Suzuki Wataru, Matsumoto Kenji, Tanaka Keiji
Cognitive Brain Mapping Laboratory, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.
J Neurosci. 2006 Oct 11;26(41):10524-35. doi: 10.1523/JNEUROSCI.1532-06.2006.
We can discriminate visual objects at multiple levels, from coarse categorization to individual identification. It is not known how the brain adapts to the varying levels of discrimination required in different behavioral contexts. In the present study, we investigated whether the stimulus selectivity of neuronal responses in the monkey inferotemporal cortex, which is the final unimodal stage in the ventral visual pathway, changes with the varying levels of discrimination required for different task conditions. Responses of each inferotemporal cell to the same set of nine object images were examined in two different task conditions. The task alternated between coarse and fine discriminations in the first experiment, and the rule alternated between categorization and individual object identification in the second experiment. Despite these changes in the task requirements and the resulting differences in the monkeys' behavior, we found that the responses of inferotemporal cells were largely unchanged in both experiments. Our results suggest that representation of object images in the inferotemporal cortex is stable and rather insensitive to these kinds of shifts in behavioral context. Neuronal adaptations to behavioral context may occur downstream of the inferotemporal cortex.
我们能够在多个层面辨别视觉对象，从粗略分类到个体识别。目前尚不清楚大脑如何适应不同行为背景下所需的不同辨别水平。在本研究中，我们调查了猴子颞下皮质（腹侧视觉通路的最后一个单峰阶段）中神经元反应的刺激选择性是否会随着不同任务条件所需的不同辨别水平而变化。在两种不同的任务条件下，检查了每个颞下细胞对同一组九张物体图像的反应。在第一个实验中，任务在粗略辨别和精细辨别之间交替，在第二个实验中，规则在分类和个体物体识别之间交替。尽管任务要求发生了这些变化以及猴子行为产生了差异，但我们发现在两个实验中颞下细胞的反应基本未变。我们的结果表明，颞下皮质中物体图像的表征是稳定的，并且对行为背景中的这类变化相当不敏感。对行为背景的神经元适应可能发生在颞下皮质的下游。
