Effect of healthy aging and sex on middle cerebral artery blood velocity dynamics during moderate-intensity exercise.

Blood velocity measured in the middle cerebral artery (MCA) increases with finite kinetics during moderate-intensity exercise, and the amplitude and dynamics of the response provide invaluable insights into the controlling mechanisms. The MCA response after exercise onset is well fit to an exponential model in young individuals but remains to be characterized in their older counterparts. The responsiveness of vasomotor control degrades with advancing age, especially in skeletal muscle.

Blunted cerebrovascular response is associated with elevated beta-amyloid.

The goal of this study was to explore the association of beta-amyloid accumulation and cerebrovascular response (CVR) in cognitively normal older adults. Beta-amyloid accumulation was characterized with [18F] Florbetapir positron emission tomography scans. CVR was calculated as middle cerebral artery blood flow velocity change from rest to moderate intensity exercise.

Dynamics of middle cerebral artery blood flow velocity during moderate-intensity exercise.

The dynamic response to a stimulus such as exercise can reveal valuable insights into systems control in health and disease that are not evident from the steady-state perturbation. However, the dynamic response profile and kinetics of cerebrovascular function have not been determined to date. We tested the hypotheses that bilateral middle cerebral artery blood flow mean velocity (MCA) increases exponentially following the onset of moderate-intensity exercise in 10 healthy young subjects.

Correlations between brain activity and components of motor learning in middle-aged adults: an fMRI study.

Implicit learning may be shown by improvements in motor performance, which occur unconsciously with practice and are typically restricted to the task that was practiced. The purpose of this study was to examine behaviorally relevant brain activation associated with change in motor behavior during sequence-specific motor learning of a perceptuomotor continuous tracking (CT) task in middle-aged adults. To gain further insight into the neural structures associated with change in motor behavior, overall improvement in tracking (root mean square error; RMSE) was decomposed into two components-temporal precision and spatial accuracy.

A novel device to measure power grip forces in squirrel monkeys.

Understanding the neural bases for grip force behaviors in both normal and neurologically impaired animals is imperative prior to improving treatments and therapeutic approaches. The present paper describes a novel device for the assessment of power grip forces in squirrel monkeys. The control of grasping and object manipulation represents a vital aspect of daily living by allowing the performance of a wide variety of complex hand movements.

Impaired grip force modulation in the ipsilesional hand after unilateral middle cerebral artery stroke.

Understanding grasping control after stroke is important for relearning motor skills. The authors examined 10 individuals (5 males; 5 females; ages 32-86) with chronic unilateral middle cerebral artery (MCA) stroke (4 right lesions; 6 left lesions) when lifting a novel test object using skilled precision grip with their ipsilesional ("unaffected") hand compared to healthy controls (n = 14; 6 males; 8 females; ages 19-86). All subjects possessed normal range of motion, cutaneous sensation, and proprioception in the hand tested and had no apraxia or cognitive deficits.

Gains in distance walking in a 3-month follow-up poststroke: what changes?

Statement Of Problem: Distance walking remains compromised for many adults poststroke. The purpose of this study was to examine if the amelioration of stroke-related neuromuscular impairments, improved cardiovascular fitness, or better balance contributed to gains in distance walking.

Method Of Study: The authors gathered baseline data of 92 adults at an average of 75 days poststroke and again 3 months later.