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Huang C, Luo J, Woo SJ, Roitman LA, Li J, Pieribone VA, Kannan M, Vasan G, Schnitzer MJ. Dopamine-mediated interactions between short- and long-term memory dynamics. Nature 2024:10.1038/s41586-024-07819-w. [PMID: 39038490 DOI: 10.1038/s41586-024-07819-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 07/11/2024] [Indexed: 07/24/2024]
Abstract
In dynamic environments, animals make behavioural decisions on the basis of the innate valences of sensory cues and information learnt about these cues across multiple timescales1-3. However, it remains unclear how the innate valence of a sensory stimulus affects the acquisition of learnt valence information and subsequent memory dynamics. Here we show that in the Drosophila brain, interconnected short- and long-term memory units of the mushroom body jointly regulate memory through dopamine signals that encode innate and learnt sensory valences. By performing time-lapse in vivo voltage-imaging studies of neural spiking in more than 500 flies undergoing olfactory associative conditioning, we found that protocerebral posterior lateral 1 dopamine neurons (PPL1-DANs)4 heterogeneously and bidirectionally encode innate and learnt valences of punishment, reward and odour cues. During learning, these valence signals regulate memory storage and extinction in mushroom body output neurons (MBONs)5. During initial conditioning bouts, PPL1-γ1pedc and PPL1-γ2α'1 neurons control short-term memory formation, which weakens inhibitory feedback from MBON-γ1pedc>α/β to PPL1-α'2α2 and PPL1-α3. During further conditioning, this diminished feedback allows these two PPL1-DANs to encode the net innate plus learnt valence of the conditioned odour cue, which gates long-term memory formation. A computational model constrained by the fly connectome6,7 and our spiking data explains how dopamine signals mediate the circuit interactions between short- and long-term memory traces, yielding predictions that our experiments confirmed. Overall, the mushroom body achieves flexible learning through the integration of innate and learnt valences in parallel learning units sharing feedback interconnections. This hybrid physiological-anatomical mechanism may be a general means by which dopamine regulates memory dynamics in other species and brain structures, including the vertebrate basal ganglia.
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Affiliation(s)
- Cheng Huang
- James Clark Center, Stanford University, Stanford, CA, USA.
- Department of Biology, Stanford University, Stanford, CA, USA.
- Dept. of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA.
| | - Junjie Luo
- James Clark Center, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Seung Je Woo
- James Clark Center, Stanford University, Stanford, CA, USA
| | | | - Jizhou Li
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
- CNC Program, Stanford University, Stanford, CA, USA
- Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong, China
| | - Vincent A Pieribone
- The John B. Pierce Laboratory, New Haven, CT, USA
- Department of Cellular & Molecular Physiology, Yale University, New Haven, CT, USA
| | - Madhuvanthi Kannan
- The John B. Pierce Laboratory, New Haven, CT, USA.
- Department of Cellular & Molecular Physiology, Yale University, New Haven, CT, USA.
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA.
| | - Ganesh Vasan
- The John B. Pierce Laboratory, New Haven, CT, USA.
- Department of Cellular & Molecular Physiology, Yale University, New Haven, CT, USA.
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA.
| | - Mark J Schnitzer
- James Clark Center, Stanford University, Stanford, CA, USA.
- Department of Biology, Stanford University, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
- CNC Program, Stanford University, Stanford, CA, USA.
- Department of Applied Physics, Stanford University, Stanford, CA, USA.
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2
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Bowman AJ, Huang C, Schnitzer MJ, Kasevich MA. Wide-field fluorescence lifetime imaging of neuron spiking and subthreshold activity in vivo. Science 2023; 380:1270-1275. [PMID: 37347862 PMCID: PMC10361454 DOI: 10.1126/science.adf9725] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 05/16/2023] [Indexed: 06/24/2023]
Abstract
The development of voltage-sensitive fluorescent probes suggests fluorescence lifetime as a promising readout for electrical activity in biological systems. Existing approaches fail to achieve the speed and sensitivity required for voltage imaging in neuroscience applications. We demonstrated that wide-field electro-optic fluorescence lifetime imaging microscopy (EO-FLIM) allows lifetime imaging at kilohertz frame-acquisition rates, spatially resolving action potential propagation and subthreshold neural activity in live adult Drosophila. Lifetime resolutions of <5 picoseconds at 1 kilohertz were achieved for single-cell voltage recordings. Lifetime readout is limited by photon shot noise, and the method provides strong rejection of motion artifacts and technical noise sources. Recordings revealed local transmembrane depolarizations, two types of spikes with distinct fluorescence lifetimes, and phase locking of spikes to an external mechanical stimulus.
