Chapter 10 Midterm 3 Flashcards
What is haptic feedback?
You push something and get feedback on how much pressure you need to move it
What are the 8 steps of movement in order?
- You get visual information required to locate the target
- The frontal lobe motor areas plan the reach and command the movement
- The spinal cord carries the information to the hand and coordinates the fingers
- The motor neurons carry the message the the muscles of the the hand and forearm
- The sensory receptors in the fingers send message back to the sensory cortex saying that we grasp the cup
- The spinal cord carries the sensory information to the brain
- The basal ganglia judges the grasp forces and the cerebellum corrects movement errors
- The sensory cortex recieves the message that the cup has been grasped
Where is the sensory area in relation to the motor areas?
Right beside
Is all movement generated by the motor cortex related on sensory cortex information?
No that’s too simple
How do you initiate a motor sequence, as in what does the prefrontal cortex, premotor cortex, and motor cortex do?
The prefrontal cortex plans the movement
the premotor cortex organizes the movement sequences
the motor cortex produces specific movements
What does the motor cortex do?
responsible for force of movement and coordinates movement- lesions in motor cortex makes you weaker
Also sends general programs to the brain stem and spinal cord
What outside of the motor cortex coordinates movement?
the spine
What does a unilateral lesion in the premotor cortex do?
it impairs performance on tasks requiring both hands
What is bloodflow an indicator of?
an indicator of neural function)
Do we have equal amounts of blood flowing to all areas of brain all the time?
no, areas stimulated get more blood
When does bloodflow increase in primary somatosensory and primary motor cortex?
It increases when you have simple movement like using a finger to push a lever
When does bloodflow increase in the premotor cortex?
When participants form a sequence of motions, ex: clap, then spin, then clap
When does bloodflow increase in the prefrontal, temporal, and parietal cortex?
through complex movement (ex: trying to put finger through maze)
What is the initial function of the brain?
To make movements
What is penfields homunculus?
Its a figure showing you the amount of sensory and motor cortical tissue that is devoted to particular areas of the body
Who made the homunculus? How?
HP kentelly, took pieces of paper that penfield put on the brain to see what parts of the body got stimulated and made a structure
How did they find out how much of the brain was devoted to different body parts?
electrical stimulation of the motor cortex which elicted movement of body parts which corresponded to the map of the body
Why do chimpanzees have faces upside down in humunculus? But humans are upside right?
Mistake, penfield made an error
Why did penfield make error of faces being upside right?
Because the map was made using atypical people, people with seizures and epilepsy and tumours which had maps come out different than what it actually was.
What do cats use whiskers for?
They use whiskers to estimate whether they know they’ll get in places, if whiskers touch, they know they’ll get switched
What do rodents with epilepsy have different in their homonculus? How does it effect the image of the homonculus?
The spaces between the different body parts overlap, so some cortical tissue goes to other places, this makes the original picture much more fuzzier so it’s not accurate the homonculus its like a picasso painting
What’s a mistake in the homoculus?
He drew the right hand side of the body on the right hemisphere of the brain, should be left hand side of the body on the right hemisphere of the brain
What is the elephants biggest cortical devoted area?
the trunk
What is intracortical microstimulation?
When you put tiny little electrodes down into the brain in a grid structure and the intersects of the grid into layer 5, and apply tiny current
What is layer 5 in the brain?
the output layer of the motor cortex
How does the current being applied to layer 5 neurons create twitches?
You stimulate output neurons, the axons go to spinal cord, makes synaptic connection with alpha motor neurons that interact with muscle groups to drive twitches
Why was 40 milliseconds of stimulation used in intracortical stimulation?
Because they believed longer stimulation would cause seizures
What did michael granziano do?
Used 100 to 200 milliseconds of stimulation - about the same length of tie it takes the animal to normally move
This made animals do natural movements
What does long stimulation of premotor cortex do? (like what actions)
Ascend or descend, jump
Reaching to clasp
Defensive posture/expression
What does long stimulation of the primary motor cortex do?
hand control in lower body space
hand control in ventral body space
masticate/lick
What experiment did Teskey do to determine whether Graziano was correct in that the motor cortex also coordinates movement?
Stimulated the rats forelimb area for long periods of time and got complex movements such as elevate, advance, grasp and retract
How did they confirm that the motor neuron is involved in the coordination of movements?
They cooled the grasp area (the rostral forelimb area) in the forelimb of the rat brain and then stimulated the rat again with long duration ICMS and found significant errors in the grasping of the rat. So we know that the motor cortex is involved with coordination of movements.
What other experiment involving monkeys proves that motor cortex neurons take part in planning and executing movements as well as regulating movement force and duration?
