Chavane

The role of cortical waves in shaping dynamically the processing of visual information

Frédéric Chavane, Alexandre Reynaud, Matteo di Volo, Alain Destexhe, Laurent Perrinet, Sandrine Chemla

INT, CNRS, Marseille, France.

Since the pioneering work of the Hubel and Wiesel, our understanding of visual processing has been dominated by the feed-forward hierarchical approach. Accordingly, low-level visual information (such as position and orientation) is extracted locally within stationary receptive fields and is rapidly cascaded to downstream areas to encode more complex features. As a consequence, the knowledge we have about the visual system mostly relies on results obtained with stimuli confined to a stationary aperture, hereby focusing on a steady-state and piecewise information confined to the receptive field.

Using recording tools at mesoscopic scale in the awake monkey, we demonstrated that any local stationary stimulus is, in itself, generating waves propagating within retinotopic maps. Local visual information does not stay confined to a particular retinotopic location but instead invades a large cortical territory. What can be the computational advantage of such cortical waves in the processing visual information? In response to a sequence of stimuli, such as an object moving along a trajectory, these waves interact non-linearly with feedforward and feedback inputs. They hereby shape and structure the representation of non-stationary stimuli through a global and dynamic input gain control. We believe that this represents a low-level mechanism that enables to keep track of object representation over the motion trajectory.