1
|
DePiero VJ, Deng Z, Chen C, Savier EL, Chen H, Wei W, Cang J. Transformation of Motion Pattern Selectivity from Retina to Superior Colliculus. J Neurosci 2024; 44:e1704232024. [PMID: 38569924 PMCID: PMC11097260 DOI: 10.1523/jneurosci.1704-23.2024] [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: 09/11/2023] [Revised: 03/07/2024] [Accepted: 03/26/2024] [Indexed: 04/05/2024] Open
Abstract
The superior colliculus (SC) is a prominent and conserved visual center in all vertebrates. In mice, the most superficial lamina of the SC is enriched with neurons that are selective for the moving direction of visual stimuli. Here, we study how these direction selective neurons respond to complex motion patterns known as plaids, using two-photon calcium imaging in awake male and female mice. The plaid pattern consists of two superimposed sinusoidal gratings moving in different directions, giving an apparent pattern direction that lies between the directions of the two component gratings. Most direction selective neurons in the mouse SC respond robustly to the plaids and show a high selectivity for the moving direction of the plaid pattern but not of its components. Pattern motion selectivity is seen in both excitatory and inhibitory SC neurons and is especially prevalent in response to plaids with large cross angles between the two component gratings. However, retinal inputs to the SC are ambiguous in their selectivity to pattern versus component motion. Modeling suggests that pattern motion selectivity in the SC can arise from a nonlinear transformation of converging retinal inputs. In contrast, the prevalence of pattern motion selective neurons is not seen in the primary visual cortex (V1). These results demonstrate an interesting difference between the SC and V1 in motion processing and reveal the SC as an important site for encoding pattern motion.
Collapse
Affiliation(s)
- Victor J DePiero
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22904
| | - Zixuan Deng
- Committee on Neurobiology, University of Chicago, Chicago, Illinois 60637
| | - Chen Chen
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22904
| | - Elise L Savier
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
- Department of Physiology, University of Michigan, Ann Arbor, Michigan 48109
| | - Hui Chen
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22904
| | - Wei Wei
- Department of Neurobiology, Neuroscience Institute, University of Chicago, Chicago, Illinois 60637
| | - Jianhua Cang
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22904
| |
Collapse
|
2
|
Manookin MB. Neuroscience: Reliable and refined motion computations in the retina. Curr Biol 2022; 32:R474-R476. [PMID: 35609547 DOI: 10.1016/j.cub.2022.04.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We can distinguish between the direction and speed of a moving object effortlessly, but this is actually a very challenging computational task. A new study demonstrates that this process begins at the first stages of visual processing in the retina.
Collapse
Affiliation(s)
- Michael B Manookin
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA; Vision Science Center, University of Washington, Seattle, WA 98109, USA; Karalis Johnson Eye Center, University of Washington, Seattle, WA 98109, USA.
| |
Collapse
|
3
|
Summers MT, Feller MB. Distinct inhibitory pathways control velocity and directional tuning in the mouse retina. Curr Biol 2022; 32:2130-2143.e3. [PMID: 35395192 PMCID: PMC9133153 DOI: 10.1016/j.cub.2022.03.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/09/2022] [Accepted: 03/17/2022] [Indexed: 11/30/2022]
Abstract
The sensory periphery is responsible for detecting ethologically relevant features of the external world, using compact, predominantly feedforward circuits. Visual motion is a particularly prevalent sensory feature, the presence of which can be a signal to enact diverse behaviors ranging from gaze stabilization reflexes to predator avoidance or prey capture. To understand how the retina constructs the distinct neural representations required for these behaviors, we investigated two circuits responsible for encoding different aspects of image motion: ON and ON-OFF direction-selective ganglion cells (DSGCs). Using a combination of two-photon targeted whole-cell electrophysiology, pharmacology, and conditional knockout mice, we show that distinct inhibitory pathways independently control tuning for motion velocity and motion direction in these two cell types. We further employ dynamic clamp and numerical modeling techniques to show that asymmetric inhibition provides a velocity-invariant mechanism of directional tuning, despite the strong velocity dependence of classical models of direction selectivity. We therefore demonstrate that invariant representations of motion features by inhibitory interneurons act as computational building blocks to construct distinct, behaviorally relevant signals at the earliest stages of the visual system.
