Factors Affecting Sensory and Motor Learning

Overview

How participants perceive the position of their own hand in various contexts will be examined. This will include changing the visual display to suggest the hand is in a slightly different position, and asking participants to indicate where they think it is by pointing with their other hand.

Detailed description

Hand position can be estimated visually, from an image on the retina, and proprioceptively, from sensors in the joints, muscles, and skin. The brain is thought to weight and combine available sensory estimates to form an integrated multisensory estimate. Inherent in this process is the capacity to realign one or both sensory estimates when they become spatially mismatched, as when washing dishes with the hands immersed in water, which refracts light. It is generally assumed that if a person knows about the sensory mismatch somehow, the realignment will not occur. This assumption will be tested in two experiments by giving people this information in different ways. Expt. A: Conscious awareness of the mismatch will be presented in different ways, or absent. Expt. B: Movement error feedback will be presented in different ways, or absent.

Interventions

• Behavioral Explanatory diagram
  Participant is told there will be a mismatch between their target finger and the visual indicator of target finger position. They will be shown a diagram explaining this.
• Behavioral Direct vision
  Foamboard under mirror removed, making the mirror see-through and the hand directly visible. Mismatch between target hand and visual indicator will be directly visible.
• Behavioral Movement feedback, target hand
  After the participant points at each target, a cursor indicating final pointing position will be displayed briefly. The visual indicator of the target hand will be displaced.
• Behavioral Movement feedback, pointing hand
  After the participant points at each target, a cursor indicating final pointing position will be displayed briefly. The visual indicator of the target hand will not change, but the cursor indicating pointing hand position will change.
• Behavioral No movement feedback
  The visual indicator of the target hand will be displaced, but there will be no cursor to indicate the pointing hand's position.
• Behavioral Attend to the targets
  Participants will not be told anything about the visuo-proprioceptive mismatch. Instead, they will be asked simply to attend to the target positions.

Primary outcome measures

• Realignment [Time frame: 1 day]

Secondary outcome measures (2)

• Visuo-proprioceptive weighting [Time frame: 1 day]
• Target estimation variance [Time frame: 1 day.]

Eligibility criteria

Inclusion criteria

• Between the ages of 18-45 years old
• Right-handed.
• Covid has been found to have neurological effects in some people, but mostly the effects on sensorimotor control and neurophysiology are unknown. So we will only include individuals who report being free of Covid symptoms in week preceding testing.

Exclusion criteria

• Past or present history of seizure, stroke, any brain or peripheral nerve disease, severe head trauma, or spinal cord surgery.
• Learning or attention conditions such as ADHD.
• Orthopedic or pain conditions, or a history of seriously injured bones, joints or muscles in either arm.
• Lack of normal or corrected-to-normal vision.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Basic science

Study locations

United States · 1 center

• Hannah Block — Bloomington

Identifiers

NCT: NCT05374460 · 14804 · R01NS112367-01A1

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