contiguity with the aversive stimulus. In addition, we show that inhibition of the small G protein Rac1, a known forgetting regulator, facilitates the association between S1/S2 odors. These results indicate that flies can infer value to olfactory stimuli based on the previous associative structure between odors, and that inhibition of Rac1 lengthens the time window of the olfactory 'sensory buffer', allowing the establishment of associations between odors presented in sequence.
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Affiliation(s)
| | - Prachi Shah
- Department of Biology, Georgetown UniversityWashington, DCUnited States
| | - Anna Phan
- Department of Biological Sciences and Neuroscience & Mental Health Institute, University of AlbertaEdmontonCanada
| | - Isaac Cervantes-Sandoval
- Department of Biology, Georgetown UniversityWashington, DCUnited States
- Interdisciplinary Program in Neuroscience, Georgetown UniversityWashington, DCUnited States
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60
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Active forgetting requires Sickie function in a dedicated dopamine circuit in Drosophila. Proc Natl Acad Sci U S A 2022; 119:e2204229119. [PMID: 36095217 PMCID: PMC9499536 DOI: 10.1073/pnas.2204229119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Forgetting is an essential component of the brain's memory management system, providing a balance to memory formation processes by removing unused or unwanted memories, or by suppressing their expression. However, the molecular, cellular, and circuit mechanisms underlying forgetting are poorly understood. Here we show that the memory suppressor gene, sickie, functions in a single dopamine neuron (DAn) by supporting the process of active forgetting in Drosophila. RNAi knockdown (KD) of sickie impairs forgetting by reducing the Ca2+ influx and DA release from the DAn that promotes forgetting. Coimmunoprecipitation/mass spectrometry analyses identified cytoskeletal and presynaptic active zone (AZ) proteins as candidates that physically interact with Sickie, and a focused RNAi screen of the candidates showed that Bruchpilot (Brp)-a presynaptic AZ protein that regulates calcium channel clustering and neurotransmitter release-impairs active forgetting like sickie KD. In addition, overexpression of brp rescued the impaired forgetting of sickie KD, providing evidence that they function in the same process. Moreover, we show that sickie KD in the DAn reduces the abundance and size of AZ markers but increases their number, suggesting that Sickie controls DAn activity for forgetting by modulating the presynaptic AZ structure. Our results identify a molecular and circuit mechanism for normal levels of active forgetting and reveal a surprising role of Sickie in maintaining presynaptic AZ structure for neurotransmitter release.
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61
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Villar ME, Pavão-Delgado M, Amigo M, Jacob PF, Merabet N, Pinot A, Perry SA, Waddell S, Perisse E. Differential coding of absolute and relative aversive value in the Drosophila brain. Curr Biol 2022; 32:4576-4592.e5. [DOI: 10.1016/j.cub.2022.08.058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/24/2022] [Accepted: 08/19/2022] [Indexed: 11/30/2022]
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Poppinga H, Çoban B, Meltzer H, Mayseless O, Widmann A, Schuldiner O, Fiala A. Pruning deficits of the developing Drosophila mushroom body result in mild impairment in associative odour learning and cause hyperactivity. Open Biol 2022; 12:220096. [PMID: 36128716 PMCID: PMC9490343 DOI: 10.1098/rsob.220096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The principles of how brain circuits establish themselves during development are largely conserved across animal species. Connections made during embryonic development that are appropriate for an early life stage are frequently remodelled later in ontogeny via pruning and subsequent regrowth to generate adult-specific connectivity. The mushroom body of the fruit fly Drosophila melanogaster is a well-established model circuit for examining the cellular mechanisms underlying neurite remodelling. This central brain circuit integrates sensory information with learned and innate valences to adaptively instruct behavioural decisions. Thereby, the mushroom body organizes adaptive behaviour, such as associative learning. However, little is known about the specific aspects of behaviour that require mushroom body remodelling. Here, we used genetic interventions to prevent the intrinsic neurons of the larval mushroom body (γ-type Kenyon cells) from remodelling. We asked to what degree remodelling deficits resulted in impaired behaviour. We found that deficits caused hyperactivity and mild impairment in differential aversive olfactory learning, but not appetitive learning. Maintenance of circadian rhythm and sleep were not affected. We conclude that neurite pruning and regrowth of γ-type Kenyon cells is not required for the establishment of circuits that mediate associative odour learning per se, but it does improve distinct learning tasks.
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Affiliation(s)
- Haiko Poppinga
- Department of Molecular Neurobiology of Behaviour, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Büşra Çoban
- Department of Molecular Neurobiology of Behaviour, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Hagar Meltzer
- Departments for Molecular Cell Biology and Molecular Neuroscience, Weizmann Institute of Science, Ullmann Building of Life Sciences, Rehovot 7610001, Israel
| | - Oded Mayseless
- Departments for Molecular Cell Biology and Molecular Neuroscience, Weizmann Institute of Science, Ullmann Building of Life Sciences, Rehovot 7610001, Israel
| | - Annekathrin Widmann
- Department of Molecular Neurobiology of Behaviour, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Oren Schuldiner
- Departments for Molecular Cell Biology and Molecular Neuroscience, Weizmann Institute of Science, Ullmann Building of Life Sciences, Rehovot 7610001, Israel
| | - André Fiala
- Department of Molecular Neurobiology of Behaviour, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
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63
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Matheson AMM, Lanz AJ, Medina AM, Licata AM, Currier TA, Syed MH, Nagel KI. A neural circuit for wind-guided olfactory navigation. Nat Commun 2022; 13:4613. [PMID: 35941114 PMCID: PMC9360402 DOI: 10.1038/s41467-022-32247-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 07/22/2022] [Indexed: 11/10/2022] Open
Abstract
To navigate towards a food source, animals frequently combine odor cues about source identity with wind direction cues about source location. Where and how these two cues are integrated to support navigation is unclear. Here we describe a pathway to the Drosophila fan-shaped body that encodes attractive odor and promotes upwind navigation. We show that neurons throughout this pathway encode odor, but not wind direction. Using connectomics, we identify fan-shaped body local neurons called h∆C that receive input from this odor pathway and a previously described wind pathway. We show that h∆C neurons exhibit odor-gated, wind direction-tuned activity, that sparse activation of h∆C neurons promotes navigation in a reproducible direction, and that h∆C activity is required for persistent upwind orientation during odor. Based on connectome data, we develop a computational model showing how h∆C activity can promote navigation towards a goal such as an upwind odor source. Our results suggest that odor and wind cues are processed by separate pathways and integrated within the fan-shaped body to support goal-directed navigation.
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Affiliation(s)
- Andrew M M Matheson
- Neuroscience Institute, NYU Medical Center, 435 E 30th St., New York, NY, 10016, USA
- Department of Biological Sciences, Columbia University, 600 Sherman Fairchild Center, New York, NY, 10027, USA
| | - Aaron J Lanz
- Neuroscience Institute, NYU Medical Center, 435 E 30th St., New York, NY, 10016, USA
| | - Ashley M Medina
- Neuroscience Institute, NYU Medical Center, 435 E 30th St., New York, NY, 10016, USA
| | - Al M Licata
- Neuroscience Institute, NYU Medical Center, 435 E 30th St., New York, NY, 10016, USA
| | - Timothy A Currier
- Neuroscience Institute, NYU Medical Center, 435 E 30th St., New York, NY, 10016, USA
- Center for Neural Science, NYU, New York, NY, 4 Washington Place, New York, NY, 10003, USA
- Department of Neurobiology, Stanford University, 299W. Campus Drive, Stanford, CA, 94305, USA
| | - Mubarak H Syed
- Department of Biology, 219 Yale Blvd NE, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Katherine I Nagel
- Neuroscience Institute, NYU Medical Center, 435 E 30th St., New York, NY, 10016, USA.
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64
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Avitan L, Stringer C. Not so spontaneous: Multi-dimensional representations of behaviors and context in sensory areas. Neuron 2022; 110:3064-3075. [PMID: 35863344 DOI: 10.1016/j.neuron.2022.06.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/20/2022] [Accepted: 06/22/2022] [Indexed: 11/27/2022]
Abstract
Sensory areas are spontaneously active in the absence of sensory stimuli. This spontaneous activity has long been studied; however, its functional role remains largely unknown. Recent advances in technology, allowing large-scale neural recordings in the awake and behaving animal, have transformed our understanding of spontaneous activity. Studies using these recordings have discovered high-dimensional spontaneous activity patterns, correlation between spontaneous activity and behavior, and dissimilarity between spontaneous and sensory-driven activity patterns. These findings are supported by evidence from developing animals, where a transition toward these characteristics is observed as the circuit matures, as well as by evidence from mature animals across species. These newly revealed characteristics call for the formulation of a new role for spontaneous activity in neural sensory computation.
