Long-term depression and long-term potentiation in horizontal connections of the barrel cortex.
Synaptic plasticity of horizontally orientated connections between barrels, in the barrel cortex of adult mice, was studied in slice preparations cut across rows of barrels. Field potentials were evoked in the middle of one barrel column (in layer IV or V) and recorded in the neighbouring barrel (in layer IV and V). In layer IV, long-term depression (LTD) by 26.5 +/- 5% was first induced by a low-frequency stimulation (2 Hz) applied for 10 min. After 30 min, theta-burst stimulation was delivered to previously depressed connections, resulting in long-term potentiation (LTP) by 28.8 +/- 11.8%. When theta-burst stimulation was delivered without an earlier low-frequency stimulation, no LTP was induced. Similar results were obtained in layer V connections (LTD: 40.6 +/- 12.5%; LTP: 26.9 +/- 12.5%). In layer IV, the application of 100 micro m d,l-2-amino-5-phosphonovaleric acid (APV), an antagonist of NMDA receptors, blocked the induction of both LTD and LTP. These experiments show that a potential for synaptic plasticity is retained in granular and infragranular layers of adult mice.
Urban
Joanna
J
Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland.
Kossut
Malgorzata
M
Hess
Grzegorz
G
D000818:Animals; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D004558:Electric Stimulation; D017774:Long-Term Potentiation / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D009473:Neuronal Plasticity; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D014633:Valine / Q000031:analogs & derivatives* / Q000494:pharmacology; D014738:Vibrissae / Q000294:innervation*
D016194:Receptors, N-Methyl-D-Aspartate; C056639:2-amino-5-phosphopentanoic acid; D014633:Valine