Large-scale signal propagation modes in the human brain.

The brain's temporal dynamics across large-scale networks are essential to understanding cognitive processes. However, a coherent framework remains elusive due to the combinatorial complexity of sequential states and methodological inconsistencies across studies. Here, we address these challenges by identifying a limited set of brain-wide signal propagation modes that capture diverse spatiotemporal features reported across studies.

Block Building Task Identifies Distinct Groups of Left/Right-hand Choice Patterns After Unilateral Peripheral Nerve Injury.

Numerous methods exist to assess hand and arm function after upper extremity peripheral nerve injury, but peripheral injuries are often unilateral, and few existing methods are designed to capture the unique consequences of unilateral injury. Unilateral impairment of an upper extremity can lead to increased or decreased use of the dominant hand, and either change may be adaptive or maladaptive depending on the individual patient's needs. To identify atypical hand usage (left/right choices), researchers and clinicians need to measure it.

M1 recruitment during interleaved practice is important for encoding, not just consolidation, of skill memory.

The primary motor cortex (M1) is crucial for motor skill learning. We examined its role in interleaved practice, which enhances retention (vs. repetitive practice) through M1-dependent consolidation.

Healthy adults favor stable left/right hand choices over performance at an unconstrained reach-to-grasp task.

Reach-to-grasp actions are fundamental to the daily activities of human life, but few methods exist to assess individuals' reaching and grasping actions in unconstrained environments. The Block Building Task (BBT) provides an opportunity to directly observe and quantify these actions, including left/right hand choices. Here we sought to investigate the motor and non-motor causes of left/right hand choices, and optimize the design of the BBT, by manipulating motor and non-motor difficulty in the BBT's unconstrained reach-to-grasp task.

Roles of Handedness and Hemispheric Lateralization: Implications for Rehabilitation of the Central and Peripheral Nervous Systems: A Rapid Review.

Importance: Handedness and motor asymmetry are important features of occupational performance. With an increased understanding of the basic neural mechanisms surrounding handedness, clinicians will be better able to implement targeted, evidence-based neurorehabilitation interventions to promote functional independence.

Objective: To review the basic neural mechanisms behind handedness and their implications for central and peripheral nervous system injury.

Patient Outcomes After Peripheral Nerve Injury Depend on Bimanual Dexterity and Preserved Use of the Affected Hand.

Background: Little is known about how peripheral nerve injury affects human performance, behavior, and life. Hand use choices are important for rehabilitation after unilateral impairment, but rarely measured, and are not changed by the normal course of rehabilitation and daily life.

Objective: To identify the relationship between hand use (L/R choices), motor performance, and patient-centered outcomes.

Healthy adults favor stable left/right hand choices over performance at an unconstrained reach-to-grasp task.

Unlabelled: Reach-to-grasp actions are fundamental to the daily activities of human life, but few methods exist to assess individuals' reaching and grasping actions in unconstrained environments. The Block Building Task (BBT) provides an opportunity to directly observe and quantify these actions, including left/right hand choices. Here we sought to investigate the motor and non-motor causes of left/right hand choices, and optimize the design of the BBT, by manipulating motor and non-motor difficulty in the BBT's unconstrained reach-to-grasp task We hypothesized that greater motor and non-motor (e.

Reducing individual differences in task fMRI with OGRE (One-step General Registration and Extraction) preprocessing.

Volumetric analysis methods continue to enjoy great popularity in the analysis of task-related functional MRI (fMRI) data. Among these methods, the software package FSL (FMRIB, Oxford, UK) is omnipresent throughout the field. However, it remains unknown what advantages might be gained by integrating FSL with alternative preprocessing tools.

Corrigendum: Changes in primary somatosensory cortex following allogeneic hand transplantation or autogenic hand replantation.

[This corrects the article DOI: 10.3389/fnimg.2022.

Motor Assessment With the STEGA iPad App to Measure Handwriting in Children.

Importance: Handwriting and the fine motor control (hand and fingers) underlying it are key indicators of numerous motor disorders, especially among children. However, current assessment methods are expensive, slow, and subjective, leading to a lack of knowledge about the relationship between handwriting and motor control.

Objective: To develop and validate the iPad precision drawing app Standardized Tracing Evaluation and Grapheme Assessment (STEGA) to enable rapid quantitative assessment of fine motor control and handwriting.

Failure to Compensate: Patients With Nerve Injury Use Their Injured Dominant Hand, Even When Their Nondominant Is More Dexterous.

Objective: To identify how individuals respond to unilateral upper extremity peripheral nerve injury via compensation (increased use of the nondominant hand). We hypothesized that injury to the dominant hand would have a greater effect on hand use (left vs right choices). We also hypothesized that compensation would not depend on current (postinjury) nondominant hand performance because many patients undergo rehabilitation that is not designed to alter hand use.

Interhemispheric Parietal-Frontal Connectivity Predicts the Ability to Acquire a Nondominant Hand Skill.

After chronic impairment of the right dominant hand, some individuals are able to compensate with increased performance with the intact left nondominant hand. This process may depend on the nondominant (right) hemisphere's ability to access dominant (left) hemisphere mechanisms. To predict or modulate patients' ability to compensate with the left hand, we must understand the neural mechanisms and connections that underpin this process.

Quality of Life and Psychosocial Factors as Predictors of Pain Relief Following Nerve Surgery.

