Learning increases stimulus salience in anterior inferior temporal cortex of the macaque
Learning increases stimulus salience in anterior inferior temporal cortex of the macaque
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DOI：
10.1152/jn.2001.86.1.290
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发表时间：
2001-07-01
影响因子：
2.5
通讯作者：
Desimone, R
中科院分区：
文献类型：
--
作者：
Jagadeesh, B;Chelazzi, L;Desimone, R
有了经验，一个对象可以变得与行为相关，从而在视觉场景中呈现时迅速吸引我们的兴趣。这些学习效应的一个可能的部位是前下颞叶（aIT）皮层，那里的神经元被认为参与了从复杂的视觉显示中过滤无关信息的过程。我们训练猴子持续扫视两张图片中的一张，以换取奖励。该阵列是通过配对两个刺激来构建的，其中一个刺激在单独呈现时引起细胞的良好反应（“好”刺激），另一个刺激引起不良反应（“差”刺激）。当猴子学习扫视阵列中的好刺激或差刺激时，aIT细胞的活动被记录下来。我们发现，神经元反应的阵列更大（前眼跳发生）时，培训加强眼跳的好刺激比培训加强眼跳的差刺激。这种差异在不正确的试验中不存在，即，当对不正确的刺激进行扫视时。因此，活动的差异与性能相关。在录制过程中，响应差异随着性能的提高而增加。与aIT皮层中线索视觉搜索和工作记忆的研究不同，这种反应差异之前并没有细胞基线活动的差异。此外，我们在一个版本的任务中发现了类似的效果，在这个版本中，在记录会话之前预先学习的10对可能的刺激中的任何一对都可能出现在给定的试验中，从而排除了工作记忆策略。结果表明，通过训练增加刺激的行为意义会改变aIT皮层中该刺激的神经表征。结果，响应于相关刺激的特征的神经元可以抑制响应于不相关刺激的特征的神经元。
With experience, an object can become behaviorally relevant and thereby quickly attract our interest when presented in a visual scene. A likely site of these learning effects is anterior inferior temporal (aIT) cortex, where neurons are thought to participate in the filtering of irrelevant information out of complex visual displays. We trained monkeys to saccade consistently to one of two pictures in an array, in return for a reward. The array was constructed by pairing two stimuli, one of which elicited a good response from the cell when presented alone ("good" stimulus) and the other of which elicited a poor response ("poor" stimulus). The activity of aIT cells was recorded while monkeys learned to saccade to either the good or poor stimulus in the array. We found that neuronal responses to the array were greater (before the saccade occurred) when training reinforced a saccade to the good stimulus than when training reinforced a saccade to the poor stimulus. This difference was not present on incorrect trials, i.e., when saccades to the incorrect stimulus were made. Thus the difference in activity was correlated with performance. The response difference grew over the course of the recording session, in parallel with the improvement in performance. The response difference was not preceded by a difference in the baseline activity of the cells, unlike what was found in studies of cued visual search and working memory in aIT cortex. Furthermore, we found similar effects in a version of the task in which any of 10 possible pairs of stimuli, prelearned before the recording session, could appear on a given trial, thereby precluding a working memory strategy. The results suggest that increasing the behavioral significance of a stimulus through training alters the neural representation of that stimulus in aIT cortex. As a result, neurons responding to features of the relevant stimulus may suppress neurons responding to features of irrelevant stimuli.