Adapting Secrete Movements Flashcards
How is vision used to plan and generate movements?
- Learning to make goal-directed movements
-Child has to learn the mapping between muscle activity and the amount and direction of limb motion - Learning to make goal directed movements with altered visual feedback
- Visual motor rotation, shift in the visual field-alter the relationship between muscle activity and visual feedback
A Common Task to Measure Visuomotor Adaptation
Modify the mapping between muscle activity and visual feedback about limb motion.
No curser rotation:
-Subject is asked to make reaching
movements in a virtual environment
-Cursor follows hand motion
Curser is rotated 45 degrees:
- Rotation transformation means
subject has to relearn/adapt
mapping between cursor and
hand motion
Results of Testing
No curser rotation:
-Subject is asked to make reaching
movements in a virtual environment
-Subject makes relatively straight
reaching movements
Curser is rotated 45 degrees:
-Subject makes reaching errors when the cursor rotation is introduced. The
size of these errors is proportional to the size of the rotation
Subject adapts and makes
accurate reaching movements
Visuomotor adaptation involves changes in the planned reach path using errors experienced in previous trials (i.e., aim point, end point)
Neural Correlates of Visuomotor Adaptation
Lesion, imaging and primate studies have identified several brain regions that are important for visuomotor learning
Lesions can come from stroke or can be created like done in monkeys to see areas of brain
rCBF means regional cerebral blood flow. It is a measure of the activity of neural tissue
PPC and Cerebellum are Involved in VMR Learning/ Adaptation
Changes of rCBF observed in:
Supramarginal Gyrus (SMG):
Superior parietal lobule (SPL):
-all editing online movments
Prefrontal cortex (PFC):
descion making and stratagizing
ALL IMPORTANT FOR VISUOMOTOR TRANSFORMATION
Cerebellum is Involved in VMR Adaptation
Cerebellum: motor adaption and errors
Increased rCBF observed in:
Posterior lobe of cerebellum: (forearm/hand areas) – thought to be
involved in learning from movement errors and adapting to properties of the body and/or environment
Cerebellar Damage Degrades Visuomotor Adaptation
Cerebellum is important for visuomotor learning. Cerebellar damage decreases learning
Healthy Control: Almost no errors, adapted with new baseline
- Washout is opposite to adaptation in terms of effort
Cerebellar damaged subject: Never learn, does not correct. Very little motor learning
Prisms Alter Visual and Auditory Processing
Normal visual map: accurate using vison
Displaced visual map: Cause use audio but visual alone will be rotated 23 degrees
If Visual and auditory is altered, prisms goggles create conflict between audition and vision. Audition realigns with vision
Before prism- fine
After placed - vision shifted but not audio
42 days after- both are realigned to the right
-after prisms removed- temporary misalignment, visual back but not audio (overtime will come back)