Collapse
Affiliation(s)
- Mathew T Summers
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Marla B Feller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
| |
Collapse
|
4
|
Ding J, Chen A, Chung J, Acaron Ledesma H, Wu M, Berson DM, Palmer SE, Wei W. Spatially displaced excitation contributes to the encoding of interrupted motion by a retinal direction-selective circuit. eLife 2021; 10:e68181. [PMID: 34096504 PMCID: PMC8211448 DOI: 10.7554/elife.68181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/06/2021] [Indexed: 12/19/2022] Open
Abstract
Spatially distributed excitation and inhibition collectively shape a visual neuron's receptive field (RF) properties. In the direction-selective circuit of the mammalian retina, the role of strong null-direction inhibition of On-Off direction-selective ganglion cells (On-Off DSGCs) on their direction selectivity is well-studied. However, how excitatory inputs influence the On-Off DSGC's visual response is underexplored. Here, we report that On-Off DSGCs have a spatially displaced glutamatergic receptive field along their horizontal preferred-null motion axes. This displaced receptive field contributes to DSGC null-direction spiking during interrupted motion trajectories. Theoretical analyses indicate that population responses during interrupted motion may help populations of On-Off DSGCs signal the spatial location of moving objects in complex, naturalistic visual environments. Our study highlights that the direction-selective circuit exploits separate sets of mechanisms under different stimulus conditions, and these mechanisms may help encode multiple visual features.
Collapse
Affiliation(s)
- Jennifer Ding
- Committee on Neurobiology Graduate Program, The University of ChicagoChicagoUnited States
- Department of Neurobiology, The University of ChicagoChicagoUnited States
| | - Albert Chen
- Department of Organismal Biology, The University of ChicagoChicagoUnited States
| | - Janet Chung
- Department of Neurobiology, The University of ChicagoChicagoUnited States
| | - Hector Acaron Ledesma
- Graduate Program in Biophysical Sciences, The University of ChicagoChicagoUnited States
| | - Mofei Wu
- Department of Neurobiology, The University of ChicagoChicagoUnited States
| | - David M Berson
- Department of Neuroscience and Carney Institute for Brain Science, Brown UniversityProvidenceUnited States
| | - Stephanie E Palmer
- Committee on Neurobiology Graduate Program, The University of ChicagoChicagoUnited States
- Department of Organismal Biology, The University of ChicagoChicagoUnited States
- Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of ChicagoChicagoUnited States
| | - Wei Wei
- Committee on Neurobiology Graduate Program, The University of ChicagoChicagoUnited States
- Department of Neurobiology, The University of ChicagoChicagoUnited States
- Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of ChicagoChicagoUnited States
| |
Collapse
|
5
|
Abstract
At various stages of the visual system, visual responses are modulated by arousal. Here, we find that in mice this modulation operates as early as in the first synapse from the retina and even in retinal axons. To measure retinal activity in the awake, intact brain, we imaged the synaptic boutons of retinal axons in the superior colliculus. Their activity depended not only on vision but also on running speed and pupil size, regardless of retinal illumination. Arousal typically reduced their visual responses and selectivity for direction and orientation. Recordings from retinal axons in the optic tract revealed that arousal modulates the firing of some retinal ganglion cells. Arousal had similar effects postsynaptically in colliculus neurons, independent of activity in the other main source of visual inputs to the colliculus, the primary visual cortex. These results indicate that arousal modulates activity at every stage of the mouse visual system.
Collapse
|
6
|
Zuk NJ, Delgutte B. Neural coding and perception of auditory motion direction based on interaural time differences. J Neurophysiol 2019; 122:1821-1842. [PMID: 31461376 DOI: 10.1152/jn.00081.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
While motion is important for parsing a complex auditory scene into perceptual objects, how it is encoded in the auditory system is unclear. Perceptual studies suggest that the ability to identify the direction of motion is limited by the duration of the moving sound, yet we can detect changes in interaural differences at even shorter durations. To understand the source of these distinct temporal limits, we recorded from single units in the inferior colliculus (IC) of unanesthetized rabbits in response to noise stimuli containing a brief segment with linearly time-varying interaural time difference ("ITD sweep") temporally embedded in interaurally uncorrelated noise. We also tested the ability of human listeners to either detect the ITD sweeps or identify the motion direction. Using a point-process model to separate the contributions of stimulus dependence and spiking history to single-neuron responses, we found that the neurons respond primarily by following the instantaneous ITD rather than exhibiting true direction selectivity. Furthermore, using an optimal classifier to decode the single-neuron responses, we found that neural threshold durations of ITD sweeps for both direction identification and detection overlapped with human threshold durations even though the average response of the neurons could track the instantaneous ITD beyond psychophysical limits. Our results suggest that the IC does not explicitly encode motion direction, but internal neural noise may limit the speed at which we can identify the direction of motion.NEW & NOTEWORTHY Recognizing motion and identifying an object's trajectory are important for parsing a complex auditory scene, but how we do so is unclear. We show that neurons in the auditory midbrain do not exhibit direction selectivity as found in the visual system but instead follow the trajectory of the motion in their temporal firing patterns. Our results suggest that the inherent variability in neural firings may limit our ability to identify motion direction at short durations.
