Institut des
NanoSciences de Paris
Accueil > Evénements > Séminaires > Archives 2015 > A light sensitive neurona

Séminaire général de l’INSP

A light sensitive neuronal oscillator that controls saccadic eye movements - Georges Debrégeas - Thursday 17th september 2015 at 4.30 pm

INSP - 4 place Jussieu - 75252 PARIS Cedex 05 - Corridor 22-23 - 3rd floor, hall 317

Georges Debrégeas - Senior research scientist - Laboratoire Jean Perrin

Abstract Zebra fish larva is an ideal vertebrate model for in vivo functional calcium imaging, due to its small dimensions, transparency, and genetic accessibility. The laser sheet technology makes it possible to obtain high- speed acquisition of the entire nervous system with a single cell resolution. I will show the interest of this full field approach for the understanding of the neuronal basis for sensorimotor integration, through the study of the dynamics of spontaneous saccadic eye movements. We recently shed light on a neuronal circuit, divided in two neuron groups symmetrically distributed within the rhombencephalon, whose activity is correlated with gaze orientation. When saccades are blocked (either through mechanical fixation or paralysis), this network reveals a spontaneous oscillation at a frequency close to the saccades’ one (period of 15-30s). Moreover, the activity of this network can be modulated through a uniform visual stimulation : in particular it is possible to lock the dynamics of this neuronal oscillator by stimulating the animal with alternating dark and bright backgrounds at a frequency close to the spontaneous oscillations’ one.