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Tring E, Dipoppa M, Ringach DL. A power law describes the magnitude of adaptation in neural populations of primary visual cortex. Nat Commun 2023; 14:8366. [PMID: 38102113 PMCID: PMC10724159 DOI: 10.1038/s41467-023-43572-w] [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: 06/08/2023] [Accepted: 11/14/2023] [Indexed: 12/17/2023] Open
Abstract
How do neural populations adapt to the time-varying statistics of sensory input? We used two-photon imaging to measure the activity of neurons in mouse primary visual cortex adapted to different sensory environments, each defined by a distinct probability distribution over a stimulus set. We find that two properties of adaptation capture how the population response to a given stimulus, viewed as a vector, changes across environments. First, the ratio between the response magnitudes is a power law of the ratio between the stimulus probabilities. Second, the response direction to a stimulus is largely invariant. These rules could be used to predict how cortical populations adapt to novel, sensory environments. Finally, we show how the power law enables the cortex to preferentially signal unexpected stimuli and to adjust the metabolic cost of its sensory representation to the entropy of the environment.
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Affiliation(s)
- Elaine Tring
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Mario Dipoppa
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Dario L Ringach
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
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2
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Tring E, Dipoppa M, Ringach DL. A power law of cortical adaptation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541834. [PMID: 37292876 PMCID: PMC10245856 DOI: 10.1101/2023.05.22.541834] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
How do neural populations adapt to the time-varying statistics of sensory input? To investigate, we measured the activity of neurons in primary visual cortex adapted to different environments, each associated with a distinct probability distribution over a stimulus set. Within each environment, a stimulus sequence was generated by independently sampling form its distribution. We find that two properties of adaptation capture how the population responses to a given stimulus, viewed as vectors, are linked across environments. First, the ratio between the response magnitudes is a power law of the ratio between the stimulus probabilities. Second, the response directions are largely invariant. These rules can be used to predict how cortical populations adapt to novel, sensory environments. Finally, we show how the power law enables the cortex to preferentially signal unexpected stimuli and to adjust the metabolic cost of its sensory representation to the entropy of the environment.
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Affiliation(s)
- Elaine Tring
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles
| | - Mario Dipoppa
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles
| | - Dario L Ringach
- Department of Psychology, David Geffen School of Medicine, University of California, Los Angeles
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles
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3
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Fruend I. Constrained sampling from deep generative image models reveals mechanisms of human target detection. J Vis 2020; 20:32. [PMID: 32729908 PMCID: PMC7424951 DOI: 10.1167/jov.20.7.32] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The first steps of visual processing are often described as a bank of oriented filters followed by divisive normalization. This approach has been tremendously successful at predicting contrast thresholds in simple visual displays. However, it is unclear to what extent this kind of architecture also supports processing in more complex visual tasks performed in naturally looking images. We used a deep generative image model to embed arc segments with different curvatures in naturalistic images. These images contain the target as part of the image scene, resulting in considerable appearance variation of target as well as background. Three observers localized arc targets in these images, with an average accuracy of 74.7%. Data were fit by several biologically inspired models, four standard deep convolutional neural networks (CNNs), and a five-layer CNN specifically trained for this task. Four models predicted observer responses particularly well; (1) a bank of oriented filters, similar to complex cells in primate area V1; (2) a bank of oriented filters followed by tuned gain control, incorporating knowledge about cortical surround interactions; (3) a bank of oriented filters followed by local normalization; and (4) the five-layer CNN. A control experiment with optimized stimuli based on these four models showed that the observers' data were best explained by model (2) with tuned gain control. These data suggest that standard models of early vision provide good descriptions of performance in much more complex tasks than what they were designed for, while general-purpose non linear models such as convolutional neural networks do not.
