The Influence of Declarative Processes upon Human Motor Cortex Physiology

Skilled movements require the ability to efficiently extract and manipulate incoming sensory information relating to our body and environment to inform motor output. To facilitate efficient sensory to motor transformations humans have developed highly tuned cognitive abilities featuring constructs such as attention and working memory. Such cognitive constructs support the development of declarative knowledge pertaining to skilled actions. Yet, our understanding of how declarative knowledge shapes the function and reorganization of subconscious procedural knowledge about a skill is limited. Importantly, understanding how declarative strategies may influence motor cortical physiology is an essential step towards understanding why some skills benefit from explicit knowledge while others do not. The purpose of this dissertation was to determine how declarative functions, specifically verbal working memory, shape procedural motor control through modulation of sensory afference. Chapter 1 reviews the role of the motor and somatosensory cortices in motor behavior. The role of attention in the activation of the sensorimotor cortex is then described. Finally, the role of verbal working memory in motor performance is discussed. Previous research looked at the role of working memory from a behavioral perspective, but the studies in this thesis investigated the neural substrates, and notably the sensory afference of the interaction of working memory and control of movement. Chapters 2 through 4 detail a series of studies investigating how working memory load and verbal instructions alter motor cortex physiology and plasticity. Specifically, Chapter 2 demonstrates that engaging verbal working memory processes can change the potential for plasticity in the motor cortex, a substrate of the procedural motor system. Chapter 3 demonstrates that working memory acts upon the motor cortex through intracortical circuits that are distinct from other cognitive functions such as attention. Finally, Chapter 4 extends these results from a model where working memory is a distractor to working memory as a task-relevant construct. Overall, the findings from the studies described in this dissertation demonstrate that working memory has the ability to influence motor cortex physiology through circuits distinct from the circuits affected by attention. Further, the way in which working memory is employed can have important modulatory effects in the motor cortex, which could then impact the acquisition and execution of motor skills. These results lay the groundwork for future studies investigating whether declarative strategies may control and limit procedural learning such that the procedural system serves to perfect the optimal kinematics and dynamics for the imposed strategy even if the imposed strategy results in sub-optimal performance.PHDKinesiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/143991/1/lsuzuki_1.pd

P-Wave Charmed-Strange Mesons

We examine charmed-strange mesons within the framework of the constituent quark model, focusing on the states with L=1. We are particularly interested in the mixing of two spin-states that are involved in $D_{s1}(2536)$ and the recently discovered $D_{sJ}(2460)$. We assume that these two mesons form a pair of states with J=1. These spin-states are mixed by a type of the spin-orbit interaction that violates the total-spin conservation. Without assuming explicit forms for the interactions as functions of the interquark distance, we relate the matrix elements of all relevant spin-dependent interactions to the mixing angle and the observed masses of the L=1 quartet. We find that the spin-spin interaction, among various types of the spin-dependent interactions, plays a particularly interesting role in determining the spin structure of $D_{s1}(2536)$ and $D_{sJ}(2460)$

Antiviral and Virucidal Activities of Nα-Cocoyl-L-Arginine Ethyl Ester

Various amino acid-derived compounds, for example, Nα-Cocoyl-L-arginine ethyl ester (CAE), alkyloxyhydroxylpropylarginine, arginine cocoate, and cocoyl glycine potassium salt (Amilite), were examined for their virucidal activities against herpes simplex virus type 1 and 2 (HSV-1 and HSV-2), influenza A virus (IAV), and poliovirus type 1 (PV-1) in comparison to benzalkonium chloride (BKC) and sodium dodecylsulfate (SDS) as a cationic and anionic control detergent and also to other commercially available disinfectants. While these amino acid-derived compounds were all effective against HSV-1 and HSV-2, CAE and Amilite were the most effective. These two compounds were, however, not as effective against IAV, another enveloped virus, as against HSV. Cytotoxicity of CAE was weak; at 0.012%, only 5% of the cells were killed under the conditions, in which 100% cells were killed by either SDS or BKC. In addition to these direct virucidal effects, CAE inhibited the virus growth in the HSV-1- or PV-1-infected cells even at 0.01%. These results suggest a potential application of CAE as a therapeutic or preventive medicine against HSV superficial infection at body surface

Commuting quantum transfer matrix approach to intrinsic Fermion system: Correlation length of a spinless Fermion model

The quantum transfer matrix (QTM) approach to integrable lattice Fermion systems is presented. As a simple case we treat the spinless Fermion model with repulsive interaction in critical regime. We derive a set of non-linear integral equations which characterize the free energy and the correlation length of $$ for arbitrary particle density at any finite temperatures. The correlation length is determined by solving the integral equations numerically. Especially in low temperature limit this result agrees with the prediction from conformal field theory (CFT) with high accuracy.Comment: 17 page