Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
187 Cards in this Set
- Front
- Back
Reaching and grasping receives input from which sensory system(s) to control this type of movement |
Vision (about object and limbs) and proprioception (limb) |
|
What must the nervous system do during hand-eye coordination |
Synchronize activity of 2 systems |
|
Is the effect of each system during hand eye coordination physically distinct? |
Yes |
|
What is the goal of the reaching and grasping movement? |
*Accuracy in distance (where the object is) *Accuracy in shape (what the object is (Size of object) and general shape) |
|
What is the required information for accuracy in reaching? |
Where (How far away is the object) |
|
What is the required informaiton for grasping of an object |
What the object is (size, shape and orientation) |
|
Which pathway is involved for reaching? |
"Where"
Dorsal stream |
|
Which pathway is involved for grasping? |
"What"
Ventral stream |
|
If our task is to move to a target, what does the degrees of freedom (motor equivalency) theory say about how we accomplish this movement? (For reaching) |
There are an infinite amount of ways to accomplish this task and will eventually select the optimal pathway |
|
When you are reaching what is the path of the hand almost? |
It is almost always a direct line
(It is the optimal solution, you are most likely to choose the shortest distance between the two) |
|
When reaching, the graph shows a smooth, bell shaped velocity of the hand. What do the peak velocity scale with? |
Movement amplitude
The peak corresponds with the time the antagonist is turned on |
|
The further awya an object is the _____ your peak velocity |
Higher |
|
Reaching movement conssit of an ______ and subsequent _____ |
*Initial impulse *Current control |
|
What areas of the brain are likley involved in initial impulse? |
Sustantia nigra SMA Basal ganglia Premotor |
|
What type of sensory informaiton is required for planning of the movement? |
Visual information To establish a plan and mainly premotor if using a visual information |
|
What type of feedback is used in current control |
Proprioception and visual |
|
What is current control |
Where make corrects to that movement based on sensory feedback |
|
How could you determine importance of sensory systems in current control |
Take it away (Remove or manipulate vision and proprioception) |
|
What is initial impulse? |
Initiation of movement |
|
What is trajectory planning for initial impulse during initial impulse? |
Internally planning the trajectory of movement (internally specifying the movement trajectory) |
|
What sensory informaiton is important for initial impulse? |
Vision of target itself (Still able to accomplish this task if have visual information of a target without information about the hand) |
|
Is initial impulse a feedback or feedforward control? |
Feedforward control
(The stimulus is generally visual information about the target) |
|
What is the process for getting to initial impulse? |
|
|
What type of informaiton do we use once the movement is initiated |
Vision and proprioception |
|
What is scientific evidence that we use visual information from the hand and target |
*Distortion of visual field using the prism goggles. Have to adapt reach to distorted visual field
*Have to "learn" adapted movement pattern. Can get straight line reach after several trials which is a learned adapted pattern. Does not make correction right away because has to wait till see the hand, not till can see hand can they make the comparission with hand (saccadic movement to see object and hand then make correction)
*Once remove distortion, continue adapted movement-Will overcompensate, even though know the target is there will still move in the opposite direction |
|
How long does it take for visual feedback to influence ongoing movement |
150 ms |
|
How do we know how long it takes for visual feedback to influence ongoing movement? |
When we calculate the movements per minute and then the absolute error that someone does, as movement speed increases so does the error for eyes pen because they are still able to incorporate visual feedback.
