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277 Cards in this Set
- Front
- Back
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What is motor control? |
How the nervous system activates and coordinates muscles to produce |
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What is motor learning? |
Acquisition or enhancement of motor skills
(It does not need to be brand new, can also be to increase a skill that is already known) |
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During the late 19th and 20th centuries what was the empahsis of motor control |
Electrophysiological
Concentrating on how electricity is moving through the mody (similar to action potentials)
Therefore people thought movement was achieved within spinal cord |
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What was the history of motor control in the 1920s and 1930s? |
Saw movement behavior as a whole
What's actually happening in movement |
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What is motor control and learning used for? |
*Development *Engineering/Ergonomics *Athletics *Rehab |
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What is the physiological approach of motor control? |
*fMRI *EMG *Motion Analysis |
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What is the psychological approach of motor control? |
To see how we store memories, etc |
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What is motor behavior? |
Behavior that involves exerting muscular forces that ffects the limbs or other body parts, that is goal-oriented |
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What is a motor skill? |
Must be learned or re-learned
(Or building on it) |
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Can you have a motor behavior that is not a skill? |
Yes, but has to be goal oriented |
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What sets human movement apart from machines? |
*Adaptability (capactiy to adjust or alter motor behavior in new conditions)
*Persistence (If an outcome is not achieved on the first attempt, further attempts may be made) |
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What are the three classifications of movement?` |
1) Precision
2) Organization
3) Predicatbility (of the environment) |
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What are the breakdown of precision? |
Fine motor skill
Gross motor skill |
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What is fine motor skill? |
Precise movements typically accomplished used smaller musculature
(IE cut something with scissors, writing, sewing] |
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Waht is gross motor skill? |
Less precise movements typically accomplished with multi-limb movements (multiple joints)
[IE karate, run, riding a bike] |
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What are the types of organization? (How movement is organized) |
*Discrete *Serial *Continuous |
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What is the discrete organization? |
Beginning and end points are clearly defined
(IE Throw dart --> Movement defined by beginning and release of dart) |
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What is the serial organization? |
A number of integrated discrete skills (Numbers of complete discrete movement)
(IE multiple backflips one after another) |
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What is the continuous organization? |
Beginning and ending points are arbitrary/not set
(IE Ride a bike --> Every time on bike there is a different start and end) |
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What are the different predictability of the environment? |
*closed skill *Open skill |
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What is the closed skill? |
Environment is stable and predictable, not going to change (IE burrowing, pins don't move in the middle of the throw) |
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What is an open skill? |
Performer must adapt performance to the changing environment
[IE riding a bike, the environment is changing around them] |
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What is the open loop (feed forward) control? |
Antivipate potential distubrances before initiating movement (use to develop a plan to the controleld system)
No mechanism for correction of errors |
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Every voluntary movement we make involves _______ control |
Feedforward |
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What is feeback control? |
(IE Reflex --> Responding to stimulus)
Reactive correction for errors |
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What is a diagram for how the feedforward and feedback control work? |
*when have a desired outcome or movement, the center that knows what needs to be done to get to the outcome is the feedforward controller and then goes to the controlled system whichi s the muscle. Then will have the outcome. Out in the periphery is a control system/sensor that goes to the feedback controller |
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What is learning? |
A relatively permanent change in a person's ability to execute a motor skill as a result of practice or experience |
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How do we assess learning? |
No actual assesment, limitation or learning, based on performance outcome |
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What is the Degrees of Freedom Problem (Nikolai Benstein, 1920s) |
AKA Motor equivalence problem
First functional movement analysis contribution to motor control field
Degrees of freedom = range of different combination of joint/limb/body positions to produce movement |
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What is the defintion of the Degrees of Freedom Problem? |
Infinite number of solutions to achieve the same goal |
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What is the degrees of freedom a problem? |
Because it is hard to study and difficult to define which way is the "best way" |
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What is learning in terms of degrees of freedom? |
