Psychology ETDs

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Prenatal alcohol exposure results in cognitive and physical impairments in children, which are collectively defined as fetal alcohol spectrum disorders (FASDs). The disorders account for the largest proportion of intellectual disabilities in the US. While few functional findings exist today that shed light on the mechanisms responsible for the observed impairments in individuals with FASD, animal models consistently report deleterious effects of early alcohol exposure on GABA-ergic inhibitory pathways. The post-motor beta rebound (PMBR), a transient increase of 15-30 Hz beta power in the motor cortex that follows the termination of movement, has been implicated as a neural signature of GABA-ergic inhibitory activity. Further, PMBR has been shown to be a reliable predictor of age in adolescents. The present study sought to investigate any differences in the development of PMBR between FASD and control groups. Twenty-two subjects with FASD and 22 age and sex-matched controls underwent magnetoencephalography scans while performing an auditory oddball task, which required a button press in response to select target stimuli. The data surrounding the button presses ([-1.5 2 s] interval) were localized to the participants motor cortices, and the time courses from the locations of the maximally evoked PMBR were subjected to wavelet analyses. In addition to age and group, early (0.5-1 s after button press) and late (1-1.5 s after button press) evoked PMBR measures were contrasted. The PMBR evoked values were analyzed with a 2 x 2 x 2 ANOVA (group, age, PMBR latency). The results revealed a significant interaction between group and age. While age had a significant effect on PMBR in the controls, no simple effects of age were detected in the FASD group. The described findings provide further evidence for broad impairments in inhibitory processes in adolescents with FASD, possibly related to aberrant development of GABA-ergic pathways.

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First Committee Member (Chair)

Derek, Hamilton

Second Committee Member

James, Cavanagh




Fetal Alcohol Spectrum Disorder (FASD), Post-Movement Beta Rebound (PMBR), Inhibition

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