FOCAL STIMULATION OF THE THALAMIC RETICULAR NUCLEUS INDUCES FOCAL GAMMA-WAVES IN CORTEX

Focal stimulation of the thalamic reticular nucleus induces focal gamm a waves in cortex. J. Neurophysiol, 79: 474-477, 1998. Electrical stim ulation of the thalamic reticular nucleus (TRN; 0.5-s trains of 500-Hz 0.5-ms pulses at 5-10 mu A) evokes focal oscillations of cortical ele ctrical potentials in the gamma frequency band (similar to 35-55 Hz). These evoked oscillations are specific to either the somatosensory or auditory cortex and to subregions of the cortical receptotopic map, de pending an what part of the TRN is stimulated. Focal stimulation of th e internal capsule, however, evokes focal slow potentials, without gam ma activity. Our results suggest that the TRN's role extends beyond th at of general cortical arousal to include specific modality and submod ality activation of the forebrain.