Stoeckel M Cornelia, Weder Bruno, Binkofski Ferdinand, Buccino Giovanni, Shah N Jon, Seitz Rüdiger J
Department of Neurology, University Hospital Düsseldorf, Düsseldorf, Germany.
Neuroimage. 2003 Jul;19(3):1103-14. doi: 10.1016/s1053-8119(03)00182-4.
Previous studies of somatosensory object discrimination have been focused on the primary and secondary sensorimotor cortices. However, we expected the prefrontal cortex to also become involved in sequential tactile discrimination on the basis of its role in working memory and stimulus discrimination as established in other domains. To investigate the contributions of the different cerebral structures to tactile discrimination of sequentially presented objects, we obtained event-related functional magnetic resonance images from seven healthy volunteers. Our results show that right hand object exploration involved left sensorimotor cortices, bilateral premotor, parietal and temporal cortex, putamen, thalamus, and cerebellum. Tactile exploration of parallelepipeds for subsequent object discrimination activated further areas in the dorsal and ventral portions of the premotor cortex, as well as parietal, midtemporal, and occipital areas of both cerebral hemispheres. Discriminating a parallelepiped from the preceding one involved a bilateral prefrontal-anterior cingulate-superior temporal-posterior parietal circuit. While the prefrontal cortex was active with right hemisphere dominance during discrimination, there was left hemispheric prefrontal activation during the delay period between object presentations. Delay related activity was further seen in the anterior intraparietal area and the fusiform gyrus. The results reveal a prominent role of the human prefrontal cortex for somatosensory object discrimination in correspondence with recent models on stimulus discrimination and working memory.
以往关于体感物体辨别能力的研究主要集中在初级和次级感觉运动皮层。然而，基于前额叶皮层在其他领域所确立的工作记忆和刺激辨别功能，我们预计它也会参与序列性触觉辨别。为了研究不同脑结构在序列呈现物体的触觉辨别中的作用，我们获取了7名健康志愿者的事件相关功能磁共振图像。我们的结果显示，右手对物体的探索涉及左侧感觉运动皮层、双侧运动前区、顶叶、颞叶皮层、壳核、丘脑和小脑。为后续物体辨别而对平行六面体进行的触觉探索激活了运动前皮层背侧和腹侧部分以及双侧大脑半球的顶叶、颞中回和枕叶的更多区域。将一个平行六面体与前一个区分开来涉及双侧前额叶-前扣带回-颞上回-顶叶后回路。在辨别过程中，前额叶皮层以右侧半球为主导而活跃，而在物体呈现之间的延迟期，左侧前额叶皮层被激活。在顶内前区和梭状回还可见与延迟相关的活动。这些结果揭示了人类前额叶皮层在体感物体辨别中发挥的重要作用，这与最近关于刺激辨别和工作记忆的模型一致。
