The Characterize Of Neuron And The Impact Of Synaptic Input In Visual Cortex Of Rats

ObjectiveTo observe the electrophysiological characteristics of visual cortex layer IV in normal development rats and the impact of different synapse and the input mode on neuron reaction of visual cortex in rats. Research if or not the time windows of different synapse affect the different afferent and how to regulation.1. To identify the electrophysiological characteristics and latency of visual cortex layer IV in normal development rats.2. To search the impact of different synapse and the input mode on neuron reaction of visual cortex in rats.3. To study the age impact on the neuron reaction.Methods1. Analyze the synaptic conductance according to the mode with current patch clamp; and dissociated the EPSC and IPSC under different voltage condition, which is used to calculate the latency of the two different current.2. Change the stimulation mode to observe the dynamics of synaptic conductance in visual cortex layer IV of rats.3. Change the distance between two stimulation pipettes to record the synaptic response and calculate the CV of before and after stimulation to describe the synaptic events under the voltage patch clamp mode.Result1. The reversal potential of EPSC is at-50.39±13.74mV, but IPSC’s is at0.47±10.33mV. The latency of EPSC is5.10±0.52ms, and the latency of IPSC is11.45±1.84ms.2. There have two different composition of synaptic conductance:excitation and inhibition.3. Different stimulation mode can result in distinct change, in which the combined stimulation with S1and S2may displays much more distinction; and the synaptic conductance has altered before and after different synaptic input.4.100-120μm may be the mini-column in visual cortex of rats. 5. Different synaptic input may alter the synaptic response in visual cortex of rats.6. The classical coefficient of variation method for "quantal" analysis of synaptic response allows unambiguous identification of the before and after stimulation synaptic plasticity mechanisms.7. LTP is absent in layer IV of visual cortex in postnatal14rats, but can be induced in postnatal20rats, whatever the stimulation mode.8. There has an nonlinear reconciliation between S1and S2during an’"time window" and the “time window”of P14is±0.5ms and P20is±0.1msConclusions1. The reversal potential and latency of EPSC and IPSC is different.2. Dynamics of excitation and inhibition underlying different current injection in rat visual cortex layer IV.3. The different synaptic inputs have impact on the synaptic conductance, respectively, including the excitation and inhibition conductance.4. mini-column or alike-column may exist in rats visual cortex.5. The synaptic mechanism may differ underlying different synaptic inputs, including pre-or/and postsynaptic mechanism.6. Age may have an role in synaptic response:LTP is absent in layer IV of visual cortex in postnatal14rats, but can be induced in postnatal20rats, whatever the stimulation mode.7. It displays an “time window” in P14and P20rats, and during this time, there has an nonlinear reconciliation between S1and S2.