title: Inhibition in subicular and entorhinal principal neurons in response to electrical stimulation of the fornix and hippocampus.
abstract: We performed experiments studying the responses of rat subicular and entorhinal neurons to electrical stimulation of the fornix and hippocampus. Four main results were obtained: (1) extracellular recordings from principal neurons showed prolonged inhibition in response to stimulation, and intracellular recordings showed prominent IPSPs; (2) neither fornical nor commissural afferents were necessary for the inhibitory responses; they were present even in animals that had received prior surgical sections of the fornix and hippocampal commissures; (3) antidromic responses to fornix or hippocampal stimulation were recorded in neurons of the subicular complex; and (4) 3 cells in the subicular and entorhinal cortex were encountered that showed some of the properties associated with interneurons. The results suggest that principal neurons of the subicular complex share a number of properties with hippocampal pyramidal cells, including intrinsic recurrent inhibitory circuitry. Further study is required to determine the pathway for entorhinal inhibitory responses.
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials; D006624:Hippocampus / Q000502:physiology*; D007395:Interneurons / Q000502:physiology; D008032:Limbic System / Q000502:physiology*; D008297:Male; D009433:Neural Inhibition; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology; D051381:Rats