Longitudinal changes in resting state fMRI brain self-similarity of asymptomatic high school American football athletes.

American football has become the focus of numerous studies highlighting a growing concern that cumulative exposure to repetitive, sports-related head acceleration events (HAEs) may have negative consequences for brain health, even in the absence of a diagnosed concussion. In this longitudinal study, brain functional connectivity was analyzed in a cohort of high school American football athletes over a single play season and compared against participants in non-collision high school sports. Football athletes underwent four resting-state functional magnetic resonance imaging sessions: once before (pre-season), twice during (in-season), and once 34-80 days after the contact activities play season ended (post-season).

Normalized Brain Tissue-Level Evaluation of Volumetric Changes of Youth Athletes Participating in Collision Sports.

Observations of short-term changes in the neural health of youth athletes participating in collision sports (e.g., football and soccer) have highlighted a need to explore potential structural alterations in brain tissue volumes for these persons.

Every hit matters: White matter diffusivity changes in high school football athletes are correlated with repetitive head acceleration event exposure.

Recent evidence of short-term alterations in brain physiology associated with repeated exposure to moderate intensity subconcussive head acceleration events (HAEs), prompts the question whether these alterations represent an underlying neural injury. A retrospective analysis combining counts of experienced HAEs and longitudinal diffusion-weighted imaging explored whether greater exposure to incident mechanical forces was associated with traditional diffusion-based measures of neural injury-reduced fractional anisotropy (FA) and increased mean diffusivity (MD). Brains of high school athletes (N = 61) participating in American football exhibited greater spatial extents (or volumes) experiencing substantial changes (increases and decreases) in both FA and MD than brains of peers who do not participate in collision-based sports (N = 15).

Mechanical Response of Human Muscle at Intermediate Strain Rates.

We experimentally determined the tensile stress-strain response of human muscle along fiber direction and compressive stress-strain response transverse to fiber direction at intermediate strain rates (100-102/s). A hydraulically driven material testing system with a dynamic testing mode was used to perform the tensile and compressive experiments on human muscle tissue. Experiments at quasi-static strain rates (below 100/s) were also conducted to investigate the strain-rate effects over a wider range.

Imaging of small animal peripheral artery disease models: recent advancements and translational potential.

Peripheral artery disease (PAD) is a broad disorder encompassing multiple forms of arterial disease outside of the heart. As such, PAD development is a multifactorial process with a variety of manifestations. For example, aneurysms are pathological expansions of an artery that can lead to rupture, while ischemic atherosclerosis reduces blood flow, increasing the risk of claudication, poor wound healing, limb amputation, and stroke.

In vivo evaluation of a μECoG array for chronic stimulation.

Advancements in neural interfaces capable of neural stimulation have shown that neural implants may potentially target the central nervous system to treat neurological disorders. Unfortunately, many of the current technologies used to stimulate and record from the brain do not suffice for this purpose; those that provide a sufficient channel density, which is required for interfacing and chronic functionality in vivo, fail quickly, while others that last for an extended period of time in vivo are limited in recording and stimulation capabilities. Of the current methodologies available, electrocorticography (ECoG) based implants show promise for providing both high channel density interfaces as well as chronic functionality after implantation.