TEMPORAL AND SPATIAL INTEGRATION IN THE RAT SI VIBRISSA CORTEX
TEMPORAL AND SPATIAL INTEGRATION IN THE RAT SI VIBRISSA CORTEX
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DOI：
10.1152/jn.1985.54.3.615
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发表时间：
1985-01-01
影响因子：
2.5
通讯作者：
SIMONS, DJ
中科院分区：
文献类型：
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作者：
SIMONS, DJ
1.用玻璃微吸管记录了16只大鼠体感触须皮层（SI）124个单位在对侧触须联合偏转时的活动。紧凑的多角度机电刺激器被用来刺激单独或两个或三个相邻的胡须的组合个别触须。每根触须都被独立地刺激，以产生受控的机械刺激的时间和空间模式。2.位移后的触须，单位放电到随后的偏转相邻的晶须减少在一个时间依赖的方式。响应抑制在短的偏转间隔处最强，即，10-20 ms，并在第一次偏转后的50-100 ms期间逐渐减小。在许多情况下，这一时期也与正在进行的单位排放量减少相对应。3.在巴比妥酸盐麻醉的大鼠三叉神经节中记录的一级神经元未观察到反应抑制。4.在皮层中，反应抑制的存在和/或程度取决于许多空间因素。这些包括（1）单个毛发移动的角度方向，（2）两个触须偏转的顺序，即哪一个首先偏转，（3）受刺激的触须的特定组合，以及（4）包括多触须刺激的触须的数量（2或3）。5.在一个垂直的电极穿透，一个特定的晶须通常electives最强的兴奋和抑制作用;其他附近的触须引起变量（或没有）的兴奋或抑制。因此，感受野的兴奋和抑制子区域可以不对称地分布在最有效的触须周围。在这些情况下，感受野显示空间取向。6.定量标准被用来分类的基础上的分布的抑制子区域的最大有效的晶须两侧的30个皮质单位。这些细胞中有21个具有对称抑制侧区的感受野（RF）。其他9个单位的反应强烈抑制了一个前偏转的触须的一侧，但相对不受影响，甚至略有促进，由前偏转的胡须的另一侧。具有不对称组织的RF的这些单元中的大多数被记录在皮层的更深的方面（. apprx.软膜表面下1，100 - 2，000 μ m），其中它们构成了分类细胞的大部分。7. 25个单位显示不同的响应峰值，每个偏转晶须在一个multiwhisker刺激。对于这些细胞中的20个，当单个触须位移的角方向与偏转的空间序列不一致时，获得了这样的响应。8.这些研究结果表明，在SI皮层，但不是在三叉神经节的神经元，是差异响应图案的刺激所产生的物体移动在特定的方向和/或以一定的速度通过触须场。这种信息处理似乎部分依赖于皮质内机制。
1. Glass micropipettes were used to record the activity of 124 single units in the somatosensory vibrissa cortex (SI) of 16 rats in response to combined deflections of contralateral vibrissae. Compact multiangular electromechanical stimulators were used to stimulate individual vibrissal hairs alone or in combinations of two or three adjacent whiskers. Each whisker was stimulated independently to produce controlled temporal and spatial patterns of mechanical stimuli. 2. Following displacement of a vibrissa, unit discharges to subsequent deflections of adjacent whiskers are reduced in a time-dependent fashion. Response suppression is strongest at short interdeflection intervals, i.e., 10-20 ms and decreases progressively during the 50-100 ms following the first deflection. In many cases this period also corresponds with a reduction in ongoing unit discharges. 3. Response suppression was not observed for first-order neurons recorded in the trigeminal ganglion of barbiturate-anesthetized rats. 4. In the cortex, the presence and/or degree of response suppression depends on a number of spatial factors. These include (1) the angular direction(s) in which the individual hairs are moved, (2) the sequence in which two whiskers are deflected, that is, which one is deflected first, (3) the particular combination of whiskers stimulated, and (4) the number (2 or 3) of vibrissae comprising the multiwhisker stimulus. 5. Within a vertical electrode penetration, one particular whisker typically elicits the strongest excitatory and inhibitory effects; other, nearby vibrissae elicit variable (or no) excitation or inhibition. Excitatory and inhibitory subregions of a receptive field could thus be distributed asymmetrically around the maximally effective whisker. In these cases, the receptive fields displayed spatial orientations. 6. Quantitative criteria were used to classify 30 cortical units on the basis of the distribution of inhibitory subregions on either side of the maximally effective whisker. Twenty-one of these cells had receptive fields (RFs) with symmetrically inhibitory side regions. Responses of the other nine units were strongly suppressed by a preceding deflection of a vibrissa one one side but relatively unaffected, or even slightly facilitated, by preceding deflection of the whisker on the other side. Most of these units with asymmetrically organized RF''s were recorded in the deeper aspects of the cortex (.apprx. 1,100-2,000 .mu.m below the pial surface) where they constituted a majority of the classified cells. 7. Twenty-five units displayed distinct response peaks to each deflected whisker in a multiwhisker stimulus. For 20 of these cells such responses were obtained when the angular direction of the individual whisker displacements paralleled the spatial sequence of the deflections. 8. These findings suggest that neurons in the SI cortex, but not in the trigeminal ganglion, are differentially responsive to patterned stimuli produced by objects moving in particular directions and/or at certain velocities through the vibrissal field. Such processing of information appears to depend in part or intracortical mechanisms.