1
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Brown ST, Medina-Pizarro M, Holla M, Vaaga CE, Raman IM. Simple spike patterns and synaptic mechanisms encoding sensory and motor signals in Purkinje cells and the cerebellar nuclei. Neuron 2024; 112:1848-1861.e4. [PMID: 38492575 PMCID: PMC11156563 DOI: 10.1016/j.neuron.2024.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 01/04/2024] [Accepted: 02/15/2024] [Indexed: 03/18/2024]
Abstract
Whisker stimulation in awake mice evokes transient suppression of simple spike probability in crus I/II Purkinje cells. Here, we investigated how simple spike suppression arises synaptically, what it encodes, and how it affects cerebellar output. In vitro, monosynaptic parallel fiber (PF)-excitatory postsynaptic currents (EPSCs) facilitated strongly, whereas disynaptic inhibitory postsynaptic currents (IPSCs) remained stable, maximizing relative inhibitory strength at the onset of PF activity. Short-term plasticity thus favors the inhibition of Purkinje spikes before PFs facilitate. In vivo, whisker stimulation evoked a 2-6 ms synchronous spike suppression, just 6-8 ms (∼4 synaptic delays) after sensory onset, whereas active whisker movements elicited broadly timed spike rate increases that did not modulate sensory-evoked suppression. Firing in the cerebellar nuclei (CbN) inversely correlated with disinhibition from sensory-evoked simple spike suppressions but was decoupled from slow, non-synchronous movement-associated elevations of Purkinje firing rates. Synchrony thus allows the CbN to high-pass filter Purkinje inputs, facilitating sensory-evoked cerebellar outputs that can drive movements.
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Affiliation(s)
- Spencer T Brown
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Mauricio Medina-Pizarro
- Department of Neurobiology, Northwestern University, Evanston, IL, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA
| | - Meghana Holla
- Department of Neurobiology, Northwestern University, Evanston, IL, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA
| | | | - Indira M Raman
- Department of Neurobiology, Northwestern University, Evanston, IL, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA.
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2
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Petrosini L, Picerni E, Termine A, Fabrizio C, Laricchiuta D, Cutuli D. The Cerebellum as an Embodying Machine. Neuroscientist 2024; 30:229-246. [PMID: 36052895 DOI: 10.1177/10738584221120187] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Whereas emotion theorists often keep their distance from the embodied approach, theorists of embodiment tend to treat emotion as a mainly physiologic process. However, intimate links between emotions and the body suggest that emotions are privileged phenomena to attempt to reintegrate mind and body and that the body helps the mind in shaping emotional responses. To date, research has favored the cerebrum over other parts of the brain as a substrate of embodied emotions. However, given the widely demonstrated contribution of the cerebellum to emotional processing, research in affective neuroscience should consider embodiment theory as a useful approach for evaluating the cerebellar role in emotion and affect. The aim of this review is to insert the cerebellum among the structures needed to embody emotions, providing illustrative examples of cerebellar involvement in embodied emotions (as occurring in empathic abilities) and in impaired identification and expression of embodied emotions (as occurring in alexithymia).
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Affiliation(s)
| | | | | | | | | | - Debora Cutuli
- Santa Lucia Foundation IRCCS, Rome, Italy
- Department of Psychology, University Sapienza of Rome, Rome, Italy
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3
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Wallach A, Sawtell NB. An internal model for canceling self-generated sensory input in freely behaving electric fish. Neuron 2023; 111:2570-2582.e5. [PMID: 37321221 PMCID: PMC10524831 DOI: 10.1016/j.neuron.2023.05.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 03/10/2023] [Accepted: 05/18/2023] [Indexed: 06/17/2023]
Abstract
Internal models that predict the sensory consequences of motor actions are vital for sensory, motor, and cognitive functions. However, the relationship between motor action and sensory input is complex, often varying from one moment to another depending on the state of the animal and the environment. The neural mechanisms for generating predictions under such challenging, real-world conditions remain largely unknown. Using novel methods for underwater neural recording, a quantitative analysis of unconstrained behavior, and computational modeling, we provide evidence for an unexpectedly sophisticated internal model at the first stage of active electrosensory processing in mormyrid fish. Closed-loop manipulations reveal that electrosensory lobe neurons are capable of simultaneously learning and storing multiple predictions of the sensory consequences of motor commands specific to different sensory states. These results provide mechanistic insights into how internal motor signals and information about the sensory environment are combined within a cerebellum-like circuitry to predict the sensory consequences of natural behavior.
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Affiliation(s)
- Avner Wallach
- Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA.
| | - Nathaniel B Sawtell
- Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA.
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4
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Muller SZ, Abbott LF, Sawtell NB. A mechanism for differential control of axonal and dendritic spiking underlying learning in a cerebellum-like circuit. Curr Biol 2023; 33:2657-2667.e4. [PMID: 37311457 PMCID: PMC10524478 DOI: 10.1016/j.cub.2023.05.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/06/2023] [Accepted: 05/17/2023] [Indexed: 06/15/2023]
Abstract
In addition to the action potentials used for axonal signaling, many neurons generate dendritic "spikes" associated with synaptic plasticity. However, in order to control both plasticity and signaling, synaptic inputs must be able to differentially modulate the firing of these two spike types. Here, we investigate this issue in the electrosensory lobe (ELL) of weakly electric mormyrid fish, where separate control over axonal and dendritic spikes is essential for the transmission of learned predictive signals from inhibitory interneurons to the output stage of the circuit. Through a combination of experimental and modeling studies, we uncover a novel mechanism by which sensory input selectively modulates the rate of dendritic spiking by adjusting the amplitude of backpropagating axonal action potentials. Interestingly, this mechanism does not require spatially segregated synaptic inputs or dendritic compartmentalization but relies instead on an electrotonically distant spike initiation site in the axon-a common biophysical feature of neurons.
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Affiliation(s)
- Salomon Z Muller
- Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - L F Abbott
- Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA; Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10027, USA
| | - Nathaniel B Sawtell
- Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA.
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5
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Rineau AL, Bringoux L, Sarrazin JC, Berberian B. Being active over one's own motion: Considering predictive mechanisms in self-motion perception. Neurosci Biobehav Rev 2023; 146:105051. [PMID: 36669748 DOI: 10.1016/j.neubiorev.2023.105051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/16/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
Self-motion perception is a key element guiding pilots' behavior. Its importance is mostly revealed when impaired, leading in most cases to spatial disorientation which is still today a major factor of accidents occurrence. Self-motion perception is known as mainly based on visuo-vestibular integration and can be modulated by the physical properties of the environment with which humans interact. For instance, several studies have shown that the respective weight of visual and vestibular information depends on their reliability. More recently, it has been suggested that the internal state of an operator can also modulate multisensory integration. Interestingly, the systems' automation can interfere with this internal state through the loss of the intentional nature of movements (i.e., loss of agency) and the modulation of associated predictive mechanisms. In this context, one of the new challenges is to better understand the relationship between automation and self-motion perception. The present review explains how linking the concepts of agency and self-motion is a first approach to address this issue.
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Affiliation(s)
- Anne-Laure Rineau
- Information Processing and Systems, ONERA, Salon de Provence, Base Aérienne 701, France.
| | | | | | - Bruno Berberian
- Information Processing and Systems, ONERA, Salon de Provence, Base Aérienne 701, France.
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6
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Perks KE, Sawtell NB. Neural readout of a latency code in the active electrosensory system. Cell Rep 2022; 38:110605. [PMID: 35354029 PMCID: PMC9045710 DOI: 10.1016/j.celrep.2022.110605] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/03/2022] [Accepted: 03/10/2022] [Indexed: 11/29/2022] Open
Abstract
The latency of spikes relative to a stimulus conveys sensory information across modalities. However, in most cases, it remains unclear whether and how such latency codes are utilized by postsynaptic neurons. In the active electrosensory system of mormyrid fish, a latency code for stimulus amplitude in electroreceptor afferent nerve fibers (EAs) is hypothesized to be read out by a central reference provided by motor corollary discharge (CD). Here, we demonstrate that CD enhances sensory responses in postsynaptic granular cells of the electrosensory lobe but is not required for reading out EA input. Instead, diverse latency and spike count tuning across the EA population give rise to graded information about stimulus amplitude that can be read out by standard integration of converging excitatory synaptic inputs. Inhibitory control over the temporal window of integration renders two granular cell subclasses differentially sensitive to information derived from relative spike latency versus spike count.
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Affiliation(s)
- Krista E Perks
- Department of Biology, Wesleyan University, Middletown, CT 06459, USA; Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Nathaniel B Sawtell
- Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA.
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7
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Shuster SA, Wagner MJ, Pan-Doh N, Ren J, Grutzner SM, Beier KT, Kim TH, Schnitzer MJ, Luo L. The relationship between birth timing, circuit wiring, and physiological response properties of cerebellar granule cells. Proc Natl Acad Sci U S A 2021; 118:e2101826118. [PMID: 34088841 PMCID: PMC8201928 DOI: 10.1073/pnas.2101826118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cerebellar granule cells (GrCs) are usually regarded as a uniform cell type that collectively expands the coding space of the cerebellum by integrating diverse combinations of mossy fiber inputs. Accordingly, stable molecularly or physiologically defined GrC subtypes within a single cerebellar region have not been reported. The only known cellular property that distinguishes otherwise homogeneous GrCs is the correspondence between GrC birth timing and the depth of the molecular layer to which their axons project. To determine the role birth timing plays in GrC wiring and function, we developed genetic strategies to access early- and late-born GrCs. We initiated retrograde monosynaptic rabies virus tracing from control (birth timing unrestricted), early-born, and late-born GrCs, revealing the different patterns of mossy fiber input to GrCs in vermis lobule 6 and simplex, as well as to early- and late-born GrCs of vermis lobule 6: sensory and motor nuclei provide more input to early-born GrCs, while basal pontine and cerebellar nuclei provide more input to late-born GrCs. In vivo multidepth two-photon Ca2+ imaging of axons of early- and late-born GrCs revealed representations of diverse task variables and stimuli by both populations, with modest differences in the proportions encoding movement, reward anticipation, and reward consumption. Our results suggest neither organized parallel processing nor completely random organization of mossy fiber→GrC circuitry but instead a moderate influence of birth timing on GrC wiring and encoding. Our imaging data also provide evidence that GrCs can represent generalized responses to aversive stimuli, in addition to recently described reward representations.
