An examination of the effects of equilibrium on the control of goal-directed reaching in humans
Bibliographic record
Abstract
Goal-directed reaching movements executed from seated positions exhibit rapid, automatic corrections in response to a change in target position. In the standing posture, corrections in arm trajectory during reaching movements are accompanied by feedforward corrections in postural activity which create the dynamical conditions necessary for successful task execution. However, it is unknown how equilibrium constraints associated with standing as opposed to sitting, which has little or no equilibrium constraints, influence the neural processes underlying online corrections of goal-directed movements. This thesis aimed to address this question. Eight healthy adult subjects (3 males, 5 females) performed regular reach-to-point movements and an online arm correction task when seated and when standing. It was hypothesized that the increased equilibrium constraints during stance would influence the online control of goal-directed reaching, resulting in differences in focal movement endpoint kinematics. The focal reaching movement was described using spatiotemporal kinematics of the reaching hand. Whole-body kinematic analyses were also performed to compare the movement strategies utilized in each postural configuration. It was found that the postural configuration (seated vs. standing) in which the movements were executed generally did not affect focal movement parameters (velocity profile, movement time, time to correction, and peak velocity), despite resulting in different whole-body kinematic strategies (i.e. extent of elbow flexion-extension, shoulder adduction-abduction, trunk rotation, pelvis rotation, pelvis obliquity, and pelvis translation). These results highlight the efficacy of the neural processes underlying the end goal of arm reaching movements and their online control. The processes of control do not appear to be affected by the higher demands placed on the CNS required for the maintenance of postural equilibrium during stance.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".