School of Behavioral and Brain Sciences, University of Texas at Dallas, 800 W. Campbell Road Richardson, TX 75080, USA.
Neuroscience. 2012 Mar 15;205:81-90. doi: 10.1016/j.neuroscience.2011.12.056. Epub 2012 Jan 8.
Many psychological and physiological studies with simple stimuli have suggested that perceptual learning specifically enhances the response of primary sensory cortex to task-relevant stimuli. The aim of this study was to determine whether auditory discrimination training on complex tasks enhances primary auditory cortex responses to a target sequence relative to non-target and novel sequences. We collected responses from more than 2000 sites in 31 rats trained on one of six discrimination tasks that differed primarily in the similarity of the target and distractor sequences. Unlike training with simple stimuli, long-term training with complex stimuli did not generate target-specific enhancement in any of the groups. Instead, cortical receptive field size decreased, latency decreased, and paired pulse depression decreased in rats trained on the tasks of intermediate difficulty, whereas tasks that were too easy or too difficult either did not alter or degraded cortical responses. These results suggest an inverted-U function relating neural plasticity and task difficulty.
许多使用简单刺激的心理和生理研究表明，知觉学习特别增强了初级感觉皮层对与任务相关刺激的反应。本研究的目的是确定在复杂任务上进行听觉辨别训练是否会增强初级听觉皮层对目标序列的反应相对于非目标和新序列的反应。我们从 31 只接受了六种不同辨别任务之一训练的大鼠中收集了超过 2000 个部位的反应，这些任务主要区别在于目标和干扰序列的相似性。与使用简单刺激的训练不同，长期使用复杂刺激的训练并没有在任何一个组中产生特定于目标的增强。相反，在接受中等难度任务训练的大鼠中，皮层感受野大小减小，潜伏期减小，成对脉冲抑制减小，而过于简单或过于困难的任务要么没有改变，要么降低了皮层反应。这些结果表明，神经可塑性与任务难度之间存在一种倒 U 型关系。