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Affiliation(s)
- Lilach Avitan
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
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65
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Hancock CE, Rostami V, Rachad EY, Deimel SH, Nawrot MP, Fiala A. Visualization of learning-induced synaptic plasticity in output neurons of the Drosophila mushroom body γ-lobe. Sci Rep 2022; 12:10421. [PMID: 35729203 PMCID: PMC9213513 DOI: 10.1038/s41598-022-14413-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 06/07/2022] [Indexed: 12/21/2022] Open
Abstract
By learning, through experience, which stimuli coincide with dangers, it is possible to predict outcomes and act pre-emptively to ensure survival. In insects, this process is localized to the mushroom body (MB), the circuitry of which facilitates the coincident detection of sensory stimuli and punishing or rewarding cues and, downstream, the execution of appropriate learned behaviors. Here, we focused our attention on the mushroom body output neurons (MBONs) of the γ-lobes that act as downstream synaptic partners of the MB γ-Kenyon cells (KCs) to ask how the output of the MB γ-lobe is shaped by olfactory associative conditioning, distinguishing this from non-associative stimulus exposure effects, and without the influence of downstream modulation. This was achieved by employing a subcellularly localized calcium sensor to specifically monitor activity at MBON postsynaptic sites. Therein, we identified a robust associative modulation within only one MBON postsynaptic compartment (MBON-γ1pedc > α/β), which displayed a suppressed postsynaptic response to an aversively paired odor. While this MBON did not undergo non-associative modulation, the reverse was true across the remainder of the γ-lobe, where general odor-evoked adaptation was observed, but no conditioned odor-specific modulation. In conclusion, associative synaptic plasticity underlying aversive olfactory learning is localized to one distinct synaptic γKC-to-γMBON connection.
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Affiliation(s)
- Clare E Hancock
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Vahid Rostami
- Computational Systems Neuroscience, Institute of Zoology, University of Cologne, Zülpicherstraße 47b, 50674, Cologne, Germany
| | - El Yazid Rachad
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Stephan H Deimel
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Martin P Nawrot
- Computational Systems Neuroscience, Institute of Zoology, University of Cologne, Zülpicherstraße 47b, 50674, Cologne, Germany
| | - André Fiala
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany.
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66
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Mo H, Wang L, Chen Y, Zhang X, Huang N, Liu T, Hu W, Zhong Y, Li Q. Age-related memory vulnerability to interfering stimuli is caused by gradual loss of MAPK-dependent protection in Drosophila. Aging Cell 2022; 21:e13628. [PMID: 35570367 PMCID: PMC9197400 DOI: 10.1111/acel.13628] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 03/14/2022] [Accepted: 04/28/2022] [Indexed: 11/30/2022] Open
Abstract
Age‐related memory impairment (AMI) is a common phenomenon across species. Vulnerability to interfering stimuli has been proposed to be an important cause of AMI. However, the molecular mechanisms underlying this vulnerability‐related AMI remain unknown. Here we show that learning‐activated MAPK signals are gradually lost with age, leading to vulnerability‐related AMI in Drosophila. Young flies (2‐ or 3‐day‐old) exhibited a significant increase in phosphorylated MAPK levels within 15 min after learning, whereas aged flies (25‐day‐old) did not. Compared to 3‐day‐old flies, significant 1 h memory impairments were observed in 15‐, 20‐, and 30‐day‐old flies, but not in 10‐day‐old flies. However, with post‐learning interfering stimuli such as cooling or electric stimuli, 10‐day‐old flies had worse memory performance at 1 h than 3‐day‐old flies, showing a premature AMI phenomenon. Increasing learning‐activated MAPK signals through acute transgene expression in mushroom body (MB) neurons restored physiological trace of 1 h memory in a pair of MB output neurons in aged flies. Decreasing such signals in young flies mimicked the impairment of 1 h memory trace in aged flies. Restoring learning‐activated MAPK signals in MB neurons in aged flies significantly suppressed AMI even with interfering stimuli. Thus, our data suggest that age‐related loss of learning‐activated neuronal MAPK signals causes memory vulnerability to interfering stimuli, thereby leading to AMI.
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Affiliation(s)
- Han Mo
- School of Life Sciences IDG/McGovern Institute for Brain Research Tsinghua University Beijing China
- Tsinghua‐Peking Center for Life Sciences Beijing China
| | - Linghan Wang
- School of Life Sciences IDG/McGovern Institute for Brain Research Tsinghua University Beijing China
- Tsinghua‐Peking Center for Life Sciences Beijing China
| | - Yuting Chen
- School of Life Sciences IDG/McGovern Institute for Brain Research Tsinghua University Beijing China
- Tsinghua‐Peking Center for Life Sciences Beijing China
| | - Xuchen Zhang
- School of Life Sciences IDG/McGovern Institute for Brain Research Tsinghua University Beijing China
- Tsinghua‐Peking Center for Life Sciences Beijing China
| | - Ning Huang
- School of Life Sciences IDG/McGovern Institute for Brain Research Tsinghua University Beijing China
- Tsinghua‐Peking Center for Life Sciences Beijing China
| | - Tingting Liu
- School of Life Sciences IDG/McGovern Institute for Brain Research Tsinghua University Beijing China
- Tsinghua‐Peking Center for Life Sciences Beijing China
| | - Wantong Hu
- School of Life Sciences IDG/McGovern Institute for Brain Research Tsinghua University Beijing China
- Tsinghua‐Peking Center for Life Sciences Beijing China
| | - Yi Zhong
- School of Life Sciences IDG/McGovern Institute for Brain Research Tsinghua University Beijing China
- Tsinghua‐Peking Center for Life Sciences Beijing China
| | - Qian Li
- School of Life Sciences IDG/McGovern Institute for Brain Research Tsinghua University Beijing China
- Tsinghua‐Peking Center for Life Sciences Beijing China
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67
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Adel M, Chen N, Zhang Y, Reed ML, Quasney C, Griffith LC. Pairing-Dependent Plasticity in a Dissected Fly Brain Is Input-Specific and Requires Synaptic CaMKII Enrichment and Nighttime Sleep. J Neurosci 2022; 42:4297-4310. [PMID: 35474278 PMCID: PMC9145224 DOI: 10.1523/jneurosci.0144-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/23/2022] [Accepted: 04/19/2022] [Indexed: 11/21/2022] Open
Abstract
In Drosophila, in vivo functional imaging studies revealed that associative memory formation is coupled to a cascade of neural plasticity events in distinct compartments of the mushroom body (MB). In-depth investigation of the circuit dynamics, however, will require an ex vivo model that faithfully mirrors these events to allow direct manipulations of circuit elements that are inaccessible in the intact fly. The current ex vivo models have been able to reproduce the fundamental plasticity of aversive short-term memory, a potentiation of the MB intrinsic neuron (Kenyon cells [KCs]) responses after artificial learning ex vivo However, this potentiation showed different localization and encoding properties from those reported in vivo and failed to generate the previously reported suppression plasticity in the MB output neurons (MBONs). Here, we develop an ex vivo model using the female Drosophila brain that recapitulates behaviorally evoked plasticity in the KCs and MBONs. We demonstrate that this plasticity accurately localizes to the MB α'3 compartment and is encoded by a coincidence between KC activation and dopaminergic input. The formed plasticity is input-specific, requiring pairing of the conditioned stimulus and unconditioned stimulus pathways; hence, we name it pairing-dependent plasticity. Pairing-dependent plasticity formation requires an intact CaMKII gene and is blocked by previous-night sleep deprivation but is rescued by rebound sleep. In conclusion, we show that our ex vivo preparation recapitulates behavioral and imaging results from intact animals and can provide new insights into mechanisms of memory formation at the level of molecules, circuits, and brain state.SIGNIFICANCE STATEMENT The mammalian ex vivo LTP model enabled in-depth investigation of the hippocampal memory circuit. We develop a parallel model to study the Drosophila mushroom body (MB) memory circuit. Pairing activation of the conditioned stimulus and unconditioned stimulus pathways in dissected brains induces a potentiation pairing-dependent plasticity (PDP) in the axons of α'β' Kenyon cells and a suppression PDP in the dendrites of their postsynaptic MB output neurons, localized in the MB α'3 compartment. This PDP is input-specific and requires the 3' untranslated region of CaMKII Interestingly, ex vivo PDP carries information about the animal's experience before dissection; brains from sleep-deprived animals fail to form PDP, whereas those from animals who recovered 2 h of their lost sleep form PDP.
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Affiliation(s)
- Mohamed Adel
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Nannan Chen
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Yunpeng Zhang
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Martha L Reed
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Christina Quasney
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Leslie C Griffith
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
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68
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Honda T. Optogenetic and thermogenetic manipulation of defined neural circuits and behaviors in Drosophila. Learn Mem 2022; 29:100-109. [PMID: 35332066 PMCID: PMC8973390 DOI: 10.1101/lm.053556.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/06/2022] [Indexed: 11/25/2022]
Abstract
Neural network dynamics underlying flexible animal behaviors remain elusive. The fruit fly Drosophila melanogaster is considered an excellent model in behavioral neuroscience because of its simple neuroanatomical architecture and the availability of various genetic methods. Moreover, Drosophila larvae's transparent body allows investigators to use optical methods on freely moving animals, broadening research directions. Activating or inhibiting well-defined events in excitable cells with a fine temporal resolution using optogenetics and thermogenetics led to the association of functions of defined neural populations with specific behavioral outputs such as the induction of associative memory. Furthermore, combining optogenetics and thermogenetics with state-of-the-art approaches, including connectome mapping and machine learning-based behavioral quantification, might provide a complete view of the experience- and time-dependent variations of behavioral responses. These methodologies allow further understanding of the functional connections between neural circuits and behaviors such as chemosensory, motivational, courtship, and feeding behaviors and sleep, learning, and memory.