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Affiliation(s)
- Ingo Fruend
- Department of Psychology, Centre for Vision Research & Vision: Science to Application, York University, Toronto, ON, Canada
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4
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Neurophysiological basis of contrast dependent BOLD orientation tuning. Neuroimage 2020; 206:116323. [PMID: 31678228 DOI: 10.1016/j.neuroimage.2019.116323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 10/03/2019] [Accepted: 10/29/2019] [Indexed: 11/22/2022] Open
Abstract
Recent work in early visual cortex of humans has shown that the BOLD signal exhibits contrast dependent orientation tuning, with an inverse oblique effect (oblique > cardinal) at high contrast and a horizontal effect (vertical > horizontal) at low contrast. This finding is at odds with decades of neurophysiological research demonstrating contrast invariant orientation tuning in primate visual cortex, yet the source of this discrepancy is unclear. We hypothesized that contrast dependent BOLD orientation tuning may arise due to contrast dependent influences of feedforward (FF) and feedback (FB) synaptic activity, indexed through gamma and alpha rhythms, respectively. To quantify this, we acquired EEG and BOLD in healthy humans to generate and compare orientation tuning curves across all neural frequency bands with BOLD. As expected, BOLD orientation selectivity in V1 was contrast dependent, preferring oblique orientations at high contrast and vertical at low contrast. On the other hand, EEG orientation tuning was contrast invariant, though frequency-specific, with an inverse-oblique effect in the gamma band (FF) and a horizontal effect in the alpha band (FB). Therefore, high-contrast BOLD orientation tuning closely matched FF activity, while at low contrast, BOLD best resembled FB orientation tuning. These results suggest that contrast dependent BOLD orientation tuning arises due to the reduced contribution of FF input to overall neurophysiological activity at low contrast, shifting BOLD orientation tuning towards the orientation preferences of FB at low contrast.
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5
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Fortier PA. Comparison of mechanisms for contrast-invariance of orientation selectivity in simple cells. Neuroscience 2017; 348:41-62. [PMID: 28189612 DOI: 10.1016/j.neuroscience.2017.01.052] [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: 09/16/2016] [Revised: 01/29/2017] [Accepted: 01/31/2017] [Indexed: 11/26/2022]
Abstract
The simple cells of the visual cortex respond over a narrow range of stimulus orientations, and this tuning is invariant to the contrast at which the stimulus is presented. The inputs to a single cell derive from a population of thalamic cells that provide a bell-shaped tuning width and offset that increases with stimulus contrast. Synaptic depression, noise and inhibition have been proposed as feedforward mechanisms to explain why these increases do not appear in simple cells. The extent to which these three mechanisms contribute to contrast-invariant orientation tuning is unknown. Consequently, the aim was to test the hypothesis that these mechanisms do not contribute equally. Unlike previous studies, all mechanisms were examined using the same network model based on Banitt et al. (2007). The results showed that thalamocortical synaptic noise was essential and sufficient to widen tuning widths at low contrasts to that of higher contrasts but could not counteract the offset at higher contrasts. Thalamocortical synaptic depression could only be used to counteract a small fraction of the offset otherwise the relationship between contrast and response rate was disrupted. Only broadly tuned simple and complex cell inhibition could counteract the remaining offset for all stimulus contrasts but complex cell inhibition reduced the gain of the response. These results suggest unequal contributions of these feedforward mechanisms with thalamic synaptic noise widening tuning widths for low contrasts, synaptic depression counteracting a small component of the offset and synaptic inhibition completely removing the remaining offset to produce contrast-invariant orientation tuning.
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Affiliation(s)
- Pierre A Fortier
- Dept. Cell. Mol. Medicine, Univ. Ottawa, Ottawa K1H 8M5, Canada.
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6
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Ghodrati M, Alwis DS, Price NSC. Orientation selectivity in rat primary visual cortex emerges earlier with low-contrast and high-luminance stimuli. Eur J Neurosci 2016; 44:2759-2773. [PMID: 27563930 DOI: 10.1111/ejn.13379] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 08/20/2016] [Accepted: 08/20/2016] [Indexed: 11/25/2022]
Abstract
In natural vision, rapid and sustained variations in luminance and contrast change the reliability of information available about a visual scene, and markedly affect both neuronal and behavioural responses. The hallmark property of neurons in primary visual cortex (V1), orientation selectivity, is unaffected by changes in stimulus contrast, but it remains unclear how sustained differences in mean luminance and contrast affect the time-course of orientation selectivity, and the amount of information that neurons carry about orientation. We used reverse correlation with characterize the temporal dynamics of orientation selectivity in rat V1 neurons under four luminance-contrast conditions. We show that orientation selectivity and mutual information between neuronal responses and stimulus orientation are invariant to contrast or mean luminance. Critically, the time-course of the emergence of orientation selectivity was affected by both factors; response latencies were longer for low- than high-luminance gratings, and surprisingly, response latencies were also longer for high- than low-contrast gratings. Modelling suggests that luminance-modulated changes in feedforward gain, in combination with hyperpolarization caused by high contrasts can account for our physiological data. The hyperpolarization at high contrasts may increase signal-to-noise ratios, whereas a more depolarized membrane may lead to greater sensitivity to weak stimuli.
