Speaker/Affiliation: Robert H. Wurtz Ph.D. Senio

r Investigator National Eye Institute at NIH Laboratory of Sensorimotor R

esearch

When/Location: 3/19/07 12:00 SEA 4.244

Title of Tal

k: Corollary Discharge and Perceptual Stability

Reception with Refre

shments at 11:30 AM

Abstract: Helmholtz argued that our percept of v

isual stability in spite of saccadic eye movements results from an input to
visual processing by an %93effort of will%94. This input known as efferen

ce copy or corollary discharge provides information about the impending ey

e movement and permits compensation for the visual effect of the movement.

We have recently identified a pathway in the monkey brain that could convey
such a corollary discharge signal from the superior colliculus in the brai

n stem through the medial dorsal nucleus of the thalamus (MD) to the fronta

l eye fields of the cerebral cortex. We have now addressed whether this pat

hway might contribute to the perception of a stable visual world. We tested
whether a possible mechanism of this stability the shifting receptive fie

lds in anticipation of an impending saccade discovered by Duhamel Colby a

nd Goldberg might be dependent upon the identified corollary discharge pat

hway. We found that inactivation of MD did alter this shift indicating that
the shift does indeed depend upon the corollary discharge. The combined fi

ndings of the shifting receptive fields and their dependence on an identifi

ed corollary discharge gives insight at a neuronal level for the brain mech

anisms underlying the stability of visual perception.