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Affiliation(s)
- Takato Honda
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA
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69
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Gkanias E, McCurdy LY, Nitabach MN, Webb B. An incentive circuit for memory dynamics in the mushroom body of Drosophila melanogaster. eLife 2022; 11:e75611. [PMID: 35363138 PMCID: PMC8975552 DOI: 10.7554/elife.75611] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 03/07/2022] [Indexed: 11/30/2022] Open
Abstract
Insects adapt their response to stimuli, such as odours, according to their pairing with positive or negative reinforcements, such as sugar or shock. Recent electrophysiological and imaging findings in Drosophila melanogaster allow detailed examination of the neural mechanisms supporting the acquisition, forgetting, and assimilation of memories. We propose that this data can be explained by the combination of a dopaminergic plasticity rule that supports a variety of synaptic strength change phenomena, and a circuit structure (derived from neuroanatomy) between dopaminergic and output neurons that creates different roles for specific neurons. Computational modelling shows that this circuit allows for rapid memory acquisition, transfer from short term to long term, and exploration/exploitation trade-off. The model can reproduce the observed changes in the activity of each of the identified neurons in conditioning paradigms and can be used for flexible behavioural control.
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Affiliation(s)
- Evripidis Gkanias
- Institute of Perception Action and Behaviour, School of Informatics, University of EdinburghEdinburghUnited Kingdom
| | - Li Yan McCurdy
- Department of Cellular and Molecular Physiology, Yale UniversityNew HavenUnited States
| | - Michael N Nitabach
- Department of Cellular and Molecular Physiology, Yale UniversityNew HavenUnited States
- Department of Genetics, Yale UniversityNew HavenUnited States
- Department of Neuroscience, Yale UniversityNew HavenUnited States
| | - Barbara Webb
- Institute of Perception Action and Behaviour, School of Informatics, University of EdinburghEdinburghUnited Kingdom
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70
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Hiratani N, Latham PE. Developmental and evolutionary constraints on olfactory circuit selection. Proc Natl Acad Sci U S A 2022; 119:e2100600119. [PMID: 35263217 PMCID: PMC8931209 DOI: 10.1073/pnas.2100600119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 01/14/2022] [Indexed: 11/18/2022] Open
Abstract
SignificanceIn this work, we explore the hypothesis that biological neural networks optimize their architecture, through evolution, for learning. We study early olfactory circuits of mammals and insects, which have relatively similar structure but a huge diversity in size. We approximate these circuits as three-layer networks and estimate, analytically, the scaling of the optimal hidden-layer size with input-layer size. We find that both longevity and information in the genome constrain the hidden-layer size, so a range of allometric scalings is possible. However, the experimentally observed allometric scalings in mammals and insects are consistent with biologically plausible values. This analysis should pave the way for a deeper understanding of both biological and artificial networks.
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Affiliation(s)
- Naoki Hiratani
- Gatsby Computational Neuroscience Unit, University College London, London W1T 4JG, United Kingdom
| | - Peter E. Latham
- Gatsby Computational Neuroscience Unit, University College London, London W1T 4JG, United Kingdom
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71
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Stahl A, Noyes NC, Boto T, Botero V, Broyles CN, Jing M, Zeng J, King LB, Li Y, Davis RL, Tomchik SM. Associative learning drives longitudinally graded presynaptic plasticity of neurotransmitter release along axonal compartments. eLife 2022; 11:e76712. [PMID: 35285796 PMCID: PMC8956283 DOI: 10.7554/elife.76712] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/11/2022] [Indexed: 12/27/2022] Open
Abstract
Anatomical and physiological compartmentalization of neurons is a mechanism to increase the computational capacity of a circuit, and a major question is what role axonal compartmentalization plays. Axonal compartmentalization may enable localized, presynaptic plasticity to alter neuronal output in a flexible, experience-dependent manner. Here, we show that olfactory learning generates compartmentalized, bidirectional plasticity of acetylcholine release that varies across the longitudinal compartments of Drosophila mushroom body (MB) axons. The directionality of the learning-induced plasticity depends on the valence of the learning event (aversive vs. appetitive), varies linearly across proximal to distal compartments following appetitive conditioning, and correlates with learning-induced changes in downstream mushroom body output neurons (MBONs) that modulate behavioral action selection. Potentiation of acetylcholine release was dependent on the CaV2.1 calcium channel subunit cacophony. In addition, contrast between the positive conditioned stimulus and other odors required the inositol triphosphate receptor, which maintained responsivity to odors upon repeated presentations, preventing adaptation. Downstream from the MB, a set of MBONs that receive their input from the γ3 MB compartment were required for normal appetitive learning, suggesting that they represent a key node through which reward learning influences decision-making. These data demonstrate that learning drives valence-correlated, compartmentalized, bidirectional potentiation, and depression of synaptic neurotransmitter release, which rely on distinct mechanisms and are distributed across axonal compartments in a learning circuit.
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Affiliation(s)
- Aaron Stahl
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Nathaniel C Noyes
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Tamara Boto
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Valentina Botero
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Connor N Broyles
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Miao Jing
- Chinese Institute for Brain ResearchBeijingChina
| | - Jianzhi Zeng
- Peking-Tsinghua Center for Life Sciences, Peking UniversityBeijingChina
- State Key Laboratory of Membrane Biology, Peking University School of Life SciencesBeijingChina
- PKU IDG/McGovern Institute for Brain ResearchBeijingChina
| | - Lanikea B King
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Yulong Li
- Chinese Institute for Brain ResearchBeijingChina
- Peking-Tsinghua Center for Life Sciences, Peking UniversityBeijingChina
- State Key Laboratory of Membrane Biology, Peking University School of Life SciencesBeijingChina
- PKU IDG/McGovern Institute for Brain ResearchBeijingChina
| | - Ronald L Davis
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Seth M Tomchik
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
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72
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Chou YH, Yang CJ, Huang HW, Liou NF, Panganiban MR, Luginbuhl D, Yin Y, Taisz I, Liang L, Jefferis GSXE, Luo L. Mating-driven variability in olfactory local interneuron wiring. SCIENCE ADVANCES 2022; 8:eabm7723. [PMID: 35179957 PMCID: PMC8856614 DOI: 10.1126/sciadv.abm7723] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
Variations in neuronal connectivity occur widely in nervous systems from invertebrates to mammals. Yet, it is unclear how neuronal variability originates, to what extent and at what time scales it exists, and what functional consequences it might carry. To assess inter- and intraindividual neuronal variability, it would be ideal to analyze the same identified neuron across different brain hemispheres and individuals. Here, using genetic labeling and electron microscopy connectomics, we show that an identified inhibitory olfactory local interneuron, TC-LN, exhibits extraordinary variability in its glomerular innervation patterns. Moreover, TC-LN's innervation of the VL2a glomerulus, which processes food signals and modulates mating behavior, is sexually dimorphic, is influenced by female's courtship experience, and correlates with food intake in mated females. Mating also affects output connectivity of TC-LN to specific local interneurons. We propose that mating-associated variability of TC-LNs regulates how food odor is interpreted by an inhibitory network to modulate feeding.
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Affiliation(s)
- Ya-Hui Chou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan
- Neuroscience Program of Academia Sinica, Academia Sinica, Taipei 11529, Taiwan
- Genome and Systems Biology Degree Program, Academia Sinica and National Taiwan University, Taipei 10617, Taiwan
| | - Chi-Jen Yang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Hao-Wei Huang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Nan-Fu Liou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan
| | | | - David Luginbuhl
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Yijie Yin
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Istvan Taisz
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Liang Liang
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Gregory S. X. E. Jefferis
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Liqun Luo
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, CA 94305, USA
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73
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Liu TX, Davoudian PA, Lizbinski KM, Jeanne JM. Connectomic features underlying diverse synaptic connection strengths and subcellular computation. Curr Biol 2022; 32:559-569.e5. [PMID: 34914905 PMCID: PMC8825683 DOI: 10.1016/j.cub.2021.11.056] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 11/02/2021] [Accepted: 11/23/2021] [Indexed: 11/28/2022]
Abstract
Connectomes generated from electron microscopy images of neural tissue unveil the complex morphology of every neuron and the locations of every synapse interconnecting them. These wiring diagrams may also enable inference of synaptic and neuronal biophysics, such as the functional weights of synaptic connections, but this requires integration with physiological data to properly parameterize. Working with a stereotyped olfactory network in the Drosophila brain, we make direct comparisons of the anatomy and physiology of diverse neurons and synapses with subcellular and subthreshold resolution. We find that synapse density and location jointly predict the amplitude of the somatic postsynaptic potential evoked by a single presynaptic spike. Biophysical models fit to data predict that electrical compartmentalization allows axon and dendrite arbors to balance independent and interacting computations. These findings begin to fill the gap between connectivity maps and activity maps, which should enable new hypotheses about how network structure constrains network function.
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Affiliation(s)
- Tony X. Liu
- Department of Neuroscience, Yale University. 333 Cedar Street, New Haven, CT 06510,These authors contributed equally
| | - Pasha A. Davoudian
- MD/PhD Program, Yale School of Medicine. 333 Cedar Street, New Haven, CT 06510,These authors contributed equally
| | - Kristyn M. Lizbinski
- Department of Neuroscience, Yale University. 333 Cedar Street, New Haven, CT 06510,These authors contributed equally
| | - James M. Jeanne
- Department of Neuroscience, Yale University. 333 Cedar Street, New Haven, CT 06510,Lead contact,Correspondence: , Twitter: @neurojeanne
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74
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Smith MAY, Honegger KS, Turner G, de Bivort B. Idiosyncratic learning performance in flies. Biol Lett 2022; 18:20210424. [PMID: 35104427 PMCID: PMC8807056 DOI: 10.1098/rsbl.2021.0424] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/21/2021] [Indexed: 11/18/2022] Open
Abstract
Individuals vary in their innate behaviours, even when they have the same genome and have been reared in the same environment. The extent of individuality in plastic behaviours, like learning, is less well characterized. Also unknown is the extent to which intragenotypic differences in learning generalize: if an individual performs well in one assay, will it perform well in other assays? We investigated this using the fruit fly Drosophila melanogaster, an organism long-used to study the mechanistic basis of learning and memory. We found that isogenic flies, reared in identical laboratory conditions, and subject to classical conditioning that associated odorants with electric shock, exhibit clear individuality in their learning responses. Flies that performed well when an odour was paired with shock tended to perform well when the odour was paired with bitter taste or when other odours were paired with shock. Thus, individuality in learning performance appears to be prominent in isogenic animals reared identically, and individual differences in learning performance generalize across some aversive sensory modalities. Establishing these results in flies opens up the possibility of studying the genetic and neural circuit basis of individual differences in learning in a highly suitable model organism.
