Synaptic plasticity dynamics in the hippocampal-prefrontal pathway in vivo.
We examined the effect of long-term potentiation (LTP) on paired-pulse responses across varied stimulus intensities and interstimulus intervals (ISIs), at ascending synapses from the intermediate and ventral hippocampus to the medial prefrontal cortex in urethane-anesthetized rats. LTP significantly shifted the median effective stimulus towards lower intensities in the intermediate route, and increased at 25-ms ISI the paired-pulse response, which was inversely proportional to the stimulus intensity. In the ventral route, the paired-pulse response varied with ISI rather than intensity, and increased at 50-ms and 100-ms ISI after LTP. The intermediate synaptic plasticity significantly exhibited total amplifier dynamics with wide ranges of frequency at lower intensity and intensity at 100-ms ISI in contrast to the ventral one.
Takita
Masatoshi
M
Cognition and Action Research Group, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan. takita.m@aist.go.jp
Izaki
Yoshinori
Y
Kuramochi
Masahito
M
Yokoi
Hiroshi
H
Ohtomi
Michiko
M
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D001703:Biophysics / Q000379:methods; D001931:Brain Mapping; D004558:Electric Stimulation / Q000379:methods; D006624:Hippocampus / Q000166:cytology* / Q000502:physiology; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D017397:Prefrontal Cortex / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000502:physiology*; D013997:Time Factors