Poster D28, Wednesday, August 21, 2019, 5:15 – 7:00 pm, Restaurant Hall
Identifying distinct functional subdivisions of the anterior temporal lobes
Andrew S Persichetti1, Stephen J Gotts1, Alex Martin1;1Laboratory of Brain and Cognition, NIMH/NIH
The functional role of the anterior regions of the temporal lobes is a contentious issue in cognitive neuroscience. A wide range of functions have been posited, and not all are mutually exclusive. For example, different theories claim that the anterior temporal lobes serve as a general convergence zone or hub for all semantic information, whereas other models posit more selective roles in object recognition, language processing, and social cognition. However, given the anatomical heterogeneity of this brain region, the anterior temporal lobes almost certainly support a wide array of cognitive functions. Our goal is to identify functionally distinct regions within the anterior temporal lobes and understand the extent to which each region is involved in specific cognitive functions. To this end, we used resting-state fMRI from 88 participants (24 female) and a novel clustering method to identify subdivisions within anterior temporal cortex, as well as medial temporal lobe structures (i.e., the amygdala and hippocampus). Specifically, we calculated the functional connectivity (Pearson correlation of the resting-state time series) between voxels within the anterior temporal lobes (defined as any temporal lobe voxels anterior to y=-35 in Talairach space) and all voxels outside of the temporal lobes. We then thresholded the resultant correlation matrices across a wide range of correlation values and clustered the group-average matrices using both Infomap and Louvain Modularity. Finally, the identified parcels were required to replicate across halves of the data (44 participants in each half) and across 10 randomized split-half samples. We found at least six functionally distinct cortical parcels in each hemisphere as well as parcellations in the medial temporal lobe structures. Thus, the parcellation profile of the anterior temporal lobes is consistent with its involvement in diverse cognitive functions. Next steps of this project will involve identifying non-temporal-lobe targets of the selective subdivisions found in the current work and using this information to design experimental task manipulations that can more precisely dissociate these parcels based on their unique contributions to specific cognitive tasks.
Themes: Meaning: Lexical Semantics, Methods
Method: Functional Imaging