LONG ADAPTATION REVEALS MOSTLY ATTRACTIVE SHIFTS OF ORIENTATION TUNING IN CAT PRIMARY VISUAL CORTEX
LONG ADAPTATION REVEALS MOSTLY ATTRACTIVE SHIFTS OF ORIENTATION TUNING IN CAT PRIMARY VISUAL CORTEX
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DOI：
10.1016/j.neuroscience.2009.09.003
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发表时间：
2009-12-15
期刊：
影响因子：
3.3
通讯作者：
Molotchnikoff, S.
中科院分区：
文献类型：
--
作者：
Ghisovan, N.;Nemri, A.;Molotchnikoff, S.
在成人大脑中，感觉皮层神经元在长时间暴露于适当的刺激（适应）后，其反应特性会发生短暂变化。在猫V1中，取向选择性细胞在适应非优选取向后改变其优选取向。关于这些转变的方向，朝向（吸引）或远离（排斥）适配器，有相互矛盾的报道。此外，吸引力变化背后的机制仍然无法解释。在本研究中，我们表明，有吸引力的转变是12分钟适应的最常见结果。总体而言，细胞显示倾斜方向的选择性表现出显着更大的变化比细胞调整到基数方向。此外，细胞选择性的基本方向有较大的位移幅度时，原始的首选方向和适应方向之间的绝对差异增加。相反，细胞调整到倾斜的方向表现出较大的位移幅度时，这个绝对的方向差异较窄。因此，调整到倾斜轮廓的神经元似乎在对小扰动的反应中表现出更多的可塑性。两种不同的机制似乎产生吸引力和排斥力的取向转变。有吸引力的转变的结果，从并发响应抑郁症的非适应侧翼和选择性响应促进适应侧翼的取向调谐曲线。相反，排斥性的变化是完全由适应侧翼上的响应抑郁症引起的。我们认为，早期的机制导致排斥性的转变，而吸引力的转变从事随后的后期促进。一个潜在的作用，有吸引力的转变可能是改善周围的适应方向的刺激歧视。(C)2009年IBRO。由爱思唯尔有限公司发布。保留所有权利。
In the adult brain, sensory cortical neurons undergo transient changes of their response properties following prolonged exposure to an appropriate stimulus (adaptation). In cat V1, orientation-selective cells shift their preferred orientation after being adapted to a non-preferred orientation. There are conflicting reports as to the direction of those shifts, towards (attractive) or away (repulsive) from the adapter. Moreover, the mechanisms underlying attractive shifts remain unexplained. In the present investigation we show that attractive shifts are the most frequent outcome of a 12 min adaptation. Overall, cells displaying selectivity for oblique orientations exhibit significantly larger shifts than cells tuned to cardinal orientations. In addition, cells selective to cardinal orientations had larger shift amplitudes when the absolute difference between the original preferred orientation and the adapting orientation increased. Conversely, cells tuned to oblique orientations exhibited larger shift amplitudes when this absolute orientation difference was narrower. Hence, neurons tuned to oblique contours appear to show more plasticity in response to small perturbations. Two different mechanisms appear to produce attractive and repulsive orientation shifts. Attractive shifts result from concurrent response depression on the non-adapted flank and selective response facilitation on the adapted flank of the orientation tuning curve. In contrast, repulsive shifts are caused solely by response depression on the adapted flank. We suggest that an early mechanism leads to repulsive shifts while attractive shifts engage a subsequent late facilitation. A potential role for attractive shifts may be improved stimulus discrimination around the adapting orientation. (C) 2009 IBRO. Published by Elsevier Ltd. All rights reserved.