Deafferentation study-internal models correct answers -absence of feedback
-visual rotation test
-have to adapt, look for aftereffect
-large error of movement in beginning, then adaptation
-better performance with visual feedback
-GL can adapt, no sensory-sensory conflict
-aftereffect shows recalibration
-error signal from difference between visual feedback and where she expects her visual feedback
to be as a result of her movement
-efference copy to predict
Force adaptation correct answers -as you're moving, push against handle to keep a straight line
path to target
-aftereffects
Inverse model correct answers -creates motor command and efference copy
-controller
-simulates behaviour of motor apparatus and estimates in advance the motor commands required
to achieve a desired state
Forward model correct answers -uses efference copy to predict
-how the body should respond to a motor command and predict sensory consequences
-forward dynamic model: predict movement
-forward sensory model: how should it feel
-simulates behaviour of body in response to motor commands and captures causal relation
between actions and their consequences
-involves cerebellum
-makes movement smooth
Internal models correct answers -sensorimotor behaviours involves CNS learning how to control
objects and to predict the consequences of this control
-sensorimotor control depends on neural mechanisms that simulate the input and output
properties of the neuromuscular system
-sensorimotor control requires a control system that can simulate the behaviour of the body and
environment
-neural mechanisms that capture forward or inverse relationships between actions and their
consequences
-not just relying on feedback
Feedback delay correct answers -oscillations in movement
Online adjustments without proprioception correct answers -GL looked and pointed to targets
without vision of the moving limb
-target changed to a new location unexpectedly
, -GL corrected her limb movements in the absence of sensory feedback
Predictive control and state estimation correct answers -brain estimates state of motor system and
motor apparatus by integrating 2 sources of info (afferent sensory info and predictive output of
forward model)
-predictive processes are necessary bc of sensorimotor and neural delays
-disruption of forward model and state estimation leads to a control system having to rely on
delayed afferent info
-cerebellum
Cerebellum correct answers -receives ascending proprioceptive inputs
-receives efference copies of descending motor commands
-involved in forward modelling
-test involvement in forward modelling and state estimation with TMS
Disrupt internal feedback loop correct answers -TMS to lateral cerebellum
-disrupt predicted reafference
-trajectory after TMS disruption of cerebellum
-reach trajectory with initial direction comparable to TMS trajectory
-trajectory based on outdated estimate of hand position at time of reach
-plan forward trajectory based on estimate of where hand is
-disrupt forward model
Why you can't tickle yourself correct answers -if what you predict matches sensory feedback, no
prediction error, brain disregards it
-take a sensory feedback and create a delay, there is now a difference between efference copy
and sensory feedback (artificial difference)
-judge ex-afferent info to be more ticklish than the same self-produced reafferent info
-perturb sensory feedback with active movement to create a difference at comparison
Tit for tat correct answers -get reference force then press down on other person's finger with
same force you felt and keep going back and forth
-force escalation
-compensating for cancelled out reafferent info
Force matching correct answers -different forces on finger, need to reproduce it
-self produced condition, overcompensate for reafferent cancellation
-joystick condition, judgements accurate
Sensory confirmation and cancellation correct answers -reafference and exafference
-classified by origin, classified by nervous system
Internal models of self-motion correct answers -computations that suppress vestibular
reafference in early vestibular processing
-record from vestibular afferents or nuclei
-passive rotation and active rotation