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Affiliation(s)
- Matthew A.-Y. Smith
- Department of Organismic and Evolutionary Biology and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Kyle S. Honegger
- Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
| | - Glenn Turner
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Benjamin de Bivort
- Department of Organismic and Evolutionary Biology and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
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75
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Weiss JT, Donlea JM. Roles for Sleep in Neural and Behavioral Plasticity: Reviewing Variation in the Consequences of Sleep Loss. Front Behav Neurosci 2022; 15:777799. [PMID: 35126067 PMCID: PMC8810646 DOI: 10.3389/fnbeh.2021.777799] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/16/2021] [Indexed: 12/13/2022] Open
Abstract
Sleep is a vital physiological state that has been broadly conserved across the evolution of animal species. While the precise functions of sleep remain poorly understood, a large body of research has examined the negative consequences of sleep loss on neural and behavioral plasticity. While sleep disruption generally results in degraded neural plasticity and cognitive function, the impact of sleep loss can vary widely with age, between individuals, and across physiological contexts. Additionally, several recent studies indicate that sleep loss differentially impacts distinct neuronal populations within memory-encoding circuitry. These findings indicate that the negative consequences of sleep loss are not universally shared, and that identifying conditions that influence the resilience of an organism (or neuron type) to sleep loss might open future opportunities to examine sleep's core functions in the brain. Here, we discuss the functional roles for sleep in adaptive plasticity and review factors that can contribute to individual variations in sleep behavior and responses to sleep loss.
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Affiliation(s)
- Jacqueline T. Weiss
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, United States
| | - Jeffrey M. Donlea
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
- *Correspondence: Jeffrey M. Donlea
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76
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Devineni AV, Scaplen KM. Neural Circuits Underlying Behavioral Flexibility: Insights From Drosophila. Front Behav Neurosci 2022; 15:821680. [PMID: 35069145 PMCID: PMC8770416 DOI: 10.3389/fnbeh.2021.821680] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 12/14/2021] [Indexed: 11/16/2022] Open
Abstract
Behavioral flexibility is critical to survival. Animals must adapt their behavioral responses based on changes in the environmental context, internal state, or experience. Studies in Drosophila melanogaster have provided insight into the neural circuit mechanisms underlying behavioral flexibility. Here we discuss how Drosophila behavior is modulated by internal and behavioral state, environmental context, and learning. We describe general principles of neural circuit organization and modulation that underlie behavioral flexibility, principles that are likely to extend to other species.
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Affiliation(s)
- Anita V. Devineni
- Department of Biology, Emory University, Atlanta, GA, United States
- Zuckerman Mind Brain Institute, Columbia University, New York, NY, United States
| | - Kristin M. Scaplen
- Department of Psychology, Bryant University, Smithfield, RI, United States
- Center for Health and Behavioral Studies, Bryant University, Smithfield, RI, United States
- Department of Neuroscience, Brown University, Providence, RI, United States
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77
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Pribbenow C, Chen YC, Heim MM, Laber D, Reubold S, Reynolds E, Balles I, Fernández-d V Alquicira T, Suárez-Grimalt R, Scheunemann L, Rauch C, Matkovic T, Rösner J, Lichtner G, Jagannathan SR, Owald D. Postsynaptic plasticity of cholinergic synapses underlies the induction and expression of appetitive and familiarity memories in Drosophila. eLife 2022; 11:80445. [PMID: 36250621 PMCID: PMC9733945 DOI: 10.7554/elife.80445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2022] Open
Abstract
In vertebrates, several forms of memory-relevant synaptic plasticity involve postsynaptic rearrangements of glutamate receptors. In contrast, previous work indicates that Drosophila and other invertebrates store memories using presynaptic plasticity of cholinergic synapses. Here, we provide evidence for postsynaptic plasticity at cholinergic output synapses from the Drosophila mushroom bodies (MBs). We find that the nicotinic acetylcholine receptor (nAChR) subunit α5 is required within specific MB output neurons for appetitive memory induction but is dispensable for aversive memories. In addition, nAChR α2 subunits mediate memory expression and likely function downstream of α5 and the postsynaptic scaffold protein discs large (Dlg). We show that postsynaptic plasticity traces can be induced independently of the presynapse, and that in vivo dynamics of α2 nAChR subunits are changed both in the context of associative and non-associative (familiarity) memory formation, underlying different plasticity rules. Therefore, regardless of neurotransmitter identity, key principles of postsynaptic plasticity support memory storage across phyla.
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Affiliation(s)
- Carlotta Pribbenow
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Yi-chun Chen
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - M-Marcel Heim
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Desiree Laber
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Silas Reubold
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Eric Reynolds
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Isabella Balles
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Tania Fernández-d V Alquicira
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Raquel Suárez-Grimalt
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany,Einstein Center for Neurosciences BerlinBerlinGermany
| | - Lisa Scheunemann
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany,NeuroCure, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany,Institut für Biologie, Freie Universität BerlinBerlinGermany
| | - Carolin Rauch
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Tanja Matkovic
- Institut für Biologie, Freie Universität BerlinBerlinGermany
| | - Jörg Rösner
- NWFZ, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthGreifswaldGermany
| | - Gregor Lichtner
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany,Universitätsmedizin Greifswald, Department of Anesthesia, Critical Care, Emergency and Pain MedicineGreifswaldGermany
| | - Sridhar R Jagannathan
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - David Owald
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany,Einstein Center for Neurosciences BerlinBerlinGermany,NeuroCure, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
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78
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Saitoe M, Naganos S, Miyashita T, Matsuno M, Ueno K. A non-canonical on-demand dopaminergic transmission underlying olfactory aversive learning. Neurosci Res 2021; 178:1-9. [PMID: 34973292 DOI: 10.1016/j.neures.2021.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 11/16/2021] [Accepted: 12/27/2021] [Indexed: 10/19/2022]
Abstract
Dopamine (DA) is involved in various brain functions including associative learning. However, it is unclear how a small number of DA neurons appropriately regulates various brain functions. DA neurons have a large number of release sites and release DA non-specifically to a large number of target neurons in the projection area in response to the activity of DA neurons. In contrast to this "broad transmission", recent studies in Drosophila ex vivo functional imaging studies have identified "on-demand transmission" that occurs independent on activity of DA neurons and releases DA specifically onto the target neurons that have produced carbon monoxide (CO) as a retrograde signal for DA release. Whereas broad transmission modulates the global function of the target area, on-demand transmission is suitable for modulating the function of specific circuits, neurons, or synapses. In Drosophila olfactory aversive conditioning, odor and shock information are associated in the brain region called mushroom body (MB) to form olfactory aversive memory. It has been suggested that DA neurons projecting to the MB mediate the transmission of shock information and reinforcement simultaneously. However, the circuit model based on on-demand transmission proposes that transmission of shock information and reinforcement are mediated by distinct neural mechanisms; while shock transmission is glutamatergic, DA neurons mediates reinforcement. On-demand transmission provides mechanical insights into how DA neurons regulate various brain functions.
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Affiliation(s)
- Minoru Saitoe
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo, 156-8506, Japan.
| | - Shintaro Naganos
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo, 156-8506, Japan
| | - Tomoyuki Miyashita
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo, 156-8506, Japan
| | - Motomi Matsuno
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo, 156-8506, Japan
| | - Kohei Ueno
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo, 156-8506, Japan
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79
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Feng KL, Weng JY, Chen CC, Abubaker MB, Lin HW, Charng CC, Lo CC, de Belle JS, Tully T, Lien CC, Chiang AS. Neuropeptide F inhibits dopamine neuron interference of long-term memory consolidation in Drosophila. iScience 2021; 24:103506. [PMID: 34934925 DOI: 10.1016/j.isci.2021.103506] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/13/2021] [Accepted: 11/22/2021] [Indexed: 11/28/2022] Open
Abstract
Long-term memory (LTM) formation requires consolidation processes to overcome interfering signals that erode memory formation. Olfactory memory in Drosophila involves convergent projection neuron (PN; odor) and dopaminergic neuron (DAN; reinforcement) input to the mushroom body (MB). How post-training DAN activity in the posterior lateral protocerebrum (PPL1) continues to regulate memory consolidation remains unknown. Here we address this question using targeted transgenes in behavior and electrophysiology experiments to show that (1) persistent post-training activity of PPL1-α2α'2 and PPL1-α3 DANs interferes with aversive LTM formation; (2) neuropeptide F (NPF) signaling blocks this interference in PPL1-α2α'2 and PPL1-α3 DANs after spaced training to enable LTM formation; and (3) training-induced NPF release and neurotransmission from two upstream dorsal-anterior-lateral (DAL2) neurons are required to form LTM. Thus, NPF signals from DAL2 neurons to specific PPL1 DANs disinhibit the memory circuit, ensuring that periodic events are remembered as consolidated LTM.
