Aglioti S, Tassinari G, Berlucchi G
Dipartimento di Scienze Neurologiche e della Visione, Sezione di Fisiologia umana, Verona, Italy.
Neurosci Biobehav Rev. 1996 Winter;20(4):623-9. doi: 10.1016/0149-7634(95)00075-5.
Subjects with partial or complete defects of the corpus callosum, either congenital or acquired, performed a choice reaction time (RT) task involving a right or left key-press response to a light presented at random in the right or left hemifield. Like normal subjects, all of them exhibited two additive effects typical of these tasks: the spatial stimulus-response compatibility effect (faster RT for stimuli and responses matched for side), and the hand placement effect (longer RT for responses performed with crossed hands). Two subjects with a complete callosal defect, one acquired and the other congenital, showed a third effect, not present in normal subjects, consisting of a marked advantage for RT of responses with hand anatomically ipsilateral to the stimulus, independent of both stimulus-response compatibility and hand placement. These findings can be interpreted according to a hierarchical model of information processing assuming that, in the absence of the corpus callosum, the matching of the mental codes for the stimulus and response sets takes place solely in the hemisphere receiving the stimulus, with a subsequent rapid-intrahemispheric or slow-interhemispheric transmission of the response command to the appropriate motor centers.
患有先天性或后天性胼胝体部分或完全缺损的受试者，执行了一项选择反应时（RT）任务，该任务要求对随机出现在右半视野或左半视野的灯光做出向右或向左的按键反应。与正常受试者一样，他们所有人都表现出了这些任务典型的两种累加效应：空间刺激-反应相容性效应（刺激和反应在同一侧时反应时更快），以及手放置效应（交叉手执行反应时反应时更长）。两名患有完全胼胝体缺损的受试者，一名是后天性的，另一名是先天性的，表现出了正常受试者中不存在的第三种效应，即与刺激在解剖学上同侧的手做出反应时的反应时具有显著优势，这与刺激-反应相容性和手放置无关。这些发现可以根据信息处理的层次模型来解释，该模型假设，在没有胼胝体的情况下，刺激和反应集的心理编码匹配仅在接收刺激的半球中进行，随后将反应指令快速在半球内或缓慢在半球间传递到适当的运动中枢。