However, during eyes closed they are consistly making the same errors no matter how fast they are doing it so 150 ms is when it doesn't matter if eyes ope nor eyes closed will stil lbe making the same errors
Any longer time than 150 ms will still ahve enough time to incorporate information to make corrections |
|
What does visual information from a target help us with? |
Trajectory planning Initial impulse |
|
When is current control most evident during? |
When we approach target |
|
What is the current control influence dependent upon? |
Movement speed (only if longer than 150 ms) |
|
How do we that proprioception is important for reaching |
Have a distortion of limb proprioception
*Have to move the joystick to the target but there is something that moves the arms to the other side and distorts proprioceptive feedback (the joystick pulls arm towards the right) so have to make corrects they have to compensate and have "learn" adapted movement patterns
Will they remove the distorition will continue the adapted movement (overcompensate) |
|
If the movement is longer than 80 ms can a person use proprioceptive feedback? |
Yes |
|
If the movement is shorter than 80 ms can they use proprioceptive feedback? |
No, not enough time |
|
Draw out the way to get to initial movement and then visual and proprioceptive corrections |
Proprioception takes around 80 ms
Vision takes around150 ms |
|
Can you incorporate proprioceptive or visual information faster? |
Proprioceptive |
|
What are the models that have been proposed to describe how the CNS controls accuracy of reaching movements? |
1) Multiple corrections model 2) Optimized impulse model |
|
What is the multiple corrections model |
Series of corrections submovements (make corrections after each points) |
|
What is each feedback during the multiple corrections model influenced by? |
Feedback from the previous sub movement |
|
How much does each sub movement travel duirng the multiple corrections model? |
Each travels a constant proportion of the distance remaining to the target
(Keep moving a distance of 50% of the target, keep doing till get to the target) |
|
What feedback is used during the multiple corrections model |
Visual feedback movel |
|
Distance to the center of the target = 20 cm
Width of the target = 5 cm
Each sub movement takes you 50% of the distance of the target
How many sub-movements would it take to be within the target |
3 |
|
Distance to the center of the target = 20 cm
Width of the target = 5 cm
Each sub movement takes you 50% of the distance of the target
If the target width was smaller (but the center position remains the same), would the total number of sub-movements increase, decrease or stay the same? |
Increase |
|
What does the optimized impulse model state? |
Initial impulse is otpimized such that the number of subsequent sub movements regarding feedback are minimized |
|
Would the multiple corrections model or the optimized initial impulse model need more time? |
Optimized initial impulse model need time for vision |
|
Between dorsal stream and ventral stream which is involved for grasping? |
Ventral |
|
Is reaching and pointing different than grasping? |
Yes |
|
Is the reaching portion of the movement slower if the end goal is to grasp an object? |
Yes
Because of speed accuracy trade off (slow down reaching speed to be more accurate) |
|
Is the reacing portion slower if the end goal is to graps then throw an object? |
Yes |
|
Show the realtionship of movement duration with target size during pointing, grasping and grasping and throwing |
|
|
What pieces of visual information are important for shaping the hand to grasp an object? |
Size/shape Orientation |
|
During prehension (grasping) what is hand posture duirng prehension influenced by? |
Severla characteristics of target object |
|
What is grip aperature dependent upon? |
Size of the object |
|
What is grip aperature |
Space between finger and thumb when hold objects |
|
If reach for a larger object have a _____ grip aperature |
Larger |
|
During prehension (grasping) what is the orientation of the hand determined by? |
The orientation of the object |
|
How does one align their major or minor axis of an object? |
Rotate the hand and wrist during approach so that grip is aligned with the axis of the object |
|
Is there specificity in planning areas of the brain for different grips? |
Yes |
|
What is the scientific evidence that there is specificity in the planning area for the type of grip? |
A monkey had the activity in its premotor cortex recorded
When the monkey had to perform a precision grip, these cells had activity
and when test with power grip such activity but activity in cells goes away a lot so showed how there were different parts of the premotor cortex dedicated to different grasps |
|
Within the premotor cortex do different types of grasps activate specific groups of cells |
Yes |
|
Is the premotor cortex very specific for the specific type of motion |
Yes
(Specifically for aperature) |
|
Where does the premotor cortex send information to |
Primary motor cortex |
|
What is the scientific evident that there is specificity in the motor cortex? |
Measured the corticio spinal neuron as well as the finger muscle EMG.