Attempt to find the "optimal solution" |
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How do you measure perforamance (two of the most common) |
Speed
Accuracy |
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What is the problem of measuring performance based on speed and accuracy |
Using that for learning means that they could counteract each other
There are many factors that impact performance such as the environment and psychological influences . They are not really independent |
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What does Fitts' Law describe? |
The speed-accruacy trade off |
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What is the Fitts' Law equation |
Movement Time (MT) = a + b log2(2D/W)
a&b = constants (a = interecept -y and b = slope of line of best fit) D=Distance to target W=width
Log base 2.... = Index of difficulty |
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When during Fitts' law are you the fastest? |
Biggest width and smallest distance |
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When during Fitts' law are you the quickest? |
Smallest width and furthest distance |
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What is the rule of the infinite edge? |
Because a pointing device can only go so far in any direction, targets at the edge of the screen technically have infinite target widths as illustrated. Corners are easiest place to reach because they have infinite dimensions. |
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What is the motor pathway? |
To do motor movement, start at the motor cortex and goes to the spinal cord which then synapses with the alpha motor neuron and goes to the muscle
There are hundreds or thousands of neurons going to the muscle |
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The motor pathway has all kinds of coordinated activiation that is sent by what? |
Action potentials |
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What is the pathway that goes from the brain to the spinal cord to the muscle |
Cortico-spinal pathway |
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What is the role of motor cortex to control motor units |
When the motor cortex increases firing rate, the motor neurons increases the firing rate |
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How do action potentials work |
When goes to the end of the axon, it is a synoptic transmission
At first the action potential the membrane potential at rest is about -70, then after a stimulus the sodium goes into the cell and makes the membrane more positive which causes depolarization, that is action potential. Then there is repolarization where the potassium ion goes out of the cell and makes the inside less positive then it goes into the refractory period and slow movements of ions to get back to the resting state |
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Synaptic transmission can either be what? |
*Excitatory *Inhibitory |
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What is excitatory? |
Depolarization |
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What is inhibitory |
Hyperpolarization of post synaptic cells and causes no more transmission |
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What does Dale's Corollary state? |
The action of a neuron (excitatory) or inhibitory) is always the same
For a given neuron:
-Action is always the same -The same substances are released
(IE if it is an excitatory neuron it will always be excitatory) |
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Neurons always have ____ axon |
1 |
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How are neurons organized? |
By the number of branches form the cell body
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Most neurons in humans are what type? |
Multipolar |
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What does a multipolar neuron mean? |
One axon, several dendrites |
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What do bipolar, unipolar and multipolar neurons look like? |
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For a neuron, what do cell bodies do? |
Sum signals then send and output down the axon and they have single inputs |
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Why don't you want multiple branches in sensory input? |
Because you want it to be specific instead of getting multiple information from multiple locations |
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Does motor system need as much specificity as sensory neurons? |
No, so have multipolar |
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What is the least frequent neuorn in humans? |
Unipolar |
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What is the 2nd least common neuron in humans |
Bipolar |
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What is a mtoro unit? |
A single motor neuron and all of the muscle fibers it is connected to
The smallest functional unti that can cause muscle movement |
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What is the two ways in which motor units work? |
*Recruitment (add in more motor units and follows the size principle) *Rate coding (Increase or decrease how often motor unit fires) |
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Activiation of what is how increase or decrease muscle action production? |
Motor units |
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What is the size principle? |
Motor units recruited from smallest to largest |
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What does the size of a motor unit mean? |
The diameter of the cell (can also talk about the muscle fibers)
(IE smaller means that it has a smaller diameter of the cell) |
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What is the Innervation Ratio (IR) |
Number of muscle fibers per motor neuron
This can vary widely j |
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Why does the eye have so many motor units (2970) but such a low Innervation ratio (9) |
Don't want to have such a high innervation ratio in the eye because would be difficult to control fine movement in the eyes.
