The relation between medial temporal lobe structures and spatial navigation following moderate-severe TBI

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Sophia Kekes-Szabo¹ (sophia.kekes-szabo@vanderbilt.edu), Annick F.N. Tanguay¹, Michael Dulas², Hillary Schwarb³, Neal Cohen⁴, Melissa C. Duff¹; ¹Vanderbilt University Medical Center, ²Binghampton University, ³University of Nebraska-Lincoln, ⁴University of Illinois Urbana-Champaign

Individuals with moderate-severe traumatic brain injury (TBI) have difficulty navigating life. Survivors struggle to integrate back into their communities, participate independently in daily activities, and act flexibly while navigating their social and physical environments. The virtual Morris water maze (vMWM; Astur et al., 1998) assesses spatial navigational behavior in a virtual environment where participants must repeatedly navigate to a hidden platform using environmental cues. Previous findings in non-injured participants reveal associations between medial temporal lobe structures and fractal dimensionality, an index of search path complexity in the vMWM environment (Daugherty et al., 2015). We investigated the impact of chronic moderate-severe TBI on spatial navigation and examined associations with volumetric measures of the medial temporal lobe. vMWM and magnetic resonance imaging data were collected and analyzed for 24 participants with chronic moderate-severe TBI and 29 non-injured comparison participants (NC). We found a significant group difference with greater distance travelled and longer path complexity on trial 15 (the final trial) for the TBI group. Increased path complexity correlated with lower parahippocampal volume, but not hippocampal volume. Future work investigating the relation between spatial navigation and hippocampal subfields or subregions may prove more sensitive in detecting the predicted associations in this population. Furthermore, extending this work to examine hippocampal contributions to the navigation of social environments could offer a test of our proposal that hippocampal dysfunction underlies a range of behavioral impairments in TBI including memory, navigation, and social functioning.

Topic Area: LONG-TERM MEMORY: Other