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Investigating the neural correlates of nonlinguistic cognitive control in left hemisphere stroke survivors
Poster Session B, Friday, September 12, 4:30 - 6:00 pm, Field House
Andrea Galvez-McDonough1,2, Yusheng Wang1,2, Peter Turkletaub3,4, Stephanie Ries1,2,5; 1SDSU/UCSD Joint Doctoral Program in Language and Communicative Disorders, 2School of Speech, Language, and Hearing Sciences, San Diego State University, 3Center for Brain Plasticity and Recovery, Georgetown University Medical Center, 4Research Division, MedStar National Rehabilitation Hospital, 5Center for Clinical and Cognitive Neuroscience, San Diego State University
While studies of left hemisphere stroke survivors tend to focus on deficits in linguistic abilities and their underlying processes following impairment, some studies have also suggested deficits in domain-general executive functions (e.g. Dekhtyar et al., 2020, Faroqi-Shah et al., 2018). In the current study we examined the relationship between cognitive control abilities and integrity of white matter tracts of interest in left hemisphere stroke survivors. We assessed nonlinguistic cognitive control abilities in 98 left hemisphere stroke survivors through their performance in a Simon task. In this task participants were presented with either a red or blue flash in one of two side-by-side squares at the top of a touchscreen laptop. Below the squares was a response button with a red square on one side and a blue square on the other. In a given trial, participants were asked to indicate the color of the flash by selecting the appropriate colored square as quickly as possible while ignoring the location of the stimulus. Diffusion weighted images were collected in 67 of these participants. We used DSI Studio to generate tractograms and apply the DTI matrix. Auto-segmentation was used to obtain the tracts of interest (arcuate fasciculus, frontal aslant tract, superior longitudinal fasciculus, uncinate fasciculus, and corticostriatal connections) and their corresponding measures of white matter integrity (FA and MD). Data preprocessing is ongoing and has been completed for 41 of the 67 participants with available diffusion weighted images. When considering our whole sample (n = 98), we observe significant effects of Condition on both Accuracy (Wald χ2(1) = 26.92, p < .001) and Reaction Times (Wald χ2(1) = 102.36, p < .001). Participants were less accurate (βraw = -.394, SE = .076, z = -5.19, p < .001) and slower (βraw = .015, SE = .002, t = 10.12, p < .001) in their responses to Incongruent relative to Congruent trials. However, when restricting our analyses (n = 41), preliminary findings show that only the significant effect of Condition on Reaction Times remains (Wald χ2(1) = 28.42, p < .001). Participants were slower in their responses to Incongruent relative to Congruent trials (βraw = .013, SE = .002, t = 5.33, p < .001). A partial correlation analysis, controlling for effects of lesion volume and aphasia severity, revealed a significant positive association between structural integrity of the left uncinate fasciculus (UF) and the effect of condition on reaction times (r(38) = .505, p = .015). Structural integrity of the UF has previously been implicated in the mediation of semantic control during word comprehension (Harvey et al., 2013). Greater structural integrity of the right UF has also been associated with better performance in executive functions (Sasson et al., 2013). The preliminary evidence presented here suggests that the left UF is not only engaged in semantic control but also in domain-general cognitive control, as is involved in Simon task performance.
Topic Areas: Control, Selection, and Executive Processes,