Vs something like the gastrocneumius which doesn't need fine movements so it has less motor untis than its innervation ratio |
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What does the electromyography (EMG) signs show? |
Electrical activity of muscles (action potentials) |
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Can you activiate just one muscle fiber of each motor unit? |
No |
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EMG sees what in terms of the mtoor action potential? |
Sees a summation for a motor command action potential |
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When you are standing and then raise your arm up what EMG activates first (which muscle activates first) |
Hamstring EMG
Because anticipates what will happen
turn on the hamstrings first because of change of COM (moving COM forward so in anticipation will be turning on hamstrings)
The nervous system has the priority which will stay upright and safe before activate primary movers |
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What is the triphasic burst pattern? |
When go from flexing to arm straight, has the triphasic burst pattern. If you measure the triceps and biceps see the burst of action in the triceps and burst from biceps then another burst from the triceps
To make the movement faster can shorten the antagonist EMG activity |
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What tells the motor unit when and how frequently to fire? |
Brain/motor cortex |
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Where is the motor cortex located? |
Just in front of the central sulcus |
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What is the pyramidal tract? |
~1 million fibers (~90% contralateral and ~10% ipsilateral)
The motor cortex sends out a signal along the pyramidal tract then that travels through the brainstem (pyramids of the brainstem and into the spinal cord), then to the spinal ord |
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When you increase the muscle force what happens to the firing of the motor neuron and the EMG rate? |
Increase and increase |
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When you move faster what happens to the EMG rate and the motor neuron? |
There is a big bolt of EMG activity in the motor units fire lot and there is an increased activity and speed of the cortiical neuron firing |
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What is electroencephalography (EEG)? |
Tons of electrodes all over the brain to measure the activity in cortical cells |
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What does transcranial magnetic stimulation (TMS) do? |
Stimulate and activate brain
Induces action potentials then measure muscular response |
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What is the motor evoked potential? |
Physiological technique used to reward a MEP from the muscle using the EMG |
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The nervous system prioritizes ______ in movements? |
Safety |
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What is the information processing model? |
1) sensing 2) Perceiving 3) Interpretation 4) Conceptualization 5) Strategy/Plan 6) Activation 7) Execution |
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what is sensing? |
Peripheral receptors (only sensory receptors but brain does not know where it's coming from yet)
IE when a ball is flying at the head, sensing is through vision (the eyes) |
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What is perceiving? |
Pereption occurs in primary and secondary sensory cortices. There is an awareness that there is a stimulus is there |
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What is interpretation |
Sensory processing in parietal occipital and prefrontal cortices. Try to make sense of situation. |
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What is conceptualization? |
Parietal Temporal lobes
Put into the cortex to determine what to do |
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What is trategy and plan? |
In
Premotor cotex, supplementary motor area and puts together everything from sensing, perceiving, interpretation and conceputalization |
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Waht is activation? |
In the primary motor cortex to initiate motor cortex |
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Waht is execution? |
In the motor neurons, muscles and joints |
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If there is a problem at the endo f the information processing mdoel is it always because of the execution? |
No
Could be issue with other steps |
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Where is the premotor cortex located? |
In front of the motor cortex and behind arcuate sulcus |
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Where does the premotor cortex receive its information form? |
*Supplementary motor area *Cerebellum *Parietal cotex |
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Where does the premotor cortex send its information to? |
*Primary motor cortex (Most of the time) *Brainstem |
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_____ and _____ located in front of the primary motor cortex |
Supplementary motor area and premotor cortex |
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Does the premotor cortex and priamry motor cortex have the same role? |
Different |
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Is there earlier onset of activity in the premotor cortex or motor cortex? |
Premotor cortex
We know this because they are activated at different times in EEG experiemnts |
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Why is there earlier onset of activity in the premotor cortex? |
There is that delay before the actual movement because there needs some time for signal to get to the muscles |
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What area is important for generating plan from an external stimulus?
