APStracts 4:266N, 1997.

Focal stimulation of the thalamic reticular nucleus induces focal gamma waves in cortex. KURT D. MACDONALD, EVA FIFKOVA, MICHAEL S. JONES and DANIEL S. BARTH. Department of Psychology, University of Colorado at Boulder, Boulder, CO 80309-0345.

APStracts 4:266N, 1997.

ABSTRACT
Electrical stimulation of the thalamic reticular nucleus (0.5 s trains of 500 Hz 0.5 ms pulses at 5-10 A; TRN) evokes focal oscillations of cortical electrical potentials in the gamma frequency band (35 - 55 Hz). These evoked oscillations are specific to either the somatosensory or auditory cortex, and to subregions of the cortical receptotopic map, depending on what part of the TRN is stimulated. Focal stimulation of the internal capsule, however, evokes focal slow potentials, without gamma activity. Our results suggest that the TRNs role extends beyond that of general cortical arousal to include specific modality and sub-modality activation of the forebrain.

Received 4 August 1997; accepted in final form 23 September 1997.
APS Manuscript Number J627-7.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 7 October 1997