Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, O&N2 Campus Gasthuisberg, Herestraat 49, bus 1021, 3000 Leuven, Belgium; Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium.
Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, O&N2 Campus Gasthuisberg, Herestraat 49, bus 1021, 3000 Leuven, Belgium.
Neuroimage. 2023 Jan;265:119780. doi: 10.1016/j.neuroimage.2022.119780. Epub 2022 Dec 1.
Neuroimaging and single cell recordings have demonstrated the presence of STS body category-selective regions (body patches) containing neurons responding to presentation of static bodies and body parts. To date, it remains unclear if these body patches and additional STS regions respond during observation of different categories of dynamic actions and to what extent categorization learning influences representations of observed actions in the STS. In the present study, we trained monkeys to discriminate videos depicting three different actions categories (grasping, touching and reaching) with a forced-choice action categorization task. Before and after categorization training, we performed fMRI recordings while monkeys passively observed the same action videos. At the behavioral level, after categorization training, monkeys generalized to untrained action exemplars, in particular for grasping actions. Before training, uni- and/or multivariate fMRI analyses suggest a broad representation of dynamic action categories in particular in posterior and middle STS. Univariate analysis further suggested action category specific training effects in middle and anterior body patches, face patch ML and posterior STS region MT and FST. Overall, our fMRI experiments suggest a widespread representation of observed dynamic bodily actions in the STS that can be modulated by visual learning, supporting its proposed role in action recognition.
神经影像学和单细胞记录已经证明了存在 STS 躯体类别选择性区域（躯体斑块），其中包含对呈现静态身体和身体部位有反应的神经元。迄今为止，尚不清楚这些躯体斑块和其他 STS 区域是否在观察不同类别的动态动作时做出反应，以及分类学习在多大程度上影响 STS 中观察到的动作的表示。在本研究中，我们训练猴子通过强制选择动作分类任务来区分描绘三个不同动作类别的视频（抓取、触摸和伸手）。在分类训练之前和之后，我们在猴子被动观察相同动作视频时进行 fMRI 记录。在行为水平上，分类训练后，猴子对未训练的动作范例进行了泛化，特别是对抓取动作进行了泛化。在训练之前，单变量和/或多变量 fMRI 分析表明，在后部和中部 STS 中，存在对动态动作类别的广泛表示。单变量分析进一步表明，在中、前躯体斑块、面部斑块 ML 和后部 STS 区域 MT 和 FST 中存在特定于动作类别的训练效应。总体而言，我们的 fMRI 实验表明，STS 中存在广泛的观察到的动态身体动作表示，可通过视觉学习进行调节，支持其在动作识别中的预期作用。
