LAMINAR PATTERN OF SYNAPTIC ACTIVITY IN RAT PRIMARY VISUAL-CORTEX - COMPARISON OF IN-VIVO AND IN-VITRO STUDIES EMPLOYING THE CURRENT SOURCE DENSITY ANALYSIS
LAMINAR PATTERN OF SYNAPTIC ACTIVITY IN RAT PRIMARY VISUAL-CORTEX - COMPARISON OF IN-VIVO AND IN-VITRO STUDIES EMPLOYING THE CURRENT SOURCE DENSITY ANALYSIS
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DOI：
10.1016/0006-8993(94)91421-4
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发表时间：
1994-01-28
期刊：
影响因子：
2.9
通讯作者：
TEYLER, TJ
中科院分区：
文献类型：
--
作者：
KENANVAKNIN, G;TEYLER, TJ
本研究采用电流源密度分析方法，在体内和体外研究了大鼠初级视觉皮层的主要兴奋/抑制通路。在体内使用自然光刺激，并作为理解体内和体外研究中使用白质电刺激获得的结果的基线。皮层突触活动的时间模式显示出早期兴奋，其特征是短时间和高振幅的下沉，随后是抑制，其特征是持续时间长，低振幅的活跃源。这种突触活动的空间模式显示早期兴奋输入到第4层和第3层。核上层较浅层的突触活动潜伏期较长。相对于第4层，小颗粒层的兴奋性活动延迟。这种突触活动的时空模式支持视觉皮层的顺序信息处理模型。基于体内电刺激和光刺激的结果，我们得出结论，白质电刺激激活丘脑-皮层输入，导致类似光刺激引起的突触后活动的层流模式。电刺激显示了额外的反正交和反正正交活性（下行轴突到白质的侧支），导致早期快速成分和第六层额外活性。体内和体外层流突触活动模式（施加电刺激）的主要区别是体外制备中第四层突触活性降低，颗粒内层突触活性增加。我们的结论是，视觉皮层切片制备保留了该区域的主要通路和电生理功能。皮层切片制备的技术优势将促进研究，并为这种复杂的皮层网络提供额外的见解。
In the present study we employed current source density analysis to study the major excitatory/inhibitory pathways in rat primary visual cortex in vivo and in vitro. A natural photic stimulus was used in vivo and served as a baseline for understanding the results obtained from in vivo and in vitro studies employing electrical stimulation of the white matter. The temporal pattern of synaptic activity in the cortex revealed an early excitation, characterized by sinks of short duration and high amplitude, that was followed by inhibition, characterized by long lasting, low amplitude active sources. The spatial pattern of this synaptic activity displayed early excitatory inputs to layer IV and lower layer III. Supragranular layers exhibited synaptic activity of longer latency at more superficial layers. The excitatory activity of the infragranular layers was delayed relative to that in layer IV. This spatial and temporal pattern of synaptic activity supports the model of sequential information processing in visual cortex. Based on the results of electrical and photic stimulations in vivo we conclude that electrical stimulation of white matter activate the thalamo-cortical input which results in a similar laminar pattern of postsynaptic activity evoked by photic stimulation. Electrical stimulation revealed additional antidromic and anti-orthodromic activity (collaterals of descending axons to white matter), resulting in the early fast components and the additional activity in layer VI. The major differences between in vivo and in vitro laminar pattern of synaptic activity (applying electrical stimulation) were reduced synaptic activity in layer IV and increased synaptic activity in the infragranular layers in the in vitro preparation. We concluded that the visual cortex slice preparation preserves the major pathways and electrophysiological function of this area. The technical advantages of the cortical slice preparation will facilitate studies and provide additional insight into this complex cortical network.