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Affiliation(s)
- Masoud Ghodrati
- Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Vic., 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, Vic., Australia
| | - Dasuni S Alwis
- Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Vic., 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, Vic., Australia
| | - Nicholas S C Price
- Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Vic., 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, Vic., Australia.,ARC Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, Vic., Australia
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7
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Seidemann E, Chen Y, Bai Y, Chen SC, Mehta P, Kajs BL, Geisler WS, Zemelman BV. Calcium imaging with genetically encoded indicators in behaving primates. eLife 2016; 5. [PMID: 27441501 PMCID: PMC4956408 DOI: 10.7554/elife.16178] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/16/2016] [Indexed: 11/30/2022] Open
Abstract
Understanding the neural basis of behaviour requires studying brain activity in behaving subjects using complementary techniques that measure neural responses at multiple spatial scales, and developing computational tools for understanding the mapping between these measurements. Here we report the first results of widefield imaging of genetically encoded calcium indicator (GCaMP6f) signals from V1 of behaving macaques. This technique provides a robust readout of visual population responses at the columnar scale over multiple mm2 and over several months. To determine the quantitative relation between the widefield GCaMP signals and the locally pooled spiking activity, we developed a computational model that sums the responses of V1 neurons characterized by prior single unit measurements. The measured tuning properties of the GCaMP signals to stimulus contrast, orientation and spatial position closely match the predictions of the model, suggesting that widefield GCaMP signals are linearly related to the summed local spiking activity. DOI:http://dx.doi.org/10.7554/eLife.16178.001 An important question in brain research is how neurons and the circuits they form process information to produce behavior. To understand what happens in a human brain, it is necessary to study a brain of similar complexity, such as that of a primate. Examining how the neurons in a brain region called the visual cortex process information about what we see is especially informative. This is because animals can be taught to perform different visual tasks, and because the visual cortex is relatively easy to access. In principle, therefore, it should be possible to use modern genetic and imaging techniques to study the primate visual system, but, until now, that has not been the case. Like much of the brain, the visual cortex consists of different classes of neurons that can excite, inhibit or modulate the activity of neighboring neurons. One way to study how these different classes of neurons interact with each other is to alter the animal’s DNA, such that only one cell type stands out during the experiment, allowing its role in the brain to be closely monitored. This technique has been used to study the interactions among neurons in the rodent brain, because rodent DNA is easy to alter. However, it is not easy to manipulate primate DNA. Seidemann et al. have, therefore, developed a new technique that can target a specific class of neurons, allowing the activity of just these cells to be distinguished from the rest. The method uses specially designed harmless viruses to produce foreign proteins in the excitatory neurons of the visual cortex in an adult macaque. The optical properties of the proteins change when the neuron they are in is active, allowing the activity of the excitatory neurons to be detected and tracked in awake animals while they perform a visual task. Previously, the activity of neurons in the primate visual cortex could only be measured using dyes that indiscriminately reported the activity of all the neurons present. Seidemann et al. found that, in addition to being more selective than the dye-based method, the new technique also more accurately depicted neuronal action potentials, which are the primary units of information in the brain. Seidemann et al. now plan to use a similar method to study the activity of the inhibitory neurons of the primate visual cortex. Further examination of both excitatory and inhibitory neurons at much higher magnification, using a different microscopy technique, will also reveal more subtle features of their responses during visual tasks. DOI:http://dx.doi.org/10.7554/eLife.16178.002
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Affiliation(s)
- Eyal Seidemann
- Center for Perceptual Systems, University of Texas, Austin, United States.,Department of Psychology, University of Texas, Austin, United States.,Department of Neuroscience, University of Texas, Austin, United States
| | - Yuzhi Chen
- Center for Perceptual Systems, University of Texas, Austin, United States.,Department of Psychology, University of Texas, Austin, United States.,Department of Neuroscience, University of Texas, Austin, United States
| | - Yoon Bai
- Center for Perceptual Systems, University of Texas, Austin, United States.,Department of Psychology, University of Texas, Austin, United States.,Department of Neuroscience, University of Texas, Austin, United States
| | - Spencer C Chen
- Center for Perceptual Systems, University of Texas, Austin, United States.,Department of Psychology, University of Texas, Austin, United States.,Department of Neuroscience, University of Texas, Austin, United States
| | - Preeti Mehta
- Department of Neuroscience, University of Texas, Austin, United States.,Center for Learning and Memory, University of Texas, Austin, United States
| | - Bridget L Kajs
- Department of Neuroscience, University of Texas, Austin, United States.,Center for Learning and Memory, University of Texas, Austin, United States
| | - Wilson S Geisler
- Center for Perceptual Systems, University of Texas, Austin, United States.,Department of Psychology, University of Texas, Austin, United States
