COOLING IN CAT VISUAL CORTEX: STABILITY OF ORIENTATION SELECTIVITY DESPITE CHANGES IN RESPONSIVENESS AND SPIKE WIDTH
COOLING IN CAT VISUAL CORTEX: STABILITY OF ORIENTATION SELECTIVITY DESPITE CHANGES IN RESPONSIVENESS AND SPIKE WIDTH
复制标题
DOI：
10.1016/j.neuroscience.2009.07.064
复制
发表时间：
2009-12-01
期刊：
影响因子：
3.3
通讯作者：
Martin, K. A. C.
中科院分区：
文献类型：
--
作者：
Girardin, C. C.;Martin, K. A. C.
冷却是几种可逆的方法之一，用于冷却大脑的局部区域。在这里，冷却的效果在麻醉和瘫痪的猫的初级视觉皮层（17区）进行了研究。当皮质表面温度冷却至约0 ℃时，表面以下2mm的温度为20 ℃。冷的横向扩散在距冷却回路至少约700 μ m的距离上是均匀的。当皮层被冷却的视觉诱发反应漂移正弦波光栅强烈降低成比例的冷却温度，但平均自发活动的细胞只略有下降。在冷却过程中，对取向调谐曲线的最强影响是在峰值响应上，并且取向带宽没有改变，这表明了分裂机制。我们的研究结果表明，皮层电路是强大的，在面对冷却，并保留其基本功能，虽然减少了响应。在几乎所有的情况下，在冷却期间，在半高处测量的细胞外尖峰波形的宽度平均增加了50%，并且在复温后恢复。尖峰宽度的增加与对最佳刺激的反应幅度的变化呈负相关。因此，细胞外锋电位的形状可以被用作一种可靠和快速的方法来评估神经元反应的变化是由于直接冷却还是对其传入源的远距离影响。(C)2009年IBRO。由爱思唯尔有限公司出版。保留所有权利。
Cooling is one of several reversible methods used to inactivate local regions of the brain. Here the effect of cooling was studied in the primary visual cortex (area 17) of anaesthetized and paralyzed cats. When the cortical surface temperature was cooled to about 0 degrees C, the temperature 2 mm below the surface was 20 degrees C. The lateral spread of cold was uniform over a distance of at least similar to 700 mu m from the cooling loop. When the cortex was cooled the visually evoked responses to drifting sine wave gratings were strongly reduced in proportion to the cooling temperature, but the mean spontaneous activity of cells decreased only slightly. During cooling the strongest effect on the orientation tuning curve was on the peak response and the orientation bandwidth did not change, suggesting a divisive mechanism. Our results show that the cortical circuit is robust in the face of cooling and retains its essential functionality, albeit with reduced responsiveness. The width of the extracellular spike waveform measured at half height increased by 50% on average during cooling in almost all cases and recovered after re-warming. The increase in spike width was inversely correlated with the change in response amplitude to the optimal stimulus. The extracellular spike shape can thus be used as a reliable and fast method to assess whether changes in the responses of a neuron are due to direct cooling or distant effects on a source of its afferents. (C) 2009 IBRO. Published by Elsevier Ltd. All rights reserved.