Collapse
Affiliation(s)
- Nathaniel J Zuk
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts
| | - Bertrand Delgutte
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts.,Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
7
|
Creamer MS, Mano O, Clark DA. Visual Control of Walking Speed in Drosophila. Neuron 2018; 100:1460-1473.e6. [PMID: 30415994 PMCID: PMC6405217 DOI: 10.1016/j.neuron.2018.10.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/29/2018] [Accepted: 10/16/2018] [Indexed: 10/27/2022]
Abstract
An animal's self-motion generates optic flow across its retina, and it can use this visual signal to regulate its orientation and speed through the world. While orientation control has been studied extensively in Drosophila and other insects, much less is known about the visual cues and circuits that regulate translational speed. Here, we show that flies regulate walking speed with an algorithm that is tuned to the speed of visual motion, causing them to slow when visual objects are nearby. This regulation does not depend strongly on the spatial structure or the direction of visual stimuli, making it algorithmically distinct from the classic computation that controls orientation. Despite the different algorithms, the visual circuits that regulate walking speed overlap with those that regulate orientation. Taken together, our findings suggest that walking speed is controlled by a hierarchical computation that combines multiple motion detectors with distinct tunings. VIDEO ABSTRACT.
Collapse
Affiliation(s)
- Matthew S Creamer
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06511, USA
| | - Omer Mano
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Damon A Clark
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06511, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA; Department of Physics, Yale University, New Haven, CT 06511, USA.
| |
Collapse
|
8
|
"Silent" NMDA Synapses Enhance Motion Sensitivity in a Mature Retinal Circuit. Neuron 2017; 96:1099-1111.e3. [PMID: 29107522 DOI: 10.1016/j.neuron.2017.09.058] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 06/09/2017] [Accepted: 09/28/2017] [Indexed: 12/30/2022]
Abstract
Retinal direction-selective ganglion cells (DSGCs) have the remarkable ability to encode motion over a wide range of contrasts, relying on well-coordinated excitation and inhibition (E/I). E/I is orchestrated by a diverse set of glutamatergic bipolar cells that drive DSGCs directly, as well as indirectly through feedforward GABAergic/cholinergic signals mediated by starburst amacrine cells. Determining how direction-selective responses are generated across varied stimulus conditions requires understanding how glutamate, acetylcholine, and GABA signals are precisely coordinated. Here, we use a combination of paired patch-clamp recordings, serial EM, and large-scale multi-electrode array recordings to show that a single high-sensitivity source of glutamate is processed differentially by starbursts via AMPA receptors and DSGCs via NMDA receptors. We further demonstrate how this novel synaptic arrangement enables DSGCs to encode direction robustly near threshold contrasts. Together, these results reveal a space-efficient synaptic circuit model for direction computations, in which "silent" NMDA receptors play critical roles.
Collapse
|
9
|
Koren D, Grove JCR, Wei W. Cross-compartmental Modulation of Dendritic Signals for Retinal Direction Selectivity. Neuron 2017; 95:914-927.e4. [PMID: 28781167 DOI: 10.1016/j.neuron.2017.07.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/08/2017] [Accepted: 07/19/2017] [Indexed: 11/19/2022]
Abstract
Compartmentalized signaling in dendritic subdomains is critical for the function of many central neurons. In the retina, individual dendritic sectors of a starburst amacrine cell (SAC) are preferentially activated by different directions of linear motion, indicating limited signal propagation between the sectors. However, the mechanism that regulates this propagation is poorly understood. Here, we find that metabotropic glutamate receptor 2 (mGluR2) signaling, which acts on voltage-gated calcium channels in SACs, selectively restricts cross-sector signal propagation in SACs, but does not affect local dendritic computation within individual sectors. mGluR2 signaling ensures sufficient electrotonic isolation of dendritic sectors to prevent their depolarization during non-preferred motion, yet enables controlled multicompartmental signal integration that enhances responses to preferred motion. Furthermore, mGluR2-mediated dendritic compartmentalization in SACs is important for the functional output of direction-selective ganglion cells (DSGCs). Therefore, our results directly link modulation of dendritic compartmentalization to circuit-level encoding of motion direction in the retina.
