 | A novel form of heterosynaptic depression in the rat auditory cortex
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| | | Cortical pyramidal cells exhibit mono- and polysynaptic field excitatory postsynaptic potentials (monoEPSPs and polyEPSPs) each characterized by the complexity of its shape and latency. An in vivo study in rat showed that medial geniculate nucleus stimulation that mimics acoustic stimulation triggers both monoEPSPs and polyEPSPs in auditory cortex. Intracortical polysynaptic excitatory connections provide the major, sustained excitation of most cortical neurons. Superficial layer pyramidal neurons exhibit a more marked polysynaptic excitatory phase than deep layer pyramidal neurons, and the excitatory effects on pyramidal neurons, particularly those in the superficial layer, are not generally due to monosynaptic input from the thalamus, but polysynaptic inputs from cortical pyramidal neurons. There are a lot of reports about homosynaptic plasticity, such as paired-pulse depression (PPD), however, heterosynaptic plasticity (between the poly- and monosynaptic pathways) has not been well characterized. In the present study, we investigated this interaction in the superficial layer of the rat auditory cortex. |
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