Frédéric Chavane

Frédéric Chavane
French National Centre for Scientific Research | CNRS · Institut de Neurosciences de la Timone

Doctor of Philosophy

About

100
Publications
12,403
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Introduction

Publications

Publications (100)
Article
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Horizontal connections in the primary visual cortex of carnivores, ungulates and primates organize on a near-regular lattice. Given the similar length scale for the regularity found in cortical orientation maps, the currently accepted theoretical standpoint is that these maps are underpinned by a like-to-like connectivity rule: horizontal axons con...
Preprint
Full-text available
Neurons in the primary visual cortex are selective to orientation with various degrees of selectivity to the spatial phase, from high selectivity in simple cells to low selectivity in complex cells. Various computational models have suggested a possible link between the presence of phase invariant cells and the existence of cortical orientation map...
Preprint
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The primary visual cortex (V1) processes complex mixtures oforientations to build neural representations of our visual en-vironment. It remains unclear how V1 adapts to the highlyvolatile distributions of orientations found in natural images.We used naturalistic stimuli and measured the response of V1neurons to orientation distributions of varying...
Article
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Three rules govern the connectivity between neurons in the thalamus and inhibitory neurons in the visual cortex of rabbits.
Article
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Both neurophysiological and psychophysical experiments have pointed out the crucial role of recurrent and feedback connections to process context-dependent information in the early visual cortex. While numerous models have accounted for feedback effects at either neural or representational level, none of them were able to bind those two levels of a...
Preprint
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arXiv:2010.14287 We report optical brain imaging using a semi-transparent organic light-emitting diode (OLED) based on the orange light-emitting polymer (LEP) Livilux PDO-124. The OLED serves as a compact, extended light source which is capable of uniformly illuminating the cortical surface when placed across a burr hole in the skull. Since all la...
Article
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Deep regions of the brain are not easily accessible to investigation at the mesoscale level in awake animals or humans. We have recently developed a functional ultrasound (fUS) technique that enables imaging hemodynamic responses to visual tasks. Using fUS imaging on two awake nonhuman primates performing a passive fixation task, we constructed ret...
Preprint
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What are the neural mechanisms underlying motion integration of translating objects? Visual motion integration is generally conceived of as a feedforward, hierarchical, information processing. However, feedforward models fail to account for many contextual effects revealed using natural moving stimuli. In particular, a translating object evokes a s...
Preprint
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It is now accepted that short-term deprivation of one eye in adults results in not only a post-deprivation strengthening of the vision in the previously deprived eye but also a deterioration in the vision of the previously non-patched eye. Such monocular deprivation of 1-2 hours induces changes that last approximately 30-90 minutes. There is some s...
Article
In amblyopia, there is an interocular suppressive imbalance that results in the fixing eye dominating perception. In this study, we aimed to determine whether these suppressive interactions were narrowband and tuned for spatial frequency or broadband and independent of spatial frequency. We measured the contrast sensitivity and masking functions of...
Article
Purpose: To better understand the role of vascular risk factors (VRF) in the pathogenesis of primary open-angle glaucoma (POAG), a detailed analysis of retinal arterial wall thickness is needed. The purpose of the present study was to make a morphological analysis of peripapillary arteriole in POAG using adaptive optics (AO) technology. Patients...
Preprint
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The relevance of α oscillations (7-12Hz) in neural processing, although recognized long ago, remains a major research question in the field. While intensively studied in humans, α oscillations appear much less often investigated (and observed) in monkeys. Here we wish to provide data from non-human primates on stimulus-related α rhythm. Indeed, in...
Article
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Dichoptic movie viewing has been shown to significantly improve visual acuity in amblyopia in children. Moreover, short-term occlusion of the amblyopic eye can transiently increase its contribution to binocular fusion in adults. In this study, we first asked whether dichoptic movie viewing could improve the visual function of amblyopic subjects bey...
Article
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How does the brain link visual stimuli across space and time? Visual illusions provide an experimental paradigm to study these processes. Whentwo stationary dots are flashed in close spatial and temporal succession,humanobservers experience a percept of apparent motion. Large spatiotemporal separation challenges the visual system to keep track of o...