Peripheral nerve injuries may result in pain, disability, and decreased quality of life (QoL). Pain is an incompletely understood experience and is associated with emotional and behavioral qualities. We hypothesized that pain following peripheral nerve surgery could be predicted by changes in emotions or QoL postoperatively.

Cortical Plasticity in Rehabilitation for Upper Extremity Peripheral Nerve Injury: A Scoping Review.

Importance: Poor outcomes after upper extremity peripheral nerve injury (PNI) may arise, in part, from the challenges and complexities of cortical plasticity. Occupational therapy practitioners need to understand how the brain changes after peripheral injury and how principles of cortical plasticity can be applied to improve rehabilitation for clients with PNI.

Objective: To identify the mechanisms of cortical plasticity after PNI and describe how cortical plasticity can contribute to rehabilitation.

Interhemispheric transfer of post-amputation cortical plasticity within the human somatosensory cortex.

Animal models reveal that deafferenting forelimb injuries precipitate reorganization in both contralateral and ipsilateral somatosensory cortices. The functional significance and duration of these effects are unknown, and it is unclear whether they also occur in injured humans. We delivered cutaneous stimulation during functional magnetic resonance imaging (fMRI) to map the sensory cortical representation of the intact hand and lower face in a group of chronic, unilateral, upper extremity amputees (N = 19) and healthy matched controls (N = 29).

Impact of Handedness on Disability After Unilateral Upper-Extremity Peripheral Nerve Disorder.

Impairment of the dominant hand should lead to greater disability than impairment of the nondominant hand, but few studies have tested this directly, especially in the domain of upper-extremity peripheral nerve disorder. The aim of this study was to identify the association between hand dominance and standardized measures of disability and health status after upper-extremity peripheral nerve disorder. An existing database was reanalyzed to identify the relationship between affected-side (dominant vs nondominant) on individuals with unilateral upper-extremity peripheral nerve disorder (N = 400).

Grasping with a new hand: Improved performance and normalized grasp-selective brain responses despite persistent functional changes in primary motor cortex and low-level sensory and motor impairments.

Hand loss can now be reversed through surgical transplantation years or decades after amputation. Remarkably, these patients come to use their new hand to skilfully grasp and manipulate objects. The brain mechanisms that make this possible are unknown.

Contributions of the parietal cortex to increased efficiency of planning-based action selection.

Response selection is foundational to adaptive behavior, and considerable attention has been devoted to investigating this behavior under conditions in which the mapping between stimuli and responses is fixed. Results from prior studies implicate the left supramarginal gyrus (SMg), premotor and prefrontal cortices, as well as the cerebellum in this essential function. Yet, many goal-directed motor behaviors have multiple solutions with flexible mappings between stimuli and responses whose solutions are believed to involve prospective planning.

Increased functional connectivity between cortical hand areas and praxis network associated with training-related improvements in non-dominant hand precision drawing.

Chronic forced use of the non-dominant left hand yields substantial improvements in the precision and quality of writing and drawing. These changes may arise from increased access by the non-dominant (right) hemisphere to dominant (left) hemisphere mechanisms specialized for end-point precision control. To evaluate this prediction, 22 healthy right-handed adults underwent resting state functional connectivity (FC) MRI scans before and after 10 days of training on a left hand precision drawing task.

Compensatory changes accompanying chronic forced use of the nondominant hand by unilateral amputees.

Amputation of the dominant hand forces patients to use the nondominant hand exclusively, including for tasks (e.g., writing and drawing) that were formerly the sole domain of the dominant hand.

Simultaneous reconstruction of continuous hand movements from primary motor and posterior parietal cortex.

Primary motor cortex (MI) and parietal area PE both participate in cortical control of reaching actions, but few studies have been able to directly compare the form of kinematic encoding in the two areas simultaneously during hand tracking movements. To directly compare kinematic coding properties in these two areas under identical behavioral conditions, we recorded simultaneously from two chronically implanted multielectrode arrays in areas MI and PE (or areas 2/5) during performance of a continuous manual tracking task. Monkeys manually pursued a continuously moving target that followed a series of straight-line movement segments, arranged in a sequence where the direction (but not length) of the upcoming segment varied unpredictably as each new segment appeared.

Stimulus-response correspondence across peripersonal space is unaffected by chronic unilateral limb loss.

Previous findings show an advantage in response speed when stimulus and response correspond spatially (i.e., the Simon effect).

Preserved grip selection planning in chronic unilateral upper extremity amputees.

Upper limb amputees receive no proprioceptive or visual sensory feedback about their absent hand. In this study, we asked whether chronic amputees nevertheless retain the ability to accurately plan gripping movements. Fourteen patients and matched controls performed two grip selection tasks: overt grip selection (OGS), in which they used their intact hand to grasp an object that appeared in different orientations using the most natural (under- or overhand) precision grip, and prospective grip selection (PGS), in which they selected the most natural grip for either hand without moving.

Performance differences in visually and internally guided continuous manual tracking movements.

Control of familiar visually guided movements involves internal plans as well as visual and other online sensory information, though how visual and internal plans combine for reaching movements remain unclear. Traditional motor sequence learning tasks, such as the serial reaction time task, use stereotyped movements and measure only reaction time. Here, we used a continuous sequential reaching task comprised of naturalistic movements, in order to provide detailed kinematic performance measures.