Mapping of the Underlying Neural Mechanisms of Maintenance and Manipulation in Visuo-Spatial Working Memory Using An n-back Mental Rotation Task: A Functional Magnetic Resonance Imaging Study

Abstract

Mapping of the underlying neural mechanisms of visuo-spatial working memory (WM) has been shown to consistently elicit activity in right hemisphere dominant fronto-parietal networks. However to date, the bulk of neuroimaging literature has focused largely on the maintenance aspect of visuo-spatial WM, with a scarcity of research into the aspects of WM involving manipulation of information. Thus, this study aimed to compare maintenance-only with maintenance and manipulation of visuo-spatial stimuli (3D cube shapes) utilizing a 1-back task while functional magnetic resonance imaging (fMRI) scans were acquired. Sixteen healthy participants (9 women, M = 23.94 years, SD = 2.49) were required to perform the 1-back task with or without mentally rotating the shapes 90° on a vertical axis. When no rotation was required (maintenance-only condition), a right hemispheric lateralization was revealed across fronto-parietal areas. However, when the task involved maintaining and manipulating the same stimuli through 90° rotation, activation was primarily seen in the bilateral parietal lobe and left fusiform gyrus. The findings confirm that the well-established right lateralized fronto-parietal networks are likely to underlie simple maintenance of visuo-spatial stimuli. The results also suggest that the added demand of manipulation of information maintained online appears to require further neural recruitment of functionally related areas. In particular mental rotation of visuospatial stimuli required bilateral parietal areas, and the left fusiform gyrus potentially to maintain a categorical or object representation. It can be concluded that WM is a complex neural process involving the interaction of an increasingly large network.

Development of white matter microstructure in relation to verbal and visuospatial working memory—A longitudinal study

“…However, we find little evidence for hemispheric differences in white matter maturation being of importance for visual vs. verbal working memory development. Also, the backward sequence for both Spatial Span and Digit Span require manipulation of the retained information, and this has been found to require bilateral neural recruitment of functionally related areas for verbal and visuospatial working memory tasks [ 40 , 41 ].…”

“…fMRI studies have shown that right lateralized networks are likely to underlie maintenance of visuospatial stimuli, while a left hemisphere dominance is thought to represent maintenance of verbal stimuli [ 37 – 39 ]. However, the added demand of manipulation of information maintained appears to require further bilateral neural recruitment of functionally related areas for both visuospatial and verbal stimuli [ 40 , 41 ].…”

Task Performance Modulates Functional Connectivity Involving the Dorsolateral Prefrontal Cortex in Patients with Schizophrenia

“…The left fusiform gyrus has also been observed to exhibit effective connectivity with the bilateral DLPFC. Although the task was not exactly the same as that utilized by Lamp et al ( 2016 ), both research groups have suggested that the left fusiform gyrus is involved in categorical representation and verbal rehearsal. On the other hand, Galashan et al ( 2015 ) have suggested that the left fusiform gyrus may also be involved in target/non-target discrimination.…”

Polymorphisms in CRYBB2 encoding βB2-crystallin are associated with antisaccade performance and memory function

“…Higher fMRI activation was observed mainly in the right hemisphere in carriers of these haplotypes (GAGTAG in block 2 and CAACCGGG in block 3), most prominent in orbitofrontal, prefrontal and parietal regions. At least the lateralization of spatial working memory to the right hemisphere was previously discussed in connection with the complexity of the tasks to be performed and the required executive functions 59,60 . Interestingly, antisaccade performance correlates positively with working memory capacity 61 and correct antisaccade trials induce a higher right hemispheric dorsolateral prefrontal cortex activation 62 , one of the brain regions that was affected in the fMRI working memory task in this study.…”