Collapse
Affiliation(s)
- David Koren
- Department of Neurobiology, The University of Chicago, Chicago, IL 60637, USA; Interdisciplinary Scientist Training Program, The University of Chicago, Chicago, IL 60637, USA
| | - James C R Grove
- Department of Neurobiology, The University of Chicago, Chicago, IL 60637, USA
| | - Wei Wei
- Department of Neurobiology, The University of Chicago, Chicago, IL 60637, USA.
| |
Collapse
|
10
|
Abstract
Abstract
How direction of image motion is detected as early as at the level of the vertebrate eye has been intensively studied in retina research. Although the first direction-selective (DS) retinal ganglion cells were already described in the 1960s and have since then been in the focus of many studies, scientists are still puzzled by the intricacy of the neuronal circuits and computational mechanisms underlying retinal direction selectivity. The fact that the retina can be easily isolated and studied in a Petri dish-by presenting light stimuli while recording from the various cell types in the retinal circuits-in combination with the extensive anatomical, molecular and physiological knowledge about this part of the brain presents a unique opportunity for studying this intriguing visual circuit in detail. This article provides a brief overview of the history of research on retinal direction selectivity, but then focuses on the past decade and the progress achieved, in particular driven by methodological advances in optical recording techniques, molecular genetics approaches and large-scale ultrastructural reconstructions. As it turns out, retinal direction selectivity is a complex, multi-tiered computation, involving dendrite-intrinsic mechanisms as well as several types of network interactions on the basis of highly selective, likely genetically predetermined synaptic connectivity. Moreover, DS ganglion cell types appear to be more diverse than previously thought, differing not only in their preferred direction and response polarity, but also in physiology, DS mechanism, dendritic morphology and, importantly, the target area of their projections in the brain.
Collapse
|
11
|
Species-specific wiring for direction selectivity in the mammalian retina. Nature 2016; 535:105-10. [PMID: 27350241 PMCID: PMC4959608 DOI: 10.1038/nature18609] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 05/27/2016] [Indexed: 12/17/2022]
Abstract
Directionally tuned signaling in starburst amacrine cell (SAC) dendrites lies at the heart of the direction selective (DS) circuit in the mammalian retina. The relative contributions of intrinsic cellular properties and network connectivity to SAC DS remain unclear. We present a detailed connectomic reconstruction of SAC circuitry in mouse retina and describe previously unknown features of synapse distributions along SAC dendrites: 1) input and output synapses are segregated, with inputs restricted to proximal dendrites; 2) the distribution of inhibitory inputs is fundamentally different from that observed in rabbit retina. An anatomically constrained SAC network model suggests that SAC-SAC wiring differences between mouse and rabbit retina underlie distinct contributions of synaptic inhibition to velocity and contrast tuning and receptive field structure. In particular, the model indicates that mouse connectivity enables SACs to encode lower linear velocities that account for smaller eye diameter, thereby conserving angular velocity tuning. These predictions are confirmed with calcium imaging of mouse SAC dendrites in response to directional stimuli.
