Theta in hippocampal slices: relation to synaptic responses of dentate neurons.

The effects of cholinergic agents on isolated dentate neurons were studied to characterize cellular mechanisms underlying carbachol-induced 'theta' EEG activity. Carbachol, eserine, and acetylcholine produced a synchronization of slow wave activity (theta) accompanied by depression of perforant path to dentate field potentials. These effects were antagonized by atropine but not d-tubocurarine. The results suggest that muscarinic receptors mediate theta activity resulting from a depolarization of dentate neurons.