(When there is a visual cue) |
Premotor cortex area |
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If you want to stand up with no external stimulus, just internal guide what do you use? |
Only supplementory motor area
(No premotor) |
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Where is the supplementary motor area located? |
In front of the motor cortex and behind the acute sulcus |
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Where is infromation to the supplementary motor area from? |
*Basal ganglia *Premotor cortex |
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Where does information from the supplementary motor area get sent to? |
*Premotor cortex *Primary motor cortex *Brainstem |
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When is the supplementary motor area active during? |
Actual and imagined sequences of movements |
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What part of the brain would be used during:
A) finger flex with a signal
B) Sequence of finger flex with one signal at the start
C) Finger flex with no external cue (just internal activation) |
A) Premotor
B) Premotor then supplementary motor area
C) Supplementary motor area |
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Suppelementary motor area cells prefer what type of movements? |
Internally generated |
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How do we know that the supplementary motor area prefers "internally generated movements" |
Because when had a 1st key touch with a visual stimulus there was no EEG activity in the SMA but when there was an internal generated movement the SMA was activated |
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How do we know that the premotor cortex prefers visual cues? |
When do a 1st key touch task, there was no difference between visual cue and internal cue during the two tasks in the motor cortex; however, in the premotor cortex cells were more active during the visual guided task |
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For the Fred Brown basketball play where did the break down occur? |
Interpretation or conceptualization
He saw the perosn there but did not interpret it as a person not on his team |
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Where does the basal ganglia sit? |
Deep in the brain on either side of the thalamus |
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Is the basal ganglia simple or complex? |
Complex |
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Is the basal ganglia poorly understood? |
Yes |
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What is basal ganglia involved in? |
Movement initiation
When we want to stand up information would be coming to the SMA to tell body to stand up |
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What is the key neurotransmitter of the basal ganglia? |
Dopamine |
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How does the SMA activation work? |
*We don't want excitatory output to the SMA on all the time and to prevent that there is inhibitory interneurons which are activated from another place in order to prevent movement to the SMA (to turn off signals to the SMA)
*Then to allow activation of the SMA is an interneuon that inhibits the inhibition. This is activated in the front cortex (primarily) and also the substantia nigra needs two because not enough to overtake the inhibition |
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What is parkinson's disease? |
*Damage to the substantia nigra
*Which decreases dopamine because they are dopamine producing cells and becomes more difficult to inhibit the inhibitor |
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What are the symptoms of parkinson's disease? |
*Difficulty initiating movements (see people rock back and forth to try to start movements) since it is the SMA that has an issue, will need an external cue to get person moving again since premotor area is just fine (so shine light and lightly kick heels)
*slowed movements |
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What is the Efference Copy? |
Most movememtns that humans perform are continuous movements so constantly correcting through feedback, how control these feedback is through the theory of efference copy.
When send motor comman and send the signal to the motor complex at same time send out to the muscle and a copy to the brain . With that copy we have an expectation of what that movement should produce
then get an actual sensory feedback (IE the feedback around the joint changes)
Then compare with what the actual vs expected is and has a sensory discrepency to correct |
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Is the cerebellum a small or large structure? |
small
It is 10% brain volume |
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How many neurons of the brain does the cerebellum have? |
More than half (does a lot of communication) |
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Where does the cerebellum receive input from? |
*Peripheral afferents *Primary motor and pre-motor areas *Parietal lobe *Somatosensory cortex (receiving feedback) |
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Where does the cerebellum send output to? |
*Motor and pre-motor areas *Spinal cord (can directly influence motor neurons) |
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What acts as the output of the cerebellum? |
Purkinje cells |
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What is the cerebellum called in terms of its involvement in movement? |
"Comparator" It is comparing what the expected outcome is to the sensory feedback it's getting |
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Can you produce voluntary movement without the cerebellum? |
Yes |
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What is the cerebellum needed for in terms of movement? |
*Coordinated movements *Timing of movements |
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How many types of neurons are there in the cerebellum? |
5 |
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How many distinct layers are there in the cerebellum? |
3 |
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Does the cerebellum interate a lot of information? |
Yes |
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What is the input:output ratio of the cerebellum? |
40:1
(For everyone one signal to effect movement, the cerebellum is receiving 40 signals) |
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Are the purkinje cells used for input or output? |
Output |
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Are the purkinje cells inhibitory or excitatory? |
Inhibitory |
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What does the prukinje cells receive input from? |
Granule cells and climibing fibers |
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What are the only cells that send signals out from the cerebellum? |
Purkinje cells |
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Which cell is the most numerous in the cerebellum? |
Granule Cells |
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What kind of axons does the granule cells have? |
Parallel fibers |
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What does the granule cells receive input from? |