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Affiliation(s)
- Adam J Bowman
- Physics Department, Stanford University, Stanford, CA 94305, USA
| | - Cheng Huang
- James H. Clark Center, Stanford University, Stanford, CA 94305, USA
| | - Mark J Schnitzer
- James H. Clark Center, Stanford University, Stanford, CA 94305, USA
- CNC Program, Stanford University, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Mark A Kasevich
- Physics Department, Stanford University, Stanford, CA 94305, USA
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Zhang R, Li LS, Rao B, Rong H, Sun MY, Yao J, Chen R, Zhou Q, Mennerick S, Raman B, Wang LV. Multiscale photoacoustic tomography of neural activities with GCaMP calcium indicators. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-220087GR. [PMID: 36088528 PMCID: PMC9463545 DOI: 10.1117/1.jbo.27.9.096004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Optical imaging of responses in fluorescently labeled neurons has progressed significantly in recent years. However, there is still a need to monitor neural activities at divergent spatial scales and at depths beyond the optical diffusion limit. AIM To meet these needs, we aim to develop multiscale photoacoustic tomography (PAT) to image neural activities across spatial scales with a genetically encoded calcium indicator GCaMP. APPROACH First, using photoacoustic microscopy, we show that depth-resolved GCaMP signals can be monitored in vivo from a fly brain in response to odor stimulation without depth scanning and even with the cuticle intact. In vivo monitoring of GCaMP signals was also demonstrated in mouse brains. Next, using photoacoustic computed tomography, we imaged neural responses of a mouse brain slice at depths beyond the optical diffusion limit. RESULTS We provide the first unambiguous demonstration that multiscale PAT can be used to record neural activities in transgenic flies and mice with select neurons expressing GCaMP. CONCLUSIONS Our results indicate that the combination of multiscale PAT and fluorescent neural activity indicators provides a methodology for imaging targeted neurons at various scales.
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Affiliation(s)
- Ruiying Zhang
- Washington University in Saint Louis, Department of Biomedical Engineering, Saint Louis, Missouri, United States
| | - Lei S. Li
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Bin Rao
- Washington University in Saint Louis, Department of Biomedical Engineering, Saint Louis, Missouri, United States
| | - Haoyang Rong
- Washington University in Saint Louis, Department of Biomedical Engineering, Saint Louis, Missouri, United States
| | - Min-Yu Sun
- Washington University School of Medicine, Department of Psychiatry, Saint Louis, Missouri, United States
| | - Junjie Yao
- Washington University in Saint Louis, Department of Biomedical Engineering, Saint Louis, Missouri, United States
| | - Ruimin Chen
- University of Southern California, Department of Biomedical Engineering, Los Angeles, California, United States
| | - Qifa Zhou
- University of Southern California, Department of Biomedical Engineering, Los Angeles, California, United States
| | - Steven Mennerick
- Washington University School of Medicine, Department of Psychiatry, Saint Louis, Missouri, United States
| | - Baranidharan Raman
- Washington University in Saint Louis, Department of Biomedical Engineering, Saint Louis, Missouri, United States
| | - Lihong V. Wang
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
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4
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Hermans L, Kaynak M, Braun J, Ríos VL, Chen CL, Friedberg A, Günel S, Aymanns F, Sakar MS, Ramdya P. Microengineered devices enable long-term imaging of the ventral nerve cord in behaving adult Drosophila. Nat Commun 2022; 13:5006. [PMID: 36008386 PMCID: PMC9411199 DOI: 10.1038/s41467-022-32571-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 08/04/2022] [Indexed: 11/09/2022] Open
Abstract
The dynamics and connectivity of neural circuits continuously change on timescales ranging from milliseconds to an animal's lifetime. Therefore, to understand biological networks, minimally invasive methods are required to repeatedly record them in behaving animals. Here we describe a suite of devices that enable long-term optical recordings of the adult Drosophila melanogaster ventral nerve cord (VNC). These consist of transparent, numbered windows to replace thoracic exoskeleton, compliant implants to displace internal organs, a precision arm to assist implantation, and a hinged stage to repeatedly tether flies. To validate and illustrate our toolkit we (i) show minimal impact on animal behavior and survival, (ii) follow the degradation of chordotonal organ mechanosensory nerve terminals over weeks after leg amputation, and (iii) uncover waves of neural activity caffeine ingestion. Thus, our long-term imaging toolkit opens up the investigation of premotor and motor circuit adaptations in response to injury, drug ingestion, aging, learning, and disease.
