Lec 3-1 Flashcards
How do we deal with delays in sensory feedback loops?
```With predictions in the form of efferent copies that get sent along with the motor command.
They provide a prediction about the afferent info that should result from the movement.
This then goes to teh comparator where the effernt copy is compared to the actual sensory information received.
What is sensorimotor integration
The processes that allows our nervous system to combine sensory information with motor commands to produce coordinated movement.
What are some themes in the study of sensorimotor integration. (common issues or topics of study)
How do we know if we are moving, or the world is moving around us?
- Brain uses information of motor commands, to predict what visual chnages will occur.
- If prediction matches outcome it is perceived as our movement (reafference), if it doesn’t match, you get an error signal and it is perceived as the world moving around you (exafferent)
Distinguish between: efference, afference, exafference, reafference.
Efference is info being sent out from CNS e.g. motor command.
Afference is info coming back to CNS e.g. sensory info
Exafference is senses caused by external stimuli.
Reafference is senses produced by your own movement.
Explain von Holst’s reafference principle
If what you predict vs what you sense is different, then you perceive it as outside world (exafferent)
Compare efferent copy of motor command with afferent feedback. You know you sent command to move so you know it’s not the world moving around you instead.
Importance of integrating efference and reafference in adapting to sensoroimotor conflicts
By using both efference and reafference, you can send a motor command along with a prediction of the reafferent feedback resulting from that command.
You then can compare the actual reafferent feedback with the predicted reafferent feedback and if it doesn’t match, the comparator sends signal to the controller to make adjustments to correct.
These corrections are how adaptation occurs.
Describe the basic protocol for adaptation studies (prism adaptation, force field adaptation)
Baseline: collect data pre-addaptation
Exposure: participants are exposed to stimulus (for prism, would be altered vision, for forcefield, would be additional resistance) leads to adaptation.
Adaptation: result of exposure.
Catch trial: sometime they will randomely remove resistance during stimulus phase to see progress of adaptation effects
Post-testing: Post test removes stimuli to test the lasting effect of adaptation.
De-adaptation: the effects of the adaptation wearing off in absence of stimulus.
Do we need proprioception to be able to adapt using sensorimotor integration? Explain how GL would perform in all these experiments.
No we don’t need proprioception to get adaptation. De-afferented patient like GL can adapt using vision for feedback. In target reaching test, GL perform like other people (have no proprio but uses vision to create reafferent prediction and get reafferent info to send to comparator).
