Plasticity Strength At Cortical Glutamatergic And GABAergic Neurons Is Associated With Learning Efficiency

Objective: To explore the relationship between learning efficiency and plasticity of different types of neurons in the barrel cortex by establishing an associative learning memory model mouse.Methods: 1.Building : choose the mice of C57Thy1-YFP / GAD67-GFP(herein after referred to as mice)in postnatal days 20,which were divided into two groups.The first group of mice was given odor stimulus(OS,butyl acetate toward the noses),at the same time 5Hz whisker stimulus(WS)was given the right beard.Each of the mice was trained 20 seconds in each time,and five times per day with two hours of intervals by ten days.During the training,each mouse was placed in a home-made cage.Cares were taken including no stressful experiment condition and circadian disturbance to the mice that showed normal whisking and symmetric whiskers.The second group was given an unpaired training,when the WS is giving and OS is not,after one hour the mice were accepted OS training only,cycling.2.Behavior experiment: the mice were beaten and analyzed for the whisker swing after the day of training,only the OS was given to the mice,we use the MATLAB software to track the whisker wobble.The learning efficiency of the mice was divided into different groups that according to the swing track of the whisker.The first group of mice appears the high efficiency group and low efficiency group,the second group were unpaired group.3.Electrophysiological experiments: the mice were tested electrophysiological experiments while associative training at 6 days.The changes of Coding ability and synaptic transmission efficiency at glutamate neurons and GABAergic neurons in the barrel cortex were importantly measurement standard.Results: 1.the results of behavioral experimentA)the high efficiency group compared with the low efficiency group,their frequency of whisker were increased(P<0.05),and the swing angle of whisker were also increased(P<0.05);B)the low efficiency group compared with the unpaired training group,their frequency of whisker were increased(P<0.01),and the swing angle of whisker were also increased(P<0.01);C)the high efficiency group compared with the unpaired training group,their frequency of whisker were increased(P<0.001),and the swing angle of whisker were also increased(P<0.001).2.the results of electrophysiological experiments A)Glutamate neuron: 1)compared with low efficiency group,the mice barrel cortex glutamate neuron spikes in unit time of high efficiency group is increased P<0.05),s EPSC(spontaneous excitatory postsynaptic currents)intervals was shorted(P <0.001),and the amplitude was increased(P<0.05),s IPSC(spontaneous inhibitory postsynaptic current)intervals was extended(P<0.05),and the amplitude was decreased(P<0.05);2)compared with unpaired training group,the mice barrel cortex glutamate neuron spikes in unit time of low efficiency group is also increased(P<0.01),s EPSC(spontaneous excitatory postsynaptic currents)intervals was shorted(P<0.01),and the amplitude was increased(P<0.01),s IPSC(spontaneous inhibitory postsynaptic current)intervals was extended(P<0.01),and the amplitude was decreased(P<0.01);3)compared with unpaired training group,the mice barrel cortex glutamate neuron spikes in unit time of high efficiency group is higher and increased(P<0.001),s EPSC(spontaneous excitatory postsynaptic currents)intervals was decreased(P<0.001),and the amplitude was increased(P<0.001),s IPSC(spontaneous inhibitory postsynaptic current)intervals was extended(P<0.001),and the amplitude was decreased(P<0.05).B)GABAergic neurons: 1)compared with low efficiency group,the mice barrel cortex GABAergic neurons in unit time of high efficiency group is decreased(P<0.05),s EPSC(spontaneous excitatory postsynaptic currents)intervals was extended(P<0.05),and the amplitude was decreased(P<0.05);2)compared with unpaired training group,the mice barrel cortex GABAergic neurons in unit time of low efficiency group is decreased(P<0.01),s EPSC(spontaneous excitatory postsynaptic currents)intervals was extended(P<0.01),and the amplitude was decreased(P<0.01);3)compared with unpaired training group,the mice barrel cortex GABAergic neurons in unit time of high efficiency group is decreased(P<0.001),s EPSC(spontaneous excitatory postsynaptic currents)intervals was extended(P<0.001),and the amplitude was decreased(P<0.001).Conclusion: Paired whisker and odor stimulations induce odorant-induced whisker motion,whose onset appears high efficiency and low efficiency.Learning efficiency is associated with plasticity strength at cortical glutamatergic and GABAergic neurons.Compared with the unpaired training group,the glutamate neurons function in the barrel cortex of the paired training group are up-regulated and the GABAergic neuron function is down-regulated;moreover those up-regulated and down-regulated in the high efficiency group were more significant.