When the monkey flexes its wrist to rotate a lever attached to a weight more neural activity is found when the weight is heavier and before they go to rotate the lever,
What experiment showed that neurons are maximally responsive to movements in a particular direction?
When a monkey moves lever in different directions, there is maximal neuron activity when it moves forward to 180 and minimal when it’s backwards to 0, shows that the firing of neurons in the motor cortex is attuned to movement
Where does the corticospinal tract descend from?
from the motor cortex the brain stem, at the pyramidal protruision (at brain stem) it defecates across and moves down the opposite side to the spinal cord
What are the two tracts the corticospinal tract breaks off into?
The lateral corticospinal tract, anterior corticospinal tract
What does the lateral corticospinal tract do?
Moves limbs and digits on the bodys right side
What anterior corticospinal tract do?
moves muscles at the body’s midline
Is there corpus collosum for finger movements?
No
How are the interneurons and motor neurons arranged?
so
that the more
lateral neurons
innervate the
more distal
parts of the
limbs.
What does the lateral corticospinal tract synapse with?
Synapse with interneurons and motor neurons that innervate muscles of the limbs and digits
Where do the interneurons project?
Project to motor neurons
Where do motor neurons project?
project to muscles of the body
What neurons does the anterior corticospinal tract synapse with?
Interneurons and motor neurons that innervate the midline of the body
If you put led lights in major joints on person what could you tell about them?
exactly what the movement is
Where are skilled movements encoded?
In the neural connections of the motor cortex as basic patterns of movements that are common to our species
The basal ganglia consist of how many large subcortical nuclei that do what?
4 large subcortical nuclei that participate in the control of movement
The basal ganglia _______ have direct input or output connections with spinal cord
DO NOT
What is the basal ganglia’s input? What do they output to?
Their input is from the cerebral cortex and their output is to the thalamus and then on to the cortex
If you have paralysis, is that caused by damage to the basal ganglia?
No, paralysis occurs when theirs damage to things (neuromuscular junction or motor cortex) anything that output to the spinal cord
What are the three things that lesions in the basal ganglia result in?
tremor and other involuntary movements
changes in posture and muscle tone
poverty and slowness of movement (but without paralysis)
What the names of the four large subcortical nuclei?
striatum
globus pallidus
subthalamic nucleus
Substantia nigra
What is the striatum composed of?
caudate nucelus and putamen
What is the global pallidus part of?
Is both internal and external and is part of the diencephalon
What is the substantia nigra composed of?
pale zone, pars reticula, and pars compacta
What are hyperkinetic disorders?
Are fast moving disorders
What are the three theories of basal ganglia movement?
The basal ganglia selectively facilitate some movements and
inhibit others. This may explain some of the diverse symptoms in
basal ganglia disorders
A comparator of motor commands from the precentral motor
fields with proprioceptive feedback from the evolving movement (when you pick things up the hand unconsciously widens to grasp object and use correct amount of force to hold it
The intiation of internally generated movements
What is included under hyperkinetic disorders?
Tremors
Athetosis
Chorea
Ballism
Dystonia
What are tremors?
Are rhythmic, involuntary, and oscillatory
What is athetosis?
slow, writhing movements of fingers/hands/toes
What is Chorea?
chorea means dance, dancing movements of limbs and facial muscles
What is Ballism?
violent, flailing movements
What is dystonia?
postural distortions
Why are musicians susceptible to dystonia? Whats therapy for them?
because with overpractice your fingering can become impaired, their motor maps become incorrect, therapy for them is removing them from violin and doing simple movements
What are hypokinetic disorders?
Are slow moving disorders
What are some hypokinetic disorders?
Akinesia
Bradykinesia
What is akinesia?
Is difficult of initiating movements
What is bradykinesia?
Is a more mild form of akinesia
Do brain maps of the neocortex change before or after behavior’s changes?
After, this is because behaviour isnt driven by neocortex, behaviour is driven by striatum, spinal cord, and cerebellum
Are movements voluntary?
No, movements are always on, if the breaks work then you won’t move.
What is parkinsons in terms of basal ganglia disease?
is a form of akinesia
Does parkinsons always come with tremors?
no
When was parkinsons first described?
in 1817 by james parkinsons
What are the symptoms of parkinsons?
1) rhythmical tremor at rest
2) increase in muscle tone or rigidity, often ratchet-like
3) difficulty in initiation and paucity of spontaneous movement
(akinesia)
4) slowness in the execution of movement (bradykinesia)
Does parkinsons start off bilaterally or unilaterally?
unilaterally, then becomes bilateral
How many percent of neurons are found in cerebellum?