| | - Boris V Zemelman
- Department of Neuroscience, University of Texas, Austin, United States.,Center for Learning and Memory, University of Texas, Austin, United States
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8
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Hietanen MA, Cloherty SL, Ibbotson MR. Contrast and response gain control depend on cortical map architecture. Eur J Neurosci 2015; 42:2963-73. [PMID: 26432621 DOI: 10.1111/ejn.13091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 09/23/2015] [Accepted: 09/28/2015] [Indexed: 11/29/2022]
Abstract
Visual cortical neurons are sensitive to visual stimulus contrast and most cells adapt their sensitivity to the prevailing visual environment. Specifically, they match the steepest region of their contrast response function to the prevailing contrast (contrast gain control), and reduce spike rates to limit saturation (response gain control). Most neurons are also tuned for stimulus orientation, and neurons with similar orientation preference are clustered together into iso-orientation zones arranged around pinwheels, i.e. points where all orientations are represented. Here we investigated the relationship between the contrast adaptation properties of neurons and their location relative to pinwheels in the orientation preference map. We measured orientation preference maps in cat cortex using optical intrinsic signal imaging. We then characterized the contrast adaptation properties of single neurons located close to pinwheels, in iso-orientation zones, and at regions in between. We found little evidence of differential contrast sensitivity of neurons adapted to zero contrast. However, after adaptation to their preferred orientation at high contrast, changes in both contrast and response gain were greater for neurons near pinwheels compared with other map regions. Therefore, in the adapted state, which is probably typical during natural viewing, there is a spatial map of contrast sensitivity that is associated with the orientation preference map. This differential adaptation revealed a new dimension of cortical functional organization, linking the contrast adaptation of cells with the orientation preference of their nearest neighbours.
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Affiliation(s)
- Markus A Hietanen
- National Vision Research Institute, Australian College of Optometry, Cnr Cardigan and Keppel Street, Carlton, Vic., 3053, Australia.,ARC Centre of Excellence for Integrative Brain Function and Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Vic., Australia
| | - Shaun L Cloherty
- National Vision Research Institute, Australian College of Optometry, Cnr Cardigan and Keppel Street, Carlton, Vic., 3053, Australia.,ARC Centre of Excellence for Integrative Brain Function and Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Vic., Australia.,Department of Electrical and Electronic Engineering, University of Melbourne, Parkville, Vic., Australia
| | - Michael R Ibbotson
- National Vision Research Institute, Australian College of Optometry, Cnr Cardigan and Keppel Street, Carlton, Vic., 3053, Australia.,ARC Centre of Excellence for Integrative Brain Function and Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Vic., Australia
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9
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Liu YJ, Hashemi-Nezhad M, Lyon DC. Contrast invariance of orientation tuning in cat primary visual cortex neurons depends on stimulus size. J Physiol 2015; 593:4485-98. [PMID: 26227285 DOI: 10.1113/jp271180] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 07/27/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The process of orientation tuning is an important and well-characterized feature of neurons in primary visual cortex. The combination of ascending and descending circuits involved is not only relevant to understanding visual processing but the function of neocortex in general. The classic feed-forward model of orientation tuning predicts a broadening effect due to increasing contrast; yet, experimental results consistently report contrast invariance. We show here that contrast invariance actually depends on stimulus size such that large stimuli extending beyond the neuron's receptive field engage circuits that promote invariance, whereas optimally sized, smaller stimuli result in contrast variance that is more in line with the classical orientation tuning model. These results illustrate the importance of optimizing stimulus parameters to best reflect the sensory pathways under study and provide new clues about different circuits that may be involved in variant and invariant response properties. ABSTRACT Selective response to stimulus orientation is a key feature of neurons in primary visual cortex, yet the underlying mechanisms generating orientation tuning are not fully understood. The combination of feed-forward and cortical mechanisms involved is not only relevant to understanding visual processing but the function of neocortex in general. The classic feed-forward model predicts that orientation tuning should broaden considerably with increasing contrast; however, experimental results consistently report contrast invariance. We show here, in primary visual cortex of anaesthetized cats under neuromuscular blockade, that contrast invariance occurs when visual stimuli are large enough to include the extraclassical surround (ECS), which is likely to involve circuits of suppression that may not be entirely feed-forward in origin. On the other hand, when stimulus size is optimized to the classical receptive field of each neuron, the population average shows a statistically significant 40% increase in tuning width at high contrast, demonstrating that contrast variance of orientation tuning can occur. Conversely, our results also suggest that the phenomenon of contrast invariance relies in part on the presence of the ECS. Moreover, these results illustrate the importance of optimizing stimulus parameters to best reflect the neural pathways under study.