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Affiliation(s)
- Laura Hermans
- Neuroengineering Laboratory, Brain Mind Institute & Institute of Bioengineering, EPFL, Lausanne, Switzerland
- Microbiorobotic Systems Laboratory, Institute of Mechanical Engineering & Institute of Bioengineering, EPFL, Lausanne, Switzerland
| | - Murat Kaynak
- Microbiorobotic Systems Laboratory, Institute of Mechanical Engineering & Institute of Bioengineering, EPFL, Lausanne, Switzerland
| | - Jonas Braun
- Neuroengineering Laboratory, Brain Mind Institute & Institute of Bioengineering, EPFL, Lausanne, Switzerland
| | - Victor Lobato Ríos
- Neuroengineering Laboratory, Brain Mind Institute & Institute of Bioengineering, EPFL, Lausanne, Switzerland
| | - Chin-Lin Chen
- Neuroengineering Laboratory, Brain Mind Institute & Institute of Bioengineering, EPFL, Lausanne, Switzerland
| | - Adam Friedberg
- Neuroengineering Laboratory, Brain Mind Institute & Institute of Bioengineering, EPFL, Lausanne, Switzerland
| | - Semih Günel
- Neuroengineering Laboratory, Brain Mind Institute & Institute of Bioengineering, EPFL, Lausanne, Switzerland
- Computer Vision Laboratory, EPFL, Lausanne, Switzerland
| | - Florian Aymanns
- Neuroengineering Laboratory, Brain Mind Institute & Institute of Bioengineering, EPFL, Lausanne, Switzerland
| | - Mahmut Selman Sakar
- Microbiorobotic Systems Laboratory, Institute of Mechanical Engineering & Institute of Bioengineering, EPFL, Lausanne, Switzerland.
| | - Pavan Ramdya
- Neuroengineering Laboratory, Brain Mind Institute & Institute of Bioengineering, EPFL, Lausanne, Switzerland.
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Aragon MJ, Mok AT, Shea J, Wang M, Kim H, Barkdull N, Xu C, Yapici N. Multiphoton imaging of neural structure and activity in Drosophila through the intact cuticle. eLife 2022; 11:e69094. [PMID: 35073257 PMCID: PMC8846588 DOI: 10.7554/elife.69094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 01/23/2022] [Indexed: 11/13/2022] Open
Abstract
We developed a multiphoton imaging method to capture neural structure and activity in behaving flies through the intact cuticle. Our measurements showed that the fly head cuticle has surprisingly high transmission at wavelengths >900nm, and the difficulty of through-cuticle imaging is due to the air sacs and/or fat tissue underneath the head cuticle. By compressing or removing the air sacs, we performed multiphoton imaging of the fly brain through the intact cuticle. Our anatomical and functional imaging results show that 2- and 3-photon imaging are comparable in superficial regions such as the mushroom body, but 3-photon imaging is superior in deeper regions such as the central complex and beyond. We further demonstrated 2-photon through-cuticle functional imaging of odor-evoked calcium responses from the mushroom body γ-lobes in behaving flies short term and long term. The through-cuticle imaging method developed here extends the time limits of in vivo imaging in flies and opens new ways to capture neural structure and activity from the fly brain.
