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277 Cards in this Set

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What is motor control?

How the nervous system activates and coordinates muscles to produce

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)

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

What was the history of motor control in the 1920s and 1930s?

Saw movement behavior as a whole



What's actually happening in movement

What is motor control and learning used for?

*Development


*Engineering/Ergonomics


*Athletics


*Rehab

What is the physiological approach of motor control?

*fMRI


*EMG


*Motion Analysis

What is the psychological approach of motor control?

To see how we store memories, etc

What is motor behavior?

Behavior that involves exerting muscular forces that ffects the limbs or other body parts, that is goal-oriented

What is a motor skill?

Must be learned or re-learned



(Or building on it)

Can you have a motor behavior that is not a skill?

Yes, but has to be goal oriented

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)

What are the three classifications of movement?`

1) Precision



2) Organization



3) Predicatbility (of the environment)

What are the breakdown of precision?

Fine motor skill



Gross motor skill

What is fine motor skill?

Precise movements typically accomplished used smaller musculature



(IE cut something with scissors, writing, sewing]

Waht is gross motor skill?

Less precise movements typically accomplished with multi-limb movements (multiple joints)



[IE karate, run, riding a bike]

What are the types of organization? (How movement is organized)

*Discrete


*Serial


*Continuous

What is the discrete organization?

Beginning and end points are clearly defined



(IE Throw dart --> Movement defined by beginning and release of dart)

What is the serial organization?

A number of integrated discrete skills (Numbers of complete discrete movement)



(IE multiple backflips one after another)

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)

What are the different predictability of the environment?

*closed skill


*Open skill

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)

What is an open skill?

Performer must adapt performance to the changing environment



[IE riding a bike, the environment is changing around them]

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

Every voluntary movement we make involves _______ control

Feedforward

What is feeback control?

(IE Reflex --> Responding to stimulus)



Reactive correction for errors

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 ...

*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

What is learning?

A relatively permanent change in a person's ability to execute a motor skill as a result of practice or experience

How do we assess learning?

No actual assesment, limitation or learning, based on performance outcome

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

What is the defintion of the Degrees of Freedom Problem?

Infinite number of solutions to achieve the same goal

What is the degrees of freedom a problem?

Because it is hard to study and difficult to define which way is the "best way"

What is learning in terms of degrees of freedom?

Attempt to find the "optimal solution"

How do you measure perforamance (two of the most common)

Speed



Accuracy

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

What does Fitts' Law describe?

The speed-accruacy trade off

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

When during Fitts' law are you the fastest?

Biggest width and smallest distance

When during Fitts' law are you the quickest?

Smallest width and furthest distance

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.

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.

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

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

The motor pathway has all kinds of coordinated activiation that is sent by what?

Action potentials

What is the pathway that goes from the brain to the spinal cord to the muscle

Cortico-spinal pathway

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

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 ca...

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

Synaptic transmission can either be what?

*Excitatory


*Inhibitory

What is excitatory?

Depolarization

What is inhibitory

Hyperpolarization of post synaptic cells and causes no more transmission

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)

Neurons always have ____ axon

1

How are neurons organized?

By the number of branches form the cell body



Most neurons in humans are what type?

Multipolar

What does a multipolar neuron mean?

One axon, several dendrites

What do bipolar, unipolar and multipolar neurons look like?

For a neuron, what do cell bodies do?

Sum signals then send and output down the axon and they have single inputs

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

Does motor system need as much specificity as sensory neurons?

No, so have multipolar

What is the least frequent neuorn in humans?

Unipolar

What is the 2nd least common neuron in humans

Bipolar

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

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)

Activiation of what is how increase or decrease muscle action production?

Motor units

What is the size principle?

Motor units recruited from smallest to largest 

Motor units recruited from smallest to largest

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)

What is the Innervation Ratio (IR)

Number of muscle fibers per motor neuron



This can vary widely j

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

What does the electromyography (EMG) signs show?

