Repeated spaced cortical paired associative stimulation promotes additive plasticity in the human parietal-motor circuit.

Objective: Repeated spaced sessions of repetitive transcranial magnetic stimulation (TMS) to the human primary motor cortex can lead to dose-dependent increases in motor cortical excitability. However, this has yet to be demonstrated in a defined cortical circuit. We aimed to examine the effects of repeated spaced cortical paired associative stimulation (cPAS) on excitability in the motor cortex.

The behavioral and neural effects of parietal theta burst stimulation on the grasp network are stronger during a grasping task than at rest.

Repetitive transcranial magnetic stimulation (TMS) is widely used in neuroscience and clinical settings to modulate human cortical activity. The effects of TMS on neural activity depend on the excitability of specific neural populations at the time of stimulation. Accordingly, the brain state at the time of stimulation may influence the persistent effects of repetitive TMS on distal brain activity and associated behaviors.

Recognize and Alleviate a Resource Management Conundrum Facing Science Diaspora Networks.

Increasingly, science diaspora networks are managed by formal organizations such as embassies or non-profit organizations. Researchers have studied these networks to understand how they influence international collaborations and science diplomacy, and to determine which network activities foster those outcomes and which do not. In this perspective, we suggest that many of these network organizations confront an underappreciated conundrum for managing resources: organizations with few resources must learn how to obtain more resources despite lacking means to do so.

Measuring Hand Sensory Function and Force Control in Older Adults: Are Current Hand Assessment Tools Enough?

Background: The ability to grasp and manipulate objects is essential for performing activities of daily living. However, there is limited information regarding age-related behavioral differences in hand sensorimotor function due, in part, to the lack of assessment tools capable of measuring subtle but important differences in hand function. The purpose of this study was to demonstrate performance differences in submaximal force control and tactile pattern recognition in healthy older adults using 2 custom-designed sensorimotor assessment tools.

Reduced Facilitation of Parietal-Motor Functional Connections in Older Adults.

Age-related changes in cortico-cortical connectivity in the human motor network in older adults are associated with declines in hand dexterity. Posterior parietal cortex (PPC) is strongly interconnected with motor areas and plays a critical role in many aspects of motor planning. Functional connectivity measures derived from dual-site transcranial magnetic stimulation (dsTMS) studies have found facilitatory inputs from PPC to ipsilateral primary motor cortex (M1) in younger adults.

Reversal of Visual Feedback Modulates Somatosensory Plasticity.

Reversed visual feedback during unimanual training increases transfer of skills to the opposite untrained hand and modulates plasticity in motor areas of the brain. However, it is unclear if unimanual training with reversed visual feedback also affects somatosensory areas. Here we manipulated visual input during unimanual training using left-right optical reversing spectacles and tested whether unimanual training with reversed vision modulates somatosensory cortical excitability to facilitate motor performance.

Measuring and Manipulating Functionally Specific Neural Pathways in the Human Motor System with Transcranial Magnetic Stimulation.

Understanding interactions between brain areas is important for the study of goal-directed behavior. Functional neuroimaging of brain connectivity has provided important insights into fundamental processes of the brain like cognition, learning, and motor control. However, this approach cannot provide causal evidence for the involvement of brain areas of interest.

Using Dual-Site Transcranial Magnetic Stimulation to Probe Connectivity between the Dorsolateral Prefrontal Cortex and Ipsilateral Primary Motor Cortex in Humans.

Dual-site transcranial magnetic stimulation to the primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) can be used to probe functional connectivity between these regions. The purpose of this study was to characterize the effect of DLPFC stimulation on ipsilateral M1 excitability while participants were at rest and contracting the left- and right-hand first dorsal interosseous muscle. Twelve participants were tested in two separate sessions at varying inter-stimulus intervals (ISI: 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, and 20 ms) at two different conditioning stimulus intensities (80% and 120% of resting motor threshold).