The Journal of Neurophysiology Vol. 88 No. 4 October 2002, pp. 1675-1684
Copyright ©2002 by the American Physiological Society

Is the Functional Connectivity Within Temporal Lobe Influenced By Saccadic Eye Movements?

Department of Neurobiology and Anatomy, University of Rochester, Rochester New York 14642

Sobotka, Stanislaw, Wei Zuo, and James L. Ringo. Is the Functional Connectivity Within Temporal Lobe Influenced By Saccadic Eye Movements?. J. Neurophysiol. 88: 1675-1684, 2002. Local evoked potentials (LEPs), recorded in response to electrical stimulation, were used to study functional connectivity between different sites of the temporal lobe. Permanent electrodes were implanted in anterior and posterior positions of both inferotemporal cortex (IT) and hippocampal formation (HF). In each experimental session, one of these four sites was stimulated and LEPs were recorded in the others. Clear LEPs were found in the anterior and posterior IT sites in response to stimulation of the anterior as well as posterior HF. Bidirectional connections (as judged by the potentials) were found between the anterior and posterior sites of the same structure (IT or HF). The timing of the LEPs indicates that much of the response was carried in multisynaptic circuits. Stimulation delivered just after the monkey made a saccade produced larger late components in the LEPs than the same stimulation delivered without a saccade. The influence was maximal when the delay between the end of the saccade and the electrical stimulation was in the range of 50-100 ms. This saccadic modulation of the functional connectivity was observed within IT (bidirectional) and between posterior HF and IT (unidirectional).