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Affiliation(s)
- Max Jameson Aragon
- Department of Neurobiology and Behavior, Cornell UniversityIthacaUnited States
| | - Aaron T Mok
- School of Applied and Engineering Physics, Cornell UniversityIthacaUnited States
| | - Jamien Shea
- Department of Neurobiology and Behavior, Cornell UniversityIthacaUnited States
| | - Mengran Wang
- School of Applied and Engineering Physics, Cornell UniversityIthacaUnited States
| | - Haein Kim
- Department of Neurobiology and Behavior, Cornell UniversityIthacaUnited States
| | - Nathan Barkdull
- Department of Physics, University of FloridaGainesvilleUnited States
| | - Chris Xu
- School of Applied and Engineering Physics, Cornell UniversityIthacaUnited States
| | - Nilay Yapici
- Department of Neurobiology and Behavior, Cornell UniversityIthacaUnited States
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6
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Valle AF, Honnef R, Seelig JD. Automated long-term two-photon imaging in head-fixed walking Drosophila. J Neurosci Methods 2021; 368:109432. [PMID: 34861285 DOI: 10.1016/j.jneumeth.2021.109432] [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: 05/03/2021] [Revised: 11/24/2021] [Accepted: 11/26/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND The brain of Drosophila shows dynamics at multiple timescales, from the millisecond range of fast voltage or calcium transients to functional and structural changes occurring over multiple days. To relate such dynamics to behavior requires monitoring neural circuits across these multiple timescales in behaving animals. NEW METHOD Here, we develop a technique for automated long-term two-photon imaging in fruit flies, during wakefulness and extended bouts of immobility, as typically observed during sleep, navigating in virtual reality over up to seven days. The method is enabled by laser surgery, a microrobotic arm for controlling forceps for dissection assistance, an automated feeding robot, as well as volumetric, simultaneous multiplane imaging. RESULTS The approach is validated in the fly's head direction system and walking behavior as well a neural activity are recorded. The head direction system tracks the fly's walking direction over multiple days. COMPARISON WITH EXISTING METHODS In comparison with previous head-fixed preparations, the time span over which tethered behavior and neural activity can be recorded at the same time is extended from hours to days. Additionally, the reproducibility and ease of dissections are improved compared with manual approaches. Different from previous laser surgery approaches, only continuous wave lasers are required. Lastly, an automated feeding system allows continuously maintaining the fly for several days in the virtual reality setup without user intervention. CONCLUSIONS Imaging in behaving flies over multiple timescales will be useful for understanding circadian activity, learning and long-term memory, or sleep.
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Affiliation(s)
| | - Rolf Honnef
- Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Johannes D Seelig
- Center of Advanced European Studies and Research (caesar), Bonn, Germany.
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7
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Boergens KM, Tadić A, Hopper MS, McNamara I, Fell D, Sahasrabuddhe K, Kong Y, Straka M, Sohal HS, Angle MR. Laser ablation of the pia mater for insertion of high-density microelectrode arrays in a translational sheep model. J Neural Eng 2021; 18. [PMID: 34038875 DOI: 10.1088/1741-2552/ac0585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 05/26/2021] [Indexed: 01/03/2023]
Abstract
Objective. The safe insertion of high density intracortical electrode arrays has been a long-standing practical challenge for neural interface engineering and applications such as brain-computer interfaces (BCIs). However, the pia mater can be difficult to penetrate and causes deformation of underlying cortical tissue during insertion of high-density intracortical arrays. This can lead to neuron damage or failed insertions. The development of a method to ease insertion through the pia mater would represent a significant step toward inserting high density intracortical arrays.Approach. Here we describe a surgical procedure, inspired by laser corneal ablation, that can be used in translational models to thin the pia mater.Main results. We demonstrate that controlled pia removal with laser ablation over a small area of cortex allows for microelectrode arrays to be inserted into the cortex with less force, thus reducing deformation of underlying tissue during placement of the microelectrodes. This procedure allows for insertion of high-density electrode arrays and subsequent acute recordings of spiking neuron activity in sheep cortex. We also show histological and electrophysiological evidence that laser removal of the pia does not acutely affect neuronal viability in the region.Significance. Laser ablation of the pia reduces insertion forces of high-density arrays with minimal to no acute damage to cortical neurons. This approach suggests a promising new path for clinical BCI with high-density microelectrode arrays.
