Sandrine Chemla

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In this review, we present the voltage-sensitive dye imaging (VSDI) method. The possibility offered for in vivo (and in vitro) brain imaging is unprecedented in terms of spatial and temporal resolution. However, the unresolved multi-component origin of the optical signal encourages us to perform a detailed analysis of the method limitation and the existing(More)
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 corresponding to(More)
High-level specification of how the brain represents and categorizes the causes of its sensory input allows to link "what is to be done" (perceptual task) with "how to do it" (neural network calculation). In this article, we describe how the variational framework, which encountered a large success in modeling computer vision tasks, has some interesting(More) Partially supported by the EC IP project FP6-015879, FACETS We propose a biological cortical column model, at a some mesoscopic scale, in order to better understand and start to interpret biological sources of voltagesensitive dye imaging signal. The mesoscopic scale, corresponding to a micro-column, is about 50 μm. Simulations are done thanks(More)
Voltage-sensitive dye (VSD) imaging produces an unprecedented real-time and high-resolution mesoscopic signal to measure the cortical population activity. We have previously shown that the neuronal compartments contributions to the signal are dynamic and stimulus-dependent (Chemla S, Chavane F. Neuroimage 53: 420-438, 2010). Moreover, the VSD signal can(More)
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 new(More)
Voltage-sensitive dye imaging (VSDI) is a powerful modern neuroimaging technique whose application is expanding worldwide because it offers the possibility to monitor the neuronal activation of a large population with high spatial and temporal resolution. In this thesis, we investigate the biological sources of the voltage-sensitive dye signal (VSD signal),(More)
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(More)
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 typical(More)
Meso AI, Chemla S. Perceptual fields reveal previously hidden dynamics of human visual motion sensitivity. J Neurophysiol 114: 1360–1363, 2015. First published October 22, 2014; doi:10.1152/jn.00698.2014.—Motion sensitivity is a fundamental property of human vision. Although its neural correlates are normally only directly accessible with neurophysiological(More)