Mossy fibers What d |
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What do the granule cells directly excited? |
Purkinje Cells |
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What do the stellate and Basket Cells do? |
Modulate Pukinje cells |
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What are the stellate and basket cells |
Inhibitory interneurons
Influence the background level activity of purkinje cells |
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What happens when the stellate and basket cells are active |
Makes it difficult for granule cells to turn on the purkinje cells |
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Is the golgie cells an inhibitory or excitatory interneuron? |
Inhibitory |
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What do the golgi cells make direct contact with? |
Granule cells |
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What are particularly affected by alcohol? |
Golgi cells
Will increase the golgi cell activity |
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What are the cerebellar input? |
Mossy fibers Climbing fibers |
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Are the mossy fibers and climbing fibers excitatory or inhibitory? |
Excitatory |
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Where are the mossy fibers bring sensory information from?? |
Brainstem and spinal cord |
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What do the mossy fibers make contact with? |
Granule cells
Influence the purkinje cells via the granule cells |
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What kind of sensory information do the mossy fibers get? |
Peripheral sensory |
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Where does the climbing fibers get information from? |
Medulla (briainstem area) |
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What are the climbing fibers in contact with? |
Purkinje cells |
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What type of sensory infroamtion do the climbing fibers receive? |
Somatosensory Vestibular Visual information |
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Each purkinje cell receives _____ mossy fiber input(s) and _____ climbing fiber input(s) |
*Many *A Single |
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The purkinje cells receives tons of information when they want specific information what do they do? |
Will receive single input form a single climbing fiber |
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When the mossy fibers activate what type of signal do the purkinje cells produce? |
Simple spikes (10-20 Hz) |
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What do simple spike signal? |
State of the sensorimotor system (state of periphery) |
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When the climbing fibers activate what type of signal does the pukinje cells produce? |
Complex spikes (1-2 Hz)
Low frequency |
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When complex spikes occur what does that signal? |
Errors have occured |
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Is all cerebellar output inhibitory or excitatory? |
Inhibitory via purkinje cells |
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Do inhibitory or excitatory internurons modulate the activity of Purkinje cell? |
Inhibitory |
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What does the purkinje cells output to? |
Deep cerebellar nuclei Vestibular nuclei |
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What is the deep cerebellar nuclei for? |
Motor planning Execution |
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What is the vestibular nuclei for? |
Balance Eye movements
(Information from the climbing neurons) |
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What happens to your movement patterns when you damage your cerebellum |
Not as coordinated movements, but can still produce the movement (because no real time feedback)
If touching nose, canstill get there but not as smooth of a pattern (have irregular movement patterns)
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What are the type of sensory receptors? |
1) Mechanoreceptors 2) Thermoreceptors 3) Electromagnetic receptors 4) Chemoreceptors 5) Nociceptors |
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What are mechanorecptors? |
Free nerve endings, Merke's discs, Ruffini's endings, meissner's, muscle spindle (stretch), golgi tendon, joint receptors, vestibular recptors |
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What ae thermoreceptors? |
Cold, warmth |
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What are electromagnetic receptors? |
Vision (rods, cones) |
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What are chemoreceptors? |
Taste, smell, arterial oxygen, blood CO2, glucose |
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What are nociceptors? |
Pain receptors |
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Do nociceptors actually exist? |
No, there isn o actual receptor for pain |
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When there is an increase in stimulus (indentation of depth) what happes to the firing rate? |
There is an increase in action potential (how perceive and interprets information from the periphery-All encoded in AP firing)
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What is fasting adapting mechanorecptor? |
Sends AP then stop sending AP |
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What is an example of fast adapting mechanorecptor? |
When wearing clothing at first notice is there and then stop getting information |
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What is a slow adapting mechanorecptor? |
There is a continual firing from when stimulus turns on and off |
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Why do we have both fast and slow adapting mechanoreceptors? |
So not always getting stimulation all the time if we don't need to (fast adapting)W |
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What is an example of slow adapting mechanoreceptor? |
Vision
Eye keeps sending out what they are seeing in the vision
Proprioception |
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What are mechanoreceptors typically? |
Large diameter and fast conducting neurons |
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What are neurons classified by? |
Size and conduction velocity |
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What are theroreceptors? |
Smaller and unmyelinated |
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What is the anatomy of the eye? |
Fovea is a protion of the retina
The lens, cornea and pupil and iris focus light onto the retina |
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Where is the "sharpest" vision of the eye? |
Focal vision |
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How does the vision pathway work? |
The top blue part is two 1/2 of visual field |
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Why are there so many crossing in the vision pathway? |
In case lose an eye (this way won't completely lose vision due to an injury) |
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What is the goal of the lateral geniculate nucleus? |