First did precision grip then power grip. Did light and heavy precision grip the corticio-spinal neuron firing did not change at all for light and heavy precision grips (meanign that force does not matter) however when between preciision grip and power grip the precision rip had more activity and the power grip had no activity |
|
What would happen to prehension movements if a patient had damage to the dorsal stream? |
Aperature wouldn't change but subject would miss the target |
|
If the pateint had damage to the ventral stream, the patient would have trouble with what? |
Interpreting object width (unable to distingusih size difference and unable to correctly interpret size of object) |
|
Would the subject be able to accurately scale the grip aperature to the same set of objects if there is damage to the ventral stream? |
Yes
Because they ahve visual feedback; able to scale larger objects larger and smalelr objects smaller |
|
If there is a sideways T. What will the subject be able to do what can't they do? |
The subject will have trouble making interpretations of the object's orientation but will be able to accurately post an object with the correct orientation |
|
Is there a differenece in speed of movement if pointing to middle circle of A vs B? |
Yes, one that subjects think is larger the target will be able to pointed at quicker
Therefore faster for circle A |
|
Is there a differnece in grip aperature if reaching for the center circle in A vs B? |
No, same grip apperture because of visual feedback |
|
What information needs to be known when picking up an object? |
Weight Surface
(These influence our force) |
|
What are the different force applied when object is grasped |
Grip force Load force Slip ratio Safety margin |
|
What is the grip force |
Force between thumb and fingers |
|
What is the laod force |
Force required to lift object from table |
|
What is the slip ratio |
Determined by grip force/load force
The point at which grip force is insufficient to carry load |
|
What is the safety margin |
How high grip force/load force is above the slip ratio |
|
For a given object does boht grip ad load force vary with object mass? |
Yes |
|
Is the rate of build up of each force constant? |
Yes,
Only final magnitude changes |
|
A higher weight = _____ load force |
Higher |
|
A heaver object needs a ____ grip force |
Higher |
|
For a given object mass with different surface materials, load force will ____ while grip force will ____ |
*Ramin constant *Vary |
|
Mroe slippery the surface, them ore or less grip force applied |
More |
|
The more slippery the surface what happens t othe rate of intiial build up in grip force |
Increases |
|
Does a higher slipperyness have a hgiher or lower safety margin |
Higher because hgiher grip force |
|
In many movement disorders do patients compensate by generating too much or too late force for a given laod? |
More |
|
Is the safety margin higher or lower for movement disorders? |
Larger |
|
What are the applications to health care for grip force? |
Developement of prostheses Functional robotic arms Amazing advances |
|
What is the process of grasping? |
Need visual feedback to correct for the grip aperature need a very specific prehension plan |
|
What is posture? |
Position of the body or body parts |
|
What is posture relative to? |
Gravitational vertical |
|
Can posture be static or dynamic |
Can be both. Posture changes when a person moves |
|
What is balance in terms of the center of mass and the base of support? |
Maintaining the center of mass within the base of support |
|
What is the ground reaction force |
Force exerted on the body by a ground |
|
What is the center of pressure (COP)? |
The point where the resultant of all ground reaction forces acts |
|
If put both feed on the ground where would be the sum of all of the GRF (center of pressure) be? |
It would be between the both feet |
|
What is the center of mass/gravity? |
The point on an object around which the mass is equally distributed |
|
Why do you change your COP? |
To keep the COM within the base of support |
|
What is the base of support |
Region bounded by contact with the support surface |
|
What is the stability in terms of the COM and the base of support |
Maintaining the COM within the base of support |
|
Does a smaller base of support necessarily equal a person being less stable? |
No |
|
Even when someone is standing "still" is there still some sway in the anterior-posterior and medial-lateral direction? |
Yes |
|
What are the factors contributing to balance control |
*Cerebellum *Physiological factors (breating and heart beat) *Psychological factors *Posture *Muscle tone (Training and fatigue) *Sensory feedback (Visual, vestibular and proprioception) |
|
For quiet stance the amoutn of sway is affected by____ |
posture |
|
When is there the least amount of sway for quiet sway? |
When the body is aligned along line of gravity |
|
How is quiet stance affected by muscle tone? |
Muscles are tonically active during stance (especially around ankle, need to be tonically active or else will fall over)
The function to keep body aligned with gravity |
|
Will having slack muscle increase or decrease sway |
Increase (Also if too taut will have increased sway as well)
Need just enough strength
If taut can detect much more strech quickly by muscle spindles |
|
Is visual input important for keeping postural sway? |
Yes, if no postural input there is increased postural sway |
|
How does optic flow show us that vision is important for balance? |
If in a box on a trolly, person would be standing in a box and when the box moves, it looks like the person is flaling foward so the people will adjust their COM (think are leaning foward so will lean backwards)
Moving lines to create illusion that person is moving foward so will shift COM backwards |
|
How do we know that vision is involved in static postural control? |
When remove vision there is greater sway as indicated by the movement of the COP and COM
After the optic flow to give the illusion that a person is swaying in one direction, he or she will move the COM in the opposite direction |
|
What type of vestibular response is used for postural control? |
Galvanic vestibular response
|
|
What type of stimulation behind the ear used to test the vestibular response in static postural control |
Electrical stimulation behind the ear to activate nerve (vestibular-cochlear nerve)
Gives sensation of falling toward stimulated side |
|
If you stimulate the right side of the vestibular system where will the subject move |
To the left |
|
During propricoception, will reduced sensory feedback form legs and feed increase postural sway? |
Yes |
|
Can COP move outside of your BOS? |
No |
|
What happens when you add in proprioceptive feedback with touch? |
There is almost identical COP displacement with light and free contact of the support. It gives extra point to know where the body is even when they take away the vision.