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Affiliation(s)
- S Andrew Shuster
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Neurosciences Graduate Program, Stanford University, Stanford, CA 94305
| | - Mark J Wagner
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Nathan Pan-Doh
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Jing Ren
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Medical Research Council Laboratory of Molecular Biology, Cambridge University, Cambridge CB2 0QH, United Kingdom
| | - Sophie M Grutzner
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Kevin T Beier
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| | - Tony Hyun Kim
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Department of Applied Physics, Stanford University, Stanford, CA 94305
| | - Mark J Schnitzer
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Department of Applied Physics, Stanford University, Stanford, CA 94305
| | - Liqun Luo
- HHMI, Stanford University, Stanford, CA 94305;
- Department of Biology, Stanford University, Stanford, CA 94305
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8
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Tang Y, An L, Wang Q, Liu JK. Regulating synchronous oscillations of cerebellar granule cells by different types of inhibition. PLoS Comput Biol 2021; 17:e1009163. [PMID: 34181653 PMCID: PMC8270418 DOI: 10.1371/journal.pcbi.1009163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 07/09/2021] [Accepted: 06/08/2021] [Indexed: 11/18/2022] Open
Abstract
Synchronous oscillations in neural populations are considered being controlled by inhibitory neurons. In the granular layer of the cerebellum, two major types of cells are excitatory granular cells (GCs) and inhibitory Golgi cells (GoCs). GC spatiotemporal dynamics, as the output of the granular layer, is highly regulated by GoCs. However, there are various types of inhibition implemented by GoCs. With inputs from mossy fibers, GCs and GoCs are reciprocally connected to exhibit different network motifs of synaptic connections. From the view of GCs, feedforward inhibition is expressed as the direct input from GoCs excited by mossy fibers, whereas feedback inhibition is from GoCs via GCs themselves. In addition, there are abundant gap junctions between GoCs showing another form of inhibition. It remains unclear how these diverse copies of inhibition regulate neural population oscillation changes. Leveraging a computational model of the granular layer network, we addressed this question to examine the emergence and modulation of network oscillation using different types of inhibition. We show that at the network level, feedback inhibition is crucial to generate neural oscillation. When short-term plasticity was equipped on GoC-GC synapses, oscillations were largely diminished. Robust oscillations can only appear with additional gap junctions. Moreover, there was a substantial level of cross-frequency coupling in oscillation dynamics. Such a coupling was adjusted and strengthened by GoCs through feedback inhibition. Taken together, our results suggest that the cooperation of distinct types of GoC inhibition plays an essential role in regulating synchronous oscillations of the GC population. With GCs as the sole output of the granular network, their oscillation dynamics could potentially enhance the computational capability of downstream neurons.
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Affiliation(s)
- Yuanhong Tang
- School of Computer Science and Technology, Xidian University, Xi’an, China
| | - Lingling An
- School of Computer Science and Technology, Xidian University, Xi’an, China
- Guangzhou institute of technology, Xidian University, Guangzhou, China
| | - Quan Wang
- School of Computer Science and Technology, Xidian University, Xi’an, China
| | - Jian K. Liu
- Centre for Systems Neuroscience, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
- School of Computing, University of Leeds, Leeds, United Kingdom
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9
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Lai NY, Bell JM, Bodznick D. Multiple behavior-specific cancellation signals contribute to suppressing predictable sensory reafference in a cerebellum-like structure. J Exp Biol 2021; 224:238095. [PMID: 34424972 DOI: 10.1242/jeb.240143] [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: 10/30/2020] [Accepted: 02/16/2021] [Indexed: 11/20/2022]
Abstract
Movement induces sensory stimulation of an animal's own sensory receptors, termed reafference. With a few exceptions, notably vestibular and proprioception, this reafference is unwanted sensory noise and must be selectively filtered in order to detect relevant external sensory signals. In the cerebellum-like electrosensory nucleus of elasmobranch fish, an adaptive filter preserves novel signals by generating cancellation signals that suppress predictable reafference. A parallel fiber network supplies the principal Purkinje-like neurons (called ascending efferent neurons, AENs) with behavior-associated internal reference signals, including motor corollary discharge and sensory feedback, from which predictive cancellation signals are formed. How distinct behavior-specific cancellation signals interact within AENs when multiple behaviors co-occur and produce complex, changing patterns of reafference is unknown. Here, we show that when multiple streams of internal reference signals are available, cancellation signals form that are specific to parallel fiber inputs temporally correlated with, and therefore predictive of, sensory reafference. A single AEN has the capacity to form more than one cancellation signal, and AENs form multiple cancellation signals simultaneously and modify them independently during co-occurring behaviors. Cancellation signals update incrementally during continuous behaviors, as well as episodic bouts of behavior that last minutes to hours. Finally, individual AENs, independently of their neighbors, form unique AEN-specific cancellation signals that depend on the particular sensory reafferent input it receives. Together, these results demonstrate the capacity of the adaptive filter to utilize multiple cancellation signals to suppress dynamic patterns of reafference arising from complex co-occurring and intermittently performed behaviors.
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Affiliation(s)
- Nicole Y Lai
- Department of Biology, Wesleyan University, Middletown, CT 06459, USA.,Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Jordan M Bell
- Department of Biology, Wesleyan University, Middletown, CT 06459, USA
| | - David Bodznick
- Department of Biology, Wesleyan University, Middletown, CT 06459, USA.,Marine Biological Laboratory, Woods Hole, MA 02543, USA
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10
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Henschke JU, Pakan JM. Disynaptic cerebrocerebellar pathways originating from multiple functionally distinct cortical areas. eLife 2020; 9:59148. [PMID: 32795386 PMCID: PMC7428308 DOI: 10.7554/elife.59148] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/28/2020] [Indexed: 12/31/2022] Open
Abstract
The cerebral cortex and cerebellum both play important roles in sensorimotor processing, however, precise connections between these major brain structures remain elusive. Using anterograde mono-trans-synaptic tracing, we elucidate cerebrocerebellar pathways originating from primary motor, sensory, and association cortex. We confirm a highly organized topography of corticopontine projections in mice; however, we found no corticopontine projections originating from primary auditory cortex and detail several potential extra-pontine cerebrocerebellar pathways. The cerebellar hemispheres were the major target of resulting disynaptic mossy fiber terminals, but we also found at least sparse cerebrocerebellar projections to every lobule of the cerebellum. Notably, projections originating from association cortex resulted in less laterality than primary sensory/motor cortices. Within molecularly defined cerebellar modules we found spatial overlap of mossy fiber terminals, originating from functionally distinct cortical areas, within crus I, paraflocculus, and vermal regions IV/V and VI - highlighting these regions as potential hubs for multimodal cortical influence.
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Affiliation(s)
- Julia U Henschke
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke-University, Magdeburg, Germany.,German Centre for Neurodegenerative Diseases, Magdeburg, Germany
| | - Janelle Mp Pakan
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke-University, Magdeburg, Germany.,German Centre for Neurodegenerative Diseases, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Universitätsplatz, Magdeburg, Germany
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11
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Markwalter KH, Yang Y, Holy TE, Bonni A. Sensorimotor Coding of Vermal Granule Neurons in the Developing Mammalian Cerebellum. J Neurosci 2019; 39:6626-6643. [PMID: 31235645 PMCID: PMC6703891 DOI: 10.1523/jneurosci.0086-19.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/18/2019] [Accepted: 06/18/2019] [Indexed: 01/17/2023] Open
Abstract
The vermal cerebellum is a hub of sensorimotor integration critical for postural control and locomotion, but the nature and developmental organization of afferent information to this region have remained poorly understood in vivo Here, we use in vivo two-photon calcium imaging of the vermal cerebellum in awake behaving male and female mice to record granule neuron responses to diverse sensorimotor cues targeting visual, auditory, somatosensory, and motor domains. Use of an activity-independent marker revealed that approximately half (54%) of vermal granule neurons were activated during these recordings. A multikernel linear model distinguished the relative influences of external stimuli and co-occurring movements on neural responses, indicating that, among the subset of activated granule neurons, locomotion (44%-56%) and facial air puffs (50%) were more commonly and reliably encoded than visual (31%-32%) and auditory (19%-28%) stimuli. Strikingly, we also uncover populations of granule neurons that respond differentially to voluntary and forced locomotion, whereas other granule neurons in the same region respond similarly to locomotion in both conditions. Finally, by combining two-photon calcium imaging with birth date labeling of granule neurons via in vivo electroporation, we find that early- and late-born granule neurons convey similarly diverse sensorimotor information to spatially distinct regions of the molecular layer. Collectively, our findings elucidate the nature and developmental organization of sensorimotor information in vermal granule neurons of the developing mammalian brain.SIGNIFICANCE STATEMENT Cerebellar granule neurons comprise over half the neurons in the brain, and their coding properties have been the subject of theoretical and experimental interest for over a half-century. In this study, we directly test long-held theories about encoding of sensorimotor stimuli in the cerebellum and compare the in vivo coding properties of early- and late-born granule neurons. Strikingly, we identify populations of granule neurons that differentially encode voluntary and forced locomotion and find that, although the birth order of granule neurons specifies the positioning of their parallel fiber axons, both early- and late-born granule neurons convey a functionally diverse sensorimotor code. These findings constitute important conceptual advances in understanding the principles underlying cerebellar circuit development and function.
