Extra-retinal modulation of cerebral blood-flow in the human visual cortex:
implications for saccadic suppression.
Paus, Toma, Sean Marrett, Keith J. Worsley and Alan C. Evans.
Montreal Neurological Institute, McGill University, 3801 University,
Montreal, Quebec, Canada, H3A 2B4.
APStracts 2:0237N, 1995.
SUMMARY AND CONCLUSIONS
1. Extra-retinal modulation of neuronal activity in the human brain was
assessed indirectly by measuring changes in regional cerebral blood-flow
(rCBF) during the execution of large horizontal saccades in complete darkness.
Using positron emission tomography, rCBF was measured in nine volunteers as
they made 40, 60, 80, 100, 110, 120, or 140 saccades during 60-sec scans. 2.
With increasing number of saccades, rCBF increased in the following oculomotor
structures: the frontal eye-field, the superior colliculus, and the cerebellar
vermis. In parallel to these rCBF increases, rCBF decreased in the striate
cortex, adjacent extra-striate cortex, and the parietal cortex. 3. The
observed rCBF decreases most likely indicate a decline in the net amount of
excitatory neutransmission in the visual cortex and, as such, may represent a
neural substrate of saccadic suppression.
Received 6 June 1995; accepted in final form 8 August 1995.
APS Manuscript Number J361-5.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 August 1995.