Also if they touch something there will also be an increase in BOS but movement of COM also changes |
|
Compared with control subjects, how would you expect damage to the cerebellum to affect COP or COM movements during static posture? |
Cerebellum --> Comparator of predicted vs what actually happens through the sensory systems (make correction to balance control)
If there is damage would move around a lot, no line control of balance. Even if proprioceptors were fine, information would not be able to be interpretated
There would be greater deviations in COP and COM because causes more sway in postural control |
|
What kind of strategies are used in response to postural perturbation |
Ankle strategy
Hip strategy
Stepping strategy |
|
For the ankle strategy what is the model? |
Inverted pendulum model |
|
For the inverted pendulum mdoel what is the bob? |
The head |
|
For the inverted pendulum model what is the fixed point? |
Ankle |
|
For the ankle strategy what sequence is activated |
Distal to proximal |
|
For the ankle strategy during forward sway what muscles activated |
Active muscles on back of body from distal to proximal sequence (EMG activities)
Gastrocnemius --> Hamstrings ---> Erector spinae |
|
For the ankle strategy during backward sway what is activated |
Muscles on the front of the body from distal to proximal sequence
Tibialis anterior ---> Quads --> Abs |
|
When is the hip strategy used? |
If too big for ankle strategy |
|
For the hip strategy during forward sway what muscles are activated |
Activate muscles on the front of the body then the bakc of the body from the proximal to distal sequence
(Activate muscles on the front of the body first (abdominals --> quads --> Tibialis anterior) then activate muscles on the back (Erector spinae --> hamstrings --> Gastrocnemius) from proximal to distal for both times |
|
During the hip strategy during the backward sway? |
Activate muscles on back of body then front of the body proxima to distal sequence for both |
|
What is a last resort to prevent fall when other strategies fail |
Stepping strategy |
|
What is the stepping strategy? |
Move BOS to catch up with the COM |
|
When there is normal and has a pretty large BOS which strategies are used? |
|
|
When there is a narrow beam what type of postural control strategies are used? |
|
|
When there is a normal condition what postural control strategy is primarily used? |
Ankle strategy |
|
When there is a narrow beam (restricted BOS) what postural control strategy is used? |
Primarily use hip strategy |
|
Why do we raise our arms when balance is compromised? |
To control COM (and easier to move arms than the hips)
Also to catch self when fall so acts as protection (key reason) |
|
For anticipatory control which muscles are activated |
postural muscles before primary movers |
|
Is anticipatory control a feedforward or feedback ocntrol? |
Feedforward |
|
What happens to muscle activation patterns if the body is supported during anticipatory control? |
Don't activate postural control muscles, just activate primary movers |
|
What is the pathway of anticipatory control? |
|
|
How does healthy and parkinson's disease patients differ in postural control? |
*Switch from ankle to hip strategy when standing on narrow beam
*Parkinsons' disease (doesn't have correct muscle tone, don't use sensory feedbak becaus emuscle tone) -Complex pattern -Unable to adapt postural strategies to different contexts |
|
What is postural control with cerebellar damage? |
Patients with cerebellar damage have problems scaling response amplitudes
Response is too large and too long, so they overshoot and must activate antagonists
(IE lean forward, lean back way too much, so have to activate front as well) |
|
Does postural sway increase or decrease with aging |
Increase particularly in fallers |
|
What is aging associated with |
*Reduced muscle strength *reduced sensory function (vision, vestibular, peripheral) |
|
With greater muscle activity is there slower or faster response to perturbations? |
Slower |
|
How do you improve balance control in older adults with history of falls? |
Vibratory insoles (additionally sensory feedback to enhance the feedback)
with "noise" sway is reduced
Older adults, diabetic neuropathy, stroke patients
Obstacle course (Combines cognitive and physical functions) |
|
Since older people operate closer to the limits of base of support what does that mean for balance control? |
Have bad balance control |
|
What kind of proprioceptive response do older people have and what does that do to to postural sway |
Have a decreased proprioceptive response and increased sway |
|
How do you help with the proprioceptive response for older people |
Give them more proprioceptive feedback with vibrating insoles to excite the skin receptors at the bottom of their feet
Helps to improve postural control with the increased proprioceptive information |
|
