Generation of High Frequency Oscillations in Local Circuits of Rat Somatosensory Cortex Cultures. Plenz, D. and S.T. Kitai. University of Tennessee, College of Medicine, Dept. of Anatomy and Neurobiology, 875 Monroe Avenue, Memphis, TN 38163, USA.
APStracts 3:0195N, 1996.
1.Rhythmic cortical activity was investigated with intracellular recordings in cortex-striatum-mesencephalon organotypic cultures grown for 42 +/- 3 days in vitro. 2.Electrical stimulation of supragranular layers induced a self- sustained high frequency oscillation (HFO) in pyramidal neurons and interneurons. 3 . The HFO started 197 +/- 39 ms after stimulation, had a mean duration of 1.0 +/- 0.2 s and an initial frequency of 38 +/- 2 Hz. A decrease in frequency at a rate of 11.5 +/- 2.7 Hz/s started on average 547 +/- 109 ms after the onset of the HFO. 4. During the HFO, local interneurons and pyramidal neurons synchronized their activities. The synaptic origin of the HFO was confirmed by its reversal potential at -57 +/- 4 mV. 6. These results suggest that a self-maintained HFO can be induced in local cortical circuits by excitation of supragranular layers. This HFO would facilitate synchronization between distant cortical and thalamic regions.

Received 26 July 1996; accepted in final form 5 September 1996.
APS Manuscript Number J600-6.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 7 October 1996