20 novOculomotor plasticity and visual attention20 nov 2013
Denis Pélisson, ImpAct team of CRNL, Lyon
Vertebrates developed sophisticated solutions to select environmental visual information, being capable of moving attention with eye movements but also without overt ocular response. My research aims at a better understanding of the mechanisms and neural substrates of both saccadic eye movements and covert visuo-spatial attention in humans. I will first present behavioural and neurophysiological data on saccadic adaptation, a plastic re-calibration of the motor commands that compensates for saccade execution errors. I will show that different adaptation processes and cortical substrates are involved for saccades elicited in a reactive mode toward a suddenly presented target and for saccades generated in a more voluntary mode between elements of a visual scene. Then, focussing on the coupling between saccadic adaptation and covert attention, I will demonstrate that the deployment of covert attention, measured in absolutely stationary eye conditions, can be boosted after adaptation of leftward reactive saccades (and not rightward reactive saccades, nor voluntary saccades). These last findings 1) confirm that human oculomotor plasticity mechanisms differ for reactive and voluntary saccades, 2) indicate that spatial attention is more widely affected by saccadic adaptation than previously thought and 3) are consistent with a neurophysiological model based on the known asymmetrical specialization of cerebral hemispheres in oculomotor and attentional control.