Electrical activity of muscles (action potentials)

Can you activiate just one muscle fiber of each motor unit?

No

EMG sees what in terms of the mtoor action potential?

Sees a summation for a motor command action potential 

Sees a summation for a motor command action potential

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

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 ...

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

What tells the motor unit when and how frequently to fire?

Brain/motor cortex

Where is the motor cortex located?

Just in front of the central sulcus

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...

~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

When you increase the muscle force what happens to the firing of the motor neuron and the EMG rate?

Increase and increase

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 

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

What is electroencephalography (EEG)?

Tons of electrodes all over the brain to measure the activity in cortical cells

What does transcranial magnetic stimulation (TMS) do?

Stimulate and activate brain



Induces action potentials then measure muscular response

What is the motor evoked potential?

Physiological technique used to reward a MEP from the muscle using the EMG

The nervous system prioritizes ______ in movements?

Safety

What is the information processing model?

1) sensing 


2) Perceiving


3) Interpretation


4) Conceptualization


5) Strategy/Plan


6) Activation


7) Execution 

1) sensing


2) Perceiving


3) Interpretation


4) Conceptualization


5) Strategy/Plan


6) Activation


7) Execution

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)

What is perceiving?



Pereption occurs in primary and secondary sensory cortices. There is an awareness that there is a stimulus is there

What is interpretation

Sensory processing in parietal occipital and prefrontal cortices. Try to make sense of situation.

What is conceptualization?

Parietal


Temporal lobes



Put into the cortex to determine what to do

What is trategy and plan?

In



Premotor cotex, supplementary motor area and puts together everything from sensing, perceiving, interpretation and conceputalization

Waht is activation?

In the primary motor cortex to initiate motor cortex

Waht is execution?

In the motor neurons, muscles and joints

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

Where is the premotor cortex located?

In front of the motor cortex and behind arcuate sulcus

Where does the premotor cortex receive its information form?

*Supplementary motor area


*Cerebellum


*Parietal cotex

Where does the premotor cortex send its information to?

*Primary motor cortex (Most of the time)


*Brainstem

_____ and _____ located in front of the primary motor cortex

Supplementary motor area and premotor cortex 

Supplementary motor area and premotor cortex

Does the premotor cortex and priamry motor cortex have the same role?

Different

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

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

What area is important for generating plan from an external stimulus?



(When there is a visual cue)

Premotor cortex area

If you want to stand up with no external stimulus, just internal guide what do you use?

Only supplementory motor area



(No premotor)

Where is the supplementary motor area located?

In front of the motor cortex and behind the acute sulcus

Where is infromation to the supplementary motor area from?

*Basal ganglia


*Premotor cortex

Where does information from the supplementary motor area get sent to?

*Premotor cortex


*Primary motor cortex


*Brainstem

When is the supplementary motor area active during?

Actual and imagined sequences of movements

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

Suppelementary motor area cells prefer what type of movements?

Internally generated

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 

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

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 

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

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

Where does the basal ganglia sit?

Deep in the brain on either side of the thalamus

Is the basal ganglia simple or complex?

Complex

Is the basal ganglia poorly understood?

Yes

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

What is the key neurotransmitter of the basal ganglia?

Dopamine

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 ...

*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

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

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

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 comple...

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

Is the cerebellum a small or large structure?

small



It is 10% brain volume

How many neurons of the brain does the cerebellum have?

More than half (does a lot of communication)

Where does the cerebellum receive input from?

*Peripheral afferents


*Primary motor and pre-motor areas


*Parietal lobe


*Somatosensory cortex (receiving feedback)

Where does the cerebellum send output to?

*Motor and pre-motor areas


*Spinal cord (can directly influence motor neurons)

What acts as the output of the cerebellum?

Purkinje cells

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

Can you produce voluntary movement without the cerebellum?

Yes

What is the cerebellum needed for in terms of movement?