Collapse
|
12
|
|
13
|
Jones IL, Russell TL, Farrow K, Fiscella M, Franke F, Müller J, Jäckel D, Hierlemann A. A method for electrophysiological characterization of hamster retinal ganglion cells using a high-density CMOS microelectrode array. Front Neurosci 2015; 9:360. [PMID: 26528115 PMCID: PMC4602149 DOI: 10.3389/fnins.2015.00360] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 09/18/2015] [Indexed: 11/24/2022] Open
Abstract
Knowledge of neuronal cell types in the mammalian retina is important for the understanding of human retinal disease and the advancement of sight-restoring technology, such as retinal prosthetic devices. A somewhat less utilized animal model for retinal research is the hamster, which has a visual system that is characterized by an area centralis and a wide visual field with a broad binocular component. The hamster retina is optimally suited for recording on the microelectrode array (MEA), because it intrinsically lies flat on the MEA surface and yields robust, large-amplitude signals. However, information in the literature about hamster retinal ganglion cell functional types is scarce. The goal of our work is to develop a method featuring a high-density (HD) complementary metal-oxide-semiconductor (CMOS) MEA technology along with a sequence of standardized visual stimuli in order to categorize ganglion cells in isolated Syrian Hamster (Mesocricetus auratus) retina. Since the HD-MEA is capable of recording at a higher spatial resolution than most MEA systems (17.5 μm electrode pitch), we were able to record from a large proportion of RGCs within a selected region. Secondly, we chose our stimuli so that they could be run during the experiment without intervention or computation steps. The visual stimulus set was designed to activate the receptive fields of most ganglion cells in parallel and to incorporate various visual features to which different cell types respond uniquely. Based on the ganglion cell responses, basic cell properties were determined: direction selectivity, speed tuning, width tuning, transience, and latency. These properties were clustered to identify ganglion cell types in the hamster retina. Ultimately, we recorded up to a cell density of 2780 cells/mm2 at 2 mm (42°) from the optic nerve head. Using five parameters extracted from the responses to visual stimuli, we obtained seven ganglion cell types.
Collapse
Affiliation(s)
- Ian L Jones
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zurich Basel, Switzerland
| | - Thomas L Russell
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zurich Basel, Switzerland
| | - Karl Farrow
- Visual Circuits Laboratory, Neuroelectronics Research Flanders Leuven, Belgium ; NERF, Imec Leuven, Belgium ; Department of Biology, KU Leuven Leuven, Belgium
| | - Michele Fiscella
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zurich Basel, Switzerland
| | - Felix Franke
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zurich Basel, Switzerland
| | - Jan Müller
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zurich Basel, Switzerland
| | - David Jäckel
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zurich Basel, Switzerland
| | - Andreas Hierlemann
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zurich Basel, Switzerland
| |
Collapse
|
14
|
Lipin MY, Taylor WR, Smith RG. Inhibitory input to the direction-selective ganglion cell is saturated at low contrast. J Neurophysiol 2015; 114:927-41. [PMID: 26063782 DOI: 10.1152/jn.00413.2015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 06/09/2015] [Indexed: 01/10/2023] Open
Abstract
Direction-selective ganglion cells (DSGCs) respond selectively to motion toward a "preferred" direction, but much less to motion toward the opposite "null" direction. Directional signals in the DSGC depend on GABAergic inhibition and are observed over a wide range of speeds, which precludes motion detection based on a fixed temporal correlation. A voltage-clamp analysis, using narrow bar stimuli similar in width to the receptive field center, demonstrated that inhibition to DSGCs saturates rapidly above a threshold contrast. However, for wide bar stimuli that activate both the center and surround, inhibition depends more linearly on contrast. Excitation for both wide and narrow bars was also more linear. We propose that positive feedback, likely within the starburst amacrine cell or its network, produces steep saturation of inhibition at relatively low contrast. This mechanism renders GABA release essentially contrast and speed invariant, which enhances directional signals for small objects and thereby increases the signal-to-noise ratio for direction-selective signals in the spike train over a wide range of stimulus conditions. The steep saturation of inhibition confers to a neuron immunity to noise in its spike train, because when inhibition is strong no spikes are initiated.
Collapse
Affiliation(s)
- Mikhail Y Lipin
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - W Rowland Taylor
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon
| | - Robert G Smith
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania; and
| |
Collapse
|
15
|
Hoggarth A, McLaughlin AJ, Ronellenfitch K, Trenholm S, Vasandani R, Sethuramanujam S, Schwab D, Briggman KL, Awatramani GB. Specific wiring of distinct amacrine cells in the directionally selective retinal circuit permits independent coding of direction and size. Neuron 2015; 86:276-91. [PMID: 25801705 DOI: 10.1016/j.neuron.2015.02.035] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 11/13/2014] [Accepted: 02/11/2015] [Indexed: 01/24/2023]
Abstract
Local and global forms of inhibition controlling directionally selective ganglion cells (DSGCs) in the mammalian retina are well documented. It is established that local inhibition arising from GABAergic starburst amacrine cells (SACs) strongly contributes to direction selectivity. Here, we demonstrate that increasing ambient illumination leads to the recruitment of GABAergic wide-field amacrine cells (WACs) endowing the DS circuit with an additional feature: size selectivity. Using a combination of electrophysiology, pharmacology, and light/electron microscopy, we show that WACs predominantly contact presynaptic bipolar cells, which drive direct excitation and feedforward inhibition (through SACs) to DSGCs, thus maintaining the appropriate balance of inhibition/excitation required for generating DS. This circuit arrangement permits high-fidelity direction coding over a range of ambient light levels, over which size selectivity is adjusted. Together, these results provide novel insights into the anatomical and functional arrangement of multiple inhibitory interneurons within a single computational module in the retina.