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Affiliation(s)
- Kuan-Lin Feng
- Institute of Biotechnology, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ju-Yun Weng
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chun-Chao Chen
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | | | - Hsuan-Wen Lin
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ching-Che Charng
- Institute of Systems Neuroscience and Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chung-Chuan Lo
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan.,Institute of Systems Neuroscience and Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - J Steven de Belle
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan.,Department of Psychological Sciences, University of San Diego, San Diego, CA 92110, USA.,School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.,MnemOdyssey LLC, Escondido, CA 92027, USA
| | - Tim Tully
- Institute of Biotechnology, National Tsing Hua University, Hsinchu 30013, Taiwan.,Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Cheng-Chang Lien
- Institute of Neuroscience and Brain Research Center, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Ann-Shyn Chiang
- Institute of Biotechnology, National Tsing Hua University, Hsinchu 30013, Taiwan.,Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan.,Institute of Systems Neuroscience and Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan.,Kaohsiung Medical University, Kaohsiung 80708, Taiwan.,National Health Research Institutes, Zhunan 35053, Taiwan.,China Medical University, Taichung 40402, Taiwan.,Kavli Institute for Brain and Mind, University of California at San Diego, La Jolla, CA 92093-0526, USA
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80
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Abdelrahman NY, Vasilaki E, Lin AC. Compensatory variability in network parameters enhances memory performance in the Drosophila mushroom body. Proc Natl Acad Sci U S A 2021; 118:e2102158118. [PMID: 34845010 PMCID: PMC8670477 DOI: 10.1073/pnas.2102158118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2021] [Indexed: 11/18/2022] Open
Abstract
Neural circuits use homeostatic compensation to achieve consistent behavior despite variability in underlying intrinsic and network parameters. However, it remains unclear how compensation regulates variability across a population of the same type of neurons within an individual and what computational benefits might result from such compensation. We address these questions in the Drosophila mushroom body, the fly's olfactory memory center. In a computational model, we show that under sparse coding conditions, memory performance is degraded when the mushroom body's principal neurons, Kenyon cells (KCs), vary realistically in key parameters governing their excitability. However, memory performance is rescued while maintaining realistic variability if parameters compensate for each other to equalize KC average activity. Such compensation can be achieved through both activity-dependent and activity-independent mechanisms. Finally, we show that correlations predicted by our model's compensatory mechanisms appear in the Drosophila hemibrain connectome. These findings reveal compensatory variability in the mushroom body and describe its computational benefits for associative memory.
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Affiliation(s)
- Nada Y Abdelrahman
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
- Department of Computer Science, University of Sheffield, Sheffield S1 4DP, United Kingdom
- Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Eleni Vasilaki
- Department of Computer Science, University of Sheffield, Sheffield S1 4DP, United Kingdom
- Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Andrew C Lin
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, United Kingdom;
- Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, United Kingdom
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81
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Lee WP, Chiang MH, Chang LY, Shyu WH, Chiu TH, Fu TF, Wu T, Wu CL. Serotonin Signals Modulate Mushroom Body Output Neurons for Sustaining Water-Reward Long-Term Memory in Drosophila. Front Cell Dev Biol 2021; 9:755574. [PMID: 34858982 PMCID: PMC8631865 DOI: 10.3389/fcell.2021.755574] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/26/2021] [Indexed: 11/27/2022] Open
Abstract
Memory consolidation is a time-dependent process through which an unstable learned experience is transformed into a stable long-term memory; however, the circuit and molecular mechanisms underlying this process are poorly understood. The Drosophila mushroom body (MB) is a huge brain neuropil that plays a crucial role in olfactory memory. The MB neurons can be generally classified into three subsets: γ, αβ, and α′β′. Here, we report that water-reward long-term memory (wLTM) consolidation requires activity from α′β′-related mushroom body output neurons (MBONs) in a specific time window. wLTM consolidation requires neurotransmission in MBON-γ3β′1 during the 0–2 h period after training, and neurotransmission in MBON-α′2 is required during the 2–4 h period after training. Moreover, neurotransmission in MBON-α′1α′3 is required during the 0–4 h period after training. Intriguingly, blocking neurotransmission during consolidation or inhibiting serotonin biosynthesis in serotoninergic dorsal paired medial (DPM) neurons also disrupted the wLTM, suggesting that wLTM consolidation requires serotonin signals from DPM neurons. The GFP Reconstitution Across Synaptic Partners (GRASP) data showed the connectivity between DPM neurons and MBON-γ3β′1, MBON-α′2, and MBON-α′1α′3, and RNAi-mediated silencing of serotonin receptors in MBON-γ3β′1, MBON-α′2, or MBON-α′1α′3 disrupted wLTM. Taken together, our results suggest that serotonin released from DPM neurons modulates neuronal activity in MBON-γ3β′1, MBON-α′2, and MBON-α′1α′3 at specific time windows, which is critical for the consolidation of wLTM in Drosophila.
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Affiliation(s)
- Wang-Pao Lee
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Meng-Hsuan Chiang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Li-Yun Chang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Wei-Huan Shyu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tai-Hsiang Chiu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tsai-Feng Fu
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan
| | - Tony Wu
- Department of Neurology, Chang Gung Memorial Hospital, Linkou, Taiwan.,Department of Neurology, New Taipei Municipal Tucheng Hospital, Tucheng, Taiwan.,Department of Neurology, Xiamen Chang Gung Hospital, Xiamen, China
| | - Chia-Lin Wu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Neurology, Chang Gung Memorial Hospital, Linkou, Taiwan.,Department of Biochemistry, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan
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82
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Buerkle N, Jeanne JM. Decision making: An analogue implementation of a drift-diffusion computation in the Drosophila mushroom body. Curr Biol 2021; 31:R1479-R1482. [PMID: 34813753 DOI: 10.1016/j.cub.2021.09.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
A new study combines electrophysiology, optogenetics, and behavior to investigate a decision-making circuit in the fly brain, revealing all the major features predicted by drift-diffusion models. Strikingly, much of this computation takes place subthreshold, independent of action potentials.
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Affiliation(s)
- Nathan Buerkle
- Department of Neuroscience, Yale University, 333 Cedar Street, New Haven, CT 06510, USA.
| | - James M Jeanne
- Department of Neuroscience, Yale University, 333 Cedar Street, New Haven, CT 06510, USA.
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83
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Vrontou E, Groschner LN, Szydlowski S, Brain R, Krebbers A, Miesenböck G. Response competition between neurons and antineurons in the mushroom body. Curr Biol 2021; 31:4911-4922.e4. [PMID: 34610272 PMCID: PMC8612741 DOI: 10.1016/j.cub.2021.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 08/03/2021] [Accepted: 09/03/2021] [Indexed: 11/04/2022]
Abstract
The mushroom bodies of Drosophila contain circuitry compatible with race models of perceptual choice. When flies discriminate odor intensity differences, opponent pools of αβ core Kenyon cells (on and off αβc KCs) accumulate evidence for increases or decreases in odor concentration. These sensory neurons and “antineurons” connect to a layer of mushroom body output neurons (MBONs) which bias behavioral intent in opposite ways. All-to-all connectivity between the competing integrators and their MBON partners allows for correct and erroneous decisions; dopaminergic reinforcement sets choice probabilities via reciprocal changes to the efficacies of on and off KC synapses; and pooled inhibition between αβc KCs can establish equivalence with the drift-diffusion formalism known to describe behavioral performance. The response competition network gives tangible form to many features envisioned in theoretical models of mammalian decision making, but it differs from these models in one respect: the principal variables—the fill levels of the integrators and the strength of inhibition between them—are represented by graded potentials rather than spikes. In pursuit of similar computational goals, a small brain may thus prioritize the large information capacity of analog signals over the robustness and temporal processing span of pulsatile codes. Mushroom body output neurons respond with excitation to odor on- and offset On and off responses reflect the convergence of oppositely tuned Kenyon cells (KCs) Opponent KCs compete by eliciting inhibitory feedback from a common interneuron pool KCs and interneurons communicate through graded potentials rather than spikes
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Affiliation(s)
- Eleftheria Vrontou
- Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Lukas N Groschner
- Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Susanne Szydlowski
- Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Ruth Brain
- Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Alina Krebbers
- Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Gero Miesenböck
- Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK.
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84
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Eschbach C, Fushiki A, Winding M, Afonso B, Andrade IV, Cocanougher BT, Eichler K, Gepner R, Si G, Valdes-Aleman J, Fetter RD, Gershow M, Jefferis GS, Samuel AD, Truman JW, Cardona A, Zlatic M. Circuits for integrating learned and innate valences in the insect brain. eLife 2021; 10:62567. [PMID: 34755599 PMCID: PMC8616581 DOI: 10.7554/elife.62567] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/03/2021] [Indexed: 12/23/2022] Open
Abstract
Animal behavior is shaped both by evolution and by individual experience. Parallel brain pathways encode innate and learned valences of cues, but the way in which they are integrated during action-selection is not well understood. We used electron microscopy to comprehensively map with synaptic resolution all neurons downstream of all mushroom body (MB) output neurons (encoding learned valences) and characterized their patterns of interaction with lateral horn (LH) neurons (encoding innate valences) in Drosophila larva. The connectome revealed multiple convergence neuron types that receive convergent MB and LH inputs. A subset of these receives excitatory input from positive-valence MB and LH pathways and inhibitory input from negative-valence MB pathways. We confirmed functional connectivity from LH and MB pathways and behavioral roles of two of these neurons. These neurons encode integrated odor value and bidirectionally regulate turning. Based on this, we speculate that learning could potentially skew the balance of excitation and inhibition onto these neurons and thereby modulate turning. Together, our study provides insights into the circuits that integrate learned and innate valences to modify behavior.