*Coordinated movements


*Timing of movements

How many types of neurons are there in the cerebellum?

5

How many distinct layers are there in the cerebellum?

3

Does the cerebellum interate a lot of information?

Yes

What is the input:output ratio of the cerebellum?

40:1



(For everyone one signal to effect movement, the cerebellum is receiving 40 signals)

Are the purkinje cells used for input or output?

Output

Are the purkinje cells inhibitory or excitatory?

Inhibitory

What does the prukinje cells receive input from?

Granule cells and climibing fibers

What are the only cells that send signals out from the cerebellum?

Purkinje cells

Which cell is the most numerous in the cerebellum?

Granule Cells

What kind of axons does the granule cells have?

Parallel fibers

What does the granule cells receive input from?

Mossy fibers What d

What do the granule cells directly excited?

Purkinje Cells

What do the stellate and Basket Cells do?

Modulate Pukinje cells

What are the stellate and basket cells

Inhibitory interneurons



Influence the background level activity of purkinje cells

What happens when the stellate and basket cells are active

Makes it difficult for granule cells to turn on the purkinje cells

Is the golgie cells an inhibitory or excitatory interneuron?

Inhibitory

What do the golgi cells make direct contact with?

Granule cells

What are particularly affected by alcohol?

Golgi cells



Will increase the golgi cell activity

What are the cerebellar input?

Mossy fibers


Climbing fibers

Are the mossy fibers and climbing fibers excitatory or inhibitory?

Excitatory

Where are the mossy fibers bring sensory information from??

Brainstem and spinal cord

What do the mossy fibers make contact with?

Granule cells



Influence the purkinje cells via the granule cells

What kind of sensory information do the mossy fibers get?

Peripheral sensory

Where does the climbing fibers get information from?

Medulla (briainstem area)

What are the climbing fibers in contact with?

Purkinje cells

What type of sensory infroamtion do the climbing fibers receive?

Somatosensory


Vestibular


Visual information

Each purkinje cell receives _____ mossy fiber input(s) and _____ climbing fiber input(s)

*Many


*A Single

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

When the mossy fibers activate what type of signal do the purkinje cells produce?

Simple spikes (10-20 Hz)

What do simple spike signal?

State of the sensorimotor system (state of periphery)

When the climbing fibers activate what type of signal does the pukinje cells produce?

Complex spikes (1-2 Hz)



Low frequency

When complex spikes occur what does that signal?

Errors have occured

Is all cerebellar output inhibitory or excitatory?

Inhibitory via purkinje cells

Do inhibitory or excitatory internurons modulate the activity of Purkinje cell?

Inhibitory

What does the purkinje cells output to?

Deep cerebellar nuclei


Vestibular nuclei

What is the deep cerebellar nuclei for?

Motor planning


Execution

What is the vestibular nuclei for?

Balance


Eye movements



(Information from the climbing neurons)

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) 


 


 

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)



What are the type of sensory receptors?

1) Mechanoreceptors


2) Thermoreceptors


3) Electromagnetic receptors


4) Chemoreceptors


5) Nociceptors

What are mechanorecptors?

Free nerve endings, Merke's discs, Ruffini's endings, meissner's, muscle spindle (stretch), golgi tendon, joint receptors, vestibular recptors

What ae thermoreceptors?

Cold, warmth

What are electromagnetic receptors?

Vision (rods, cones)

What are chemoreceptors?

Taste, smell, arterial oxygen, blood CO2, glucose

What are nociceptors?

Pain receptors

Do nociceptors actually exist?

No, there isn o actual receptor for pain

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)


 


 

There is an increase in action potential (how perceive and interprets information from the periphery-All encoded in AP firing)



What is fasting adapting mechanorecptor?

Sends AP then stop sending AP 

Sends AP then stop sending AP

What is an example of fast adapting mechanorecptor?

When wearing clothing at first notice is there and then stop getting information

What is a slow adapting mechanorecptor?