Collapse
Affiliation(s)
- Alex Hoggarth
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | | | - Kara Ronellenfitch
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | - Stuart Trenholm
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | - Rishi Vasandani
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | | | - David Schwab
- Department of Physics & Astronomy, Northwestern University, 2145 Sheridan Road F165, Evanston, IL 60208, USA
| | - Kevin L Briggman
- Circuit Dynamics and Connectivity Unit, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gautam B Awatramani
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada.
| |
Collapse
|
16
|
Interacting linear and nonlinear characteristics produce population coding asymmetries between ON and OFF cells in the retina. J Neurosci 2013; 33:14958-73. [PMID: 24027295 DOI: 10.1523/jneurosci.1004-13.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The early visual system is a model for understanding the roles of cell populations in parallel processing. Cells in this system can be classified according to their responsiveness to different stimuli; a prominent example is the division between cells that respond to stimuli of opposite contrasts (ON vs OFF cells). These two cell classes display many asymmetries in their physiological characteristics (including temporal characteristics, spatial characteristics, and nonlinear characteristics) that, individually, are known to have important roles in population coding. Here we describe a novel distinction between the information that ON and OFF ganglion cell populations carry in mouse--that OFF cells are able to signal motion information about both light and dark objects, while ON cells have a selective deficit at signaling the motion of dark objects. We found that none of the previously reported asymmetries in physiological characteristics could account for this distinction. We therefore analyzed its basis via a recently developed linear-nonlinear-Poisson model that faithfully captures input/output relationships for a broad range of stimuli (Bomash et al., 2013). While the coding differences between ON and OFF cell populations could not be ascribed to the linear or nonlinear components of the model individually, they had a simple explanation in the way that these components interact. Sensory transformations in other systems can likewise be described by these models, and thus our findings suggest that similar interactions between component properties may help account for the roles of cell classes in population coding more generally.
Collapse
|
17
|
Abstract
Starburst amacrine cells (SBACs) within the adult mammalian retina provide the critical inhibition that underlies the receptive field properties of direction-selective ganglion cells (DSGCs). The SBACs generate direction-selective output of GABA that differentially inhibits the DSGCs. We review the biophysical mechanisms that produce directional GABA release from SBACs and test a network model that predicts the effects of reciprocal inhibition between adjacent SBACs. The results of the model simulations suggest that reciprocal inhibitory connections between closely spaced SBACs should be spatially selective, while connections between more widely spaced cells could be indiscriminate. SBACs were initially identified as cholinergic neurons and were subsequently shown to contain release both acetylcholine and GABA. While the role of the GABAergic transmission is well established, the role of the cholinergic transmission remains unclear.
Collapse
|
18
|
Auferkorte ON, Baden T, Kaushalya SK, Zabouri N, Rudolph U, Haverkamp S, Euler T. GABA(A) receptors containing the α2 subunit are critical for direction-selective inhibition in the retina. PLoS One 2012; 7:e35109. [PMID: 22506070 PMCID: PMC3323634 DOI: 10.1371/journal.pone.0035109] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 03/13/2012] [Indexed: 01/08/2023] Open
Abstract
Far from being a simple sensor, the retina actively participates in processing visual signals. One of the best understood aspects of this processing is the detection of motion direction. Direction-selective (DS) retinal circuits include several subtypes of ganglion cells (GCs) and inhibitory interneurons, such as starburst amacrine cells (SACs). Recent studies demonstrated a surprising complexity in the arrangement of synapses in the DS circuit, i.e. between SACs and DS ganglion cells. Thus, to fully understand retinal DS mechanisms, detailed knowledge of all synaptic elements involved, particularly the nature and localization of neurotransmitter receptors, is needed. Since inhibition from SACs onto DSGCs is crucial for generating retinal direction selectivity, we investigate here the nature of the GABA receptors mediating this interaction. We found that in the inner plexiform layer (IPL) of mouse and rabbit retina, GABA(A) receptor subunit α2 (GABA(A)R α2) aggregated in synaptic clusters along two bands overlapping the dendritic plexuses of both ON and OFF SACs. On distal dendrites of individually labeled SACs in rabbit, GABA(A)R α2 was aligned with the majority of varicosities, the cell's output structures, and found postsynaptically on DSGC dendrites, both in the ON and OFF portion of the IPL. In GABA(A)R α2 knock-out (KO) mice, light responses of retinal GCs recorded with two-photon calcium imaging revealed a significant impairment of DS responses compared to their wild-type littermates. We observed a dramatic drop in the proportion of cells exhibiting DS phenotype in both the ON and ON-OFF populations, which strongly supports our anatomical findings that α2-containing GABA(A)Rs are critical for mediating retinal DS inhibition. Our study reveals for the first time, to the best of our knowledge, the precise functional localization of a specific receptor subunit in the retinal DS circuit.