What is a training to help older adult's increase postural control |
Put older individuals navigating thorugh an obstacle course of real life items (contains both cognitivee (reading newspaper) with motor movements) so acts as a dual tasking |
|
What is locomotion? |
Rhythemic alternating of limbs on opposing sides of the body for the purpose of progression |
|
Locomotion is a series of what? |
Balance perturbations |
|
Does locomotion have sensory contributions? |
Yes |
|
What is one stride cycle? |
From heel strike - heel strike |
|
What percent of the stride cycle is the swing phase? |
40% |
|
When the swing phase start? |
Starts at toe-off |
|
When does the swing phase end? |
Ends at heel strike |
|
What percent of the stride cycle? |
60% |
|
When does the stance phase start? |
Starts at heel strike |
|
When does the stance phase end? |
End at toe off |
|
How much of the stride cycle is the double support? |
10% |
|
What is double support? |
Both feet on ground |
|
What is the heel strike used? |
Absorb shock so head is not bouncing around with every step n |
|
What is the mid-stance used for? |
Transfer center of pressure (Move COP through foot and toe off allows for propulsion forward) |
|
What is the toe off for? |
Propulsion |
|
What is the equation for gait speed? |
Gait length * Stride frequency |
|
How could you increase speed? |
Increase stride length Increase stride frequency |
|
To increase speed by increasing stride length and stride frequency which one is increased first? |
Will be a combo of the two but does depend.
|
|
If you are walking up a hill and have to increase speed will you increase stride frequency or stride length? |
Frequency |
|
If you are walking down a hill and have to increase speed will you increase stride frequency or stride length? |
Stride length |
|
How do we select gait speed? |
Look for the one with a decreased metabolic cost of walking
When map out the graph of different walking speeds at different levels see a parabala shaped and when choose speed will be walking at the speed with the lowest cost of transport
As increase the terrain the energetic sot increases but still walks at the minimal cost of transport speed
This is part of the learning process |
|
What is the key compoenent to accurate processing of visual information/ |
Head stability |
|
What does head stability do for the visual system |
Allows visual system to pick up visual flow information more clearly |
|
Do people with damage to vestibular system have problems with gait stability? |
Yes |
|
When stepping to the right would the right side or the left feet be in stance phase? Which would be in swing phase? |
Right foot is n stance phase Left foot is in swing phase |
|
If take a step to the right which way is the head moving |
Right |
|
When step is to right, head is moving to right and the eyes will be moving to _____ |
Left |
|
Is the eye movement in synch with leg movement? |
Yes |
|
What happens when the cerebellum is damaged |
Coordination breaks down and movement patterns suffer
The movement is not as smooth as the control and have saccades in middle (made for correction) because eye movement help to make corrections isnce vestibular information is off
Not able to get vestibular feedback to keep head stable so constnat corrections to keep gaze fixated |
|
Where is gaze generally focused? |
In the direction of movement |
|
What kind of fixations do you have on an obstacel? |
Brief, intermittent fixations |
|
Do you look at an obstacle when cross it? |
No W |
|
Why can you complete an obstacle course with eyes closed? |
Had visual information to begin with and did it once and so can form a subconcious (procedural) memory of the movement and motor behavior |
|
If something is in the procedural memory, can you get to it slower or faster? |
Quicker |
|
What is procedural memory? |
Working memory of task-specific visuo-spatial informaiton "the mind's eye" |
|
Is visual information about optic flow is important to gait velocity? |
Yes |
|
As locomotion speed increase does visual flow speed increase or decrease? |
Increase |
|
How do they test optic flow on gait speed? |
Have subject walking on treadmill with a dome to change how optic flow shown either increase or decrease. If increase optic flow speed gait speed decreases. The brain trusts visual information more and thinks is more accurate and ffel that the body movement is incorrect so want to slow down visual information and slow down gait speed |
|
When optic flow is faster than expect, gait speed _____ |
Decreases |
|
When optic flow is slower than expected, gait speed ____ |
Increases |
|
What are other factors affecting gait? |
Change posture IE high heels |
|
What postural control factors affected by wearing high heels |
High heels change activation of muscles
And make it more difficult to keep self aligned with gravity and need to make lots of hcanges for body
Change activation of muscle especially in back etc |