Experience-dependent depression of vibrissae responses in adolescent rat barrel cortex
Experience-dependent depression of vibrissae responses in adolescent rat barrel cortex
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DOI：
10.1046/j.1460-9568.1998.00222.x
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发表时间：
1998-06-01
影响因子：
3.4
通讯作者：
Fox, K
中科院分区：
文献类型：
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作者：
Glazewski, S;McKenna, M;Fox, K
在青春期（大约1个月大）大鼠中，短时间的触须剥夺可导致对再生触须的刺激的皮质反应的抑制。在代表被剥夺触须的桶柱中，对于位于代表备用触须的桶柱附近的神经元，抑制更大。一种可能的解释是，备用触须产生异突触抑制的主要触须反应（Glazewski & Fox，1996）。为了进一步验证这一观点，我们比较了剥夺所有触须（完全没有异突触影响）与剥夺单个触须（预期最大异突触影响）的效果。另外，我们还通过皮层下结构的记录来检测抑制的起源，在7天的剥夺和6-8天的再生后，我们检测了桶皮层细胞、丘脑vPm神经元和三叉神经节细胞对再生触须刺激的反应。我们发现，抑郁症是更大的皮层，如果一个单一的触须已被剥夺比如果所有触须已被剥夺。（对于第II/III层，单一触须剥夺动物的平均主触须反应是所有触须剥夺动物的36%，对于第IV层，为41%。）这暗示了被保留的触须在主动下调对被剥夺的触须的反应。然而，一些抑郁症也可以产生在动物剥夺所有触须（第II/III层为39%，第IV层为74%的控制水平）。这些结果表明，简单的激活撤回有一个抑郁的反应，但抑郁症是更大的，如果一些积极的投入仍然存在。然而，两种形式的剥夺都不会影响丘脑或三叉神经节对主要触须刺激的反应，这表明抑郁症起源于皮质。在皮质内，皮质内连接似乎受影响最大，因为在第II/III层和第IV层中发现了在中间延迟（9-14 ms）响应的细胞中的最大抑郁。
A short period of vibrissae deprivation in an adolescent (approximate to 1 month old) rat can lead to depression of the cortical response to stimulation of the regrown vibrissae, In a barrel column representing the deprived vibrissa, depression is greater for neurons located close to the barrel column representing the spared vibrissa. One possible explanation is that the spared vibrissa produces heterosynaptic depression of the principal vibrissa response (Glazewski & Fox, 1996). To test this idea further, we compared the effect of depriving all vibrissae (no heterosynaptic influence at all) with depriving a single vibrissa (maximal heterosynaptic influence expected). In addition we tested the origin of the depression by recording from subcortical structures.After 7 days' deprivation and 6-8 days' regrowth, we tested the responses of barrel cortex cells, thalamic vPm neurons and trigeminal ganglion cells to stimulation of the regrown vibrissae. We found that depression was greater in cortex if a single vibrissa had been deprived than if all vibrissae had been deprived. (Average principal vibrissae responses in single vibrissae deprived animals were 36% of those in all vibrissae deprived animals for layer II/III and 41% for later IV.) This implicates the spared vibrissae in actively down-regulating responses to the deprived vibrissae. However, some depression could also be produced in animals deprived of all vibrissae (layers II/III were 39% and layer IV 74% of control levels). These results indicate that simple withdrawal of activation has a depressive effect on responses but that depression is far greater if some active inputs remain. Neither form of deprivation had an effect on responses to principal vibrissa stimulation in the thalamus or trigeminal ganglion however, suggesting that depression originates in the cortex. Within the cortex, intracortical connections seem most affected as the greatest depression was found in layers II/III and in layer IV among cells responding at intermediate latencies (9-14 ms).