Neural correlates of spatial working memory manipulation in a sequential Vernier discrimination task.

ABSTRACT

Visuospatial working memory refers to the short-term storage and manipulation of visuospatial information. To study the neural bases of these processes, 17 participants took part in a modified sequential Vernier task while they were being scanned using an event-related functional MRI protocol. During each trial, participants retained the spatial position of a line during a delay period to later evaluate if it was presented aligned to a second line. This design allowed testing the manipulation of the spatial information from memory. During encoding, there was a larger parietal and cingulate activation under the experimental condition, whereas the opposite was true for the occipital cortex. Throughout the delay period of the experimental condition there was significant bilateral activation in the caudal superior frontal sulcus/middle frontal gyrus, as well as the insular and superior parietal lobes, which confirms the findings from previous studies. During manipulation of spatial memory, the analysis showed higher activation in the lingual gyrus. This increase of activity in visual areas during the manipulation phase fits with the hypothesis that information stored in sensory cortices becomes reactivated once the information is needed to be utilized.