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Affiliation(s)
- Kelly H Markwalter
- Department of Neuroscience, and
- MD-PhD Program, Washington University School of Medicine, St. Louis, Missouri 63110
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12
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Abstract
Supervised learning plays a key role in the operation of many biological and artificial neural networks. Analysis of the computations underlying supervised learning is facilitated by the relatively simple and uniform architecture of the cerebellum, a brain area that supports numerous motor, sensory, and cognitive functions. We highlight recent discoveries indicating that the cerebellum implements supervised learning using the following organizational principles: ( a) extensive preprocessing of input representations (i.e., feature engineering), ( b) massively recurrent circuit architecture, ( c) linear input-output computations, ( d) sophisticated instructive signals that can be regulated and are predictive, ( e) adaptive mechanisms of plasticity with multiple timescales, and ( f) task-specific hardware specializations. The principles emerging from studies of the cerebellum have striking parallels with those in other brain areas and in artificial neural networks, as well as some notable differences, which can inform future research on supervised learning and inspire next-generation machine-based algorithms.
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Affiliation(s)
- Jennifer L Raymond
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California 94305, USA;
| | - Javier F Medina
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA;
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13
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Prediction, Psychosis, and the Cerebellum. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2019; 4:820-831. [PMID: 31495402 DOI: 10.1016/j.bpsc.2019.06.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/30/2019] [Accepted: 06/01/2019] [Indexed: 12/19/2022]
Abstract
An increasingly influential hypothesis posits that many of the diverse symptoms of psychosis can be viewed as reflecting dysfunctional predictive mechanisms. Indeed, to perceive something is to take a sensory input and make a prediction of the external source of that signal; thus, prediction is perhaps the most fundamental neural computation. Given the ubiquity of prediction, a more challenging problem is to specify the unique predictive role or capability of a particular brain structure. This question is relevant when considering recent claims that one aspect of the predictive deficits observed in psychotic disorders might be related to cerebellar dysfunction, a subcortical structure known to play a critical role in predictive sensorimotor control and perhaps higher-level cognitive function. Here, we review evidence bearing on this question. We first focus on clinical, behavioral, and neuroimaging findings suggesting cerebellar involvement in psychosis and, specifically, schizophrenia. We then review a relatively novel line of research exploring whether computational models of cerebellar motor function can also account for cerebellar involvement in higher-order human cognition, and in particular, language function. We end the review by highlighting some key gaps in these literatures, limitations that currently preclude strong conclusions regarding cerebellar involvement in psychosis.
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14
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Balmer TS, Trussell LO. Selective targeting of unipolar brush cell subtypes by cerebellar mossy fibers. eLife 2019; 8:44964. [PMID: 30994458 PMCID: PMC6469928 DOI: 10.7554/elife.44964] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/12/2019] [Indexed: 01/26/2023] Open
Abstract
In vestibular cerebellum, primary afferents carry signals from single vestibular end organs, whereas secondary afferents from vestibular nucleus carry integrated signals. Selective targeting of distinct mossy fibers determines how the cerebellum processes vestibular signals. We focused on vestibular projections to ON and OFF classes of unipolar brush cells (UBCs), which transform single mossy fiber signals into long-lasting excitation or inhibition respectively, and impact the activity of ensembles of granule cells. To determine whether these contacts are indeed selective, connectivity was traced back from UBC to specific ganglion cell, hair cell and vestibular organ subtypes in mice. We show that a specialized subset of primary afferents contacts ON UBCs, but not OFF UBCs, while secondary afferents contact both subtypes. Striking anatomical differences were observed between primary and secondary afferents, their synapses, and the UBCs they contact. Thus, each class of UBC functions to transform specific signals through distinct anatomical pathways. While out jogging, you have no trouble keeping your eyes fixed on objects in the distance even though your head and eyes are moving with every step. Humans owe this stability of the visual world partly to a region of the brain called the vestibular cerebellum. From its position underneath the rest of the brain, the vestibular cerebellum detects head motion and then triggers compensatory movements to stabilize the head, body and eyes. The vestibular cerebellum receives sensory input from the body via direct and indirect routes. The direct input comes from five structures within the inner ear, each of which detects movement of the head in one particular direction. The indirect input travels to the cerebellum via the brainstem, which connects the brain with the spinal cord. The indirect input contains information on head movements in multiple directions combined with input from other senses such as vision. By studying the mouse brain, Balmer and Trussell have now mapped the direct and indirect circuits that carry sensory information to the vestibular cerebellum. Both types of input activate cells within the vestibular cerebellum called unipolar brush cells (UBCs). There are two types of UBCs: ON and OFF. Direct sensory input from the inner ear activates only ON UBCs. These cells respond to the arrival of sensory input by increasing their activity. Indirect input from the brainstem activates both ON UBCs and OFF UBCs. The latter respond to the input by decreasing their activity. The vestibular cerebellum thus processes direct and indirect inputs via segregated pathways containing different types of UBCs. The next step in understanding how the cerebellum maintains a stable visual world is to identify the circuitry beyond the UBCs. Understanding these circuits will ultimately provide insights into balance disorders, such as vertigo.
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Affiliation(s)
- Timothy S Balmer
- Vollum Institute and Oregon Hearing Research Center, Oregon Health and Science University, Portland, United States
| | - Laurence O Trussell
- Vollum Institute and Oregon Hearing Research Center, Oregon Health and Science University, Portland, United States
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15
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Dempsey C, Abbott LF, Sawtell NB. Generalization of learned responses in the mormyrid electrosensory lobe. eLife 2019; 8:e44032. [PMID: 30860480 PMCID: PMC6457893 DOI: 10.7554/elife.44032] [Citation(s) in RCA: 5] [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] [Received: 11/29/2018] [Accepted: 02/21/2019] [Indexed: 02/01/2023] Open
Abstract
Appropriate generalization of learned responses to new situations is vital for adaptive behavior. We provide a circuit-level account of generalization in the electrosensory lobe (ELL) of weakly electric mormyrid fish. Much is already known in this system about a form of learning in which motor corollary discharge signals cancel responses to the uninformative input evoked by the fish's own electric pulses. However, for this cancellation to be useful under natural circumstances, it must generalize accurately across behavioral regimes, specifically different electric pulse rates. We show that such generalization indeed occurs in ELL neurons, and develop a circuit-level model explaining how this may be achieved. The mechanism involves regularized synaptic plasticity and an approximate matching of the temporal dynamics of motor corollary discharge and electrosensory inputs. Recordings of motor corollary discharge signals in mossy fibers and granule cells provide direct evidence for such matching.
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Affiliation(s)
- Conor Dempsey
- Department of Neuroscience, Zuckerman Mind Brain Behavior InstituteColumbia UniversityNew YorkUnited States
| | - LF Abbott
- Department of Neuroscience, Zuckerman Mind Brain Behavior InstituteColumbia UniversityNew YorkUnited States
- Department of Physiology and Cellular BiophysicsColumbia UniversityNew YorkUnited States
| | - Nathaniel B Sawtell
- Department of Neuroscience, Zuckerman Mind Brain Behavior InstituteColumbia UniversityNew YorkUnited States
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16
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Cayco-Gajic NA, Silver RA. Re-evaluating Circuit Mechanisms Underlying Pattern Separation. Neuron 2019; 101:584-602. [PMID: 30790539 PMCID: PMC7028396 DOI: 10.1016/j.neuron.2019.01.044] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/07/2019] [Accepted: 01/18/2019] [Indexed: 11/22/2022]
Abstract
When animals interact with complex environments, their neural circuits must separate overlapping patterns of activity that represent sensory and motor information. Pattern separation is thought to be a key function of several brain regions, including the cerebellar cortex, insect mushroom body, and dentate gyrus. However, recent findings have questioned long-held ideas on how these circuits perform this fundamental computation. Here, we re-evaluate the functional and structural mechanisms underlying pattern separation. We argue that the dimensionality of the space available for population codes representing sensory and motor information provides a common framework for understanding pattern separation. We then discuss how these three circuits use different strategies to separate activity patterns and facilitate associative learning in the presence of trial-to-trial variability.
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Affiliation(s)
- N Alex Cayco-Gajic
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - R Angus Silver
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK.