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Affiliation(s)
- Yong-Jun Liu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, 364 Med Surge II, Irvine, CA, 92697, USA
| | - Maziar Hashemi-Nezhad
- Department of Anatomy and Neurobiology, School of Medicine, University of California, 364 Med Surge II, Irvine, CA, 92697, USA
| | - David C Lyon
- Department of Anatomy and Neurobiology, School of Medicine, University of California, 364 Med Surge II, Irvine, CA, 92697, USA
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10
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Mitchell JF, Leopold DA. The marmoset monkey as a model for visual neuroscience. Neurosci Res 2015; 93:20-46. [PMID: 25683292 PMCID: PMC4408257 DOI: 10.1016/j.neures.2015.01.008] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 01/16/2015] [Accepted: 01/16/2015] [Indexed: 11/26/2022]
Abstract
The common marmoset (Callithrix jacchus) has been valuable as a primate model in biomedical research. Interest in this species has grown recently, in part due to the successful demonstration of transgenic marmosets. Here we examine the prospects of the marmoset model for visual neuroscience research, adopting a comparative framework to place the marmoset within a broader evolutionary context. The marmoset's small brain bears most of the organizational features of other primates, and its smooth surface offers practical advantages over the macaque for areal mapping, laminar electrode penetration, and two-photon and optical imaging. Behaviorally, marmosets are more limited at performing regimented psychophysical tasks, but do readily accept the head restraint that is necessary for accurate eye tracking and neurophysiology, and can perform simple discriminations. Their natural gaze behavior closely resembles that of other primates, with a tendency to focus on objects of social interest including faces. Their immaturity at birth and routine twinning also makes them ideal for the study of postnatal visual development. These experimental factors, together with the theoretical advantages inherent in comparing anatomy, physiology, and behavior across related species, make the marmoset an excellent model for visual neuroscience.
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Affiliation(s)
- Jude F Mitchell
- Brain and Cognitive Sciences Department, Meliora Hall, University of Rochester, Rochester, NY 14627, USA.
| | - David A Leopold
- Section on Cognitive Neurophysiology and Imaging, Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA; Neurophysiology Imaging Facility, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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11
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Solomon SG, Rosa MGP. A simpler primate brain: the visual system of the marmoset monkey. Front Neural Circuits 2014; 8:96. [PMID: 25152716 PMCID: PMC4126041 DOI: 10.3389/fncir.2014.00096] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 07/22/2014] [Indexed: 12/15/2022] Open
Abstract
Humans are diurnal primates with high visual acuity at the center of gaze. Although primates share many similarities in the organization of their visual centers with other mammals, and even other species of vertebrates, their visual pathways also show unique features, particularly with respect to the organization of the cerebral cortex. Therefore, in order to understand some aspects of human visual function, we need to study non-human primate brains. Which species is the most appropriate model? Macaque monkeys, the most widely used non-human primates, are not an optimal choice in many practical respects. For example, much of the macaque cerebral cortex is buried within sulci, and is therefore inaccessible to many imaging techniques, and the postnatal development and lifespan of macaques are prohibitively long for many studies of brain maturation, plasticity, and aging. In these and several other respects the marmoset, a small New World monkey, represents a more appropriate choice. Here we review the visual pathways of the marmoset, highlighting recent work that brings these advantages into focus, and identify where additional work needs to be done to link marmoset brain organization to that of macaques and humans. We will argue that the marmoset monkey provides a good subject for studies of a complex visual system, which will likely allow an important bridge linking experiments in animal models to humans.
