Domain-general mechanisms of complex working memory span

A new fMRI complex working memory span paradigm was used to identify brain regions making domain-general contributions to working memory task performance. For both verbal and spatial versions of the task, complex working memory span performance increased the activity in lateral prefrontal, anterior cingulate, and parietal cortices during the Encoding, Maintenance, and Coordination phase of task performance. Meanwhile, overlapping activity in anterior prefrontal and medial temporal lobe regions was associated with both verbal and spatial recall from working memory. These findings help to adjudicate several contested issues regarding the executive mechanisms of working memory, the separability of short-term and working memory in the verbal and spatial domains, and the relative contribution of short-term and long-term memory mechanisms to working memory capacity. The study also provides a vital bridge between psychometric and neuroimaging approaches to working memory, and constrains our understanding of how working memory may contribute to the broader landscape of cognitive performance.

Research Highlights►A new fMRI complex working memory span paradigm was used to identify brain regions making domain-general contributions to working memory task performance. ►Verbal and spatial complex working memory span tasks recruit overlapping prefrontal, cingulate, and parietal processes to support encoding and maintenance, and to coordinate the concurrent demands of storage and processing. ►Recall from verbal and spatial working memory relies on domain-general medial temporal lobe processes that support retrieval of information displaced into long-term memory. ►Findings inform debates regarding the executive mechanisms of working memory, the separability of short-term and working memory in the verbal and spatial domains, and the relative contribution of short-term and long-term memory mechanisms to working memory capacity.