Biology subjects

Larson, M. S.

Publications and source records attributed to Larson, M. S..

3 recordsLinked to original sources

bioRxiv2025

Divergence of Functional Brain Network Configurations in Same and Other Race Face Recognition

The "Other-Race Effect" (ORE) refers to the enhanced memory individuals have for faces within their own racial group compared to other races. This effect is attributed to limited exposure to different races and social-motivational factors affecting face processing. While past research has explored this effect through neuroimaging methods, the precise neural mechanisms that underlie the ORE remain a subject of ongoing investigation. Previous studies have largely adopted a modular perspective, concentrating on the differential activation of face-processing regions when comparing same-race and other-race facial recognition behaviors. However, given the multifaceted nature of the ORE, an exclusive focus on specialized regions may miss the pivotal role played by non-face-preferential brain areas in modulating this phenomenon. In the present study, we take a broader data-driven perspective using graph-theoretical techniques to investigate whole-brain network disparities in same- and other-race facial recognition. Our findings reveal a substantial impact of race on functional connectivity during face memorization. While other-race face recognition benefitted from higher local efficiency during encoding, reduced local efficiency was advantageous for memorization of same-race faces. Notably, successful other-race recognition was disproportionately supported by locally efficient processing in regions among the ventral and dorsal attention networks.

neuroscience↗

bioRxiv2023

Theta mediated dynamics of human hippocampal-neocortical learning systems in memory formation and retrieval

Episodic memory arises as a function of dynamic interactions between the hippocampus and the neocortex, yet the mechanisms have remained elusive. Here, using human intracranial recordings during a mnemonic discrimination task, we report that 4-5 Hz (theta) power is differentially recruited during discrimination vs. overgeneralization, and its phase supports hippocampal-neocortical when memories are being formed and correctly retrieved. Interactions were largely bidirectional, with small but significant net directional biases; a hippocampus-to-neocortex bias during acquisition of new information that was subsequently correctly discriminated, and a neocortex-to-hippocampus bias during accurate discrimination of new stimuli from similar previously learned stimuli. The 4-5 Hz rhythm may facilitate the initial stages of information acquisition by neocortex during learning and the recall of stored information from cortex during retrieval. Future work should further probe these dynamics across different types of tasks and stimuli and computational models may need to be expanded accordingly to accommodate these findings.

neuroscience↗

bioRxiv2022

Posterior white matter hyperintensities are associated with reduced medial temporal lobe subregional integrity and long-term memory in older adults

White matter hyperintensities are a marker of small vessel cerebrovascular disease that are strongly related to cognition in older adults. Similarly, medial temporal lobe atrophy is well-documented in aging and Alzheimers disease and is associated with memory decline. Here, we assessed the relationship between lobar white matter hyperintensities, medial temporal lobe subregional volumes, and hippocampal memory in older adults. We collected MRI scans in a sample of 139 older adults without dementia (88 females, mean age (SD) = 76.95 (10.61)). Participants were administered the Rey Auditory Verbal Learning Test (RAVLT). Regression analyses tested for associations among medial temporal lobe subregional volumes, regional white matter hyperintensities and memory, while adjusting for age, sex, and education and correcting for multiple comparisons. Increased occipital white matter hyperintensities were related to worse RAVLT delayed recall performance, and to reduced CA1, dentate gyrus, perirhinal cortex (Brodmann area 36), and parahippocampal cortex volumes. These medial temporal lobe subregional volumes were related to delayed recall performance. The association of occipital white matter hyperintensities with delayed recall performance was fully mediated statistically only by perirhinal cortex volume. These results suggest that white matter hyperintensities may be associated with memory decline through their impact on medial temporal lobe atrophy. These findings provide new insights into the role of vascular pathologies in memory loss in older adults and suggest that future studies should further examine the neural mechanisms of these relationships in longitudinal samples.

neuroscience↗