There is a continual firing from when stimulus turns on and off 

There is a continual firing from when stimulus turns on and off

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

What is an example of slow adapting mechanoreceptor?

Vision



Eye keeps sending out what they are seeing in the vision



Proprioception

What are mechanoreceptors typically?

Large diameter and fast conducting neurons

What are neurons classified by?

Size and conduction velocity

What are theroreceptors?

Smaller and unmyelinated

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

Fovea is a protion of the retina



The lens, cornea and pupil and iris focus light onto the retina

Where is the "sharpest" vision of the eye?

Focal vision

How does the vision pathway work?

The top blue part is two 1/2 of visual field 

The top blue part is two 1/2 of visual field

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)

What is the goal of the lateral geniculate nucleus?

To get information from the visual field to the visual cortex



Retinotopically organized

What happens when you have a lesion in 1?

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

What happens when you have a lesion in 2? 

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

What happens when you have a lesion of 3? 

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

How many layers does the lateral genigulate nucleus have?

6

What are layers 1 and 2 of the lateral genigulate nucleus called?

Magnocellular

Does layers 1 and 2 mainly have rods or cones?

Rod cellsW

What does the magnocellular (layers 1 and 2 of the lateral genigulate nucleus detect)?

Movement


Depth (depth perception)


Brightness

What type of response does the magnocellular (layer 1 and 2 of the lateral genigulate nucleus) have?

Rapid, transient response (rapid, fast acting receptors)

What are layers 2-6 of the lateral genigulate nucleus called?

Parvocellular

What type of cells are in the parvocellular (layers 3-6 of the lateral enigulate nucleus)

Cone cells W

hat does the parvocellular (layers 3-6 of the lateral genigulate nucleus) detect?

Color


Form



(Shapes) W

What type of response does the parvocellualr (layers 3-6 of the lateral genigulate nucleus) have?

Slow, sustained response



(slow adapting)

What are the contralateral input from the lateral genigulate nucleus from?

Layers 1, 4, 6

Where is the ipsilateral input from the lateral genigulate nucleus go to?

Layers 2, 3 and 5

What does the ventral stream of the visual cortex tell you?

What does the ventral stream of the visual cortex tell you?

What an object is

What does the dorsal stream of the visual cortex tell you about the object?

What does the dorsal stream of the visual cortex tell you about the object?

Where an object is

When get into the visual cortex how many pathways does the visual information go through?

2 pathways

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

What is a word description of what the vestibular system is used for?

Balance

What is a general description of vestibular physology?

Sensory receptors in the inner ear that sense head rotation and linear acceleration

Waht do the 3 semicircular canals do?

They sense head rotation

What are there 3 semiciruclar canals to sense head rotation?

For the three planes of motion

How far are each semiciruclar canals away from each other?

90 degrees

What are the saccule and utricle used for

To detect linear acceleration of the head

What are semicircular canals filled with?

Endolymph fluid

What happens with the endolympth fluid when the head rotates?

The fluid moves with the head rotation

What detects the movement of fluid in the semicircular canals?

Detected by hair cells in the cupula

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

What are the hair cells of the cupula like?

Composed of many stereocilia and one kinocilium that move with fluid movement

What does the movement of the stereocilia transduce into?

Neural activity

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 

*Hair cell depolarizes



*Hair cell hyperpolarizes

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

The balance between _______ leads to sensation of head rotation

Left and right excitation and inhibition

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 semicircul...

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

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 

Equal specific gravity (relatively similar density, so no movement of the capula)



Still some signals

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 


 


 

The fluid goes to the right



The stereocilia are away from the kinocilium so it hyperpolarizes



When the head rotates to the right (clockwise) what happens to the fluid and the signaling of the hair cells

Fluid left, depolarization 

Fluid left, depolarization

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) 

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)

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) 

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)

If the hair cell in the LEFT horizntal canal, what is happening ot the head movement at each time point 

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)

What are otoliths?

