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Revealing the neuroanatomical basis of working memory: a multivoxel morphometric study
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Revealing the neuroanatomical basis of working memory: a multivoxel morphometric study

Xin Niu
Master of Science (M.S.), Drexel University
May 2018
DOI:
https://doi.org/10.17918/D8P08N
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Abstract

Brain--Imaging Short-term memory Neuropsychology Psychology
Working memory is an important higher-level cognitive function that plays a crucial role in people's life, study and academic work. Although behavioral and functional magnetic resonance imaging (fMRI) studies have extensively examined the cognitive and neural mechanism of working memory, controversies over the core structure and the neural mechanism of working memory still remain. In particular, existing studies have revealed very low correlations between the performances measured by the two classical and popularly used working memory tasks - the n-back task and the complex span task, yet the neural substrates underlying these working memory performances have not been directly compared. In the present study, large number of college students were recruited to perform four working memory tasks belonging to two categories. Combining brain structure imaging data and multivariate pattern analysis, we aimed at examine the neuroanatomic basis of different components of working memory. Factor analysis on behavioral data revealed two orthogonal factors underlying working memory, with high factor loads on the performance of n-back tasks and complex span tasks, respectively. Multivariate support vector regression shows that the gray matter volume (GMV) of different regions across the brain was associated with individual differences in the two working memory components. Specifically, complex span performance could be predicted by the GMV of the left precuneus and posterior cingulate cortex, right middle frontal gyrus (rMFG), bilateral frontal pole and left inferior frontal gyrus (lIFG), and that of the n-back tasks could be predicted by the GMV of the left middle frontal gyrus (lMFG), bilateral caudate nucleus and putamen, and left parahippocampus. These results provide anatomical evidence to suggest that complex span tasks and the n-back tasks measure different aspects of working memory and are supported by distinct neural networks. The complex span tasks are associated with the executive control and plan function of the frontal and parietal cortex, whereas the n-back tasks are supported by the circuit of frontal-basal ganglia.

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