title: Modulation of memory processes induced by stimulation of the entorhinal cortex.
abstract: This study investigated the effects of posttrial electrical stimulation of the entorhinal cortex in rats (3 mA or 300 microA; 60 sec, 3 hr or 6 hr after training) on retention of inhibitory or active avoidance responses. In the inhibitory avoidance task 3 mA, but not 300 microA, 60 sec after training produced retrograde amnesia. The 300 microA stimulation produced amnesia when given 3 hr after training, but 3 mA was without effect. Neither level of stimulation affected retention if given 6 hr after training. In the active avoidance task 300 microA given 60 sec and 3 hr after training significantly facilitated acquisition in comparison with unoperated, but not operated control rats. The 3 mA stimulation had no effect in the active avoidance task. Cortical afterdischarge activity occurred 64%, 23%, and 77% of the time when the 300 microA stimulation was given 60 sec, 3 hr, or 6 hr after inhibitory avoidance training, and 54%, 69%, and 92% for 3 mA. In the two conditions where amnesia was observed (3 mA at 60 sec and 300 microA at 3 hr) the lowest proportion of animals exhibited afterdischarge activity. Afterdischarge activity was not related to active avoidance performance.
authors.affiliation: Department of Psychobiology, School of Biological Sciences, University of California, Irvine, CA 92717, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Martinez
authors.forename: J L
authors.initials: JL
authors.lastname: McGaugh
authors.forename: C L
authors.initials: CL
authors.lastname: Hanes
authors.forename: J S
authors.initials: JS
authors.lastname: Lacob
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D001931:Brain Mapping; D004558:Electric Stimulation; D018728:Entorhinal Cortex / Q000502:physiology*; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D012153:Retention, Psychology / Q000502:physiology*