To get information from the visual field to the visual cortex
Retinotopically organized |
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What happens when you have a lesion in 1? |
You can see everything from the left visual field
Can't see anything from the right visual field |
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What happens when you have a lesion in 2? |
On the left visual field: Can see medial side only
On the right visual field: Can see medial side only |
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What happens when you have a lesion of 3? |
Left visual field: Can see medial 1/2
Right visual field: Can see lateral 1/2 |
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How many layers does the lateral genigulate nucleus have? |
6 |
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What are layers 1 and 2 of the lateral genigulate nucleus called? |
Magnocellular |
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Does layers 1 and 2 mainly have rods or cones? |
Rod cellsW |
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What does the magnocellular (layers 1 and 2 of the lateral genigulate nucleus detect)? |
Movement Depth (depth perception) Brightness |
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What type of response does the magnocellular (layer 1 and 2 of the lateral genigulate nucleus) have? |
Rapid, transient response (rapid, fast acting receptors) |
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What are layers 2-6 of the lateral genigulate nucleus called? |
Parvocellular |
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What type of cells are in the parvocellular (layers 3-6 of the lateral enigulate nucleus) |
Cone cells W |
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hat does the parvocellular (layers 3-6 of the lateral genigulate nucleus) detect? |
Color Form
(Shapes) W |
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What type of response does the parvocellualr (layers 3-6 of the lateral genigulate nucleus) have? |
Slow, sustained response
(slow adapting) |
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What are the contralateral input from the lateral genigulate nucleus from? |
Layers 1, 4, 6 |
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Where is the ipsilateral input from the lateral genigulate nucleus go to? |
Layers 2, 3 and 5 |
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What does the ventral stream of the visual cortex tell you? |
What an object is |
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What does the dorsal stream of the visual cortex tell you about the object? |
Where an object is |
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When get into the visual cortex how many pathways does the visual information go through? |
2 pathways |
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What hapepns to a person who has been blind from a young age? Does this happen with people who become blind later in life? |
Visual cortex starts to respond to touch associated with reading braille
No, this does not happen for people who become blind later in life, there is no change of function of the visual cortex |
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What is a word description of what the vestibular system is used for? |
Balance |
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What is a general description of vestibular physology? |
Sensory receptors in the inner ear that sense head rotation and linear acceleration |
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Waht do the 3 semicircular canals do? |
They sense head rotation |
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What are there 3 semiciruclar canals to sense head rotation? |
For the three planes of motion |
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How far are each semiciruclar canals away from each other? |
90 degrees |
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What are the saccule and utricle used for |
To detect linear acceleration of the head |
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What are semicircular canals filled with? |
Endolymph fluid |
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What happens with the endolympth fluid when the head rotates? |
The fluid moves with the head rotation |
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What detects the movement of fluid in the semicircular canals? |
Detected by hair cells in the cupula |
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What is the cupula |
Gelatenous substance with hair cells that is deflected with the movement of liquid
The cupula sends signals down the afferent axon and down to the brain |
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What are the hair cells of the cupula like? |
Composed of many stereocilia and one kinocilium that move with fluid movement |
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What does the movement of the stereocilia transduce into? |
Neural activity |
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When stereocilia are pushed towards the kinocilium what happens to the hair cells?
When the stereocilia are pushed away from the kinocilium what happens to the hair cells? |
*Hair cell depolarizes
*Hair cell hyperpolarizes |
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When a head is rotating one way will the fluid be moving in the same direction or the other way? |
Other way in the beginning |
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The balance between _______ leads to sensation of head rotation |
Left and right excitation and inhibition |
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CCW head rotation causes what to happen to the endolymph fluid movement and what does that do to the knocilium movement on both sides |
Causes CW endolympth fluid movement
Causes the stereocilia to be pushed towards the kinocilium in the left semicircular canal = excitation
Causes the stereocilia to be pushed away from the kinocilium in the right semicircular canal = inhibition |
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At rest, what type of specific gravity do the cupula and endolymph have? |
Equal specific gravity (relatively similar density, so no movement of the capula)
Still some signals |
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When the head rotates to the left, whwat happens to the fluid movement and the signals fro mthe kinocilium? |
The fluid goes to the right
The stereocilia are away from the kinocilium so it hyperpolarizes
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When the head rotates to the right (clockwise) what happens to the fluid and the signaling of the hair cells |
Fluid left, depolarization |
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If hte head continues to rotate right what happens with fluid, etc? |
With continued movement, the fluid and head move at the same rate and if it reaches head velocity constant, and the acceleration is zero but would just have resting discharge (most likely is an instantaneous thing) |
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After rotating head but then stops what happens to the fluid? |
The fluid keeps moving for a brief amoutn of time which is why get dizziness.
