Frequency-specific RSA-like hippocampal patterns elicited by septal, hypothalamic, and brain stem electrical stimulation.

Hippocampal electrographic patterns comprised of specific frequencies of slow waves electrographically similar to the waves comprising normal hippocampal rhythmical slow activity (RSA, theta) may be generated by appropriate electrical stimulation of specific septal, hypothalamic, and brain stem sites. The waves elicited from some but not all sites are further similar to normal RSA patterns in that they may be differentiated into atropine-sensitive (immobility-related) and atropine-resistant (movement-related) types by the same criteria used to define atropine-sensitive and atropine-resistant RSA. The high degree of behavioral, pharmacological, and electrographic similarity between the electrically elicited hippocampal activity and normal hippocampal RSA would seem to warrant further use of the present technique in the investigation of hippocampal function.