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Affiliation(s)
- Claire Eschbach
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Akira Fushiki
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Neuroscience & Neurology, & Zuckerman Mind Brain Institute, Columbia University, New York, United States
| | - Michael Winding
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Bruno Afonso
- HHMI Janelia Research Campus, Richmond, United Kingdom
| | - Ingrid V Andrade
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Molecular, Cell and Developmental Biology, University California Los Angeles, Los Angeles, United States
| | - Benjamin T Cocanougher
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Katharina Eichler
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Ruben Gepner
- Department of Physics, New York University, New York, United States
| | - Guangwei Si
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Javier Valdes-Aleman
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom.,Department of Molecular, Cell and Developmental Biology, University California Los Angeles, Los Angeles, United States
| | | | - Marc Gershow
- Department of Physics, New York University, New York, United States.,Center for Neural Science, New York University, New York, United States.,Neuroscience Institute, New York University, New York, United States
| | - Gregory Sxe Jefferis
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Aravinthan Dt Samuel
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - James W Truman
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Biology, University of Washington, Seattle, United States
| | - Albert Cardona
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Marta Zlatic
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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85
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Scheffer LK, Meinertzhagen IA. A connectome is not enough - what is still needed to understand the brain of Drosophila? J Exp Biol 2021; 224:272599. [PMID: 34695211 DOI: 10.1242/jeb.242740] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Understanding the structure and operation of any nervous system has been a subject of research for well over a century. A near-term opportunity in this quest is to understand the brain of a model species, the fruit fly Drosophila melanogaster. This is an enticing target given its relatively small size (roughly 200,000 neurons), coupled with the behavioral richness that this brain supports, and the wide variety of techniques now available to study both brain and behavior. It is clear that within a few years we will possess a connectome for D. melanogaster: an electron-microscopy-level description of all neurons and their chemical synaptic connections. Given what we will soon have, what we already know and the research that is currently underway, what more do we need to know to enable us to understand the fly's brain? Here, we itemize the data we will need to obtain, collate and organize in order to build an integrated model of the brain of D. melanogaster.
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Affiliation(s)
- Louis K Scheffer
- Howard Hughes Medical Institute, 19741 Smith Circle, Ashburn, VA 20147, USA
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86
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Zolin A, Cohn R, Pang R, Siliciano AF, Fairhall AL, Ruta V. Context-dependent representations of movement in Drosophila dopaminergic reinforcement pathways. Nat Neurosci 2021; 24:1555-1566. [PMID: 34697455 PMCID: PMC8556349 DOI: 10.1038/s41593-021-00929-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 09/01/2021] [Indexed: 11/09/2022]
Abstract
Dopamine plays a central role in motivating and modifying behavior, serving to invigorate current behavioral performance and guide future actions through learning. Here we examine how this single neuromodulator can contribute to such diverse forms of behavioral modulation. By recording from the dopaminergic reinforcement pathways of the Drosophila mushroom body during active odor navigation, we reveal how their ongoing motor-associated activity relates to goal-directed behavior. We found that dopaminergic neurons correlate with different behavioral variables depending on the specific navigational strategy of an animal, such that the activity of these neurons preferentially reflects the actions most relevant to odor pursuit. Furthermore, we show that these motor correlates are translated to ongoing dopamine release, and acutely perturbing dopaminergic signaling alters the strength of odor tracking. Context-dependent representations of movement and reinforcement cues are thus multiplexed within the mushroom body dopaminergic pathways, enabling them to coordinately influence both ongoing and future behavior.
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Affiliation(s)
- Aryeh Zolin
- Laboratory of Neurophysiology and Behavior, The Rockefeller University, New York, NY, USA
| | - Raphael Cohn
- Laboratory of Neurophysiology and Behavior, The Rockefeller University, New York, NY, USA
| | - Rich Pang
- Neuroscience Graduate Program, Department of Physiology and Biophysics and Computational Neuroscience Center, University of Washington, Seattle, WA, USA
| | - Andrew F Siliciano
- Laboratory of Neurophysiology and Behavior, The Rockefeller University, New York, NY, USA
| | - Adrienne L Fairhall
- Neuroscience Graduate Program, Department of Physiology and Biophysics and Computational Neuroscience Center, University of Washington, Seattle, WA, USA
| | - Vanessa Ruta
- Laboratory of Neurophysiology and Behavior, The Rockefeller University, New York, NY, USA.
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87
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Devineni AV, Deere JU, Sun B, Axel R. Individual bitter-sensing neurons in Drosophila exhibit both ON and OFF responses that influence synaptic plasticity. Curr Biol 2021; 31:5533-5546.e7. [PMID: 34731675 DOI: 10.1016/j.cub.2021.10.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 09/04/2021] [Accepted: 10/08/2021] [Indexed: 01/07/2023]
Abstract
The brain generates internal representations that translate sensory stimuli into appropriate behavior. In the taste system, different tastes activate distinct populations of sensory neurons. We investigated the temporal properties of taste responses in Drosophila and discovered that different types of taste sensory neurons show striking differences in their response dynamics. Strong responses to stimulus onset (ON responses) and offset (OFF responses) were observed in bitter-sensing neurons in the labellum, whereas bitter neurons in the leg and other classes of labellar taste neurons showed only an ON response. Individual labellar bitter neurons generate both ON and OFF responses through a cell-intrinsic mechanism that requires canonical bitter receptors. A single receptor complex likely generates both ON and OFF responses to a given bitter ligand. These ON and OFF responses in the periphery are propagated to dopaminergic neurons that mediate aversive learning, and the presence of the OFF response impacts synaptic plasticity when bitter is used as a reinforcement cue. These studies reveal previously unknown features of taste responses that impact neural circuit function and may be important for behavior. Moreover, these studies show that OFF responses can dramatically influence timing-based synaptic plasticity, which is thought to underlie associative learning.
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Affiliation(s)
- Anita V Devineni
- Zuckerman Mind Brain Behavior Institute, Columbia University, 3227 Broadway, New York, NY 10027, USA.
| | - Julia U Deere
- Zuckerman Mind Brain Behavior Institute, Columbia University, 3227 Broadway, New York, NY 10027, USA
| | - Bei Sun
- Zuckerman Mind Brain Behavior Institute, Columbia University, 3227 Broadway, New York, NY 10027, USA
| | - Richard Axel
- Zuckerman Mind Brain Behavior Institute, Columbia University, 3227 Broadway, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA.
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88
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A pair of dopamine neurons mediate chronic stress signals to induce learning deficit in Drosophila melanogaster. Proc Natl Acad Sci U S A 2021; 118:2023674118. [PMID: 34654742 DOI: 10.1073/pnas.2023674118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2021] [Indexed: 11/18/2022] Open
Abstract
Chronic stress could induce severe cognitive impairments. Despite extensive investigations in mammalian models, the underlying mechanisms remain obscure. Here, we show that chronic stress could induce dramatic learning and memory deficits in Drosophila melanogaster The chronic stress-induced learning deficit (CSLD) is long lasting and associated with other depression-like behaviors. We demonstrated that excessive dopaminergic activity provokes susceptibility to CSLD. Remarkably, a pair of PPL1-γ1pedc dopaminergic neurons that project to the mushroom body (MB) γ1pedc compartment play a key role in regulating susceptibility to CSLD so that stress-induced PPL1-γ1pedc hyperactivity facilitates the development of CSLD. Consistently, the mushroom body output neurons (MBON) of the γ1pedc compartment, MBON-γ1pedc>α/β neurons, are important for modulating susceptibility to CSLD. Imaging studies showed that dopaminergic activity is necessary to provoke the development of chronic stress-induced maladaptations in the MB network. Together, our data support that PPL1-γ1pedc mediates chronic stress signals to drive allostatic maladaptations in the MB network that lead to CSLD.
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89
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Lesar A, Tahir J, Wolk J, Gershow M. Switch-like and persistent memory formation in individual Drosophila larvae. eLife 2021; 10:e70317. [PMID: 34636720 PMCID: PMC8510578 DOI: 10.7554/elife.70317] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 08/27/2021] [Indexed: 11/15/2022] Open
Abstract
Associative learning allows animals to use past experience to predict future events. The circuits underlying memory formation support immediate and sustained changes in function, often in response to a single example. Larval Drosophila is a genetic model for memory formation that can be accessed at molecular, synaptic, cellular, and circuit levels, often simultaneously, but existing behavioral assays for larval learning and memory do not address individual animals, and it has been difficult to form long-lasting memories, especially those requiring synaptic reorganization. We demonstrate a new assay for learning and memory capable of tracking the changing preferences of individual larvae. We use this assay to explore how activation of a pair of reward neurons changes the response to the innately aversive gas carbon dioxide (CO2). We confirm that when coupled to CO2 presentation in appropriate temporal sequence, optogenetic reward reduces avoidance of CO2. We find that learning is switch-like: all-or-none and quantized in two states. Memories can be extinguished by repeated unrewarded exposure to CO2 but are stabilized against extinction by repeated training or overnight consolidation. Finally, we demonstrate long-lasting protein synthesis dependent and independent memory formation.