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17
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Carrillo RR, Naveros F, Ros E, Luque NR. A Metric for Evaluating Neural Input Representation in Supervised Learning Networks. Front Neurosci 2019; 12:913. [PMID: 30618549 PMCID: PMC6302114 DOI: 10.3389/fnins.2018.00913] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 11/20/2018] [Indexed: 11/13/2022] Open
Abstract
Supervised learning has long been attributed to several feed-forward neural circuits within the brain, with particular attention being paid to the cerebellar granular layer. The focus of this study is to evaluate the input activity representation of these feed-forward neural networks. The activity of cerebellar granule cells is conveyed by parallel fibers and translated into Purkinje cell activity, which constitutes the sole output of the cerebellar cortex. The learning process at this parallel-fiber-to-Purkinje-cell connection makes each Purkinje cell sensitive to a set of specific cerebellar states, which are roughly determined by the granule-cell activity during a certain time window. A Purkinje cell becomes sensitive to each neural input state and, consequently, the network operates as a function able to generate a desired output for each provided input by means of supervised learning. However, not all sets of Purkinje cell responses can be assigned to any set of input states due to the network's own limitations (inherent to the network neurobiological substrate), that is, not all input-output mapping can be learned. A key limiting factor is the representation of the input states through granule-cell activity. The quality of this representation (e.g., in terms of heterogeneity) will determine the capacity of the network to learn a varied set of outputs. Assessing the quality of this representation is interesting when developing and studying models of these networks to identify those neuron or network characteristics that enhance this representation. In this study we present an algorithm for evaluating quantitatively the level of compatibility/interference amongst a set of given cerebellar states according to their representation (granule-cell activation patterns) without the need for actually conducting simulations and network training. The algorithm input consists of a real-number matrix that codifies the activity level of every considered granule-cell in each state. The capability of this representation to generate a varied set of outputs is evaluated geometrically, thus resulting in a real number that assesses the goodness of the representation.
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Affiliation(s)
- Richard R Carrillo
- Department of Computer Architecture and Technology, University of Granada, Granada, Spain.,Centro de Investigación en Tecnologías de la Información y de las Comunicaciones (CITIC-UGR), University of Granada, Granada, Spain
| | - Francisco Naveros
- Department of Computer Architecture and Technology, University of Granada, Granada, Spain.,Centro de Investigación en Tecnologías de la Información y de las Comunicaciones (CITIC-UGR), University of Granada, Granada, Spain
| | - Eduardo Ros
- Department of Computer Architecture and Technology, University of Granada, Granada, Spain.,Centro de Investigación en Tecnologías de la Información y de las Comunicaciones (CITIC-UGR), University of Granada, Granada, Spain
| | - Niceto R Luque
- Department of Computer Architecture and Technology, University of Granada, Granada, Spain.,Centro de Investigación en Tecnologías de la Información y de las Comunicaciones (CITIC-UGR), University of Granada, Granada, Spain.,Aging in Vision and Action, Institut de la Vision, Inserm-UPMC-CNRS, Paris, France
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18
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Hansel C. Deregulation of synaptic plasticity in autism. Neurosci Lett 2019; 688:58-61. [DOI: 10.1016/j.neulet.2018.02.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 02/02/2018] [Indexed: 12/17/2022]
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19
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Suvrathan A, Raymond JL. Depressed by Learning-Heterogeneity of the Plasticity Rules at Parallel Fiber Synapses onto Purkinje Cells. CEREBELLUM (LONDON, ENGLAND) 2018; 17:747-755. [PMID: 30069835 PMCID: PMC6550343 DOI: 10.1007/s12311-018-0968-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Climbing fiber-driven long-term depression (LTD) of parallel fiber synapses onto cerebellar Purkinje cells has long been investigated as a putative mechanism of motor learning. We recently discovered that the rules governing the induction of LTD at these synapses vary across different regions of the cerebellum. Here, we discuss the design of LTD induction protocols in light of this heterogeneity in plasticity rules. The analytical advantages of the cerebellum provide an opportunity to develop a deeper understanding of how the specific plasticity rules at synapses support the implementation of learning.
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Affiliation(s)
- Aparna Suvrathan
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Department of Pediatrics, Brain Repair and Integrative Neuroscience Program, the Research Institute of the McGill University Health Centre, McGill University, Montréal General Hospital, Montréal, Quebec, H3G 1A4, Canada
| | - Jennifer L Raymond
- Department of Neurobiology, Stanford University, Stanford, CA, 94305, USA.
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20
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Hernandez O, Pietrajtis K, Mathieu B, Dieudonné S. Optogenetic stimulation of complex spatio-temporal activity patterns by acousto-optic light steering probes cerebellar granular layer integrative properties. Sci Rep 2018; 8:13768. [PMID: 30213968 PMCID: PMC6137064 DOI: 10.1038/s41598-018-32017-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 08/28/2018] [Indexed: 12/11/2022] Open
Abstract
Optogenetics provides tools to control afferent activity in brain microcircuits. However, this requires optical methods that can evoke asynchronous and coordinated activity within neuronal ensembles in a spatio-temporally precise way. Here we describe a light patterning method, which combines MHz acousto-optic beam steering and adjustable low numerical aperture Gaussian beams, to achieve fast 2D targeting in scattering tissue. Using mossy fiber afferents to the cerebellar cortex as a testbed, we demonstrate single fiber optogenetic stimulation with micron-scale lateral resolution, >100 µm depth-penetration and 0.1 ms spiking precision. Protracted spatio-temporal patterns of light delivered by our illumination system evoked sustained asynchronous mossy fiber activity with excellent repeatability. Combining optical and electrical stimulations, we show that the cerebellar granular layer performs nonlinear integration, whereby sustained mossy fiber activity provides a permissive context for the transmission of salient inputs, enriching combinatorial views on mossy fiber pattern separation.
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Affiliation(s)
- Oscar Hernandez
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Université, 46 rue d'Ulm, 75005, Paris, France
- Wavefront-engineering Microscopy Group, Neurophotonics Laboratory, CNRS UMR8250, Paris Descartes University, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270, Paris Cedex 06, France
- CNC Program, Stanford University, Stanford, California, 94305, USA
| | - Katarzyna Pietrajtis
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Université, 46 rue d'Ulm, 75005, Paris, France
| | - Benjamin Mathieu
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Université, 46 rue d'Ulm, 75005, Paris, France
| | - Stéphane Dieudonné
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Université, 46 rue d'Ulm, 75005, Paris, France.
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21
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Locomotor activity modulates associative learning in mouse cerebellum. Nat Neurosci 2018; 21:725-735. [PMID: 29662214 PMCID: PMC5923878 DOI: 10.1038/s41593-018-0129-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/01/2018] [Indexed: 11/26/2022]
Abstract
Changes in behavioral state can profoundly influence brain function. Here we show that behavioral state modulates performance in delay eyeblink conditioning, a cerebellum-dependent form of associative learning. Increased locomotor speed in head-fixed mice drove earlier onset of learning and trial-by-trial enhancement of learned responses that were dissociable from changes in arousal and independent of sensory modality. Eyelid responses evoked by optogenetic stimulation of mossy fiber inputs to the cerebellum, but not at sites downstream, were positively modulated by ongoing locomotion. Substituting prolonged, low-intensity optogenetic mossy fiber stimulation for locomotion was sufficient to enhance conditioned responses. Our results suggest that locomotor activity modulates delay eyeblink conditioning through increased activation of the mossy fiber pathway within the cerebellum. Taken together, these results provide evidence for a novel role for behavioral state modulation in associative learning and suggest a potential mechanism through which engaging in movement can improve an individual’s ability to learn.
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22
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Xiao L, Scheiffele P. Local and long-range circuit elements for cerebellar function. Curr Opin Neurobiol 2018; 48:146-152. [PMID: 29316490 DOI: 10.1016/j.conb.2017.12.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 11/29/2017] [Accepted: 12/22/2017] [Indexed: 12/22/2022]
Abstract
The view of cerebellar functions has been extended from controlling sensorimotor processes to processing 'contextual' information and generating predictions for a diverse range of behaviors. These functions rely on the computation of the local cerebellar microcircuits and long-range connectivity that relays cerebellar output to various brain areas. In this review, we discuss recent work on two of the circuit elements, which are thought to be fundamental for a wide range of non-sensorimotor behaviors: The role for cerebellar granule cells in multimodal integration in the cerebellar cortex and the long-range connectivity between the deep cerebellar nuclei and the basal ganglia. Lastly, we discuss how studies on synapses and circuits of the cerebellum in rodent models of autism-spectrum disorders might contribute to our understanding of the pathophysiology of this class of neurodevelopmental disorders.
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Affiliation(s)
- Le Xiao
- Biozentrum, University of Basel, 4056 Basel, Switzerland.
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23
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Population-scale organization of cerebellar granule neuron signaling during a visuomotor behavior. Sci Rep 2017; 7:16240. [PMID: 29176570 PMCID: PMC5701187 DOI: 10.1038/s41598-017-15938-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 11/03/2017] [Indexed: 11/10/2022] Open
Abstract
Granule cells at the input layer of the cerebellum comprise over half the neurons in the human brain and are thought to be critical for learning. However, little is known about granule neuron signaling at the population scale during behavior. We used calcium imaging in awake zebrafish during optokinetic behavior to record transgenically identified granule neurons throughout a cerebellar population. A significant fraction of the population was responsive at any given time. In contrast to core precerebellar populations, granule neuron responses were relatively heterogeneous, with variation in the degree of rectification and the balance of positive versus negative changes in activity. Functional correlations were strongest for nearby cells, with weak spatial gradients in the degree of rectification and the average sign of response. These data open a new window upon cerebellar function and suggest granule layer signals represent elementary building blocks under-represented in core sensorimotor pathways, thereby enabling the construction of novel patterns of activity for learning.
