TY - JOUR
T1 - Differential effect of dark rearing on long-term potentiation induced by layer IV and white matter stimulation in rat visual cortex
AU - Salami, Mahmoud
AU - Fathollahi, Yaghoub
AU - Semnanian, Saeed
AU - Atapour, Nafiseh
PY - 2000/12/1
Y1 - 2000/12/1
N2 - In the earlier work, we showed that primed-burst stimulation (PBs) is an effective protocol to induce long-term potentiation (LTP) in layer II/III of adult rat visual cortex in vitro. In the present study, we investigated effects of dark rearing on potentiation of layer II/III responses to stimulation of layer IV or the underlying white matter in the visual cortex in vitro. Long-term potentiation was induced by PBs applied to white matter or layer IV of the cortex in light and dark reared rats. Regardless of the stimulation site, layer II/III field potentials consisted of two components. In general, the latency of responses in dark reared rats was shorter than that in light reared ones. Whereas PBs of layer IV produced LTP of two components in both the groups, that of white matter induced an appreciable potentiation of the second component in both groups and the first component only in dark reared rats. These results indicate that PBs of either white matter or layer IV can gain access to the modifiable synapses that are related to the second component of layer II/III responses in light and dark reared visual cortex, but accessibility of the modifiable synapses that are related to first component depends on the tetanization site. The dark rearing enhances accessibility of the modifiable synapses that are related to the first component following PBs of the white matter. It is suggested that the immaturity of inhibitory circuits and/or better function of excitatory ones in the visual cortex of dark reared rats may contribute to the enhanced accessibility of the first component.
AB - In the earlier work, we showed that primed-burst stimulation (PBs) is an effective protocol to induce long-term potentiation (LTP) in layer II/III of adult rat visual cortex in vitro. In the present study, we investigated effects of dark rearing on potentiation of layer II/III responses to stimulation of layer IV or the underlying white matter in the visual cortex in vitro. Long-term potentiation was induced by PBs applied to white matter or layer IV of the cortex in light and dark reared rats. Regardless of the stimulation site, layer II/III field potentials consisted of two components. In general, the latency of responses in dark reared rats was shorter than that in light reared ones. Whereas PBs of layer IV produced LTP of two components in both the groups, that of white matter induced an appreciable potentiation of the second component in both groups and the first component only in dark reared rats. These results indicate that PBs of either white matter or layer IV can gain access to the modifiable synapses that are related to the second component of layer II/III responses in light and dark reared visual cortex, but accessibility of the modifiable synapses that are related to first component depends on the tetanization site. The dark rearing enhances accessibility of the modifiable synapses that are related to the first component following PBs of the white matter. It is suggested that the immaturity of inhibitory circuits and/or better function of excitatory ones in the visual cortex of dark reared rats may contribute to the enhanced accessibility of the first component.
KW - Dark rearing
KW - Layer IV
KW - Light rearing
KW - Long-term potentiation
KW - Primed-bursts stimulation
KW - White matter
UR - http://www.scopus.com/inward/record.url?scp=0034516550&partnerID=8YFLogxK
U2 - 10.1016/S0168-0102(00)00187-5
DO - 10.1016/S0168-0102(00)00187-5
M3 - Article
C2 - 11164561
AN - SCOPUS:0034516550
SN - 0168-0102
VL - 38
SP - 349
EP - 356
JO - Neuroscience Research
JF - Neuroscience Research
IS - 4
ER -