-transparent.png){kind=logo}
1. Potentiation of synaptic transmission in visual cortex (areas 17 and 18) of kittens was investigated by extracellular recording of field potentials (FPs) and cortical units in cortical slices and whole-animal preparations. Responses to test stimulation (0.05 Hz) of the white matter (WM), lateral geniculate nucleus (LGN), and optic chiasm (OC) were documented before and after conditioning stimulation (2 Hz for 1 h). 2. In slice preparations of area 17, the FPs were always depressed during conditioning stimulation and were usually potentiated immediately after conditioning stimulation. Long-term potentiation (LTP) of FPs developed rapidly during the initial 1-2 h and continued to increase slowly for several hours after conditioning. 3. LTP of FPs was age dependent: LTP occurred most frequently (43/53) at the ages of 21-34 days, less frequently (4/7 and 5/11) at 14-20 and 35-41 days, and never (0/5 and 0/5) at 7-13 and 42-49 days. LTP age relationship determined as a ratio of the amplitudes of FPs after conditioning to that before conditioning was greater at 21-34 days (mean potentiation, 2.4 +/- 0.6) than at 14-20 or 35-41 days (1.7 +/- 0.5). 4. LTP was also documented by the shortening in latencies of orthodromic responses of cortical units sampled from 10 pairs of conditioned and unconditioned control slices. Unit responses were classified into mono- and polysynaptic groups according to the central delay, defined as the time required for their activation after the arrival of afferent impulses. The monosynaptic central delays were 0.22 ms shorter in conditioned (0.60 +/- 0.17 ms, n = 56) than in control slices (0.82 +/- 0.22 ms, n = 57); similarly, polysynaptic central delays were 0.66 ms smaller (1.70 +/- 0.43 ms, n = 51; and 2.36 +/- 0.79 ms, n = 51). Both differences were statistically significant (P less than 0.001). 5. There were laminar differences in LTP of mono- and polysynaptic transmission. LTP of monosynaptic transmission occurred throughout layers II-V (central delays shortened about 0.2 ms), whereas LTP of polysynaptic transmission was greatest in layer II (1.17 ms), moderate in layer III (0.66 ms), and slight in layer IV (0.3 ms). The time course of shortening in orthodromic latency in five polysynaptic units agreed with the time course of LTP of FP. 6. Location of synapses involved in LTP of synaptic transmission was studied by current source-density (CSD) analysis in slice preparations of area 17 during test stimulation of WM. CSD analysis demonstrated two components of current sinks (early and late), probably representing mono- and polysynaptic transmission.(ABSTRACT TRUNCATED AT 400 WORDS)
Y Komatsu, and
K Fujii, and
J Maeda, and
H Sakaguchi, and
K Toyama
January 1994,
Experimental brain research,
Y Komatsu, and
K Fujii, and
J Maeda, and
H Sakaguchi, and
K Toyama
November 1994,
The Journal of neuroscience : the official journal of the Society for Neuroscience,
Y Komatsu, and
K Fujii, and
J Maeda, and
H Sakaguchi, and
K Toyama
February 1992,
Journal of neurophysiology,
Y Komatsu, and
K Fujii, and
J Maeda, and
H Sakaguchi, and
K Toyama
September 1998,
Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme,
Y Komatsu, and
K Fujii, and
J Maeda, and
H Sakaguchi, and
K Toyama
May 2018,
Cerebral cortex (New York, N.Y. : 1991),
Y Komatsu, and
K Fujii, and
J Maeda, and
H Sakaguchi, and
K Toyama
July 1993,
Neuroreport,
Y Komatsu, and
K Fujii, and
J Maeda, and
H Sakaguchi, and
K Toyama
April 1992,
Journal of neurophysiology,
Y Komatsu, and
K Fujii, and
J Maeda, and
H Sakaguchi, and
K Toyama
January 1995,
Brain research,
Y Komatsu, and
K Fujii, and
J Maeda, and
H Sakaguchi, and
K Toyama
October 1996,
Sheng li ke xue jin zhan [Progress in physiology],
Y Komatsu, and
K Fujii, and
J Maeda, and
H Sakaguchi, and
K Toyama
December 2001,
The Journal of neuroscience : the official journal of the Society for Neuroscience,
