ADENOSINIC MODULATION OF 7-14 HZ SPINDLE RHYTHMS IN INTERCONNECTED THALAMIC RELAY AND NUCLEUS-RETICULARIS NEURONS

Intrathalamic spindle rhythms have been shown in vitro and in vivo to recur at frequencies of 0.1-0.3 Hz and last for periods of 1-3 s depen ding on the species observed. Although it is now generally agreed that both the intrinsic properties of relay and reticularis neurons, as we ll as their circuit dependency, contribute to the 7-14 Hz interburst s pindle frequency, it is not presently known what mechanisms generate t hese slower oscillations. A model of interconnected thalamocortical re lay and nucleus reticularis thalami cells was developed to investigate these properties. The model suggests that modulation of the hyperpola rization-activated cation current, I-h, by the nucleoside adenosine ca n serve to regulate both the duration of spindling and frequency of re currence. These results suggest that the waxing and waning characteris tics of thalamic spindle rhythms are, in part, dependent on the changi ng levels of extracellular adenosine and its influence on I-h in thala mocortical relay cells within this neuronal network. (C) 1996 IBRO. Pu blished by Elsevier Science Ltd.