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Affiliation(s)
| | | | | | | | - Devin Fell
- Paradromics, Inc., Austin, TX, United States of America
| | | | - Yifan Kong
- Paradromics, Inc., Austin, TX, United States of America
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8
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Huang C, Maxey JR, Sinha S, Savall J, Gong Y, Schnitzer MJ. Long-term optical brain imaging in live adult fruit flies. Nat Commun 2018; 9:872. [PMID: 29491443 PMCID: PMC5830414 DOI: 10.1038/s41467-018-02873-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 01/05/2018] [Indexed: 11/09/2022] Open
Abstract
Time-lapse in vivo microscopy studies of cellular morphology and physiology are crucial toward understanding brain function but have been infeasible in the fruit fly, a key model species. Here we use laser microsurgery to create a chronic fly preparation for repeated imaging of neural architecture and dynamics for up to 50 days. In fly mushroom body neurons, we track axonal boutons for 10 days and record odor-evoked calcium transients over 7 weeks. Further, by using voltage imaging to resolve individual action potentials, we monitor spiking plasticity in dopamine neurons of flies undergoing mechanical stress. After 24 h of stress, PPL1-α’3 but not PPL1-α’2α2 dopamine neurons have elevated spike rates. Overall, our chronic preparation is compatible with a broad range of optical techniques and enables longitudinal studies of many biological questions that could not be addressed before in live flies. Time-lapse imaging studies of more than a day in the fly brain have been infeasible until now. Here the authors present a laser microsurgery approach to create a permanent window in the fly cuticle to enable time-lapse imaging of neural architecture and dynamics for up to 10–50 days.
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Affiliation(s)
- Cheng Huang
- James H. Clark Center, Stanford University, Stanford, CA, 94305, USA.
| | - Jessica R Maxey
- James H. Clark Center, Stanford University, Stanford, CA, 94305, USA.,CNC Program, Stanford University, Stanford, CA, 94305, USA
| | - Supriyo Sinha
- James H. Clark Center, Stanford University, Stanford, CA, 94305, USA
| | - Joan Savall
- James H. Clark Center, Stanford University, Stanford, CA, 94305, USA.,CNC Program, Stanford University, Stanford, CA, 94305, USA.,Howard Hughes Medical Institute, Stanford University, Stanford, CA, 94305, USA
| | - Yiyang Gong
- James H. Clark Center, Stanford University, Stanford, CA, 94305, USA.,CNC Program, Stanford University, Stanford, CA, 94305, USA.,Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Mark J Schnitzer
- James H. Clark Center, Stanford University, Stanford, CA, 94305, USA. .,CNC Program, Stanford University, Stanford, CA, 94305, USA. .,Howard Hughes Medical Institute, Stanford University, Stanford, CA, 94305, USA.
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9
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Kay AR, Raccuglia D, Scholte J, Sivan-Loukianova E, Barwacz CA, Armstrong SR, Guymon CA, Nitabach MN, Eberl DF. Goggatomy: A Method for Opening Small Cuticular Compartments in Arthropods for Physiological Experiments. Front Physiol 2016; 7:398. [PMID: 27695420 PMCID: PMC5025716 DOI: 10.3389/fphys.2016.00398] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 08/26/2016] [Indexed: 11/30/2022] Open
Abstract
Most sense organs of arthropods are ensconced in small exoskeletal compartments that hinder direct access to plasma membranes. We have developed a method for exposing live sensory and supporting cells in such structures. The technique uses a viscous light cured resin to embed and support the structure, which is then sliced with a sharp blade. We term the procedure a “goggatomy,” from the Khoisan word for a bug, gogga. To demonstrate the utility of the method we show that it can be used to expose the auditory chordotonal organs in the second antennal segment and the olfactory receptor neurons in the third antennal segment of Drosophila melanogaster, preserving the transduction machinery. The procedure can also be used on other small arthropods, like mosquitoes and mites to expose a variety of cells.
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Affiliation(s)
- Alan R Kay
- Department of Biology, University of Iowa Iowa, IA, USA
| | - Davide Raccuglia
- Department of Cellular and Molecular Physiology, Yale University New Haven, CT, USA
| | - Jon Scholte
- Department of Chemical Engineering, University of Iowa Iowa, IA, USA
| | | | | | | | - C Allan Guymon
- Department of Chemical Engineering, University of Iowa Iowa, IA, USA
| | - Michael N Nitabach
- Department of Cellular and Molecular Physiology, Yale University New Haven, CT, USA
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10
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Bartussek J, Lehmann FO. Proprioceptive feedback determines visuomotor gain in Drosophila. ROYAL SOCIETY OPEN SCIENCE 2016; 3:150562. [PMID: 26909184 PMCID: PMC4736939 DOI: 10.1098/rsos.150562] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 12/04/2015] [Indexed: 05/11/2023]
Abstract
Multisensory integration is a prerequisite for effective locomotor control in most animals. Especially, the impressive aerial performance of insects relies on rapid and precise integration of multiple sensory modalities that provide feedback on different time scales. In flies, continuous visual signalling from the compound eyes is fused with phasic proprioceptive feedback to ensure precise neural activation of wing steering muscles (WSM) within narrow temporal phase bands of the stroke cycle. This phase-locked activation relies on mechanoreceptors distributed over wings and gyroscopic halteres. Here we investigate visual steering performance of tethered flying fruit flies with reduced haltere and wing feedback signalling. Using a flight simulator, we evaluated visual object fixation behaviour, optomotor altitude control and saccadic escape reflexes. The behavioural assays show an antagonistic effect of wing and haltere signalling on visuomotor gain during flight. Compared with controls, suppression of haltere feedback attenuates while suppression of wing feedback enhances the animal's wing steering range. Our results suggest that the generation of motor commands owing to visual perception is dynamically controlled by proprioception. We outline a potential physiological mechanism based on the biomechanical properties of WSM and sensory integration processes at the level of motoneurons. Collectively, the findings contribute to our general understanding how moving animals integrate sensory information with dynamically changing temporal structure.