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24
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Morphological Constraints on Cerebellar Granule Cell Combinatorial Diversity. J Neurosci 2017; 37:12153-12166. [PMID: 29118107 DOI: 10.1523/jneurosci.0588-17.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 10/19/2017] [Accepted: 11/02/2017] [Indexed: 11/21/2022] Open
Abstract
Combinatorial expansion by the cerebellar granule cell layer (GCL) is fundamental to theories of cerebellar contributions to motor control and learning. Granule cells (GrCs) sample approximately four mossy fiber inputs and are thought to form a combinatorial code useful for pattern separation and learning. We constructed a spatially realistic model of the cerebellar GCL and examined how GCL architecture contributes to GrC combinatorial diversity. We found that GrC combinatorial diversity saturates quickly as mossy fiber input diversity increases, and that this saturation is in part a consequence of short dendrites, which limit access to diverse inputs and favor dense sampling of local inputs. This local sampling also produced GrCs that were combinatorially redundant, even when input diversity was extremely high. In addition, we found that mossy fiber clustering, which is a common anatomical pattern, also led to increased redundancy of GrC input combinations. We related this redundancy to hypothesized roles of temporal expansion of GrC information encoding in service of learned timing, and we show that GCL architecture produces GrC populations that support both temporal and combinatorial expansion. Finally, we used novel anatomical measurements from mice of either sex to inform modeling of sparse and filopodia-bearing mossy fibers, finding that these circuit features uniquely contribute to enhancing GrC diversification and redundancy. Our results complement information theoretic studies of granule layer structure and provide insight into the contributions of granule layer anatomical features to afferent mixing.SIGNIFICANCE STATEMENT Cerebellar granule cells are among the simplest neurons, with tiny somata and, on average, just four dendrites. These characteristics, along with their dense organization, inspired influential theoretical work on the granule cell layer as a combinatorial expander, where each granule cell represents a unique combination of inputs. Despite the centrality of these theories to cerebellar physiology, the degree of expansion supported by anatomically realistic patterns of inputs is unknown. Using modeling and anatomy, we show that realistic input patterns constrain combinatorial diversity by producing redundant combinations, which nevertheless could support temporal diversification of like combinations, suitable for learned timing. Our study suggests a neural substrate for producing high levels of both combinatorial and temporal diversity in the granule cell layer.
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25
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Singla S, Dempsey C, Warren R, Enikolopov AG, Sawtell NB. A cerebellum-like circuit in the auditory system cancels responses to self-generated sounds. Nat Neurosci 2017; 20:943-950. [PMID: 28530663 PMCID: PMC5525154 DOI: 10.1038/nn.4567] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 04/19/2017] [Indexed: 12/15/2022]
Abstract
The dorsal cochlear nucleus (DCN) integrates auditory nerve input with a
diverse array of sensory and motor signals processed within circuity similar to
the cerebellum. Yet how the DCN contributes to early auditory processing has
been a longstanding puzzle. Using electrophysiological recordings in mice during
licking behavior we show that DCN neurons are largely unaffected by
self-generated sounds while remaining sensitive to external acoustic stimuli.
Recordings in deafened mice, together with neural activity manipulations,
indicate that self-generated sounds are cancelled by non-auditory signals
conveyed by mossy fibers. In addition, DCN neurons exhibit gradual reductions in
their responses to acoustic stimuli that are temporally correlated with licking.
Together, these findings suggest that DCN may act as an adaptive filter for
cancelling self-generated sounds. Adaptive filtering has been established
previously for cerebellum-like sensory structures in fish suggesting a conserved
function for such structures across vertebrates.
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Affiliation(s)
- Shobhit Singla
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, New York, USA
| | - Conor Dempsey
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, New York, USA
| | - Richard Warren
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, New York, USA
| | - Armen G Enikolopov
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Nathaniel B Sawtell
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, New York, USA
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26
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Sensorimotor Representations in Cerebellar Granule Cells in Larval Zebrafish Are Dense, Spatially Organized, and Non-temporally Patterned. Curr Biol 2017; 27:1288-1302. [DOI: 10.1016/j.cub.2017.03.029] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/24/2017] [Accepted: 03/14/2017] [Indexed: 01/25/2023]
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27
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Exploring the significance of morphological diversity for cerebellar granule cell excitability. Sci Rep 2017; 7:46147. [PMID: 28406156 PMCID: PMC5390267 DOI: 10.1038/srep46147] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 03/13/2017] [Indexed: 11/09/2022] Open
Abstract
The relatively simple and compact morphology of cerebellar granule cells (CGCs) has led to the view that heterogeneity in CGC shape has negligible impact upon the integration of mossy fibre (MF) information. Following electrophysiological recording, 3D models were constructed from high-resolution imaging data to identify morphological features that could influence the coding of MF input patterns by adult CGCs. Quantification of MF and CGC morphology provided evidence that CGCs could be connected to the multiple rosettes that arise from a single MF input. Predictions from our computational models propose that MF inputs could be more densely encoded within the CGC layer than previous models suggest. Moreover, those MF signals arriving onto the dendrite closest to the axon will generate greater CGC excitation. However, the impact of this morphological variability on MF input selectivity will be attenuated by high levels of CGC inhibition providing further flexibility to the MF → CGC pathway. These features could be particularly important when considering the integration of multimodal MF sensory input by individual CGCs.
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28
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Abstract
Electric fish are privileged animals for bio-inspiring man-built autonomous systems since they have a multimodal sense that allows underwater navigation, object classification and intraspecific communication. Although there are taxon dependent variations adapted to different environments, this multimodal system can be schematically described as having four main components: active electroreception, passive electroreception, lateral line sense and, proprioception. Amongst these sensory modalities, proprioception and electroreception show 'active' systems that extrct information carried by self generated forms of energy. This ensemble of four sensory modalities is present in African mormyriformes and American gymnotiformes. The convergent evolution of similar imaging, peripheral encoding, and central processing mechanisms suggests that these mechanisms may be the most suitable for dealing with electric images in the context of the other and self generated actions. This review deals with the way in which biological organisms address three of the problems that are faced when designing a bioinspired electroreceptive agent: (a) body shape, material and mobility, (b) peripheral encoding of electric images, and (c) early processing of electrosensory signals. Taking into account biological solutions I propose that the new generation of underwater agents should have electroreceptive arms, use complex peripheral sensors for encoding the images and cerebellum like architecture for image feature extraction and implementing sensory-motor transformations.
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Affiliation(s)
- Angel Ariel Caputi
- Departamento de Neurociencias Integrativas y Computacionales Instituto de Investigaciones Biológicas Clemente Estable. Av. Italia 3318 Montevideo, Uruguay
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29
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Warren R, Sawtell NB. A comparative approach to cerebellar function: insights from electrosensory systems. Curr Opin Neurobiol 2016; 41:31-37. [PMID: 27504860 PMCID: PMC5123925 DOI: 10.1016/j.conb.2016.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/28/2016] [Accepted: 07/20/2016] [Indexed: 12/19/2022]
Abstract
Despite its simple and highly-ordered circuitry the function of the cerebellum remains a topic of vigorous debate. This review explores connections between the cerebellum and sensory processing structures that closely resemble the cerebellum in terms of their evolution, development, patterns of gene expression, and circuitry. Recent studies of cerebellum-like structures involved in electrosensory processing in fish have provided insights into the functions of granule cells and unipolar brush cells-cell types shared with the cerebellum. We also discuss the possibility, supported by recent studies, that generating and subtracting predictions of the sensory consequences of motor commands may be core functions shared by both cerebellum-like structures and the cerebellum.
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Affiliation(s)
- Richard Warren
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, NY 10032, United States
| | - Nathaniel B Sawtell
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, NY 10032, United States.
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30
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Sawtell NB. Neural Mechanisms for Predicting the Sensory Consequences of Behavior: Insights from Electrosensory Systems. Annu Rev Physiol 2016; 79:381-399. [PMID: 27813831 DOI: 10.1146/annurev-physiol-021115-105003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Perception of the environment requires differentiating between external sensory inputs and those that are self-generated. Some of the clearest insights into the neural mechanisms underlying this process have come from studies of the electrosensory systems of fish. Neurons at the first stage of electrosensory processing generate negative images of the electrosensory consequences of the animal's own behavior. By canceling out the effects of predictable, self-generated inputs, negative images allow for the selective encoding of unpredictable, externally generated stimuli. Combined experimental and theoretical studies of electrosensory systems have led to detailed accounts of how negative images are formed at the level of synaptic plasticity rules, cells, and circuits. Here, I review these accounts and discuss their implications for understanding how predictions of the sensory consequences of behavior may be generated in other sensory structures and the cerebellum.
