final

Question 1

forward model

Answer 1

simulates behavior of the body in response to motor commands and captures causal relationship b/t action and consequence
-“predictor”

Question 2

inverse model

Answer 2

simulates behavior of the motor apparatus and estimates motor commands required to achieve a desired state in advance of the movement and based on current state and corollary discharge
“controller”

Question 3

describe internal model as part of a mechanism for internal feedback loops

Answer 3

• forward dynamic model provides a constant closed loop feedback system for online adjustment
• together with the inverse model

Question 4

predictive and anticipatory control in terms of forward model

Answer 4

• predictor (forward model) uses the efference copy to predict the sensory feedback, which allows for anticipatory control of things like grip control
• eg ketchup
• prediction happens due to sensory delay which would be reactive control

Question 5

sensory confirmation and cancellation in terms of forward model

Answer 5

• sensory signals from the environment during movement are compared to the predicted signals that the forward model predictor predicts from the efference copy
• if they match, the signal is interpreted as reafferent
• if they do not match, it is interpreted as exafferent information
• eg why external stimulation is more intense than self-produce
• but anything that disrupts this comparison (rotation of robot, delay of stimulus) can create a mismatch again in signals
• eg self produced force matching is inaccurate b/c you cancel out some of the feedback and have to create more force to feel it on your finger

Question 6

internal forward model and action agency

Answer 6

• ability to distinguish an action as self-produced based on comparison of afference to efference copy
• eg schizophrenia patients have symptoms where they are not the agent of their own control
• could be due to a. generating inadequate internal predictions or b. impaired comparison of predicted and actual

Question 7

reafference principle/internal model at the single neuron level

Answer 7

recorded from vestibular afferents in monkeys

• no difference b/t active and passive movements
• vestibular signal not attenuated on the single neuron level during active movement
• when recording from vestibular nuclei, there was a attenuation of the signal for head movements

Question 8

vestibular signals during head movements

Answer 8

-active: vestibular signal is attenuated
passive head movement: codes for movement
-simultaneous passive and active movements: proprioception and vestibular afferent signal compared to reafference in vestibular nuclei
-active movement if vestibular attenuation, passive if no attenuation

Question 9

how is an internal model updated for learning?

Answer 9

• brain learns to expect unexpected signals
• monkeys introduced to unexpected signal (causes error of attribution) over learning trials supressed the vestibular signal more and more
• internal model is reclaibrated
• after effect shown when unexpected signal removed

Question 10

explain how the CNS determines whether a muscle is actively engaged in balance

Answer 10

it does if the efference copy of the motor command is congruent w/ the sensory signals

• is a balance response when congruent
  a. active balancing vs. b. passive balancing where robot does for you
• subject doesn’t know they aren’t actually balancing, so this is unconsciously controlled
• when it’s passive movement, the signals are incongruent w/motor response (because of robot) so there’s no balance response

Question 11

division 1 of visual streams

Answer 11

1st: what vs. where
what=inferior temporal, where=post. parietal
-distinction is based on stimulus features
-both based on conscious perception
-how the stimulus is processed is important

Question 12

division 2 of visual streams

Answer 12

• what vs. how
• ventral (inferior temporal)=what, dorsal (post. parietal)=how
• visual processing for online control of action
• separate systems to serve visual perception and action

Question 13

eg of same info different visual system

Answer 13

• use info about shape and size to know it’s a remote
• also to know how to pick it up and how to shape the hand to grasp it
• what vs. how

Question 14

blindsight

Answer 14

“seeing” what you can’t see

• evidence in monkeys w/visual cortex lesion
• they could still avoid objects and grasp objects and moving objects
• ie this is mediated through subcortical pathways

Question 15

dorsal vs. ventral streams

Answer 15

both streams go through the visual cortex, ventral goes to inferior occipitotemporal cortex and dorsal to post. parietal

• ventral responsible for object recognition (textures, orientation, etc.)-conscious
• dorsal responsible for spatial recognition (depth perception, location, on-line actions)

Question 16

evidence for what/how division

Answer 16

patient DF-visual agnosia w/ventral stream damage

• unable to recognize size and orientation of objects
• but preserved dorsal stream
  posting: can’t accurately orient card for slot but can put it in the mail slot
• can’t estimate size of objects by matching hand size but can go out and grab the object

Question 17

Patient RV

Answer 17

• damage to dorsal stream (PPC)
• interrupted visuomotor processing for visually guided actions
• optic ataxia-can’t reach for obects accurately
• can recognize objects, can describe orientation of slot
• cannot draw well b/c uses visual info , can’t put card in slot
• grip aperture perception accurate, not accurate when picking up object

Question 18

how are illusions used in visual systems studying

Answer 18

• illusion fools perception but not grip aperture

- allows for distinguishing b/t memory based and real time control of actions

Question 19

how are patients w/optic ataxia still able to accurately perform grasping movements?

Answer 19

evidence for real-time vs. memory based control: patients w/optic ataxia (dorsal stream damage) who are still able to perform accurate grasping movements based on memory and internal predictive model

Question 20

hand eye coordination during movement

Answer 20

• eye movement then initiation of reaching
• proprioceptive and visual information used to calculate appropriate motor output and efference copy
• error computed against efference copy to correct movement

Question 21

double step paradigm

Answer 21

target moved, then jumps again during eye movement

-takes advantage of saccadic supression to dissociate perception and action

Question 22

saccadic supression

Answer 22

reduction in sensitivity to visual inflow during eye movements

• affects only CONSCIOUS perception of target location
• limb movements to correct error show correction (guided to dorsal visual stream)

Question 23

volitional vs. automatic control

Answer 23

• volitional relies on perceptual visual info
• automatic uses visuomotor info largely unavailable to conscious perception
• reaching vs. anti reaching movements