(Head stabilizaton following continued mvoement results in continued SSC stimulation past roation, head velocity = zero; acceleration = negative) |
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If the hair cell in the LEFT horizntal canal, what is happening ot the head movement at each time point |
1) Rest 2) Head rotating right 3) Rest (or constant acceleration) 4) Head rotate left 5) Rest (or constant acceleration) |
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What are otoliths? |
Small calcium carbonate crystals embedded int ogelatinous material
Hair cells project into gelatinous material |
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What does the utricle sense? |
Horizontal linear acceleration |
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What does the saccule sense? |
Vertical linear acceleration |
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What is the hair movement of each of these movements? |
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What happens when you accelerate forward to the otoliths and the firing rates? |
Otholiths push backwards which increases the firing rates |
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What happens if there is no linear acceleration of the head |
There is a resting firing rate and gravity holds the hairs in place |
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When there is a linear acceleration backwards what happens to the hair cells then |
Momentum pushes the crystal in the opposite direction and the firing rate decreases |
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Output of hte vestibular system is via _____ nerve to _____ nuclei in brainstem |
*Vestibulocochlear nerve *Vestibular nuclei |
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Does the vestibular system have lots of outputs of the vestibular nuclei? |
Yes |
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What fiber is the input of the cerebellum for vestibular nuclei? |
Climbing fibers |
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What is the vestibular-ocular reflex (VOR) |
Counter-rotation of the eyes in response to head rotation
1) Move eyes as far then move head to gaze and then move eyes back to where need to fix them on |
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When there is someone with vestibular damage what happens to their vestibular-ocular reflex? |
It will overshoot, eyes don't go back as quickly as they should and they overhsoot the gaze |
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Draw a diagram of the vestibular ocular reflex and excitatory and inhibitory? |
A CW head movement allows for a CCW eye movement
There is an inhibition of extraoccular muslces on one sisde and excitation of extraocular muscles on the other sides |
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What is proprioception? |
Sensation of the orientation of body and limbs in space (how we know when our body and limbs are in space)
*Allows the posture of arms and feet |
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What are the three levels of sensory integration? |
1) Receptor level - the sensory receptors...input
2) Circuit level - Ascending pathways ... relay
3) Perceptual level-neuronal circuits in the cerebral cortex |
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What are the two sensory pathways to the CNS? |
Dorsal-Medial Leminiscal (Blue)
Anterolateral spinothalamic (Green) |
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The dorsal-medial leminiscal has ______ fibers, _____ spatial localization. Are/aren't mechanorecptive. Are they fast or slow? |
*Larger, myelinated *High degree spatial localization *Mechanoreceptive *faster (30-110 m/s) |
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The anterolateral spinothalamic tract has ______ fibers, _____ spatial localization. Are/aren't mechorecptive. Are they fast or slow? |
*Smaller, myelinated *Poor spatial localization *Not mechanorecptive (Maybe theromo or chemorecptors) *Slower (2-40 m/s) |
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Does the crossings of the spinothalmic tract and dorsal column-medial leminiscal pathway. |
Spinothalamic crosses right at the spinal cord
Dorsal column crosses over at the medula |
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If you were to damage the brain stem on the left side what would you feel from your right arm |
Still feel muscle stretch on right arm just not hot/cold on right arm |
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What does reflex go from ? |
Sensory receptor --> Interneuon --> Motor neuron/muscle |
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If you step your foot on a tac and move your foot so you don't havethe tac embedded in the foot what is your crossed extensor reflex? |
Activate knee flexors and inhibit knee extensors on side of tac
On opposite side, inhbiit knee flexors and activate knee extensors
So can balance and don't fall when shift weight ot oposite side |
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Wen you touch something hot with your left hand, what happesn to the elbow flexors and extensors in the right arm |
*Flex = inhibited; extensor = excited |
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When you touch something hot with your left hand what happens to the elbow flexors and extensors in the right arm |
Flex is excited Extensor is inhibited |
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What is the purpose of the spinal reflex? |
Speed, so do not have to go through the entire information processing model. Can go straight from sensation to excitation |
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Do we need vision for accurate motor behavior |
