Reading auditory discrimination behaviour of freely moving rats from hippocampal EEG

It has been suggested that hippocampal rhythmical slow activity (theta rhythm) is related to cognitive process and the genesis of P300 response. To test this hypothesis, hippocampal EEG data from CA1 were recorded from rats trained to perform auditory discrimination oddball paradigm. In well-trained rats, signi"cant changes in the hippocampal theta rhythm were observed during an auditory oddball paradigm. Here we used an arti"cial modular neural network with wavelet coe$cients to investigate whether changes in the hippocampal theta rhythm are related to cognition of right tone objectively. However, an objective data interpretation with the modular neural network does not support the hypothesis that changes in theta rhythm are related to cognitive process. In addition, it was con"rmed that changes in taskrelated theta rhythm before/after learning the auditory oddball paradigm resulted from the fact that training changed the character of the motor behaviour. 2001 Elsevier Science B.V. All