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Affiliation(s)
- Nathaniel B Sawtell
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, NY 10032;
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31
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Zampini V, Liu JK, Diana MA, Maldonado PP, Brunel N, Dieudonné S. Mechanisms and functional roles of glutamatergic synapse diversity in a cerebellar circuit. eLife 2016; 5. [PMID: 27642013 PMCID: PMC5074806 DOI: 10.7554/elife.15872] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 09/17/2016] [Indexed: 02/04/2023] Open
Abstract
Synaptic currents display a large degree of heterogeneity of their temporal characteristics, but the functional role of such heterogeneities remains unknown. We investigated in rat cerebellar slices synaptic currents in Unipolar Brush Cells (UBCs), which generate intrinsic mossy fibers relaying vestibular inputs to the cerebellar cortex. We show that UBCs respond to sinusoidal modulations of their sensory input with heterogeneous amplitudes and phase shifts. Experiments and modeling indicate that this variability results both from the kinetics of synaptic glutamate transients and from the diversity of postsynaptic receptors. While phase inversion is produced by an mGluR2-activated outward conductance in OFF-UBCs, the phase delay of ON UBCs is caused by a late rebound current resulting from AMPAR recovery from desensitization. Granular layer network modeling indicates that phase dispersion of UBC responses generates diverse phase coding in the granule cell population, allowing climbing-fiber-driven Purkinje cell learning at arbitrary phases of the vestibular input. DOI:http://dx.doi.org/10.7554/eLife.15872.001 Whether walking, riding a bicycle or simply standing still, we continually adjust our posture in small ways to prevent ourselves from falling. Our sense of balance depends on a set of structures inside the inner ear called the vestibular system. These structures detect movements of the head and relay this information to the brain in the form of electrical signals. A brain area called the vestibulo-cerebellum then combines these signals with sensory input from the eyes and muscles, before sending out further signals to trigger any adjustments necessary for balance. One of the main cell types within the vestibulo-cerebellum is the unipolar brush cell (or UBC for short). UBCs pass on signals to another type of neuron called Purkinje cells, which support the learning of motor skills such as adjusting posture. Zampini, Liu et al. set out to test the idea that UBCs transform inputs from the vestibular system into a format that makes it easier for cerebellar Purkinje cells to drive this kind of learning. First, recordings from slices of rodent brain revealed that UBCs respond in highly variable ways to vestibular input, with both the size and timing of responses varying between cells. This is because vestibular signals trigger the release of a chemical messenger called glutamate onto UBCs, but UBCs possess a variety of different types of glutamate receptors. Vestibular input therefore activates distinct signaling cascades from one UBC to the next. According to a computer model, this variability in UBC responses ensures that a subset of UBCs will always be active at any point during vestibular input. This in turn means that Purkinje cells can fire at any stage of a movement, which boosts the learning of motor skills. The next steps will be to test this hypothesis using mutant mice that lack specific receptor subtypes in UBCs or UBCs completely. A further challenge for the future will be to build a computer model of the vestibulo-cerebellar system that includes all of its component cell types. DOI:http://dx.doi.org/10.7554/eLife.15872.002
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Affiliation(s)
- Valeria Zampini
- Institut de Biologie de l'ENS, Ecole Normale Supérieure, Paris, France.,Inserm, U1024, Paris, France.,CNRS, UMR 8197, Paris, France
| | - Jian K Liu
- Neurosciences Federation, Université Paris Descartes, Paris, France.,Department of Ophthalmology, University Medical Center Goettingen, Goettingen, Germany.,Bernstein Center for Computational Neuroscience, Göttingen, Germany
| | - Marco A Diana
- Institut de Biologie de l'ENS, Ecole Normale Supérieure, Paris, France.,Inserm, U1024, Paris, France.,CNRS, UMR 8197, Paris, France
| | - Paloma P Maldonado
- Institut de Biologie de l'ENS, Ecole Normale Supérieure, Paris, France.,Inserm, U1024, Paris, France.,CNRS, UMR 8197, Paris, France
| | - Nicolas Brunel
- Neurosciences Federation, Université Paris Descartes, Paris, France.,Department of Statistics and Neurobiology, University of Chicago, Chicago, United States
| | - Stéphane Dieudonné
- Institut de Biologie de l'ENS, Ecole Normale Supérieure, Paris, France.,Inserm, U1024, Paris, France.,CNRS, UMR 8197, Paris, France
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32
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Yaeger DB, Trussell LO. Auditory Golgi cells are interconnected predominantly by electrical synapses. J Neurophysiol 2016; 116:540-51. [PMID: 27121584 PMCID: PMC4978786 DOI: 10.1152/jn.01108.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 04/26/2016] [Indexed: 11/22/2022] Open
Abstract
The mossy fiber-granule cell-parallel fiber system conveys proprioceptive and corollary discharge information to principal cells in cerebellum-like systems. In the dorsal cochlear nucleus (DCN), Golgi cells inhibit granule cells and thus regulate information transfer along the mossy fiber-granule cell-parallel fiber pathway. Whereas excitatory synaptic inputs to Golgi cells are well understood, inhibitory and electrical synaptic inputs to Golgi cells have not been examined. Using paired recordings in a mouse brain slice preparation, we find that Golgi cells of the cochlear nucleus reliably form electrical synapses onto one another. Golgi cells were only rarely electrically coupled to superficial stellate cells, which form a separate network of electrically coupled interneurons in the DCN. Spikelets had a biphasic effect on the excitability of postjunctional Golgi cells, with a brief excitatory phase and a prolonged inhibitory phase due to the propagation of the prejunctional afterhyperpolarization through gap junctions. Golgi cells and stellate cells made weak inhibitory chemical synapses onto Golgi cells with low probability. Electrical synapses are therefore the predominant form of synaptic communication between auditory Golgi cells. We propose that electrical synapses between Golgi cells may function to regulate the synchrony of Golgi cell firing when electrically coupled Golgi cells receive temporally correlated excitatory synaptic input.
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Affiliation(s)
- Daniel B Yaeger
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon; and
| | - Laurence O Trussell
- Vollum Institute and Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon
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33
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Moberget T, Ivry RB. Cerebellar contributions to motor control and language comprehension: searching for common computational principles. Ann N Y Acad Sci 2016; 1369:154-71. [PMID: 27206249 PMCID: PMC5260470 DOI: 10.1111/nyas.13094] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The past 25 years have seen the functional domain of the cerebellum extend beyond the realm of motor control, with considerable discussion of how this subcortical structure contributes to cognitive domains including attention, memory, and language. Drawing on evidence from neuroanatomy, physiology, neuropsychology, and computational work, sophisticated models have been developed to describe cerebellar function in sensorimotor control and learning. In contrast, mechanistic accounts of how the cerebellum contributes to cognition have remained elusive. Inspired by the homogeneous cerebellar microanatomy and a desire for parsimony, many researchers have sought to extend mechanistic ideas from motor control to cognition. One influential hypothesis centers on the idea that the cerebellum implements internal models, representations of the context-specific dynamics of an agent's interactions with the environment, enabling predictive control. We briefly review cerebellar anatomy and physiology, to review the internal model hypothesis as applied in the motor domain, before turning to extensions of these ideas in the linguistic domain, focusing on speech perception and semantic processing. While recent findings are consistent with this computational generalization, they also raise challenging questions regarding the nature of cerebellar learning, and may thus inspire revisions of our views on the role of the cerebellum in sensorimotor control.
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Affiliation(s)
- Torgeir Moberget
- Norwegian Centre for Mental Disorders Research (NORMENT), KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, Norway
| | - Richard B. Ivry
- Department of Psychology, and the Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California
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34
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Computational Architecture of the Granular Layer of Cerebellum-Like Structures. THE CEREBELLUM 2016; 16:15-25. [DOI: 10.1007/s12311-016-0759-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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35
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Ishikawa T, Shimuta M, Häusser M. Multimodal sensory integration in single cerebellar granule cells in vivo. eLife 2015; 4. [PMID: 26714108 PMCID: PMC4798944 DOI: 10.7554/elife.12916] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/21/2015] [Indexed: 12/04/2022] Open
Abstract
The mammalian cerebellum is a highly multimodal structure, receiving inputs from multiple sensory modalities and integrating them during complex sensorimotor coordination tasks. Previously, using cell-type-specific anatomical projection mapping, it was shown that multimodal pathways converge onto individual cerebellar granule cells (Huang et al., 2013). Here we directly measure synaptic currents using in vivo patch-clamp recordings and confirm that a subset of single granule cells receive convergent functional multimodal (somatosensory, auditory, and visual) inputs via separate mossy fibers. Furthermore, we show that the integration of multimodal signals by granule cells can enhance action potential output. These recordings directly demonstrate functional convergence of multimodal signals onto single granule cells. DOI:http://dx.doi.org/10.7554/eLife.12916.001
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Affiliation(s)
- Taro Ishikawa
- Wolfson Institute for Biomedical Research, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.,Department of Pharmacology, Jikei University School of Medicine, Tokyo, Japan
| | - Misa Shimuta
- Wolfson Institute for Biomedical Research, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.,Department of Pharmacology, Jikei University School of Medicine, Tokyo, Japan
| | - Michael Häusser
- Wolfson Institute for Biomedical Research, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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36
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Powell K, Mathy A, Duguid I, Häusser M. Synaptic representation of locomotion in single cerebellar granule cells. eLife 2015; 4. [PMID: 26083712 PMCID: PMC4499793 DOI: 10.7554/elife.07290] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/16/2015] [Indexed: 11/13/2022] Open
Abstract
The cerebellum plays a crucial role in the regulation of locomotion, but how movement is represented at the synaptic level is not known. Here, we use in vivo patch-clamp recordings to show that locomotion can be directly read out from mossy fiber synaptic input and spike output in single granule cells. The increase in granule cell spiking during locomotion is enhanced by glutamate spillover currents recruited during movement. Surprisingly, the entire step sequence can be predicted from input EPSCs and output spikes of a single granule cell, suggesting that a robust gait code is present already at the cerebellar input layer and transmitted via the granule cell pathway to downstream Purkinje cells. Thus, synaptic input delivers remarkably rich information to single neurons during locomotion.
