Recent intracellular recordings from reticular thalamic (RE) neurons at resting and hyperpolarized membrane potentials in vivo suggest that thereversed inhibitory postsynapitc potentials (IPSPs) between RE cells can directly trigger a low-threshold spike. The oscillatory mechanisms underlying IPSP-triggered low-threshold spikes crowned by spike-bursts within the RE nucleus and their effect on the network behavior were investigated in models of an isolated RE network and network of RE and thalamocortical (TC) cells. In a one-dimensional RE network the external stimulation resulted in waves of excitation propagatng with constant velocity 25-150 cells/sec controlled by the GABA_A conductance, readius of synaptic interconnections in the network and the level of membrane potential in RE cells. In a one-dimensional network of RE and TC cells sequences of spindle oscillations were followed by localized w aves propagating inside the RE network, triggering oscillations involving both RE and TC cells. This model predicts that the isolated reticular nucleus may initiate sequences of spindle oscillations in thalmorcortial networks in vivo.
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