Role of the Human Medial Frontal Cortex in Task Switching: A Combined fMRI and TMS Study

作者：Matthew F. S. Rushworth, K. A. Hadland, Tomáš Paus, Perttu Sipilä · 发表于：Journal of Neurophysiology · 年份：2002 · DOI：10.1152/jn.2002.87.5.2577 · 被引用次数：526 · 研究领域：Neural and Behavioral Psychology Studies、Functional Brain Connectivity Studies、Transcranial Magnetic Stimulation Studies

We used event-related functional magnetic resonance imaging (fMRI) to measure brain activity when subjects were performing identical tasks in the context of either a task-set switch or a continuation of earlier performance. The context, i.e., switching or staying with the current task, influenced medial frontal cortical activation; the medial frontal cortex is transiently activated at the time that subjects switch from one way of performing a task to another. Two types of task-set-switching paradigms were investigated. In the response-switching (RS) paradigm, subjects switched between different rules for response selection and had to choose between competing responses. In the visual-switching (VS) paradigm, subjects switched between different rules for stimulus selection and had to choose between competing visual stimuli. The type of conflict, sensory (VS) or motor (RS), involved in switching was critical in determining medial frontal activation. Switching in the RS paradigm was associated with clear blood-oxygenation-level-dependent signal increases ("activations") in three medial frontal areas: the rostral cingulate zone, the caudal cingulate zone, and the presupplementary motor area (pre-SMA). Switching in the VS task was associated with definite activation in just one medial frontal area, a region on the border between the pre-SMA and the SMA. Subsequent to the fMRI session, we used MRI-guided frameless stereotaxic procedures and repetitive transcranial magnetic stimulati...