title: Visual experience regulates the development of long-term synaptic modifications induced by low-frequency stimulation in mouse visual cortex.
abstract: Manipulation of visual experience can considerably modify visual responses of visual cortical neurons even in adulthood in the mouse, although the modification is less profound than that observed during the critical period. Our previous studies demonstrated that low-frequency (2Hz) stimulation for 15min applied to layer 4 induces T-type Ca2+channel-dependent long-term potentiation (LTP) at excitatory synapses in layer 2/3 neurons of visual cortex during the critical period. In this study, we investigated whether low-frequency stimulation could induce synaptic plasticity in adult mice. We found that 2Hz stimulation induced LTP of extracellular field potentials evoked by stimulation of layer 4 in layer 2/3 in adulthood as during the critical period. LTP in adulthood was blocked by L-type, but not T-type, Ca2+channel antagonists, whereas LTP during the critical period was blocked by T-type, but not L-type, Ca2+channel antagonists. This developmental change in LTP was prevented by dark rearing. Under pharmacological blockade of GABAAreceptors, T-type Ca2+channel-dependent LTP occurred, whereas L-type Ca2+channel-dependent LTP did not occur. These results suggest that different forms of synaptic plasticity can contribute separately to experience-dependent modification of visual responses during the critical period and in adulthood.
authors.affiliation: Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan; Department of Neurophysiology, Nara Medical University, Kashihara 634-8521, Japan.
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Sugimura
authors.affiliation: Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Division of Physical Therapy, Faculty of Rehabilitation and Care, Seijoh University, Tokai 476-8588, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Yamada
authors.affiliation: Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan. Electronic address: yukiok@nips.ac.jp.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Komatsu
authors.affiliation: Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan. Electronic address: yumikoy@nips.ac.jp.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Yoshimura
mesh_terms: D000818:Animals; D020746:Calcium Channels, L-Type / Q000502:physiology; D020747:Calcium Channels, T-Type / Q000502:physiology; D004558:Electric Stimulation; D017774:Long-Term Potentiation; D008810:Mice, Inbred C57BL; D012683:Sensory Deprivation; D014793:Visual Cortex / Q000254:growth & development / Q000502:physiology*
chemical_list: D020746:Calcium Channels, L-Type; D020747:Calcium Channels, T-Type
keywords: Development; Experience-dependent modification; L-type Ca(2+) channel; Long-term potentiation; Plasticity; T-type Ca(2+) channel; Visual cortex