Zhou Y D, Fuster J M
Neuropsychiatric Institute and Brain Research Institute, School of Medicine, University of California, Los Angeles 90024, USA.
Proc Natl Acad Sci U S A. 2000 Aug 15;97(17):9777-82. doi: 10.1073/pnas.97.17.9777.
Recent studies show that cells in the somatosensory cortex are involved in the short-term retention of tactile information. In addition, some somatosensory cells appear to retain visual information that has been associated with the touch of an object. The presence of such cells suggests that nontactile stimuli associated with touch have access to cortical neuron networks engaged in the haptic sense. Thus, we inferred that somatosensory cells would respond to behaviorally associated visual and tactile stimuli. To test this assumption, single units were recorded from the anterior parietal cortex (Brodmann's areas 3a, 3b, 1, and 2) of monkeys performing a visuo-haptic delay task, which required the memorization of a visual cue for a tactile choice. Most cells responding to that cue responded also to the corresponding object presented for tactile choice. Significant correlations were observed in some cells between their differential reactions to tactile objects and their differential reactions to the associated visual cues. Some cells were recorded in both the cross-modal task and a haptic unimodal task, where the animal had to retain a tactile cue for a tactile choice. In most of these cells, correlations were observed between stimulus-related firing in corresponding cue periods of the two tasks. These findings suggest that cells in somatosensory cortex are the components of neuronal networks representing tactile information. Associated visual stimuli may activate such networks through visuo-haptic associations established by behavioral training.
最近的研究表明，体感皮层中的细胞参与触觉信息的短期保留。此外，一些体感细胞似乎保留了与物体触摸相关的视觉信息。这些细胞的存在表明，与触摸相关的非触觉刺激能够进入参与触觉感知的皮层神经元网络。因此，我们推断体感细胞会对行为上相关的视觉和触觉刺激做出反应。为了验证这一假设，我们从执行视觉 - 触觉延迟任务的猴子的顶叶前部皮层（布罗德曼区3a、3b、1和2）记录单个神经元活动，该任务要求记住视觉线索以进行触觉选择。大多数对该线索做出反应的细胞也对呈现用于触觉选择的相应物体做出反应。在一些细胞中，观察到它们对触觉物体的差异反应与其对相关视觉线索的差异反应之间存在显著相关性。在跨模态任务和触觉单模态任务中都记录了一些细胞，在触觉单模态任务中动物必须记住触觉线索以进行触觉选择。在大多数这些细胞中，观察到两个任务相应线索期内与刺激相关的放电之间存在相关性。这些发现表明，体感皮层中的细胞是代表触觉信息的神经元网络的组成部分。相关的视觉刺激可能通过行为训练建立的视觉 - 触觉关联来激活此类网络。
