Neuropsychological and neuroimaging studies provide evidence for a degree of category-related organization of conceptual knowledge in the brain. Some of this evidence indicates that body part concepts are distinctly represented from other categories; yet, the neural correlates and mechanisms underlying these dissociations are unclear. We expand on the limited prior data by measuring functional magnetic resonance imaging responses induced by body part words and performing a series of analyses investigating the cortical representation of this semantic category. Across voxel-level contrasts, pattern classification, representational similarity analysis, and vertex-wise encoding analyses, we find converging evidence that the posterior middle temporal gyrus, the supramarginal gyrus, and the ventral premotor cortex in the left hemisphere play important roles in the preferential representation of this category compared to other concrete objects.
@article{10.1093/cercor/bhae213,year={2024},title={{The neural representation of body part concepts}},author={Mazurchuk, Stephen and Fernandino, Leonardo and Tong, Jia-Qing and Conant, Lisa L and Binder, Jeffrey R},journal={Cerebral Cortex},issn={1047-3211},doi={10.1093/cercor/bhae213},pages={bhae213},number={6},volume={34},keywords={},}
2023
Stimulus repetition and sample size considerations in item-level representational similarity analysis
Stephen Mazurchuk, Lisa L. Conant, Jia-Qing Tong, Jeffrey R. Binder, and Leonardo Fernandino
In studies using representational similarity analysis (RSA) of fMRI data, the reliability of the neural representational dissimilarity matrix (RDM) is a limiting factor in the ability to detect neural correlates of a model. A common strategy for boosting neural RDM reliability is to employ repeated presentations of the stimulus set across imaging runs or sessions. However, little is known about how the benefits of stimulus repetition are affected by repetition suppression, or how they compare with the benefits of increasing the number of participants. We examined the effects of these design parameters in two large data sets where participants performed a semantic decision task on visually presented words. We found that reliability gains from stimulus repetition were strongly affected by repetition suppression, both within and across scanning sessions separated by multiple weeks. The results provide new insights into these experimental design choices, particularly for item-level RSA studies of semantic cognition.
@article{10.1080/23273798.2023.2232903,year={2023},title={{Stimulus repetition and sample size considerations in item-level representational similarity analysis}},author={Mazurchuk, Stephen and Conant, Lisa L. and Tong, Jia-Qing and Binder, Jeffrey R. and Fernandino, Leonardo},journal={Language, Cognition and Neuroscience},issn={2327-3798},doi={10.1080/23273798.2023.2232903},pages={1--12},number={ahead-of-print},volume={ahead-of-print},keywords={},}
