Measuring age differences in executive control using rapid motor decisions in a robotic object hit and avoid task.

Age-related declines in executive control are commonly assessed with neuropsychological tests that also rely on sensory and motor processes that are not typically measured in those tasks. It is therefore difficult to isolate the cognitive contributions from sensorimotor contributions to performance impairments. Rapid motor decision-making tasks may also be sensitive to age differences in executive control but allow for the measurement of sensorimotor contributors to task performance.

Advanced spatial knowledge of target location eliminates age-related differences in early sensorimotor learning.

Motor learning has been shown to decline in healthy aging, particularly in the early stages of acquisition. There is now ample evidence that motor learning relies on multiple interacting learning processes that operate on different timescales, but the specific cognitive mechanisms that contribute to motor learning remain unclear. Working memory resources appear to be particularly important during the early stages of motor learning, and declines in early motor learning have been associated with working memory performance in older adults.

Linking actions and objects: Context-specific learning of novel weight priors.

Distinct explicit and implicit memory processes support weight predictions used when lifting objects and making perceptual judgments about weight, respectively. The first time that an object is encountered weight is predicted on the basis of learned associations, or priors, linking size and material to weight. A fundamental question is whether the brain maintains a single, global representation of priors, or multiple representations that can be updated in a context specific way.

Distinct contributions of explicit and implicit memory processes to weight prediction when lifting objects and judging their weights: an aging study.

Weight predictions used to scale lifting forces adapt quickly when repeatedly lifting unusually weighted objects and are readily updated by explicit information provided about weight. In contrast, weight predictions used when making perceptual judgments about weight are more resistant to change and are largely unaffected by explicit information about weight. These observations suggest that distinct memory systems underlie weight prediction when lifting objects and judging their weights.

Effects of age and cognitive load on response reprogramming.

A dual-task paradigm was used to examine the effect of cognitive load on motor reprogramming. We propose that in the face of conflict, both executive control and motor control mechanisms become more interconnected in the process of reprogramming motor behaviors. If so, one would expect a concurrent cognitive load to compromise younger adults' (YAs) motor reprogramming ability and further exacerbate the response reprogramming ability of older adults (OAs).

Integrating actions into object location memory: a benefit for active versus passive reaching movements.

We tested whether learning the mapping between objects and their locations is better when actively moving the hand to these locations, to reveal the object, compared to when the hand is passively moved by a robotic manipulandum. Recall of object locations was more accurate in the active compared to passive condition. We also found that recall was less accurate when participant made active movements that were not directed to the object locations.

Fast but fleeting: adaptive motor learning processes associated with aging and cognitive decline.

Motor learning has been shown to depend on multiple interacting learning processes. For example, learning to adapt when moving grasped objects with novel dynamics involves a fast process that adapts and decays quickly-and that has been linked to explicit memory-and a slower process that adapts and decays more gradually. Each process is characterized by a learning rate that controls how strongly motor memory is updated based on experienced errors and a retention factor determining the movement-to-movement decay in motor memory.

Detecting self-produced speech errors before and after articulation: an ERP investigation.

It has been argued that speech production errors are monitored by the same neural system involved in monitoring other types of action errors. Behavioral evidence has shown that speech errors can be detected and corrected prior to articulation, yet the neural basis for such pre-articulatory speech error monitoring is poorly understood. The current study investigated speech error monitoring using a phoneme-substitution task known to elicit speech errors.

Context-updating processes facilitate response reprogramming in younger but not older adults.

The current study used concurrent acquisition of motion capture and event-related potential (ERP) data to test the prediction that response reprogramming relies on context-updating processes, and that age differences in conflicting-response performance are related to context-updating deficits in the elderly. Participants performed a motor sequencing task that included prepotent pairs of key presses, and conflicting pairs that started with the same first key press of the prepotent pair, but ended in an unexpected alternate response. ERP analyses were used to measure the P3b component as an electrophysiological correlate of context updating.

Movement kinematics of prepotent response suppression in aging during conflict adaptation.

Objectives: The purpose of the current study was to explore the role of adjustments in motor control and conflict adaptation in younger and older adults' prepotent response suppression.

Methods: Participants performed repeated pairs of key-presses on a piano-type keyboard as well as key-presses that conflicted with that prepotent pair. We used motion capture to assess cognitive and motor contributions to conflicting responses presented once, twice, or three times within single trials.

Examining prepotent response suppression in aging: a kinematic analysis.

Two experiments were designed to explore how age differences in conflict detection may contribute to poorer motor performance. In each experiment, 12 young adults (YAs) and 12 older adults (OAs) performed a finger sequencing task in which the frequency of specific critical transitions was varied. These critical transitions were contrasted with violation transitions to assess the ability to detect a conflict in response requirements.