@phdthesis{oai:oist.repo.nii.ac.jp:00001923,
 author = {Watanabe, Sakurako},
 month = {2021-02-08, 2021-02-08},
 note = {Dopamine-dependent plasticity in synapses between the cortical pyramidal neurons and the spiny projection neurons (SPNs) in the striatum is associated with reinforcement learning. Spike timing-dependent plasticity (STDP), which depends on the relative timing of pre- and postsynaptic activity, has been described in these synapses. Previously the STDP profile has been determined by testing single input-output events in isolation from the context of concurrently occurring multiple inputs into the same neuron. However, interactions among synaptic inputs at the level of the dendrites might influence STDP induction. The overall aim of this thesis is to study whether the activation of multiple synaptic inputs alters the characteristics of STDP in the corticostriatal pathway. Whole-cell electrophysiological recordings of SPNs in the dorsomedial striatum (DMS) of mouse brain slices were made in the presence of two inputs stimulated at different time points relative to postsynaptic firing. This protocol induced LTD depending on the timing of each input in SPNs expressing dopamine D1 receptors but not in SPNs expressing D2 receptors. When two inputs showed interactions, indicated by nonlinear summation of evoked EPSPs, STDP profiles were altered from those seen when single inputs were studied. In addition, pairing of two presynaptic inputs without postsynaptic firing also induced LTD, suggesting that pairing of synaptic inputs alone within a temporal window can induce associative synaptic plasticity. In separate experiments, optogenetic release of dopamine two seconds after each pairing modified STDP, depending on the input timing and interactions. Dopamine also modulated associative synaptic plasticity induced in the absence of postsynaptic firing. These results suggest that the rules for synaptic plasticity observed with multiple inputs to the same neuron are not identical to those observed when inputs are tested one at a time per neuron. This new knowledge helps to place STDP in the context of whole brain activity and adds to current understanding of associative learning in the striatum.},
 school = {Okinawa Institute of Science and Technology Graduate University},
 title = {皮質線条体シナプス可塑性における複数入力の相互作用},
 year = {}
}