Small calcium carbonate crystals embedded int ogelatinous material



Hair cells project into gelatinous material

What does the utricle sense?

Horizontal linear acceleration

What does the saccule sense?

Vertical linear acceleration

What is the hair movement of each of these movements?

What is the hair movement of each of these movements?

What happens when you accelerate forward to the otoliths and the firing rates?

Otholiths push backwards which increases the firing rates

Otholiths push backwards which increases the firing rates

What happens if there is no linear acceleration of the head

There is a resting firing rate and gravity holds the hairs in place

There is a resting firing rate and gravity holds the hairs in place

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 

Momentum pushes the crystal in the opposite direction and the firing rate decreases

Output of hte vestibular system is via _____ nerve to _____ nuclei in brainstem

*Vestibulocochlear nerve


*Vestibular nuclei

Does the vestibular system have lots of outputs of the vestibular nuclei?

Yes 

Yes

What fiber is the input of the cerebellum for vestibular nuclei?

Climbing fibers

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 

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

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

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 

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

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

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 

1) Receptor level - the sensory receptors...input



2) Circuit level - Ascending pathways ... relay



3) Perceptual level-neuronal circuits in the cerebral cortex

What are the two sensory pathways to the CNS?

Dorsal-Medial Leminiscal (Blue)


 


Anterolateral spinothalamic (Green) 

Dorsal-Medial Leminiscal (Blue)



Anterolateral spinothalamic (Green)

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)

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)

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 

Spinothalamic crosses right at the spinal cord



Dorsal column crosses over at the medula

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 

Still feel muscle stretch on right arm just not hot/cold on right arm

What does reflex go from ?

Sensory receptor --> Interneuon --> Motor neuron/muscle 

Sensory receptor --> Interneuon --> Motor neuron/muscle

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

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

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

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

Do we need vision for accurate motor behavior

No, but it helps with accuracy but is not absolutely necessary

If turn the head to the right, the right hair cells are depolarized or hyperpolarized?

Depolarized

If turn the head to the left, the left hair cells will be hyperpolarized or depolarized?

Depolarized

The kinocellium is always to the ________ position

Anterior position

What are saccades?

Brief, rapid eye movements

How many degrees per second can you have of Saccades?

Up to 900 degrees/second

How long do saccades last?

20-200 ms (rief time)

The average adult makes ~ ____ saccades/ day

100,000

Is the saccade a very smooth movement?

Yes

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 Foc...

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

How is the superior colliculus (SC) organized?

Topographically

The fovea represents the _______ region

Rostral

When do the fovea cells fire?

During fixation 


 


(They fire when vision is focused on an object) 

During fixation



(They fire when vision is focused on an object)

Periphery is represented in ______ region

Caudal

Caudal

Periphery cells fire _______

During saccade

Rostral cells inhibit _____

Caudal cell

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 i...

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)

When caudal cells start firing what will happen to rostral cells

They will be inhibited

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

What is a smooth pursuit?

It is a voluntary, slow continuous eye movement

What is the smooth pursuit generally capable of tracking in terms of degrees/second

~40 degrees/second

Smooth pursuit breaks down at velocities above ______

40 degrees/second

If also follow target with our hand, slow pursuit velocities will be increased or decreased?

Increased



Usually up to 100 degrees/sec

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

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) 

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)

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 u...

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

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) 

Alternative slow and rapid phases to follow target objects flowing past observer



(Typically slow path in one direction and opposition direction in other place)

What is vergence?

Inward/outward rotation of the eyes in response to blurry vision. 


 


Both eyes move in opposite directions 

Inward/outward rotation of the eyes in response to blurry vision.



Both eyes move in opposite directions

What eye movement when you are at the top of the grandstand?

Smooth pursuit

What eye movement when you are on the infield of the racetrack?

Optokinetic Nystagmus