S3-4 Sensorimotor Integration - Adaptation (1)

Sensorimotor Transformations

• Focus on perceptual-motor integration, internal models, and adaptations in motor behavior.

Objectives of the Study

• Key objectives are to understand sensorimotor adaptation through specific protocols:

  • Describe basic protocols for sensorimotor adaptation studies.

  • Explain the visuomotor rotation protocol as a tool for examining adaptation.

  • Characterize basic adaptation behaviors in response to visuomotor rotation.

  • Differentiate between explicit and implicit learning processes in adaptation.

  • Identify the various sources of error affecting adaptation.

Mechanisms of Adaptation

• Successful adaptation requires:

  • Motor Commands: Desired state defined by the motor controller.

  • Sensory Afference System: Sends sensory feedback to the motor controller.

  • Comparator: Compares actual movements against predicted outcomes.

  • Error Signal Generation: The difference between expected and actual feedback influences motor adjustment.

Sensorimotor Adaptation Experiment Steps

• Baseline Examination: Pre-test before introducing any rotation.

• Early Exposure Phase: Participant engages with visual feedback to identify discrepancies.

• Late Exposure Phase: Begin adaptation in a controlled environment based on sensory feedback errors.

  • Collect post-test data to assess adaptation effect.

Adaptation Protocol

• Exposure Phases:

  • Purpose is to create inconsistencies between expected sensorimotor results and feedback from movement.

  • Focus on recording aftereffects to evaluate adaptation success.

Study Settings

• Study includes various operational settings such as hypergravity, microgravity, and standard gravity environments to assess adaptation differences across conditions.

  • Participants likely experience movements under varied gravity settings, pushing their sensorimotor adaptability.

The Visuomotor Rotation Protocol

• Target movements are examined while introducing angular rotations in the visual modality.

• Understanding the relationship between hand positions and target locations is critical.

Error Source Analysis

• Identification of Target Error (TE) and Sensory Prediction Error (SPE):

  • TE: Difference between cursor feedback (visual guidance) and target position.

  • SPE: Discrepancies between anticipated and actual feedback lead to adjustments in movement strategy.

Learning Components

• Explicit Learning: Involves conscious adjustment in aiming towards targets influenced by visual feedback.

• Implicit Learning: Slower adaptation forming behaviors without conscious awareness, driven by sensory prediction errors, typically observed as aftereffects during post-tests.

Observational Findings from Adaptation Studies

• During initial stages of adaptation, significant adjustments in aiming direction are made.

  • Over time, adjustments move towards implicit adaptations, showcasing involuntary shifts in targeting based on feedback discrepancies.

Implications for Rehabilitation

• Effective sensorimotor adaptation theories inform therapies for conditions such as spatial neglect in stroke patients and other rehabilitation approaches.

• Demonstrating the utility of implicit strategies during recovery highlights potential pathways for enhancing rehabilitation techniques.