[Activity of septal and hippocampal neurons during isolated and combined growth in the anterior chamber of the eye in the rat].

Neuronal activity of the septal and hippocampal grafts, developing in the anterior eye chamber of the rat for 3-6 months was recorded extracellularly in curarized or cerveau isolé animals. While the units of isolated septum had background activity of regular, irregular and rhythmic burst type, the hippocampal units displayed no background discharges or produced very low-frequency population spikes. In the paired septal-hippocampal grafts neurons of the hippocampus possessed the same types of activity, as that of the septum. Spontaneous epileptiform phenomena were observed in many paired grafts; such phenomena were easily provoked by mild electrical stimulation of one of the grafts. Superfusion with low Ca2+, high Mg2+ medium abolished spontaneous activity in most of hippocampal units but not in septal units. Epileptic discharges were also partly suppressed.