Preprint
Full-text available
Deep regions of the brain are not easily accessible to investigation at the mesoscale level in awake animals or humans. We have recently developed functional Ultrasound (fUS) imaging fUS imaging technique to uncover deep hemodynamic functional responses. Applying fUS imaging on two awake non-human primates performing a passive fixation task, we rec...
Preprint
Full-text available
How does the brain link visual stimuli across space and time? Visual illusions provide an experimental paradigm to study these processes. When two stationary dots are flashed in close spatial and temporal succession, human observers experience a percept of motion. Large spatio-temporal separation challenges the visual system to keep track of object...
Article
Full-text available
Multichannel recording technologies have revealed travelling waves of neural activity in multiple sensory, motor and cognitive systems. These waves can be spontaneously generated by recurrent circuits or evoked by external stimuli. They travel along brain networks at multiple scales, transiently modulating spiking and excitability as they pass. Her...
Article
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Voltage-sensitive dye imaging (VSDi) has revealed fundamental properties of neocortical processing at macroscopic scales. Since for each pixel VSDi signals report the average membrane potential over hundreds of neurons, it seems natural to use a mean-field formalism to model such signals. Here, we present a mean-field model of networks of Adaptive...
Preprint
Full-text available
Voltage-sensitive dye imaging (VSDi) has revealed fundamental properties of neocortical processing at macroscopic scales. Since for each pixel VSDi signals report the average membrane potential over hundreds of neurons, it seems natural to use a mean-field formalism to model such signals. Here, we present a mean-field model of networks of Adaptive...
Article
Full-text available
Voltage-sensitive dye imaging experiments in primary visual cortex (V1) have shown that local, oriented visual stimuli elicit stable orientation-selective activation within the stimulus retinotopic footprint. The cortical activation dynamically extends far beyond the retinotopic footprint, but the peripheral spread stays non-selective—a surprising...
Data
Animations corresponding to Figs 5B, 5E and 7D, 7E, 7F are available as supporting information. (ZIP)
Data
Matlab source code for the model, allowing for independent reproduction of the results, is available as supporting information. The code is also available on the following public repository: https://github.com/QBME/rankin-chavane-neural-field/. (ZIP)
Article
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Brain activity displays a large repertoire of dynamics across the sleep-wake cycle and even during anesthesia. It was suggested that criticality could serve as a unifying principle underlying the diversity of dynamics. This view has been supported by the observation of spontaneous bursts of cortical activity with scale-invariant sizes and durations...
Data
Loglikelihood ratios for power law and lognormal fits to size distributions of different cortical states across all cat and monkey data and for different thresholds of spike cluster definition. Negative values indicate a better lognormal fit. State differences were assessed using a one-way rm-ANOVA test (threshold 1: cat: F4,12 = 4.03, p = 0.1, ε =...
Data
Avalanche shape collapse. (A–B) Averaged temporal profile of avalanche of lifetime Δt, i.e., <S(t,Δt)>, in the Desyn I cortical state (A) and the SynSlow cortical state (B) for an example cat dataset. (C–D) Scaled avalanche profiles as a function of the scaled time t/Δt, in the Desyn I cortical state (C) and the SynSlow cortical state (D). Red line...
Data
Loglikelihood ratios for power law and lognormal fits to liftime distributions of different cortical states across all cat and monkey data and for different thresholds of spike cluster definition. Negative values indicate a better lognormal fit. State differences were assessed using a one-way rm-ANOVA test (threshold 1: cat: F4,12 = 7.45, p = 0.02,...
Data
Separation of different states within the synchronized state of the model. (A-B) Mean Fano factor (FF) for different states in cat and monkey recordings (bin-size = 100ms). Error bars indicate SEM. (C) Distribution of FFs computed for each one second segment of the modeled synchronized state (bin-size = 50ms). (D) Mean firing rate of model neurons...
