Excitability, Inhibition, and Neurotransmitter Levels in the Motor Cortex of Symptomatic and Asymptomatic Individuals Following Mild Traumatic Brain Injury.

The purpose of this study was to determine the level of excitability and inhibition, as well as the concentrations of excitatory and inhibitory neurotransmitters, in the motor cortex of individuals with acute and chronic symptoms from mTBI. Fifty-three individuals were assigned to one of four groups: (i) without history of mTBI (Control), (ii) within 72-h of diagnosis of mTBI (Acute), (iii) with history of mTBI and no remaining symptoms (Chronic Asymptomatic), and (iv) with chronic symptoms from mTBI, lasting at least 3 months post-injury (Chronic Symptomatic). Measures of corticospinal excitability and inhibition were obtained using transcranial magnetic stimulation (TMS).

Motor Cortex Function in APOE4 Carriers and Noncarriers.

Purpose: The ε4 allele of the apolipoprotein-E gene has been associated with disease activity including Alzheimer disease, multiple sclerosis, and cardiovascular disease. Individuals who possess the ε4 variant of this gene (ε4 carriers) also demonstrate higher levels of cognitive impairment and lower motor scores compared with noncarriers. The purpose of this study was to establish whether there is a difference in motor cortex function between apoε4 carriers and noncarriers.

Glutamate and GABA concentrations following mild traumatic brain injury: a pilot study.

Animal models of mild traumatic brain injury (mTBI) suggest that metabolic changes in the brain occur immediately after a mechanical injury to the head. Proton magnetic resonance spectroscopy (H-MRS) can be used to determine relative concentrations of metabolites in vivo in the human brain. The purpose of this study was to determine concentrations of glutamate and GABA in the brain acutely after mTBI and throughout 2 mo of recovery.

Cortical and Physical Function after Mild Traumatic Brain Injury.

Purpose: The aim of this study was to prospectively examine the association between intracortical inhibition and functional recovery after mild traumatic brain injury (mTBI).

Methods: Twenty individuals with mTBI and 20 matched control participants were assessed using transcranial magnetic stimulation, the Attentional Network Test, and gait analysis. Hierarchical linear modeling was used to longitudinally examine potential differences between groups and relationships in the pattern of recovery in cortical silent period (CSP) duration, cognitive reaction time, and single- and dual-task walking speeds across five testing time points.

Reliability of glutamate and GABA quantification using proton magnetic resonance spectroscopy.

The consistency and reliability of proton magnetic resonance spectroscopy (H-MRS) assessments of neurotransmitter concentration has not been widely examined over multiple days. The purpose of this study was to determine the reliability of glutamate and GABA measures using a single-voxel H-MRS protocol in healthy men and women. Glutamate and GABA quantitations were obtained from the primary motor cortex (M1) and the dorsolateral prefrontal cortex (DLPFC) in 13 healthy individuals across 3 data collection sessions, including a baseline (Visit 1), 2-week (Visit 2), and 2-month time point (Visit 3).

Motor Cortex Inhibition is Increased During a Secondary Cognitive Task.

The purpose of this study was to assess the effect of a cognitive task on motor cortex excitability and inhibition. Transcranial magnetic stimulation of the motor cortex was performed on 20 healthy individuals (18-24 years; 9 females) to measure motor evoked potentials (MEPs) and cortical silent periods at baseline, during, and following a secondary cognitive task. The MEP amplitude increased from 0.

Sex, but not Apolipoprotein E Polymorphism, Differences in Spatial Performance in Young Adults.

The purpose of this study was to examine how sex and apolipoprotein E (APOE) genotype contribute to individual differences in spatial learning and memory. The associations of APOE genotype with neurocognitive function have been well studied among the elderly but less is known at earlier ages. Young adults (n = 169, 88 females) completed three neurocognitive tasks: mental rotation, spatial span, and Memory Island, a spatial navigation test.

Acute and longitudinal changes in motor cortex function following mild traumatic brain injury.

Primary Objective: To evaluate excitability and inhibition of the motor cortex acutely and longitudinally following mild traumatic brain injury (mTBI).

Research Design: A longitudinal paired case-control design was used to examine cortical excitability and inhibition in 15 adults who had sustained an mTBI (mean age = 20.8 ± 1.

Non-replication of an association of Apolipoprotein E2 with sinistrality.

A recent report found that left-handed adolescents were more than three times more likely to have an Apolipoprotein (APOE) ϵ2 allele. This study was unable to replicate this association in young adults (N=166). A meta-analysis of nine other datasets (N=360 to 7559, Power > 0.