Physical Activity Engagement Associated With Dorsolateral Prefrontal Cortex Connectivity In Traumatic Brain Injury

Functional integrity of the dorsolateral prefrontal cortex (dlPFC) is particularly vulnerable to damage following a traumatic brain injury (TBI). Connections of the dlPFC have also been shown to predict adherence to physical activity (PA) in older adults. As such, functional plasticity of the dlPFC following TBI may related to engagement in PA, as well as decreases in PA with age in this population. Testing for mechanistic predictors of PA engagement following TBI across the lifespan can lead to development of interventions to increase PA adherence in this population. PURPOSE: To test the association between dlPFC-based functional connectivity and PA engagement in those with a prior TBI across the lifespan. METHODS: 57 adults with a prior TBI and 593 adults without a history of TBI from Cambridge Centre for Ageing and Neuroscience (Cam-CAN) were included in this secondary analysis. Resting-state functional MRI and a self-reported PA questionnaire were collected. Seed-based connectivity (SBC) within a general linear model framework using CONN toolbox was applied to test associations between connectivity of the dlPFC and PA (Cluster p < .05, Voxel p < .001). RESULTS: Functional connectivity between the dlPFC and precuneus and postcentral gyrus was different in those with a history of TBI compared to those without. Higher functional connectivity between the dlPFC and the medial temporal gyrus was associated with higher PA across the lifespan, controlling for age, sex, education, and age of TBI. To test if PA engagement following TBI differed in older adults, we split the sample into older (>55) and younger (<55) adults, with results showing that older adults engage in less PA than younger adults (p < 0.01). To test if connectivity of the dlPFC differentially predicted PA following TBI in older compared to younger adults, an interaction between age group and PA on dlPFC connectivity was examined. Results revealed differences in connectivity between the dlPFC and frontal pole, occipital cortex, and temporal gyrus and its associations with PA in older adults versus younger adults with TBI. CONCLUSION: Our results show differences in how brain networks promote PA engagement between individuals with and without TBI, implying that these connections may hold benefits for engaging in PA after a TBI, especially in the context of aging.