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Affiliation(s)
- Kate Powell
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Alexandre Mathy
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Ian Duguid
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Michael Häusser
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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37
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Abstract
In cerebellum-like circuits, synapses from thousands of granule cells converge onto principal cells. This fact, combined with theoretical considerations, has led to the concept that granule cells encode afferent input as a population and that spiking in individual granule cells is relatively unimportant. However, granule cells also provide excitatory input to Golgi cells, each of which provide inhibition to hundreds of granule cells. We investigated whether spiking in individual granule cells could recruit Golgi cells and thereby trigger widespread inhibition in slices of mouse cochlear nucleus. Using paired whole-cell patch-clamp recordings, trains of action potentials at 100 Hz in single granule cells was sufficient to evoke spikes in Golgi cells in ∼40% of paired granule-to-Golgi cell recordings. High-frequency spiking in single granule cells evoked IPSCs in ∼5% of neighboring granule cells, indicating that bursts of activity in single granule cells can recruit feedback inhibition from Golgi cells. Moreover, IPSPs mediated by single Golgi cell action potentials paused granule cell firing, suggesting that inhibitory events recruited by activity in single granule cells were able to control granule cell firing. These results suggest a previously unappreciated relationship between population coding and bursting in single granule cells by which spiking in a small number of granule cells may have an impact on the activity of a much larger number of granule cells.
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38
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Borges-Merjane C, Trussell LO. ON and OFF unipolar brush cells transform multisensory inputs to the auditory system. Neuron 2015; 85:1029-42. [PMID: 25741727 DOI: 10.1016/j.neuron.2015.02.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 12/27/2014] [Accepted: 01/22/2015] [Indexed: 12/15/2022]
Abstract
Unipolar brush cells (UBCs) of the dorsal cochlear nucleus (DCN) and vestibular cerebellar cortex receive glutamatergic mossy fiber input on an elaborate brush-like dendrite. Two subtypes of UBC have been established based on immunohistochemical markers and physiological profiles, but the relation of these subtypes to the response to mossy fiber input is not clear. We examined the synaptic physiology of auditory UBCs in mouse brain slices, identifying two response profiles, and correlated each with a specific UBC subtype. One subtype had a striking biphasic excitatory response mediated by AMPAR and mGluR1α. The second was mGluR1α negative and was dominated by a strongly inhibitory outward K(+) current. These two subtypes upregulated or downregulated spontaneous firing, respectively. By analogy to the retina, we propose that UBCs comprise ON and OFF cells with respect to their response to glutamatergic input and may therefore provide distinct parallel processing of multisensory input to their targets.
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Affiliation(s)
- Carolina Borges-Merjane
- Neuroscience Graduate Program, Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA; Vollum Institute and Oregon Hearing Research Center, Oregon Health and Science University, Portland, OR 97239, USA
| | - Laurence O Trussell
- Vollum Institute and Oregon Hearing Research Center, Oregon Health and Science University, Portland, OR 97239, USA.
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39
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Sawtell NB, Abbott LF. Strength in more than numbers. Nat Neurosci 2015; 18:614-6. [PMID: 25919958 DOI: 10.1038/nn.4006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - L F Abbott
- Department of Neuroscience, Columbia University, New York, New York, USA
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40
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Synaptic diversity enables temporal coding of coincident multisensory inputs in single neurons. Nat Neurosci 2015; 18:718-27. [PMID: 25821914 PMCID: PMC4413433 DOI: 10.1038/nn.3974] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/12/2015] [Indexed: 02/08/2023]
Abstract
The ability of the brain to rapidly process information from multiple pathways is critical for reliable execution of complex sensory-motor behaviors, yet the cellular mechanisms underlying a neuronal representation of multimodal stimuli are poorly understood. Here we explored the possibility that the physiological diversity of mossy fiber (MF) to granule cell (GC) synapses within the mouse vestibulocerebellum may contribute to the processing of coincident multisensory information at the level of individual GCs. We found that the strength and short-term dynamics of individual MF-GC synapses can act as biophysical signatures for primary vestibular, secondary vestibular and visual input pathways. The majority of GCs receive inputs from different modalities, which when co-activated, produced enhanced GC firing rates and distinct first spike latencies. Thus, pathway-specific synaptic response properties permit temporal coding of correlated multisensory input by single GCs, thereby enriching sensory representation and facilitating pattern separation.
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41
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A role for mixed corollary discharge and proprioceptive signals in predicting the sensory consequences of movements. J Neurosci 2015; 34:16103-16. [PMID: 25429151 DOI: 10.1523/jneurosci.2751-14.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Animals must distinguish behaviorally relevant patterns of sensory stimulation from those that are attributable to their own movements. In principle, this distinction could be made based on internal signals related to motor commands, known as corollary discharge (CD), sensory feedback, or some combination of both. Here we use an advantageous model system--the electrosensory lobe (ELL) of weakly electric mormyrid fish--to directly examine how CD and proprioceptive feedback signals are transformed into negative images of the predictable electrosensory consequences of the fish's motor commands and/or movements. In vivo recordings from ELL neurons and theoretical modeling suggest that negative images are formed via anti-Hebbian plasticity acting on random, nonlinear mixtures of CD and proprioception. In support of this, we find that CD and proprioception are randomly mixed in spinal mossy fibers and that properties of granule cells are consistent with a nonlinear recoding of these signals. The mechanistic account provided here may be relevant to understanding how internal models of movement consequences are implemented in other systems in which similar components (e.g., mixed sensory and motor signals and synaptic plasticity) are found.
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42
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Amey-Özel M, von der Emde G, Engelmann J, Grant K. More a finger than a nose: the trigeminal motor and sensory innervation of the Schnauzenorgan in the elephant-nose fish Gnathonemus petersii. J Comp Neurol 2014; 523:769-89. [PMID: 25388854 DOI: 10.1002/cne.23710] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 11/02/2014] [Accepted: 11/03/2014] [Indexed: 11/11/2022]
Abstract
The weakly electric fish Gnathonemus petersii uses its electric sense to actively probe the environment. Its highly mobile chin appendage, the Schnauzenorgan, is rich in electroreceptors. Physical measurements have demonstrated the importance of the position of the Schnauzenorgan in funneling the fish's self-generated electric field. The present study focuses on the trigeminal motor pathway that controls Schnauzenorgan movement and on its trigeminal sensory innervation and central representation. The nerves entering the Schnauzenorgan are very large and contain both motor and sensory trigeminal components as well as an electrosensory pathway. With the use of neurotracer techniques, labeled Schnauzenorgan motoneurons were found throughout the ventral main body of the trigeminal motor nucleus but not among the population of larger motoneurons in its rostrodorsal region. The Schnauzenorgan receives no motor or sensory innervation from the facial nerve. There are many anastomoses between the peripheral electrosensory and trigeminal nerves, but these senses remain separate in the sensory ganglia and in their first central relays. Schnauzenorgan trigeminal primary afferent projections extend throughout the descending trigeminal sensory nuclei, and a few fibers enter the facial lobe. Although no labeled neurons could be identified in the brain as the trigeminal mesencephalic root, some Schnauzenorgan trigeminal afferents terminated in the trigeminal motor nucleus, suggesting a monosynaptic, possibly proprioceptive, pathway. In this first step toward understanding multimodal central representation of the Schnauzenorgan, no direct interconnections were found between the trigeminal sensory and electromotor command system, or the electrosensory and trigeminal motor command. The pathways linking perception to action remain to be studied.
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Affiliation(s)
- Monique Amey-Özel
- Department of Neuroethology/Sensory Ecology, Institute for Zoology, University of Bonn, Bonn, Germany
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43
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Pereira AC, Rodríguez-Cattáneo A, Caputi AA. The slow pathway in the electrosensory lobe of Gymnotus omarorum: field potentials and unitary activity. ACTA ACUST UNITED AC 2014; 108:71-83. [PMID: 25088503 DOI: 10.1016/j.jphysparis.2014.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 07/15/2014] [Accepted: 07/17/2014] [Indexed: 11/26/2022]
Abstract
This is a first communication on the self-activation pattern of the electrosensory lobe in the pulse weakly electric fish Gymnotus omarorum. Field potentials in response to the fish's own electric organ discharge (EOD) were recorded along vertical tracks (50μm step) and on a transversal lattice array across the electrosensory lobe (resolution 50μm×100μm). The unitary activity of 82 neurons was recorded in the same experiments. Field potential analysis indicates that the slow electrosensory path shows a characteristic post-EOD pattern of activity marked by three main events: (i) a small and early component at about 7ms, (ii) an intermediate peak about 13ms and (iii) a late broad component peaking after 20ms. Unit firing rate showed a wide range of latencies between 3 and 30ms and a variable number of spikes (median 0.28units/EOD). Conditional probability analysis showed monomodal and multimodal post-EOD histograms, with the peaks of unit activity histograms often matching the timing of the main components of the field potentials. Monomodal responses were sub-classified as phase locked monomodal (variance smaller than 1ms), early monomodal (intermediate variance, often firing in doublets, peaking range 10-17ms) and late monomodal (large variance, often firing two spikes separated about 10ms, peaking beyond 17ms). The responses of multimodal units showed that their firing probability was either enhanced, or depressed just after the EOD. In this last (depressed) subtype of unit the probability stepped down just after the EOD. Early inhibition and the presence of early phase locked units suggest that the observed pattern may be influenced by a fast feed forward inhibition. We conclude that the ELL in pulse gymnotiformes is activated in a complex sequence of events that reflects the ELL network connectivity.
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Affiliation(s)
- Ana Carolina Pereira
- Departamento de Neurociencias Integrativas y Computacionales, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Alejo Rodríguez-Cattáneo
- Departamento de Neurociencias Integrativas y Computacionales, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Angel A Caputi
- Departamento de Neurociencias Integrativas y Computacionales, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.