Question 24

parietal lobe and online control of reaching movements

Answer 24

lesion and TMS leads to impairments in online corrections to mvmt jump

Question 25

visual masking

Answer 25

=hiding a prime from conscious perception by displaying it briefly then replacing with mask - mask overrides previously stored sensory stimuli - prime produces compatibility effect on RT

Question 26

address specific control

Answer 26

executive exerts control over each individual variable

Question 27

univocal control

Answer 27

assumes one-to-one correspondence over motor command to output -same command=same output in different circumstances

Question 28

bernstein's challenges

Answer 28

degrees of freedom -too many variables to control (even more considering muscles and motor units) -address specific control of MU's would be 1000s of DOF context conditioned variability -role of muscle changes based on limb position, body position, etc-univocal control not possible

Question 29

solution to DOF problem

Answer 29

-functional constraints an motor units and muscle groups evidence -longer RT w/bimanual movements (would be the same if controlled independently) -during bimanual assymetric task, movements to close objects resemble the long ones (slower and synchronized velocity than expected) b/c limbs are functionally constrained -both flight paths of limbs affected by obstruction in one's path

Question 30

coordinative structure

Answer 30

=functional linkage of mm that act of a single unit to minimize DOF for CNS during response programming -synchronation can interfere w/tasks that require different actions for each limb

Question 31

self organization

Answer 31

system that shows organized behavior/patterns of behavior where nothing is dictating it

Question 32

dynamical dystems

Answer 32

=system w/mutually interacting components and some kind of spatial or temporal definition that changes over time -tends toward equilibrium or attractor states

Question 33

attractor state

Answer 33

state the system will move toward b/c of inherent stability | -system returns to this after perturbation through negative feedback loop

Question 34

spring as example of attractor states

Answer 34

restoring force opposes the stretch/compression of the spring and moves it back to attractor state -damping force opposes velocity and moves in opposite direction to displacement (essentially friction)

Question 35

von holsts rules of coordination

Answer 35

1. only a few patterns easily performed and are distinguised by stability 2. stable patterns are maintained until critical limiting condition is reached, then transition occurs 3. tend toward increasing stability

Question 36

magnet effect and maintenance tendency

Answer 36

``` magnet effect (entrainment dynamics)-one part of system tends toward other to synchronize maintenance tendancy-each part of system has a preferred rhythm that the magnet effect pulls it out of ```

Question 37

importance of transitions

Answer 37

- studied as functional adaptations based on their stability, metabolic cost, and interference - preferred (more stable) patterns will have lower metabolic cost - patterns are self-organizing: spinal cat can change pattern - lower metabolic cost of running/walking preferred

Question 38

phase transition paradigm and pattern transitions

Answer 38

- in phase and out of phase are inherently stable and can be maintained at lower frequencies - as frequency increases, it becomes a limiting condition for antiphase and transition to more stable in phase happens

Question 39

egocentric principle

Answer 39

holds for tasks involving same limb (homologous muscles) | -stability of pattern in in phase depends on symmetric activation of homologous muscles

Question 40

allocentric principle

Answer 40

holds for tasks involving different limbs/people | -same direction of mvmt is more stable

Question 41

HKB Model

Answer 41

models intrinsic dynamics of motor coordination - maps stability of the state as a function of relative phase - mathematical model predicts attractor states - stability is analogous to potential energy, current state's relative position is to attractor states - z=frequency of oscillation

Question 42

evidence from HKB model

Answer 42

-constant error and variation decrease as relative phase approaches an attractor state

Question 43

HKB model predictions and coordination

Answer 43

- HKB model predicts behavior will move toward one attractor state - some are stronger - spontaneous transition in ONE direction (hysteresis) - as parameters of the system change, the strength of the atrractor determines ability to stay in that pattern - staying in weaker attractor will lead to coordination breaking down and moving toward stronger attractor - critical fluctuations=variability increases as you approach a transition b/c attractor is weaker - critical slowing down: how long it takes to get back to a pattern depends on stability of pattern (longer for antiphase)

Question 44

intention and dynamics landscape

Answer 44

- intention is a specific influence on a pattern - intrinsic pattern can be further stabalized by intention - you can attract dynamics toward the pattern you want to perform - -*coordination dynamics reflect intention interacting w/underlying intrinsic pattern

Question 45

interaction b/t intention and intrinsic dynamics

Answer 45

- if intention is supported by intrinsic dynamics, the pattern will be helped along - others will be harder to accomplish - intending to stay in antiphase as frequency increases-->breakdown of pattern back to inphase or phase wander - ie intention and ability to carry out intention is very influenced by underlying intrinsic dynamics

Question 46

learning and coordination dynamics

Answer 46

learning=developing new attractor state to learn new pattern of movement - requires modification of underlying landscape - error plot changes and new attractor state error starts high and reduces

Question 47

scanning coordination landscape

Answer 47

establishes a person's intrinsic patterns - most people have seagull effect of in phase and antiphase attractor states - some people would have more

Question 48

contingent negative variation

Answer 48

- slow wave during foreperiod - snesory motor association and expectancy (anticiptation) - early orienting wave, late expectancy motor prep related wave - amplitude decreases w/long foreperiod

Question 49

readiness potential

Answer 49

-slow shift in cortical potential preceding a self initiated voluntary movement associated with volitional preparation of movement -earlyRP, late RP, and motor potential

Question 50

LRP

Answer 50

- detects when on side is more active - portion of RP on one specific side - onset=response selection and polarity indicates activation of correct/incorrect hand

Question 51

LRP fractioning

Answer 51

- pre-motoric processes occur b/t stim onset and LRP onset (stim identification and response selection) - motoric processes occur b/t LRP onset and EMG onset-final motor preparation/end of response selection