Data
Spiking data from four cat and four monkey datasets. The data include the spike timings, electrode index and state information. Details can be found in the README file. (ZIP)
Data
Shape collapse and state analysis of the synchronized model state. (DOCX)
Article
Full-text available
Voltage-sensitive dye imaging (VSDI) is a key neurophysiological recording tool because it reaches brain scales that remain inaccessible to other techniques. The development of this technique from in vitro to the behaving nonhuman primate has only been made possible thanks to the long-lasting, visionary work of Amiram Grinvald. This work has opened...
Article
Full-text available
Retinal prostheses are promising tools for recovering visual functions in blind patients but, unfortunately, with still poor gains in visual acuity. Improving their resolution is thus a key challenge that warrants understanding its origin through appropriate animal models. Here, we provide a systematic comparison between visual and prosthetic activ...
Presentation
Full-text available
Presentation on "25th Annual Computational Neuroscience Meeting: CNS-2016 " BMC Neuroscience 17, 112-113 (2016).
Article
Voltage-Sensitive Dye (VSD) imaging produces an unprecedented real-time and high-resolution mesoscopic the cortical population activity. We have previously shown that the neuronal compartments contributions to the signal are dynamic and stimulus-dependent (Chemla and Chavane 2010a). Moreover, the VSD signal can also be strongly affected by the netw...
Conference Paper
Full-text available
ICGenealogy: towards a common topology of neuronal ion channel function and genealogy in model and experiment Ion channels are fundamental constituents determining the function of single neurons and neuronal circuits. To understand their complex interactions, the field of computational modeling has proven essential: since its emergence, thousands...
Article
Full-text available
The repeated presentation of an identical visual stimulus in the receptive field of a neuron may evoke different spiking patterns at each trial. Probabilistic methods are essential to understand the functional role of this variance within the neural activity. In that case, a Poisson process is the most common model of trial-to-trial variability. Fo...
Working Paper
Visual motion integration in area V1 is traditionally investigated with local stimuli drifting over many cycles within a fixed aperture. However, psychophysical studies have suggested that motion signals can be optimally integrated along the trajectory of a single, translating dot. High detection performance can be explained by the propagation of i...
Conference Paper
Two stationary stimuli successively flashed in spatially separated positions generates the so-called apparent motion illusion. The illusion depends on the precise spatial and temporal separations of the stimuli and is called long-range apparent motion (lrAM) for large spatiotemporal(ST) separations[1]. Since these values extend well beyond the typi...
Article
Using observations of spiking activity in a population of neurons from macaque primary visual area, we studied simultaneously the dynamics of direction and orientation decoding. Stimuli consisted of oriented bars moving in 12 different directions, the orientation being orthogonal to the direction. Bars move from 3 degrees before to 1.5 degrees afte...
Conference Paper
Full-text available
Propagating waves of activity are seen in many types of excitable media, and in recent years, were found in the neocortex of anesthetized animals [1,2]. To date, however, it still remains unclear whether propagating waves appear during awake and conscious states [3,4]. One possibility is that these waves are systematically missed in trial-averaged...
Article
La cécité et le handicap visuel représentent un problème majeur de santé publique dans toutes les régions du monde et dans toutes les sociétés. Un grand nombre de travaux de recherche fondamentale ou clinique visent à permettre une réhabilitation et une autonomisation des patients. Diverses modalités sont explorées de la thérapie cellulaire et molé...
Article
Full-text available
The existence of propagating waves, either spontaneous or stimulus-evoked, in neocortex during the awake state has been a subject of recent interest [1,2]. Here, following work done previously in voltage-sensitive dye imaging of the primary visual cortex in the awake monkey [3], we apply an analysis method for non-parametric, automated detection of...
Article
Full-text available
Propagating waves occur in many excitable media and were recently found in neural systems from retina to neocortex. While propagating waves are clearly present under anaesthesia, whether they also appear during awake and conscious states remains unclear. One possibility is that these waves are systematically missed in trial-averaged data, due to va...
Article
Full-text available
Optical imaging is the only technique that allows to record the activity of a neuronal population at the mesoscopic scale. A large region of the cortex (10-20 mm diameter) is directly imaged with a CCD camera while the animal performs a behavioral task, producing spatio-temporal data with an unprecedented combination of spatial and temporal resolut...