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Affiliation(s)
- Amanda Lesar
- Department of Physics, New York UniversityNew YorkUnited States
| | - Javan Tahir
- Department of Physics, New York UniversityNew YorkUnited States
| | - Jason Wolk
- Department of Physics, New York UniversityNew YorkUnited States
| | - Marc Gershow
- Department of Physics, New York UniversityNew YorkUnited States
- Center for Neural Science, New York UniversityNew YorkUnited States
- NYU Neuroscience Institute, New York University Langone Medical CenterNew YorkUnited States
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90
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Driscoll M, Buchert SN, Coleman V, McLaughlin M, Nguyen A, Sitaraman D. Compartment specific regulation of sleep by mushroom body requires GABA and dopaminergic signaling. Sci Rep 2021; 11:20067. [PMID: 34625611 PMCID: PMC8501079 DOI: 10.1038/s41598-021-99531-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 09/15/2021] [Indexed: 11/30/2022] Open
Abstract
Sleep is a fundamental behavioral state important for survival and is universal in animals with sufficiently complex nervous systems. As a highly conserved neurobehavioral state, sleep has been described in species ranging from jellyfish to humans. Biogenic amines like dopamine, serotonin and norepinephrine have been shown to be critical for sleep regulation across species but the precise circuit mechanisms underlying how amines control persistence of sleep, arousal and wakefulness remain unclear. The fruit fly, Drosophila melanogaster, provides a powerful model system for the study of sleep and circuit mechanisms underlying state transitions and persistence of states to meet the organisms motivational and cognitive needs. In Drosophila, two neuropils in the central brain, the mushroom body (MB) and the central complex (CX) have been shown to influence sleep homeostasis and receive aminergic neuromodulator input critical to sleep–wake switch. Dopamine neurons (DANs) are prevalent neuromodulator inputs to the MB but the mechanisms by which they interact with and regulate sleep- and wake-promoting neurons within MB are unknown. Here we investigate the role of subsets of PAM-DANs that signal wakefulness and project to wake-promoting compartments of the MB. We find that PAM-DANs are GABA responsive and require GABAA-Rdl receptor in regulating sleep. In mapping the pathways downstream of PAM neurons innervating γ5 and β′2 MB compartments we find that wakefulness is regulated by both DopR1 and DopR2 receptors in downstream Kenyon cells (KCs) and mushroom body output neurons (MBONs). Taken together, we have identified and characterized a dopamine modulated sleep microcircuit within the mushroom body that has previously been shown to convey information about positive and negative valence critical for memory formation. These studies will pave way for understanding how flies balance sleep, wakefulness and arousal.
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Affiliation(s)
- Margaret Driscoll
- Department of Psychological Sciences, College of Arts and Sciences, University of San Diego, 5998 Alcala Park, San Diego, CA, 92110, USA
| | - Steven N Buchert
- Department of Psychology, College of Science, California State University- East Bay, 25800 Carlos Bee Blvd, Hayward, CA, 94542, USA
| | - Victoria Coleman
- Department of Psychological Sciences, College of Arts and Sciences, University of San Diego, 5998 Alcala Park, San Diego, CA, 92110, USA
| | - Morgan McLaughlin
- Department of Psychological Sciences, College of Arts and Sciences, University of San Diego, 5998 Alcala Park, San Diego, CA, 92110, USA
| | - Amanda Nguyen
- Department of Psychological Sciences, College of Arts and Sciences, University of San Diego, 5998 Alcala Park, San Diego, CA, 92110, USA
| | - Divya Sitaraman
- Department of Psychological Sciences, College of Arts and Sciences, University of San Diego, 5998 Alcala Park, San Diego, CA, 92110, USA. .,Department of Psychology, College of Science, California State University- East Bay, 25800 Carlos Bee Blvd, Hayward, CA, 94542, USA.
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91
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Abstract
[Figure: see text].
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Affiliation(s)
- Liqun Luo
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
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92
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Jiang L, Litwin-Kumar A. Models of heterogeneous dopamine signaling in an insect learning and memory center. PLoS Comput Biol 2021; 17:e1009205. [PMID: 34375329 PMCID: PMC8354444 DOI: 10.1371/journal.pcbi.1009205] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 06/22/2021] [Indexed: 11/25/2022] Open
Abstract
The Drosophila mushroom body exhibits dopamine dependent synaptic plasticity that underlies the acquisition of associative memories. Recordings of dopamine neurons in this system have identified signals related to external reinforcement such as reward and punishment. However, other factors including locomotion, novelty, reward expectation, and internal state have also recently been shown to modulate dopamine neurons. This heterogeneity is at odds with typical modeling approaches in which these neurons are assumed to encode a global, scalar error signal. How is dopamine dependent plasticity coordinated in the presence of such heterogeneity? We develop a modeling approach that infers a pattern of dopamine activity sufficient to solve defined behavioral tasks, given architectural constraints informed by knowledge of mushroom body circuitry. Model dopamine neurons exhibit diverse tuning to task parameters while nonetheless producing coherent learned behaviors. Notably, reward prediction error emerges as a mode of population activity distributed across these neurons. Our results provide a mechanistic framework that accounts for the heterogeneity of dopamine activity during learning and behavior. Dopamine neurons across the animal kingdom are involved in the formation of associative memories. While numerous studies have recorded activity in these neurons related to external and predicted rewards, the diversity of these neurons’ activity and their tuning to non-reward-related quantities such as novelty, movement, and internal state have proved challenging to account for in traditional modeling approaches. Using a well-characterized model system for learning and memory, the mushroom body of Drosophila fruit flies, Jiang and Litwin-Kumar provide an account of the diversity of signals across dopamine neurons. They show that models optimized to solve tasks like those encountered by flies exhibit heterogeneous activity across dopamine neurons, but nonetheless this activity is sufficient for the system to solve the tasks. The models will be useful to generate testable hypotheses about dopamine neuron activity across different experimental conditions.
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Affiliation(s)
- Linnie Jiang
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, New York, United States of America
- Neurosciences Program, Stanford University, Stanford, California, United States of America
| | - Ashok Litwin-Kumar
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, New York, United States of America
- * E-mail:
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93
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Weiss JT, Donlea JM. Sleep deprivation results in diverse patterns of synaptic scaling across the Drosophila mushroom bodies. Curr Biol 2021; 31:3248-3261.e3. [PMID: 34107302 PMCID: PMC8355077 DOI: 10.1016/j.cub.2021.05.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/22/2021] [Accepted: 05/11/2021] [Indexed: 11/19/2022]
Abstract
Sleep is essential for a variety of plastic processes, including learning and memory. However, the consequences of insufficient sleep on circuit connectivity remain poorly understood. To better appreciate the effects of sleep loss on synaptic connectivity across a memory-encoding circuit, we examined changes in the distribution of synaptic markers in the Drosophila mushroom body (MB). Protein-trap tags for active zone components indicate that recent sleep time is inversely correlated with Bruchpilot (BRP) abundance in the MB lobes; sleep loss elevates BRP while sleep induction reduces BRP across the MB. Overnight sleep deprivation also elevated levels of dSyd-1 and Cacophony, but not other pre-synaptic proteins. Cell-type-specific genetic reporters show that MB-intrinsic Kenyon cells (KCs) exhibit increased pre-synaptic BRP throughout the axonal lobes after sleep deprivation; similar increases were not detected in projections from large interneurons or dopaminergic neurons that innervate the MB. These results indicate that pre-synaptic plasticity in KCs is responsible for elevated levels of BRP in the MB lobes of sleep-deprived flies. Because KCs provide synaptic inputs to several classes of post-synaptic partners, we next used a fluorescent reporter for synaptic contacts to test whether each class of KC output connections is scaled uniformly by sleep loss. The KC output synapses that we observed here can be divided into three classes: KCs to MB interneurons; KCs to dopaminergic neurons; and KCs to MB output neurons. No single class showed uniform scaling across each constituent member, indicating that different rules may govern plasticity during sleep loss across cell types.
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Affiliation(s)
- Jacqueline T Weiss
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA; Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jeffrey M Donlea
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA.
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94
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Wissink M, Nehring V. Appetitive olfactory learning suffers in ants when octopamine or dopamine receptors are blocked. J Exp Biol 2021; 224:271209. [PMID: 34357377 DOI: 10.1242/jeb.242732] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 07/14/2021] [Indexed: 01/24/2023]
Abstract
Associative learning relies on the detection of coincidence between a stimulus and a reward or punishment. In the insect brain, this process is carried out in the mushroom bodies under the control of octopaminergic and dopaminergic neurons. It was assumed that appetitive learning is governed by octopaminergic neurons, while dopamine is required for aversive learning. This view has recently been challenged: both neurotransmitters are involved in both types of learning in bees and flies. Here, we tested which neurotransmitters are required for appetitive learning in ants. We trained Lasius niger workers to discriminate two mixtures of linear hydrocarbons and to associate one of them with a sucrose reward. We analysed the walking paths of the ants using machine learning and found that the ants spent more time near the rewarded odour than near the other, a preference that was stable for at least 24 h. We then treated the ants before learning with either epinastine, an octopamine receptor blocker, or flupentixol, a dopamine receptor blocker. Ants with blocked octopamine receptors did not prefer the rewarded odour. Octopamine signalling is thus necessary for appetitive learning of olfactory cues, probably because it signals information about odours or reward to the mushroom body. In contrast, ants with blocked dopamine receptors initially learned the rewarded odour but failed to retrieve this memory 24 h later. Dopamine is thus probably required for long-term memory consolidation, independent of short-term memory formation. Our results show that appetitive olfactory learning depends on both octopamine and dopamine signalling in ants.
