成年大鼠视皮层局部场电位振荡特性的研究

Study on local field potential oscillation features in visual cortex of adult rats

目的从神经元集群层次上探讨大鼠初级视皮层(V1区)局部场电位振荡的层间特性。方法利用细胞外记录技术,记录麻醉状态下成年大鼠V1区的局部场电位振荡活动。经过快速傅立叶转换获得功率频谱图,分析V1区2+3层(L2/3)和5层(L5)低频段和高频段的功率成分,并计算功率比值。绘制功率比值与微电极穿行皮层深度分布散点图,比较L2/3和L511～20Hz局部场电位的频段功率值和功率比值差异,来观察成年大鼠V1区局部场电位振荡的层间差异。结果成年大鼠V1区L2/3以低频(2～5Hz)振荡为主,L5除了2～5Hz频段存在功率频谱高峰,在10～20Hz频段也出现了强烈的振荡活动。对皮层深度与功率比值绘制散点图并进行相关分析,结果显示两者呈正相关(r=0.663,P=0.000),回归方程为y=-0.649+0.001x。L2/311～20Hz频段功率值为(0.97±0.50)×10-8μV2·Hz-1,L5该频段功率值为(6.38±2.94)×10-8μV2·Hz-1,2层间比较差异有显著统计学意义(P=0.000)。结论成年大鼠V1区自发局部场电位振荡存在层间特性,较高频段振荡活动倾向于出现在L5。

Objective To investigate the laminar processing mechanism of local field potential oscillation in primary visual cortex（V1 area） of adult rats from the neuron assembly level.Methods With extracellular recording techniques,the spontaneous local field oscillation of neural population in the primary visual cortex（V1 area） of adult rat was tested.Power spectrums were got via fast Fourier transformation of local field oscillation.The power of low high frequency in layer 2/3（L 2/3） and layer 5（L5） were analyzed.The scatter plot of power ratio as a function of cortical depth was drawn,and the differences of power and its ratio between L2/3 and L5 from 11 Hz to 20 Hz frequency were compared to observe the laminar difference of spontaneous local field oscillation of neural population in the primary visual cortex（V1 area） of adult rat.Results L2/3 showed a prominent peak from 2 Hz to 5 Hz in power spectrum,while the power spectrum of local field potential showed a prominent peak at 10-20 Hz in L5,apart from low-frequency activity.Power ratio was positively correlated with cortical depth which was estimated from distance traveled by electrode（r=0.663,P=0.000）,the regression equation was y=-0.649＋0.001x.The power from 11 Hz to 20 Hz were（0.97±0.50）×10-8 μV2·Hz-1 in L2/3 recording sites and（6.38±2.94）×10-8 μV2·Hz-1 in L5 recording sites,there was significant difference between two layers（P=0.000）.Conclusion The spontaneous local field potentials in V1 of adult rats show the laminar specificity,the high oscillation is prone to appear in L5.