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11
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Chemical biology strategies for posttranslational control of protein function. ACTA ACUST UNITED AC 2015; 21:1238-52. [PMID: 25237866 DOI: 10.1016/j.chembiol.2014.08.011] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 08/08/2014] [Accepted: 08/25/2014] [Indexed: 02/07/2023]
Abstract
A common strategy to understand a biological system is to selectively perturb it and observe its response. Although technologies now exist to manipulate cellular systems at the genetic and transcript level, the direct manipulation of functions at the protein level can offer significant advantages in precision, speed, and reversibility. Combining the specificity of genetic manipulation and the spatiotemporal resolution of light- and small molecule-based approaches now allows exquisite control over biological systems to subtly perturb a system of interest in vitro and in vivo. Conditional perturbation mechanisms may be broadly characterized by change in intracellular localization, intramolecular activation, or degradation of a protein-of-interest. Here we review recent advances in technologies for conditional regulation of protein function and suggest further areas of potential development.
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12
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Geary N. A physiological perspective on the neuroscience of eating. Physiol Behav 2014; 136:3-14. [PMID: 24704192 DOI: 10.1016/j.physbeh.2014.03.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 03/17/2014] [Indexed: 12/31/2022]
Abstract
I present the thesis that 'being physiological,' i.e., analyzing eating under conditions that do not perturb, or minimally perturb, the organism's endogenous processes, should be a central goal of the neuroscience of eating. I describe my understanding of 'being physiological' based on [i] the central neural-network heuristic of CNS function that traces back to Cajal and Sherrington, [ii] research on one of the simpler problems in the neuroscience of eating, identification of endocrine signals that control eating. In this context I consider natural meals, physiological doses and ranges, and antagonist studies. Several examples involve CCK. Next I describe my view of the cutting edge in the molecular neuroscience of eating as it has evolved from the discovery of leptin signaling through the application of optogenetic and pharmacogenetic methods. Finally I describe some novel approaches that may advance the neuroscience of eating in the foreseeable future. I conclude that [i] the neuroscience of eating may soon be able to discern 'physiological' function in the operation of CNS networks mediating eating, [ii] the neuroscience of eating should capitalize on methods developed in other areas of neuroscience, e.g., improved methods to record and manipulate CNS function in behaving animals, identification of canonical regional circuits, use of population electrophysiology, etc., and [iii] subjective aspects of eating are crucial aspects of eating science, but remain beyond mechanistic understanding.
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Affiliation(s)
- Nori Geary
- Department of Psychiatry, Weill Medical College of Cornell University, New York, NY, United States.
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13
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Abstract
Historical milestones in neuroscience have come in diverse forms, ranging from the resolution of specific biological mysteries via creative experimentation to broad technological advances allowing neuroscientists to ask new kinds of questions. The continuous development of tools is driven with a special necessity by the complexity, fragility, and inaccessibility of intact nervous systems, such that inventive technique development and application drawing upon engineering and the applied sciences has long been essential to neuroscience. Here we highlight recent technological directions in neuroscience spurred by progress in optical, electrical, mechanical, chemical, and biological engineering. These research areas are poised for rapid growth and will likely be central to the practice of neuroscience well into the future.
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Affiliation(s)
- Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; CNC Program, Stanford University, Stanford, CA 94305, USA.
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