The right parahippocampal gyrus contributes to the formation and maintenance of bound information in working memory

Working memory is devoted to the temporary storage and on-line manipulation of information. Recently, an integrative system termed the episodic buffer has been proposed to integrate and hold information being entered or retrieved from episodic memory. Although the brain system supporting such an integrative buffer is still in debate, the medial temporal lobe appears to be a promising candidate for the maintenance of bound information. In the current work, binding was assessed by comparing two conditions in which participants had to retain three letters and three spatial locations presented either bound or separate. At the behavioral level, lower performance was found for bound information than for separate information. When contrasting the two conditions, activation in the right parahippocampal gyrus was greater for the encoding and maintenance of bound information. No activation was observed in the medial temporal lobe during the retrieval of bound information. Together, our results suggest that the parahippocampal gyrus may underlie the integrative and maintenance functions of the episodic buffer.