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Affiliation(s)
- Maarten Wissink
- Evolutionary Biology & Ecology, Institute for Biology I (Zoology), University of Freiburg, D-79104 Freiburg, Germany
| | - Volker Nehring
- Evolutionary Biology & Ecology, Institute for Biology I (Zoology), University of Freiburg, D-79104 Freiburg, Germany
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95
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Jacob PF, Vargas-Gutierrez P, Okray Z, Vietti-Michelina S, Felsenberg J, Waddell S. Prior experience conditionally inhibits the expression of new learning in Drosophila. Curr Biol 2021; 31:3490-3503.e3. [PMID: 34146482 PMCID: PMC8409488 DOI: 10.1016/j.cub.2021.05.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/29/2021] [Accepted: 05/26/2021] [Indexed: 11/19/2022]
Abstract
Prior experience of a stimulus can inhibit subsequent acquisition or expression of a learned association of that stimulus. However, the neuronal manifestations of this learning effect, named latent inhibition (LI), are poorly understood. Here, we show that prior odor exposure can produce context-dependent LI of later appetitive olfactory memory performance in Drosophila. Odor pre-exposure forms a short-lived aversive memory whose lone expression lacks context-dependence. Acquisition of odor pre-exposure memory requires aversively reinforcing dopaminergic neurons that innervate two mushroom body compartments—one group of which exhibits increasing activity with successive odor experience. Odor-specific responses of the corresponding mushroom body output neurons are suppressed, and their output is necessary for expression of both pre-exposure memory and LI of appetitive memory. Therefore, odor pre-exposure attaches negative valence to the odor itself, and LI of appetitive memory results from a temporary and context-dependent retrieval deficit imposed by competition with the parallel short-lived aversive memory. Odor pre-exposure alters the expression of a learned association of that odor Pre-exposure memory only affects subsequent retrieval if context is consistent Pre-exposure memory can complement or compete with a learned association Odor pre-exposure forms a labile mushroom body-dependent aversive memory
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Affiliation(s)
- Pedro F Jacob
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | | | - Zeynep Okray
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | | | - Johannes Felsenberg
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - Scott Waddell
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK.
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96
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Thoener J, König C, Weiglein A, Toshima N, Mancini N, Amin F, Schleyer M. Associative learning in larval and adult Drosophila is impaired by the dopamine-synthesis inhibitor 3-Iodo-L-tyrosine. Biol Open 2021; 10:269081. [PMID: 34106227 PMCID: PMC8214425 DOI: 10.1242/bio.058198] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 05/04/2021] [Indexed: 11/30/2022] Open
Abstract
Across the animal kingdom, dopamine plays a crucial role in conferring reinforcement signals that teach animals about the causal structure of the world. In the fruit fly Drosophila melanogaster, dopaminergic reinforcement has largely been studied using genetics, whereas pharmacological approaches have received less attention. Here, we apply the dopamine-synthesis inhibitor 3-Iodo-L-tyrosine (3IY), which causes acute systemic inhibition of dopamine signaling, and investigate its effects on Pavlovian conditioning. We find that 3IY feeding impairs sugar-reward learning in larvae while leaving task-relevant behavioral faculties intact, and that additional feeding of a precursor of dopamine (L-3,4-dihydroxyphenylalanine, L-DOPA), rescues this impairment. Concerning a different developmental stage and for the aversive valence domain. Moreover, we demonstrate that punishment learning by activating the dopaminergic neuron PPL1-γ1pedc in adult flies is also impaired by 3IY feeding, and can likewise be rescued by L-DOPA. Our findings exemplify the advantages of using a pharmacological approach in combination with the genetic techniques available in D. melanogaster to manipulate neuronal and behavioral function. Summary: We surveyed the effects of a dopamine-synthesis inhibitor on associative learning in larval and adult Drosophila. This approach can supplement genetic tools in investigating the conserved reinforcing function of dopamine.
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Affiliation(s)
- Juliane Thoener
- Leibniz Institute for Neurobiology, Department of Genetics, 39118 Magdeburg, Germany
| | - Christian König
- Leibniz Institute for Neurobiology, Department of Genetics, 39118 Magdeburg, Germany
| | - Aliće Weiglein
- Leibniz Institute for Neurobiology, Department of Genetics, 39118 Magdeburg, Germany
| | - Naoko Toshima
- Leibniz Institute for Neurobiology, Department of Genetics, 39118 Magdeburg, Germany
| | - Nino Mancini
- Leibniz Institute for Neurobiology, Department of Genetics, 39118 Magdeburg, Germany
| | - Fatima Amin
- Leibniz Institute for Neurobiology, Department of Genetics, 39118 Magdeburg, Germany
| | - Michael Schleyer
- Leibniz Institute for Neurobiology, Department of Genetics, 39118 Magdeburg, Germany
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97
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Yamagata N, Ezaki T, Takahashi T, Wu H, Tanimoto H. Presynaptic inhibition of dopamine neurons controls optimistic bias. eLife 2021; 10:64907. [PMID: 34061730 PMCID: PMC8169112 DOI: 10.7554/elife.64907] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 05/16/2021] [Indexed: 01/04/2023] Open
Abstract
Regulation of reward signaling in the brain is critical for appropriate judgement of the environment and self. In Drosophila, the protocerebral anterior medial (PAM) cluster dopamine neurons mediate reward signals. Here, we show that localized inhibitory input to the presynaptic terminals of the PAM neurons titrates olfactory reward memory and controls memory specificity. The inhibitory regulation was mediated by metabotropic gamma-aminobutyric acid (GABA) receptors clustered in presynaptic microdomain of the PAM boutons. Cell type-specific silencing the GABA receptors enhanced memory by augmenting internal reward signals. Strikingly, the disruption of GABA signaling reduced memory specificity to the rewarded odor by changing local odor representations in the presynaptic terminals of the PAM neurons. The inhibitory microcircuit of the dopamine neurons is thus crucial for both reward values and memory specificity. Maladaptive presynaptic regulation causes optimistic cognitive bias.
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Affiliation(s)
| | - Takahiro Ezaki
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | | | - Hongyang Wu
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Hiromu Tanimoto
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
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98
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Adel M, Griffith LC. The Role of Dopamine in Associative Learning in Drosophila: An Updated Unified Model. Neurosci Bull 2021; 37:831-852. [PMID: 33779893 PMCID: PMC8192648 DOI: 10.1007/s12264-021-00665-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/25/2020] [Indexed: 10/21/2022] Open
Abstract
Learning to associate a positive or negative experience with an unrelated cue after the presentation of a reward or a punishment defines associative learning. The ability to form associative memories has been reported in animal species as complex as humans and as simple as insects and sea slugs. Associative memory has even been reported in tardigrades [1], species that diverged from other animal phyla 500 million years ago. Understanding the mechanisms of memory formation is a fundamental goal of neuroscience research. In this article, we work on resolving the current contradictions between different Drosophila associative memory circuit models and propose an updated version of the circuit model that predicts known memory behaviors that current models do not. Finally, we propose a model for how dopamine may function as a reward prediction error signal in Drosophila, a dopamine function that is well-established in mammals but not in insects [2, 3].
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Affiliation(s)
- Mohamed Adel
- Department of Biology, Volen National Center for Complex Systems and National Center for Behavioral Genomics, Brandeis University, Waltham, MA, 02454-9110, USA.
| | - Leslie C Griffith
- Department of Biology, Volen National Center for Complex Systems and National Center for Behavioral Genomics, Brandeis University, Waltham, MA, 02454-9110, USA
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99
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di Volo M, Chemla S, Destexhe A. Cortical propagating waves: amplifying and suppressive? J Comput Neurosci 2021; 49:371-373. [PMID: 34003423 DOI: 10.1007/s10827-021-00792-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 11/28/2022]
Affiliation(s)
- Matteo di Volo
- Paris-Saclay University, CNRS, Gif-sur-Yvette, France.,Paris-Cergy University, Cergy, France
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100
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Bennett JEM, Philippides A, Nowotny T. Learning with reinforcement prediction errors in a model of the Drosophila mushroom body. Nat Commun 2021; 12:2569. [PMID: 33963189 PMCID: PMC8105414 DOI: 10.1038/s41467-021-22592-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/16/2021] [Indexed: 02/03/2023] Open
Abstract
Effective decision making in a changing environment demands that accurate predictions are learned about decision outcomes. In Drosophila, such learning is orchestrated in part by the mushroom body, where dopamine neurons signal reinforcing stimuli to modulate plasticity presynaptic to mushroom body output neurons. Building on previous mushroom body models, in which dopamine neurons signal absolute reinforcement, we propose instead that dopamine neurons signal reinforcement prediction errors by utilising feedback reinforcement predictions from output neurons. We formulate plasticity rules that minimise prediction errors, verify that output neurons learn accurate reinforcement predictions in simulations, and postulate connectivity that explains more physiological observations than an experimentally constrained model. The constrained and augmented models reproduce a broad range of conditioning and blocking experiments, and we demonstrate that the absence of blocking does not imply the absence of prediction error dependent learning. Our results provide five predictions that can be tested using established experimental methods.
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Affiliation(s)
- James E. M. Bennett
- grid.12082.390000 0004 1936 7590Department of Informatics, University of Sussex, Brighton, UK
| | - Andrew Philippides
- grid.12082.390000 0004 1936 7590Department of Informatics, University of Sussex, Brighton, UK
| | - Thomas Nowotny
- grid.12082.390000 0004 1936 7590Department of Informatics, University of Sussex, Brighton, UK
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