Researchers from Niigata University, Brain Research Institute describe findings in brain research
2007 NOV 20 -- New investigation results, 'Long-term depression induced by local tetanic stimulation in the rat auditory cortex,' are detailed in a study published in Brain Research. According to recent research from Niigata, Japan, "In sensory cortices, synaptic plasticities such as long-term potentiation (LTP) and long-term depression (LTD) have important roles in the development of neural circuits and sensory information processing. However, the differential roles and mechanisms of the various types of LTP and LTD are not clear." "In the present study, we investigated LTP and two types of LTD in slices obtained from the rat auditory cortex. Supragranular field potentials elicited by layer VI stimulation were recorded through a metal electrode. Transsynaptic field potentials exhibited marked LTP after tetanic stimulation (TS, 100 Hz for 1 s) was applied to layer VI. The same field potential components exhibited LTD after low-frequency stimulation (LFS, 1 Hz for 900 s) was applied to layer VI. LTD of supragranular field potentials was also induced by local TS applied to supragranular layers 0.3 mm from the recording site. Neither LTP nor LTD of either type was induced in the presence of 50 mcM d-(-)-2-amino-5-phosphonovalerate (APV), an NMDA receptor antagonist. However, 500 mcM (+)-alpha-methyl-4-carboxyphenylglycine (MCPG), an antagonist of metabotropic glutamate receptors, had no effect. LTD induced by LFS and that induced by local TS were suppressed in the presence of 3 mcM bicuculline, an antagonist of GABA(A) receptors. Each of these forms of LTD occluded the other," wrote K. Watanabe and colleagues, Niigata University, Brain Research Institute. The researchers concluded: "These results and intracellular recordings in supragranular pyramidal neurons during LFS and local TS strongly suggest that the two types of LTD share common neural circuits for their induction." Watanabe and colleagues published their study in Brain Research (Long-term depression induced by local tetanic stimulation in the rat auditory cortex. Brain Research, 2007;1166():20-8). For additional information, contact K. Watanabe, Brain Research Institute, Dept. of Neurophysiology, Niigata University, Asahi-machi, Niigata 951-8585, Japan. Publisher contact information for the journal Brain Research is: Elsevier Science BV, PO Box 211, 1000 AE Amsterdam, Netherlands. Keywords: Japan, Niigata, Brain Research. This article was prepared by Life Science Weekly editors from staff and other reports. Copyright 2007, Life Science Weekly via NewsRx.com.
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