Laboratory and Basic Science Research Commons^™

Motor Unit Firing Rate Control Of Agonist Skeletal Muscle During Voluntary Isometric And Shortening Contractions With Limb Movement, Eric A. Kirk

Electronic Thesis and Dissertation Repository

Voluntary movements throughout mammalian lifespan require skeletal muscle contractions that are controlled by time- and recruitment-dependent firing rate patterns. Single motor unit (MU) activity reflects the final efferent neural drive to the muscle, yet the underlying neural control of movement at the MU level is not well understood. Using intramuscular electromyography single MU recordings, relationships between voluntary contraction kinematics and MU firing rates were evaluated in vivo, in groups of young and older adult participants.

The purpose of study one was to characterize how MU firing rates are differently scaled among muscles relative to voluntary contraction intensity. Across 12 …

The Role Of The Leucine-Rich (Leur) Domain Of Rho Guanine Nucleotide Exchange Factor (Rgnef) In The Regulation Of Amyotrophic Lateral Sclerosis (Als) Associated Protein Tar Dna-Binding Protein Of 43 Kda (Tdp-43), Hind Amzil

Electronic Thesis and Dissertation Repository

The presence of neuronal cytoplasmic inclusions (NCIs) composed of RNA-binding proteins (RBPs) and neurofilaments is considered to be ALS’s neuropathological hallmark. RGNEF has been previously shown to interact with TDP-43 and to have a regulatory effect on the expression levels of NEFL mRNA and NFL protein in vitro. Here, I examined the mechanism of the RGNEF N-terminus, leucine-rich domain (LeuR) domain’s interaction with TDP-43. I observed that the minimal domain required is 110 amino acids (LeuR110), that the Ankyrin domain adjacent to LeuR110 does not participate, and that LeuR110 forms of a high molecular weight complex with TDP-43 in …