Article
Purpose This aims to develop and improve the use of retinal prosthesis in animal model For that purpose we measured retinal and cortical response to direct subretinal electrical stimulation to understand how the patterns of stimuli can be adapted to improve stimulation to get closer to the response evoked by natural visual stimuli Methods In a rat...
Article
Full-text available
Objective: Previous studies have shown that single-frequency impedance measurements could provide useful information about the distance between the neuroprosthesis and the retina. This work investigates the use of impedance spectroscopy in monitoring subretinal implantations of flexible micro-electrode arrays and focuses on determining what is gov...
Article
Full-text available
To efficiently drive many behaviors, sensory systems have to integrate the activity of large neuronal populations within a limited time window. These populations need to rapidly achieve a robust representation of the input image, probably through canonical computations such as divisive normalization. However, little is known about the dynamics of t...
Conference Paper
In psychophysics and physiology, it is well established that the contrast gain control is context-dependent. In both human and monkey ocular following studies, it has been shown that modulations of the contrast response functions (CRF) induced by a peripheral stimulus are delayed relative to center-alone conditions. We investigated the role of cort...
Article
The increasing number of channels offered by new Microelectrode Array (MEA) systems raises the problem of data handling and analysis in real time. The goal of the RETINE project is to develop a new MEA system, called NeuroPXI, offering 256 channels with online features for MEA data recording, processing and stimulation. This system is a complete re...
Article
Full-text available
Neurons in the primary visual cortex receive subliminal information originating from the periphery of their receptive fields (RF) through a variety of cortical connections. In the cat primary visual cortex, long-range horizontal axons have been reported to preferentially bind to distant columns of similar orientation preferences, whereas feedback c...
Data
SupplMovie_M1.mpg. Movie showing the cortical response propagation evoked by a local stimulus (averaged over four orientations, left) and dynamics of polar orientation maps (right). Time after stimulus onset is given above each frame. The example is the same than Figure 1A and 3A. The red (left) or white (right) contours delineate the region signif...
Data
SupplMovie_M2(3).avi. Movies showing examples of subthreshold responses maps evoked by local Gabor stimuli. In the movies, the position corresponds to positions tested in the visual field (similar to Figure 9), and the orientation of the bars, the preferred orientation of the evoked response. White contours delineate significant subthreshold respon...
Article
Full-text available
Voltage sensitive dye imaging (VSDI) is the only technique that allows to directly measure neuronal activity over a large cortical population. It thus gives access to the dynamics of lateral interactions within or between cortical areas. However, VSDI signal suffers from a weak signal-to-noise ratio and processing methods are either rudimentary or...
Article
We propose a biological cortical column model, at an intermediate mesoscopic scale, in order to better understand and interpret biological sources of voltage-sensitive dye imaging signal (VSD signal). To perform a quantitative analysis of the relative contributions to the VSD signal, a detailed compartmental model was developed at a scale correspon...
Conference Paper
Lateral interactions are crucial mechanisms involved in contextual modulation of visual processing from which motion percept can emerge, such as in the case of apparent motion. Integration of a sequence of static stimuli could evoke motion signal in the visual system through spatio-temporal interactions originating from horizontal intra-cortical in...
Article
Full-text available
To compare the effects of different doses of bevacizumab with both saline and dexamethasone on inflammatory angiogenesis in the rat cornea induced by small chemical lesions. Corneal chemical cauterization was performed on 24 rats. Animals were divided randomly into six groups and received a daily subconjunctival injection for 7 days of: balanced sa...
Chapter
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In vivo intracellular electrophysiology offers the unique possibility of listening to the “synaptic rumor” of the cortical network captured by the recording electrode in a single V1 cell. The analysis of synaptic echoes evoked during sensory processing is used to reconstruct the distribution of input sources in visual space and time. It allows us t...
Chapter
In primary visual areas any local input is initially transmitted via horizontal connections giving rise to a transient peak of activity with spreading surround. How does this scenario change when the stimulus starts to move? Psychophysical experiments indicate that localization is different for stationary flashed and moving objects depending on the...