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Affiliation(s)
- Samuel G Solomon
- Department of Experimental Psychology, University College London London, UK
| | - Marcello G P Rosa
- Department of Physiology, Monash University, Clayton, VIC Australia ; Monash Vision Group, Monash University, Clayton, VIC Australia ; Australian Research Council Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC Australia
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12
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Uniformity and diversity of response properties of neurons in the primary visual cortex: selectivity for orientation, direction of motion, and stimulus size from center to far periphery. Vis Neurosci 2013; 31:85-98. [PMID: 24160942 DOI: 10.1017/s0952523813000448] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although the primary visual cortex (V1) is one of the most extensively studied areas of the primate brain, very little is known about how the far periphery of visual space is represented in this area. We characterized the physiological response properties of V1 neurons in anaesthetized marmoset monkeys, using high-contrast drifting gratings. Comparisons were made between cells with receptive fields located in three regions of V1, defined by eccentricity: central (3-5°), near peripheral (5-15°), and far peripheral (>50°). We found that orientation selectivity of individual cells was similar from the center to the far periphery. Nonetheless, the proportion of orientation-selective neurons was higher in central visual field representation than in the peripheral representations. In addition, there were similar proportions of cells representing all orientations, with the exception of the representation of the far periphery, where we detected a bias favoring near-horizontal orientations. The proportions of direction-selective cells were similar throughout V1. When the center/surround organization of the receptive fields was tested with gratings with varying diameters, we found that the population of neurons that was suppressed by large gratings was smaller in the far periphery, although the strength of suppression in these cells tended to be stronger. In addition, the ratio between the diameters of the excitatory centers and suppressive surrounds was similar across the entire visual field. These results suggest that, superimposed on the broad uniformity of V1, there are subtle physiological differences, which indicate that spatial information is processed differently in the central versus far peripheral visual fields.
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13
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Mejias JF, Marsat G, Bol K, Maler L, Longtin A. Learning contrast-invariant cancellation of redundant signals in neural systems. PLoS Comput Biol 2013; 9:e1003180. [PMID: 24068898 PMCID: PMC3772051 DOI: 10.1371/journal.pcbi.1003180] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 07/01/2013] [Indexed: 11/18/2022] Open
Abstract
Cancellation of redundant information is a highly desirable feature of sensory systems, since it would potentially lead to a more efficient detection of novel information. However, biologically plausible mechanisms responsible for such selective cancellation, and especially those robust to realistic variations in the intensity of the redundant signals, are mostly unknown. In this work, we study, via in vivo experimental recordings and computational models, the behavior of a cerebellar-like circuit in the weakly electric fish which is known to perform cancellation of redundant stimuli. We experimentally observe contrast invariance in the cancellation of spatially and temporally redundant stimuli in such a system. Our model, which incorporates heterogeneously-delayed feedback, bursting dynamics and burst-induced STDP, is in agreement with our in vivo observations. In addition, the model gives insight on the activity of granule cells and parallel fibers involved in the feedback pathway, and provides a strong prediction on the parallel fiber potentiation time scale. Finally, our model predicts the existence of an optimal learning contrast around 15% contrast levels, which are commonly experienced by interacting fish.
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Affiliation(s)
- Jorge F. Mejias
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
| | - Gary Marsat
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Department of Biology, University of West Virginia, Morgantown, West Virginia, United States of America
| | - Kieran Bol
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada
| | - Leonard Maler
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Centre for Neural Dynamics, University of Ottawa, Ottawa, Ontario, Canada
| | - André Longtin
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada
- Centre for Neural Dynamics, University of Ottawa, Ottawa, Ontario, Canada
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14
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Durand JB, Girard P, Barone P, Bullier J, Nowak LG. Effects of contrast and contrast adaptation on static receptive field features in macaque area V1. J Neurophysiol 2012; 108:2033-50. [DOI: 10.1152/jn.00936.2011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The spatiotemporal features of the “static” receptive field (RF), as revealed with flashing bars or spots, determine other RF properties. We examined how some of these static RF features vary with contrast and contrast adaptation in area V1 of the anesthetized macaque monkey. RFs were mapped with light and dark flashing bars presented at three different contrasts, with the low and medium contrasts eliciting approximately 1/3 and 2/3 of the high-contrast response amplitude. The main results are as follows: 1) RF widths decreased when contrast decreased; however, the amount of decrease was less than that expected from an iceberg model and closer to the expectation of a contrast invariance of the RF width. 2) Area tuning experiments with drifting gratings showed an opposite effect of contrast: an increase in preferred stimulus diameter when contrast decreased. This implies that the effect of contrast on preferred stimulus size is not predictable from the static RF. 3) Contrast adaptation attenuated the effect of contrast on RF amplitude but did not significantly modify RF width. 4) RF subregion overlap was only marginally affected by changes in contrast and contrast adaptation; the classification of cells as simple and complex, when established from subregion overlap, appears to be robust with respect to changes in contrast and adaptation state. Previous studies have shown that the spatiotemporal features of the RF depend largely on the stimuli used to map the RF. This study shows that contrast is one elemental feature that contributes to the dynamics of the RF.
