Medicine and Health Sciences Commons^™

Paired Associative Transspinal And Transcortical Stimulation Produces Bidirectional Plasticity Of Human Cortical And Spinal Motor Pathways, Luke Dixon, Mohamed Ibrahim, Danielle Santora

Dissertations, Theses, and Capstone Projects

Anatomical, physiological, and functional connectivity exists between primary motor cortex (M1) and spinal cord neurons. Paired associative stimulation (PAS) produces enduring changes in M1 based on the Hebbian principle of associative plasticity. The present study aims to discover immediate neurophysiological changes on human corticomotor pathways by pairing noninvasive transspinal and transcortical stimulation via transcranial magnetic stimulation (TMS). We delivered paired transspinal and transcortical stimulation for 40-min at precise interstimulus intervals with TMS being delivered after (transspinal-transcortical PAS) or before (transcortical-transspinal PAS) transspinal stimulation. Transspinal-transcortical PAS markedly decreased intracortical inhibition, increased intracortical facilitation and M1 excitability with concomitant decreases of motor …

The Relationship Between Lexical Performance And Regional Gray Matter Volumes: A Longitudinal Study Of Cognitively Healthy Elderly, Jungmoon Hyun

Dissertations, Theses, and Capstone Projects

This study investigated the longitudinal relationship among aging, performance on lexical tasks, and regional gray matter volumes over 2-7 years. A total of 137 older participants who remained cognitively normal were administered four lexical tasks at each time point: the Boston Naming Test (BNT), Vocabulary Test, Semantic- and Phonemic-Fluency task. In addition, they underwent repeated magnetic resonance imaging (MRI) scanning acquired within two months of the lexical tasks. The average interval between time points was 2.36 years (range 1.50-7.64) and the average number of time points was 2.65 times (range 2-5).

Results indicated that age differentially affects lexical task performance …