Collapse
|
19
|
Borst A, Euler T. Seeing Things in Motion: Models, Circuits, and Mechanisms. Neuron 2011; 71:974-94. [PMID: 21943597 DOI: 10.1016/j.neuron.2011.08.031] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2011] [Indexed: 12/31/2022]
|
20
|
Nowak P, Dobbins AC, Gawne TJ, Grzywacz NM, Amthor FR. Separability of stimulus parameter encoding by on-off directionally selective rabbit retinal ganglion cells. J Neurophysiol 2011; 105:2083-99. [PMID: 21325684 DOI: 10.1152/jn.00941.2010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ganglion cell output of the retina constitutes a bottleneck in sensory processing in that ganglion cells must encode multiple stimulus parameters in their responses. Here we investigate encoding strategies of On-Off directionally selective retinal ganglion cells (On-Off DS RGCs) in rabbits, a class of cells dedicated to representing motion. The exquisite axial discrimination of these cells to preferred vs. null direction motion is well documented: it is invariant with respect to speed, contrast, spatial configuration, spatial frequency, and motion extent. However, these cells have broad direction tuning curves and their responses also vary as a function of other parameters such as speed and contrast. In this study, we examined whether the variation in responses across multiple stimulus parameters is systematic, that is the same for all cells, and separable, such that the response to a stimulus is a product of the effects of each stimulus parameter alone. We extracellularly recorded single On-Off DS RGCs in a superfused eyecup preparation while stimulating them with moving bars. We found that spike count responses of these cells scaled as independent functions of direction, speed, and luminance. Moreover, the speed and luminance functions were common across the whole sample of cells. Based on these findings, we developed a model that accurately predicted responses of On-Off DS RGCs as products of separable functions of direction, speed, and luminance (r = 0.98; P < 0.0001). Such a multiplicatively separable encoding strategy may simplify the decoding of these cells' outputs by the higher visual centers.
Collapse
Affiliation(s)
- Przemyslaw Nowak
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, AL 35294-1170, USA
| | | | | | | | | |
Collapse
|
21
|
Properties of stimulus-dependent synchrony in retinal ganglion cells. Vis Neurosci 2008; 24:827-43. [PMID: 18093370 DOI: 10.1017/s0952523807070757] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Accepted: 10/01/2007] [Indexed: 11/06/2022]
Abstract
Neighboring retinal ganglion cells often spike synchronously, but the possible function and mechanism of this synchrony is unclear. Recently, the strength of the fast correlation between ON-OFF directionally selective cells of the rabbit retina was shown to be stimulus dependent. Here, we extend that study, investigating stimulus-dependent correlation among multiple ganglion-cell classes, using multi-electrode recordings. Our results generalized those for directionally selective cells. All cell pairs exhibiting significant spike synchrony did it for an extended edge but rarely for full-field stimuli. The strength of this synchrony did not depend on the amplitude of the response and correlations could be present even when the cells' receptive fields did not overlap. In addition, correlations tended to be orientation selective in a manner predictable by the relative positions of the receptive fields. Finally, extended edges and full-field stimuli produced significantly greater and smaller correlations than predicted by chance respectively. We propose an amacrine-network model for the enhancement and depression of correlation. Such an apparently purposeful control of correlation adds evidence for retinal synchrony playing a functional role in vision.
Collapse
|