论文部分内容阅读
A network of frontal,parietal and subcortical(e.g.,the thalamus)areas is often found active during visual working memory and visual search tasks.However,the role of thalamocortical interaction in task performance remains unknown despite the knowledge that thalamic lesions can significantly influence cortical activity and produce severe cognitive deficits.In one fMRI experiment,we examined whether thalamocortical activity and connectivity are modulated by task relevance during a retrocue visual working memory task.Our results showed that thalamus connectivity with a particular category-selective extrastriate area is enhanced when the preferred visual category is task relevant and lower when irrelevant.For example,the functional connectivity between thalamus and fusiform face area was stronger when the to-be-remembered item was a face than when it was a scene.In another fMRI experiment,we investigated whether variation in thalamocortical connectivity during visual target maintenance is associated with subsequent visual search performance.We found differential thalamocortical connectivity patterns in association with different search performance measures.Further,our EEG data showed greater alpha power in corresponding to the relevant memory load but not irrelevant memory load.These findings together suggest that,beyond the previously implicated frontoparietal network in working memory,thalamocortical networks may also play a significant role in maintaining task relevant visual information and guiding visual search behavior.Prioritizing visual working memory may involve synchronization of thalamo-cortical activity.