Shifting and scaling adaptation to dynamic stimuli in somatosensory cortex
Shifting and scaling adaptation to dynamic stimuli in somatosensory cortex
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DOI：
10.1111/j.1460-9568.2007.05847.x
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发表时间：
2007-10-01
影响因子：
3.4
通讯作者：
Schnupp, J. W. H.
中科院分区：
文献类型：
--
作者：
Garcia-Lazaro, J. A.;Ho, S. S. M.;Schnupp, J. W. H.
最近的报告表明，豚鼠中脑神经元的反应迅速改变其反应的动态范围，以跟踪持续声级分布统计数据的变化。这会提高最常见刺激强度的编码准确性。为了研究这种类型的适应是否也存在于其他感觉方式中，我们描述了大鼠初级体感皮层 (S1) 神经元对胡须连续正弦振动的强度响应功能，其振幅每 40 毫秒改变一次。振动幅度是随机选择的，因此有 80% 的机会从相对狭窄的“高概率区域”(HPR) 中提取振动幅度。然后通过移动或扩大 HPR 来操纵刺激均值和方差。我们发现，大鼠 S1 神经元主要通过改变其阈值来适应 HPR 的变化，并通过改变其速率水平曲线的斜率来适应 HPR 宽度的变化。使用现实的单神经元模型，我们继续证明后超极化电流（例如 K-Ca(2+) 通道携带的电流）可能导致阈值漂移，但不是斜率变化。
Recent reports have shown that responses of midbrain neurons in the guinea pig rapidly shift the dynamic range of their responses to track changes in the statistics of ongoing sound-level distributions. This results in an increased coding accuracy for the most commonly occurring stimulus intensities. To investigate whether this type of adaptation might also be found in other sensory modalities, we characterized the intensity-response functions of neurons in rat primary somatosensory cortex (S1) to continuous sinusoidal vibration of the whiskers with amplitudes that were changed every 40 ms. Vibration amplitudes were selected randomly such that there was an 80% chance for the amplitude to be drawn from a relatively narrow 'high-probability region' (HPR). Stimulus mean and variance were then manipulated by shifting or widening the HPR. We found that rat S1 neurons adapt to shifts of the HPR mainly by shifting their thresholds, and to changes in HPR width by changing the slope of their rate-level curves. Using realistic single-neuron models, we go on to show that after-hyperpolarizing currents, such as those carried by K-Ca(2+) channels, may be responsible for the threshold shifts, but not the slope changes.