Stimulation-induced RSA-like field activity in region CA1 of the hippocampal slice: amplitude maxima and topography.

In the present experiment RSA-patterned stimulation was applied to afferents in the CA1 region of the hippocampal slice preparation and depth profiles of the resultant field activity were performed. RSA-patterned stimulation applied to the stratum lacunosum-moleculare region resulted in field activity through the CA1 region with similar morphology, phase, and amplitude profiles to the type 1 RSA profile found in vivo. In contrast, RSA-patterned stimulation applied to the stratum oriens and midstratum radiatum regions did not result in field profiles characteristic of the RSA recorded in vivo. The results of the present study confirm predictions made by previous modelling experiments and CSD analyses performed in the freely moving animal, which suggest that the type 1 RSA profile is primarily the result of distal excitation onto CA1 pyramidal cells.