80%
Why are so many neurons found in cerebellum?
because they’r emostly small and inhibitory
Does cerebellum have homunculi in them?
Yes, several
What does the cerebellum consist of?
the cerebellar hemispheres and the flocculus
What does the cerebellar hemispheres control?
body movements
What does the flocculus do?
helps in balance
What does the medial parts of the cerebellar hemispheres control?
the bodies midline and face and trunk
What does the lateral parts of the cerebellar hemispheres control?
the movement of the bodies apendages
What does the floccular lobe control?
eye movements and balance
Does the cerebellum have a role in adjustments required to keep movements accurate? What study showed this?
Yes! Subject threw darts at target, then wore prism glasses, and then threw the dart after some tries they adapted, the prisms are removed and the person readjusts, in a person with cerebellum damage they don’t adjust with prisms and show no effects when prisms are removed
Perceptions from the skin derive from what?
senses of nociception, hapsis, and proprioception
What does pain come from? What about temperature? How does this work in the brain?
free nerve endings for pain and free nerve endings for temperature, both are under nociception
In the brain- Damage or irritation to the dendrite or to surrounding cells releases chemicals that stimulate that dendrite to produce action potential- results in these sensations
What is senses of hapsis?
fine touch and pressure
What things cause hapsis? How does this work in the brain?
Meissner corpuscle (touch)
Pacinian corpuscle (flutter)
Ruffini corpuscle (indentation)
Merkel disc (steady skin indentation)
Hair receptors (flutter or steady skin indentation)
In the brain- Pressure on the various types of tissue capsules mechanically stimulates the dendrites within them to produce action potentials
What is proproception?
body awareness
What things contribute to proprioception? How does it work in the brain?
Muscle spindles (muscle stretch)
Golgi tendon organs (tendon stretch)
Joint receptors (joint movement)
In the brain- Movements stretch the receptors to mechanically stimulate the dendrites within them to produce action potentials
Why would you pick up a heavy weight and automatically drop it?
because the tendon organ feels force as it’s smaller than muscle so it drops as it thinks it’ll rip muscle
How does hapsis work in the brain, as in how do you touch something and get info upto somatosensory cortex?
Your finger touches something:
The posterior root ganglion neurons carry fine-touch and pressure information and they have large myelintated axons (are fast) , whos receptors are located in the skin, muscles, and tendons, the cell body is located in the posterior root ganglion (outside the spinal cord), then the axons ascend in the ipsilateral spinal cord and form the posterior spinothalamic tract allowing info to go the to the somatosensory homunculus
How many homunculi are in the primary somatosensory cortex? What do they do?
4, all right beside eachother
Muscles
skin(slow acting)
skin(fast acting)
joints,pressure
What is special about the joints, pressure area?
is responsive to combines somatosensory information, so information form other homunculi pass onto it
Why does a tap on the knee result in kicking the leg up?
when you tap the patellar tendon that stretches the quadriceps muscle, the sensory nerve then responds to the muscle stretch by sending a signal to the spinal cord, it connects to a motor neuron in that spinal cord when then stimulates the muscle to contact to reduce the stretch making it go up.
What is phantom limb pain, whats a treatment to reduce it?
is when you miss a limb and fell pain of it, the treatment is looking at mirror to see the reflection of one hand which reduces pain because your brain thinks you still have both arms
What is the gate theory of pain?
The pain and temperature pathway from body receptors has small unmyelinated receptors, this connects to the pain and temperature pathway to the brain.
The fine touch and pressure pathway makes a synaptic connection with an interneuron that influences the pain pathway, this causes the inhibition of the pain pathway therefore reducing pain
How does tiger balm work?
using gate theory of pain, the tiger balm stimulates the fine touch and pressure pathway inhibiting the nociceptive inputs, however does NOT treat nociception
What is the sixth sense?
balance
What structure in ear helps with balance?
The vestibular system
the otolith organs (which include the utricle and the saccule) and semicircular canals have hair which help with balance
When hairs in semicircular canals move right what happens?
depolarization- increased impulse frequency
When hairs in semicircular canals move left what happens?
Hyperpolarization (decreased impulse frequency)
When is the vestibular system created?
in the gesticular period
Why can’t we tickle ourselves?
Because we anticipate it
What is apraxia?
the inability to make voluntary movements even though your not paralyzed
What types of info does the secondary somatosensory cortex give to the dorsal stream and the ventral stream?
The secondary somatosensory cortex contributes to the dorsal stream by specifying the the movement used to grasp the target
it contributes to the ventral stream by providing info about objects size, shape, and texture
