Poster E45, Monday, March 27, 2:30 – 4:30 pm, Pacific Concourse
The Causal Role of Prefrontal Cortex and Somatosensory Cortex in Tactile Working Memory
Di Zhao1, Yixuan Ku1,2; 1The Key Lab of Brain Functional Genomics, MOE & STCSM, School of Psychology and Cognitive Science, East China Normal University, Shanghai, China, 2NYU-ECNU Institute of Brain and Cognitive Science, NYU Shanghai and Collaborative Innovation Center for Brain Science, Shanghai, China
The neural activity in the dorsolateral prefrontal cortex (DLPFC) and contralateral primary somatosensory cortex (SI) has been found to be associated with short-term retention of sensory information in tactile working memory (WM) tasks. Yet, two questions still remain unclear: (1) whether the ipsilateral SI is also involved in retention of tactile information in WM; (2) whether SI in both hemispheres receive the top-down regulatory influence of the DLPFC during WM processes. Here, we examined the role of bilateral SΙs and the contralateral DLPFC in WM at different temporal stages using single–pulse transcranial magnetic stimulation (sp-TMS) while participants performed a vibrotactile delayed matching-to-sample task. In experiment-1, participants in one group received vibrotactile stimulation on the left index finger. sp-TMS over the contralateral SI at an early sensory stage (100 ms after the vibrotactile onset) deteriorated performance accuracy, and over the ipsilateral SI at a late maintenance stage (1600 ms after the vibrotactile onset) also impaired performance accuracy. In experiment-2, participants in another group received vibrotactile stimulation on the right index finger. sp-TMS over the bilateral SIs as in experiment-1 showed similar results. Furthermore, the deteriorating effects caused by sp-TMS over the contralateral DLPFC at 1600 ms were correlated with the effects caused by sp-TMS over the ipsilateral SI, indicating that information retained in the ipsilateral SI during the late delay may be associated with the DLPFC. Taken together, these results suggest that at different stages tactile WM involves the bilateral SIs that receive top-down signals from the DLPFC.
Topic Area: EXECUTIVE PROCESSES: Working memory