Matsuyoshi, D., Ikeda, T., Sawamoto, N., Kakigi, R., Fukuyama, H., &

Osaka, N.


Differential roles for parietal and occipital cortices in visual working








Visual working memory (VWM) is known as a highly capacity-limited

cognitive system that can hold 3-4 items. Recent studies have

demonstrated that activity in the intraparietal sulcus (IPS) and

occipital cortices correlates with the number of representations held in

VWM. However, differences among those regions are poorly understood,

particularly when task-irrelevant items are to be ignored. The present

fMRI-based study investigated whether memory load-sensitive regions such

as the IPS and occipital cortices respond differently to task-relevant

information. Using a change detection task in which participants are

required to remember pre-specified targets, here we show that while the

IPS exhibited comparable responses to both targets and distractors, the

dorsal occipital cortex manifested significantly weaker responses to an

array containing distractors than to an array containing only targets,

despite that the number of objects presented was the same for the two

arrays. These results suggest that parietal and occipital cortices

engage differently in distractor processing and that the dorsal

occipital, rather than parietal, activity appears to reflect output of

stimulus filtering and selection based on behavioral relevance.

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