Effects of the unilateral dynamic handgrip on resting cortical activity levels: A replication and extension.

Previous studies have linked unilateral hand contractions to subsequent changes in hemispheric asymmetric activity, as reflected in the electroencephalographic alpha (8-12 Hz) range in each hemisphere. However, debate continues regarding the state of asymmetry induced by unilateral contractions. We have previously found a bilateral enhancement of alpha amplitude that occurs after contractions, reflecting cortical downregulation instead of changes in asymmetric activity.

Central theta amplitude as a negative correlate of performance proficiency in a dynamic visuospatial task.

Dynamic visuospatial tasks, requiring continuous engagement of attention over long time periods, have been little studied with the electroencephalogram. Specifically, the role of the theta band in these tasks is unclear, with task-related theta enhancements improving performance in some studies, and hindering it in others. In this study, 30 participants performed the Pong videogame as a dynamic visuospatial task to analyze the influence of theta and alpha amplitude as well as alpha asymmetry on performance.

Unilateral Left-Hand Contractions Produce Widespread Depression of Cortical Activity after Their Execution.

The execution of unilateral hand contractions before performance has been reported to produce behavioral aftereffects in various tasks. These effects have been regularly attributed to an induced shift in activation asymmetry to the contralateral hemisphere produced by the contractions. An alternative explanation proposes a generalized state of reduced bilateral cortical activity following unilateral hand contractions.

The Speed of Visual Attention and Motor-Response Decisions in Adult Attention-Deficit/Hyperactivity Disorder.

Background: Adults with attention-deficit/hyperactivity disorder (ADHD) exhibit slowed reaction times (RTs) in various attention tasks. The exact origins of this slowing, however, have not been established. Potential candidates are early sensory processes mediating the deployment of focal attention, stimulus response translation processes deciding upon the appropriate motor response, and motor processes generating the response.