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Affiliation(s)
- Jean-Baptiste Durand
- Centre de Recherche Cerveau et Cognition, Université Toulouse 3-CNRS, Toulouse, France
| | - Pascal Girard
- Centre de Recherche Cerveau et Cognition, Université Toulouse 3-CNRS, Toulouse, France
| | - Pascal Barone
- Centre de Recherche Cerveau et Cognition, Université Toulouse 3-CNRS, Toulouse, France
| | - Jean Bullier
- Centre de Recherche Cerveau et Cognition, Université Toulouse 3-CNRS, Toulouse, France
| | - Lionel G. Nowak
- Centre de Recherche Cerveau et Cognition, Université Toulouse 3-CNRS, Toulouse, France
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15
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Sadagopan S, Ferster D. Feedforward origins of response variability underlying contrast invariant orientation tuning in cat visual cortex. Neuron 2012; 74:911-23. [PMID: 22681694 DOI: 10.1016/j.neuron.2012.05.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2012] [Indexed: 11/15/2022]
Abstract
Contrast invariant orientation tuning in simple cells of the visual cortex depends critically on contrast dependent trial-to-trial variability in their membrane potential responses. This observation raises the question of whether this variability originates from within the cortical circuit or the feedforward inputs from the lateral geniculate nucleus (LGN). To distinguish between these two sources of variability, we first measured membrane potential responses while inactivating the surrounding cortex, and found that response variability was nearly unaffected. We then studied variability in the LGN, including contrast dependence, and the trial-to-trial correlation in responses between nearby neurons. Variability decreased significantly with contrast, whereas correlation changed little. When these experimentally measured parameters of variability were applied to a feedforward model of simple cells that included realistic mechanisms of synaptic integration, contrast-dependent, orientation independent variability emerged in the membrane potential responses. Analogous mechanisms might contribute to the stimulus dependence and propagation of variability throughout the neocortex.
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Affiliation(s)
- Srivatsun Sadagopan
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
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16
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Hansel D, van Vreeswijk C. The mechanism of orientation selectivity in primary visual cortex without a functional map. J Neurosci 2012; 32:4049-64. [PMID: 22442071 PMCID: PMC6621225 DOI: 10.1523/jneurosci.6284-11.2012] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Accepted: 01/16/2012] [Indexed: 11/21/2022] Open
Abstract
Neurons in primary visual cortex (V1) display substantial orientation selectivity even in species where V1 lacks an orientation map, such as in mice and rats. The mechanism underlying orientation selectivity in V1 with such a salt-and-pepper organization is unknown; it is unclear whether a connectivity that depends on feature similarity is required, or a random connectivity suffices. Here we argue for the latter. We study the response to a drifting grating of a network model of layer 2/3 with random recurrent connectivity and feedforward input from layer 4 neurons with random preferred orientations. We show that even though the total feedforward and total recurrent excitatory and inhibitory inputs all have a very weak orientation selectivity, strong selectivity emerges in the neuronal spike responses if the network operates in the balanced excitation/inhibition regime. This is because in this regime the (large) untuned components in the excitatory and inhibitory contributions approximately cancel. As a result the untuned part of the input into a neuron as well as its modulation with orientation and time all have a size comparable to the neuronal threshold. However, the tuning of the F0 and F1 components of the input are uncorrelated and the high-frequency fluctuations are not tuned. This is reflected in the subthreshold voltage response. Remarkably, due to the nonlinear voltage-firing rate transfer function, the preferred orientation of the F0 and F1 components of the spike response are highly correlated.
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Affiliation(s)
- David Hansel
- Institute of Neuroscience and Cognition, University Paris Descartes, Paris, France.
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17
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Nauhaus I, Nielsen KJ, Callaway EM. Nonlinearity of two-photon Ca2+ imaging yields distorted measurements of tuning for V1 neuronal populations. J Neurophysiol 2011; 107:923-36. [PMID: 22114159 DOI: 10.1152/jn.00725.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We studied the relative accuracy of drifting gratings and noise stimuli for functionally characterizing neural populations using two-photon calcium imaging. Calcium imaging has the potential to distort measurements due to nonlinearity in the conversion from spikes to observed fluorescence. We demonstrate a dramatic impact of fluorescence saturation on functional measurements in ferret V1 by showing that responses to drifting gratings strongly violate contrast invariance of orientation tuning, a fundamental property of the spike rates. The observed relationship is consistent with saturation that clips the high-contrast tuning curve peaks by ∼40%. The nonlinearity was also apparent in mouse V1 responses to drifting gratings, but not as strong as in the ferret. Contrast invariance holds, however, for tuning curves measured with a randomized grating stimulus. This finding is consistent with prior work showing that the linear portion of a linear-nonlinear system can be recovered with reverse correlation. Furthermore, we demonstrate that a noise stimulus is more effective at keeping spike rates in the linear operating regime of a saturating nonlinearity, which both maximizes signal-to-noise ratios and simplifies the recovery of fast spike dynamics from slow calcium transients. Finally, we uncover spatiotemporal receptive fields by removing the nonlinearity and slow calcium transient from a model of fluorescence generation, which allowed us to observe dynamic sharpening of orientation tuning. We conclude that for two-photon recordings it is imperative that one considers the nonlinear distortion when designing stimuli and interpreting results, especially in sensory areas, species, or cell types with high firing rates.