No, but it helps with accuracy but is not absolutely necessary |
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If turn the head to the right, the right hair cells are depolarized or hyperpolarized? |
Depolarized |
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If turn the head to the left, the left hair cells will be hyperpolarized or depolarized? |
Depolarized |
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The kinocellium is always to the ________ position |
Anterior position |
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What are saccades? |
Brief, rapid eye movements |
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How many degrees per second can you have of Saccades? |
Up to 900 degrees/second |
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How long do saccades last? |
20-200 ms (rief time) |
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The average adult makes ~ ____ saccades/ day |
100,000 |
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Is the saccade a very smooth movement? |
Yes |
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What are the parts of the brain involved in the Saccade? |
The superior colliculus (Part of basal ganglia) receives input from the visual centers and sends it to the reticular formations in the brainstem
Mesencephalic reticular formation is for vertical saccades
Pontine Reticular Focmation is for horizontal saccades |
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How is the superior colliculus (SC) organized? |
Topographically |
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The fovea represents the _______ region |
Rostral |
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When do the fovea cells fire? |
During fixation
(They fire when vision is focused on an object) |
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Periphery is represented in ______ region |
Caudal |
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Periphery cells fire _______ |
During saccade |
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Rostral cells inhibit _____ |
Caudal cell |
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How do you initiate the saccade? |
1) The rostral cell of the supieror colliculus are active and inhibite the caudal cells because we don't want random movement
2) The substantia nigra is also inhibit caudal cells
3) When need to initiate, a single xcitatory input is not enough to overcome the rostral cell and substantia nigra. So send information to the caudate cell from the front eye fields (cortex) to excite it and also send a signal to the caudate to inhibit the substantia nigra which inhibits and inhibitor and allow for the xcitation of the caudal cells and saccade to occur
(Excitatory input to Caudal cells of SC (direct) and excitatory input to caudate cells of vasal gnaglia to inhibit the substantia nigra (indirect) |
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When caudal cells start firing what will happen to rostral cells |
They will be inhibited |
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When have a sccade how to start fixation again? |
Has motor plan to tell muscles how far to go and once get there the muscles will turn off so the eye can start fixating again |
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What is a smooth pursuit? |
It is a voluntary, slow continuous eye movement |
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What is the smooth pursuit generally capable of tracking in terms of degrees/second |
~40 degrees/second |
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Smooth pursuit breaks down at velocities above ______ |
40 degrees/second |
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If also follow target with our hand, slow pursuit velocities will be increased or decreased? |
Increased
Usually up to 100 degrees/sec |
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Why is it that when we follow a target with out hand, the smooth pursuit velocities are increased? |
Eye's visual feedback from hand that is important |
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When ask particpants to trakc targets on computer with eyes and with mouse, how does the deafferented patient (no proprioception) behave |
The hand is slightly good, the eye is not smooth and is not able to follow. Trying to compensate by tracking the target with the hand get to move between the hand then the target position) |
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Does a lesion to the cerebellum lead to a break down in smooth pursuit? |
Yes
Eyes jumps to move instead of a smooth movement
Can follow the target with hand but the eyes are constantly going back and forth between the hand and target.
Have sensory information but can't process and use comparator so compensate by using the vision.
While for the control, using feedback from the hand and the eye to smoothly track the target. If have disconeect because of no afferent |
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What is Optokinetic Nystagmus? |
Alternative slow and rapid phases to follow target objects flowing past observer
(Typically slow path in one direction and opposition direction in other place) |
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What is vergence? |
Inward/outward rotation of the eyes in response to blurry vision.
Both eyes move in opposite directions |
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What eye movement when you are at the top of the grandstand? |
Smooth pursuit |
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What eye movement when you are on the infield of the racetrack? |
Optokinetic Nystagmus |
