Evelyne Sernagor

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In this review, we summarize the main stages of structural and functional development of retinal ganglion cells (RGCs). We first consider the various mechanisms that are involved in restructuring of dendritic trees. To date, many mechanisms have been implicated including target-dependent factors, interactions from neighboring RGCs, and afferent signaling.(More)
1. Receptive field properties of adult retinal ganglion cells are well documented, but little is known about their development. We made extracellular recordings of activity from turtle retinal ganglion cells during embryogenesis (stages 22-26), during the first 40 days posthatching, and in adults. 2. From stage 22 the cells fired in spontaneous recurring(More)
BACKGROUND The role played by early neural activity in shaping retinal functions has not yet been established. In the developing vertebrate retina, ganglion cells fire spontaneous bursts of action potentials before the onset of visual experience. This spontaneous bursting disappears shortly after birth or eye opening. In the present study, we have(More)
In the immature vertebrate retina, neighboring ganglion cells express spontaneous bursting activity (SBA), resulting in propagating waves. Previous studies suggest that the spontaneous bursting activity, asynchronous between the two eyes, controls the refinement of retinal ganglion cell projections to central visual targets. To understand how the patterns(More)
Recent successes in the stem cell field have identified some of the key chemical and biological cues which drive photoreceptor derivation from human embryonic stem cells (hESC) and human induced pluripotent stem cells (hiPSC); however, the efficiency of this process is variable. We have designed a three-step photoreceptor differentiation protocol combining(More)
1. Voltage-clamp experiments were used to study N-methyl-D-aspartic acid (NMDA) receptor antagonists applied by fast perfusion to mouse hippocampal neurons in dissociated culture. 2. Preincubation with the NMDA antagonists zinc (3-30 microM) and magnesium (30-300 microM) reduced subsequent responses to 100 microM NMDA applied together with these(More)
Extracellular recordings were obtained from the ganglion cell (GC) layer during correlated spontaneous bursting activity (SBA) in the immature turtle retina. Pharmacological agents were bath-applied, and their effects on burst and correlation parameters were determined. SBA requires synaptic transmission. It was blocked in the presence of curare and(More)
The isolated spinal cord of the chick embryo generates episodes of rhythmic bursting in which sartorius (hip flexor) and femorotibialis (knee extensor) motoneurons exhibit characteristic patterns of activity. At the beginning of each cycle both sets of motoneurons discharge synchronously. Following this brief synchronous activation sartorius motoneurons(More)
A novel, biophysically realistic model for early-stage, acetylcholine-mediated retinal waves is presented. In this model, neural excitability is regulated through a slow after-hyperpolarization (sAHP) operating on two different temporal scales. As a result, the simulated network exhibits competition between a desynchronizing effect of spontaneous,(More)
Embryonic spontaneous activity, in the form of propagating waves, is crucial for refining visual connections. To study what aspects of this correlated activity are instructive, we must first understand how their dynamics change with development and what factors trigger their disappearance after birth. Here we report that in the turtle retina, GABA, rather(More)