If we pursue a moving object with the eyes, our eyes remain open. This
means, that e.g. the images of stationary objects in the world are
moving on our retinae. Still, we are able to distinguish between such
self induced motion and real object motion. This is the basis for our
skill to successfully interact with our environment regardless of actual
ongoing SPEMs.In the posterior parietal cortex (PPC) of the macaque,
spatial and motion signals arising from different sensory sources
converge. One of the functional subregions within the PPC, the ventral
intraparietal area (VIP), is thought to play an important role for the
multisensory encoding of self- and object motion. VIP is thus an
excellent target for the search for brain areas possibly dealing with
the sensory consequences of SPEM. Yet, the relation of area VIP to such
eye-movements is only poorly understood. We therefore examined the
activity of area VIP neurons related to different parameters of SPEMs.
More than half of the neurons were selective to the direction of the
SPEMs. We additionally found a clear preference for high pursuit
velocities. In everyday life, high pursuit velocities most frequently
occur if the pursuit target is located in near extrapersonal space, i.e.
the action space of the head. Our study shows that visual motion
information and extraretinal information about the SPEMs are both
represented in area VIP. By combining these signals it would be possible
to correct for the self induced motion on the retina and thus to create
a representation of target position and movement in relation to the
head.This representation could then be used to successfully guide head
movements e.g. to avoid contact with an obstacle even if ongoing SPEMs
induce motion on the retinae.