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44
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Plastic corollary discharge predicts sensory consequences of movements in a cerebellum-like circuit. Neuron 2014; 82:896-907. [PMID: 24853945 DOI: 10.1016/j.neuron.2014.03.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2014] [Indexed: 11/21/2022]
Abstract
The capacity to predict the sensory consequences of movements is critical for sensory, motor, and cognitive function. Though it is hypothesized that internal signals related to motor commands, known as corollary discharge, serve to generate such predictions, this process remains poorly understood at the neural circuit level. Here we demonstrate that neurons in the electrosensory lobe (ELL) of weakly electric mormyrid fish generate negative images of the sensory consequences of the fish's own movements based on ascending spinal corollary discharge signals. These results generalize previous findings describing mechanisms for generating negative images of the effects of the fish's specialized electric organ discharge (EOD) and suggest that a cerebellum-like circuit endowed with associative synaptic plasticity acting on corollary discharge can solve the complex and ubiquitous problem of predicting sensory consequences of movements.
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45
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Popa LS, Hewitt AL, Ebner TJ. The cerebellum for jocks and nerds alike. Front Syst Neurosci 2014; 8:113. [PMID: 24987338 PMCID: PMC4060457 DOI: 10.3389/fnsys.2014.00113] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/27/2014] [Indexed: 11/13/2022] Open
Abstract
Historically the cerebellum has been implicated in the control of movement. However, the cerebellum's role in non-motor functions, including cognitive and emotional processes, has also received increasing attention. Starting from the premise that the uniform architecture of the cerebellum underlies a common mode of information processing, this review examines recent electrophysiological findings on the motor signals encoded in the cerebellar cortex and then relates these signals to observations in the non-motor domain. Simple spike firing of individual Purkinje cells encodes performance errors, both predicting upcoming errors as well as providing feedback about those errors. Further, this dual temporal encoding of prediction and feedback involves a change in the sign of the simple spike modulation. Therefore, Purkinje cell simple spike firing both predicts and responds to feedback about a specific parameter, consistent with computing sensory prediction errors in which the predictions about the consequences of a motor command are compared with the feedback resulting from the motor command execution. These new findings are in contrast with the historical view that complex spikes encode errors. Evaluation of the kinematic coding in the simple spike discharge shows the same dual temporal encoding, suggesting this is a common mode of signal processing in the cerebellar cortex. Decoding analyses show the considerable accuracy of the predictions provided by Purkinje cells across a range of times. Further, individual Purkinje cells encode linearly and independently a multitude of signals, both kinematic and performance errors. Therefore, the cerebellar cortex's capacity to make associations across different sensory, motor and non-motor signals is large. The results from studying how Purkinje cells encode movement signals suggest that the cerebellar cortex circuitry can support associative learning, sequencing, working memory, and forward internal models in non-motor domains.
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Affiliation(s)
- Laurentiu S Popa
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA
| | - Angela L Hewitt
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA
| | - Timothy J Ebner
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA
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46
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Alviña K, Sawtell NB. Sensory processing and corollary discharge effects in posterior caudal lobe Purkinje cells in a weakly electric mormyrid fish. J Neurophysiol 2014; 112:328-39. [PMID: 24790163 DOI: 10.1152/jn.00016.2014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although it has been suggested that the cerebellum functions to predict the sensory consequences of motor commands, how such predictions are implemented in cerebellar circuitry remains largely unknown. A detailed and relatively complete account of predictive mechanisms has emerged from studies of cerebellum-like sensory structures in fish, suggesting that comparisons of the cerebellum and cerebellum-like structures may be useful. Here we characterize electrophysiological response properties of Purkinje cells in a region of the cerebellum proper of weakly electric mormyrid fish, the posterior caudal lobe (LCp), which receives the same mossy fiber inputs and projects to the same target structures as the electrosensory lobe (ELL), a well-studied cerebellum-like structure. We describe patterns of simple spike and climbing fiber activation in LCp Purkinje cells in response to motor corollary discharge, electrosensory, and proprioceptive inputs and provide evidence for two functionally distinct Purkinje cell subtypes within LCp. Protocols that induce rapid associative plasticity in ELL fail to induce plasticity in LCp, suggesting differences in the adaptive functions of the two structures. Similarities and differences between LCp and ELL are discussed in light of these results.
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Affiliation(s)
- Karina Alviña
- Department of Neuroscience, Columbia University, New York, New York
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47
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Brooks JX, Cullen KE. Early vestibular processing does not discriminate active from passive self-motion if there is a discrepancy between predicted and actual proprioceptive feedback. J Neurophysiol 2014; 111:2465-78. [PMID: 24671531 DOI: 10.1152/jn.00600.2013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Most of our sensory experiences are gained by active exploration of the world. While the ability to distinguish sensory inputs resulting of our own actions (termed reafference) from those produced externally (termed exafference) is well established, the neural mechanisms underlying this distinction are not fully understood. We have previously proposed that vestibular signals arising from self-generated movements are inhibited by a mechanism that compares the internal prediction of the proprioceptive consequences of self-motion to the actual feedback. Here we directly tested this proposal by recording from single neurons in monkey during vestibular stimulation that was externally produced and/or self-generated. We show for the first time that vestibular reafference is equivalently canceled for self-generated sensory stimulation produced by activation of the neck musculature (head-on-body motion), or axial musculature (combined head and body motion), when there is no discrepancy between the predicted and actual proprioceptive consequences of self-motion. However, if a discrepancy does exist, central vestibular neurons no longer preferentially encode vestibular exafference. Specifically, when simultaneous active and passive motion resulted in activation of the same muscle proprioceptors, neurons robustly encoded the total vestibular input (i.e., responses to vestibular reafference and exafference were equally strong), rather than exafference alone. Taken together, our results show that the cancellation of vestibular reafference in early vestibular processing requires an explicit match between expected and actual proprioceptive feedback. We propose that this vital neuronal computation, necessary for both accurate sensory perception and motor control, has important implications for a variety of sensory systems that suppress self-generated signals.
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Affiliation(s)
- Jessica X Brooks
- Aerospace Medical Research Unit, Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Kathleen E Cullen
- Aerospace Medical Research Unit, Department of Physiology, McGill University, Montreal, Quebec, Canada
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48
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Abstract
Tinnitus and cochlear damage have been associated with changes in somatosensory-auditory integration and plasticity in the dorsal cochlear nucleus (DCN). Recently, we demonstrated in vivo that DCN bimodal plasticity is stimulus timing-dependent, with Hebbian and anti-Hebbian timing rules that reflect in vitro spike timing-dependent plasticity. In this in vivo study, we assessed the stimulus timing dependence of bimodal plasticity in a tinnitus model. Guinea pigs were exposed to a narrowband noise that produced a temporary elevation of auditory brainstem response thresholds. A total of 60% of the guinea pigs developed tinnitus as indicated by gap-induced prepulse inhibition of the acoustic startle. After noise exposure and tinnitus induction, stimulus timing-dependent plasticity was measured by comparing responses to sound before and after paired somatosensory and auditory stimulation presented with varying intervals and orders. In comparison with Sham and noise-exposed animals that did not develop tinnitus, timing rules in verified tinnitus animals were more likely to be anti-Hebbian and broader for those bimodal intervals in which the neural activity showed enhancement. Furthermore, units from exposed animals with tinnitus were more weakly suppressed than either Sham animals or exposed animals without tinnitus. The broadened timing rules in the enhancement phase in animals with tinnitus, and in the suppressive phase in exposed animals without tinnitus was in contrast to narrow, Hebbian-like timing rules in Sham animals. These findings implicate alterations in DCN bimodal spike timing-dependent plasticity as underlying mechanisms in tinnitus, opening the way for a therapeutic target.
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49
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A temporal basis for predicting the sensory consequences of motor commands in an electric fish. Nat Neurosci 2014; 17:416-22. [PMID: 24531306 DOI: 10.1038/nn.3650] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 01/16/2014] [Indexed: 11/08/2022]
Abstract
Mormyrid electric fish are a model system for understanding how neural circuits predict the sensory consequences of motor acts. Medium ganglion cells in the electrosensory lobe create negative images that predict sensory input resulting from the fish's electric organ discharge (EOD). Previous studies have shown that negative images can be created through plasticity at granule cell-medium ganglion cell synapses, provided that granule cell responses to the brief EOD command are sufficiently varied and prolonged. Here we show that granule cells indeed provide such a temporal basis and that it is well-matched to the temporal structure of self-generated sensory inputs, allowing rapid and accurate sensory cancellation and explaining paradoxical features of negative images. We also demonstrate an unexpected and critical role of unipolar brush cells (UBCs) in generating the required delayed responses. These results provide a mechanistic account of how copies of motor commands are transformed into sensory predictions.
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50
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Sensory-evoked synaptic integration in cerebellar and cerebral cortical neurons. Nat Rev Neurosci 2014; 15:71-83. [PMID: 24434910 DOI: 10.1038/nrn3648] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neurons integrate synaptic inputs across time and space, a process that determines the transformation of input signals into action potential output. This article explores how synaptic integration contributes to the richness of sensory signalling in the cerebellar and cerebral cortices. Whether a neuron receives a few or a few thousand discrete inputs, most evoked synaptic activity generates only subthreshold membrane potential fluctuations. Sensory tuning of synaptic inputs is typically broad, but short-term dynamics and the interplay between excitation and inhibition restrict action potential firing to narrow windows of opportunity. We highlight the challenges and limitations of the use of somatic recordings in the study of synaptic integration and the importance of active dendritic mechanisms in sensory processing.
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