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Affiliation(s)
- Ian Nauhaus
- Systems Neurobiology Laboratories, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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18
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Persi E, Hansel D, Nowak L, Barone P, van Vreeswijk C. Power-law input-output transfer functions explain the contrast-response and tuning properties of neurons in visual cortex. PLoS Comput Biol 2011; 7:e1001078. [PMID: 21390280 PMCID: PMC3044767 DOI: 10.1371/journal.pcbi.1001078] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Accepted: 01/11/2011] [Indexed: 12/01/2022] Open
Abstract
We develop a unified model accounting simultaneously for the contrast invariance of the width of the orientation tuning curves (OT) and for the sigmoidal shape of the contrast response function (CRF) of neurons in the primary visual cortex (V1). We determine analytically the conditions for the structure of the afferent LGN and recurrent V1 inputs that lead to these properties for a hypercolumn composed of rate based neurons with a power-law transfer function. We investigate what are the relative contributions of single neuron and network properties in shaping the OT and the CRF. We test these results with numerical simulations of a network of conductance-based model (CBM) neurons and we demonstrate that they are valid and more robust here than in the rate model. The results indicate that because of the acceleration in the transfer function, described here by a power-law, the orientation tuning curves of V1 neurons are more tuned, and their CRF is steeper than those of their inputs. Last, we show that it is possible to account for the diversity in the measured CRFs by introducing heterogeneities either in single neuron properties or in the input to the neurons. We show how correlations among the parameters that characterize the CRF depend on these sources of heterogeneities. Comparison with experimental data suggests that both sources contribute nearly equally to the diversity of CRF shapes observed in V1 neurons. Both the response and membrane potential of neurons in the primary visual cortex (V1) are selective to the orientation of elongated stimuli. The widths of the tuning curves, which characterize this selectivity, hardly depend on stimulus contrast whereas their amplitude does. The contrast dependence of this amplitude, the contrast response function (CRF), has a sigmoidal shape. Saturation of the spike response is substantially lower than the neurons' maximal firing rate. These well established facts constrain the possible mechanisms for orientation selectivity in V1. Furthermore, the single neuron CRFs in V1 display a broad diversity in their shape. This adds other constraints. Many theoretical works have tried to elaborate mechanisms of orientation selectivity that are compatible with the contrast invariant tuning widths. However, these mechanisms are usually incompatible with sigmoidal CRFs. We propose a mechanism which accounts simultaneously for contrast invariant tuning width for both rate and voltage response and for the shape and diversity of the CRFs. This mechanism relies on the interplay between power-law frequency-current transfer functions of single neurons, as measured in vivo in cortex, and on the recurrent interactions in the cortical circuit.
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Affiliation(s)
- Erez Persi
- Laboratoire de Neurophysique et Physiologie, Université Paris Descartes, Paris, France
| | - David Hansel
- Laboratoire de Neurophysique et Physiologie, Université Paris Descartes, Paris, France
- Interdisciplinary Center for Neural Computation, The Hebrew University, Jerusalem, Israel
| | - Lionel Nowak
- Cerco, Université Toulouse 3, CNRS, Toulouse, France
| | - Pascal Barone
- Cerco, Université Toulouse 3, CNRS, Toulouse, France
| | - Carl van Vreeswijk
- Laboratoire de Neurophysique et Physiologie, Université Paris Descartes, Paris, France
- * E-mail:
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19
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Yu HH, Verma R, Yang Y, Tibballs HA, Lui LL, Reser DH, Rosa MGP. Spatial and temporal frequency tuning in striate cortex: functional uniformity and specializations related to receptive field eccentricity. Eur J Neurosci 2010; 31:1043-62. [DOI: 10.1111/j.1460-9568.2010.07118.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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