ID 389 – Studies of neuronal circuits underlying information processing through late P300 event-related potentials in rats

Abstract

Cognitive event related potentials (ERPs) and oscillations synchrony (EROS) provide a powerful tool for studying brain’s synaptic function underlying information processing. The P300 component of ERPs indexing attention and working memory is altered in neurologic and psychiatric diseases, and is sensitive to pharmacological agents. Here, we investigated whether the P300-like potentials can be generated in rats performing an active auditory discriminant task, and to what extent this response is sensitive to modulation of the cholinergic neurotransmission. In the active oddball paradigm, behavior and auditory evoked potentials (AEPs) were simultaneously recorded in rats as they were presented with frequent non-target and rare target tones during baseline conditions and following the administration of donepezil and scopolamine. Rats that consistently discriminate target tones showed P300 peaks with early and late components. Donepezil enhanced P300 amplitude and evoked theta/gamma oscillations to target tones and attenuated scopolamine-induced deficits in behavioral and AEPs/EROS. We demonstrate that P300-like response can be elicited by rats engaged in stimulus discrimination processing and outline the relevance of the cholinergic system in this response. The AEP P300 paradigm is valuable for characterizing targets and/or drugs that may contribute to facilitation and/or suppression of synaptic responses underlying early and late P300 components.