The Journal of Neurophysiology Vol. 87 No. 2 February 2002, pp. 1118-1122
Copyright ©2002 by the American Physiological Society

RAPID COMMUNICATION

Multisecond Periodicities in Basal Ganglia Firing Rates Correlate With Theta Bursts in Transcortical and Hippocampal EEG

Experimental Therapeutics Branch, Neurophysiological Pharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892-1406

Allers, Kelly A., David N. Ruskin, Debra A. Bergstrom, Lauren E. Freeman, Leyla J. Ghazi, Patrick L. Tierney, and Judith R. Walters. Multisecond Periodicities in Basal Ganglia Firing Rates Correlate With Theta Bursts in Transcortical and Hippocampal EEG. J. Neurophysiol. 87: 1118-1122, 2002. Multisecond oscillations in firing rate with periods in the range of 2-60 s (mean, 20-35 s) are present in 50-90% of spike trains from basal ganglia neurons recorded from locally anesthetized, immobilized rats. To determine whether these periodic oscillations are associated with similar periodicities in cortical activity, transcortical electroencephalographic (EEG) activity was recorded in conjunction with single- or dual-unit neuronal activity in the subthalamic nucleus (STN) or the globus pallidus (GP), and the data were analyzed with spectral and wavelet analyses. Multisecond oscillations in firing rates of 31% of the STN neurons and 46% of the GP neurons with periodicities significantly correlated with bursts of theta (4-7 Hz) activity in transcortical EEG. Further recordings of localized field potentials in the hippocampus and frontal or parietal cortices simultaneously with GP unit activity showed field potentials from the hippocampus, but not from the frontal or parietal cortices, exhibited bursts of theta rhythm that were correlated with GP firing rate oscillations. These results demonstrate a functional connectivity between basal ganglia neuronal activity and theta band activity in the hippocampus.