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Neuro Exam 3
Spinal Control of Movement & Brain Control of Movement
295
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Undergraduate 3
10/12/2014

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Term
who said "the spinal cord is the FINAL COMMON PATHWAY"
Definition
Sir Charles Sherrington
Term
the spinal cord is the main pathway connecting what?
Definition
the brain and peripheral nervous system
Term
explain segmental organization of the spinal cord.
Definition
the spinal cord is enlarged in the cervical and lumbar regions and smaller in the thoracic region
Term
why is the spinal cord enlarged in the lumbar and cervical regions?
Definition
these areas of the spinal cord are involved in more precise movements.
Term
what types of movements are mediated by the spinal cord?
Definition
reflex
Term
in a cross section of the spinal cord, the white matter represents what?
Definition
neuronal tracts containing sensory and motor neruons
Term
in a cross section of the spinal cord, the grey matter represents what?
how is it shaped?
Definition
the nerve cell bodies in a butterfly shape
Term
motor programs of the spinal cord do what?
Definition
coordinate and generate reflexive movements and postural control
Term
Bell and Magendi dissected live animals and found what about the spinal cord?
Definition
plexuses where sensory and motor nerves come together
Term
T/F in the spinal cord, lower motor neurons bundle together to form ventral roots and each ventral root joining with each dorsal root to form a spinal nerve.
Definition
true
Term
in the spinal cord, lower motor neurons bundle together to form what?
Definition
ventral roots
Term
in the spinal cord, ventral roots joint with the dorsal root to form what?
Definition
spinal nerves
Term
motor nerves that proved fibers to one special nerve belong to what?
Definition
a spinal segment
Term
each spinal segment is named by what?
what are the possible names?
Definition
the vertebrae where the nerve originates
cervical
thoracic
lumbar
sacral
Term
are skeletal muscles and lower motor neurons distributed evenly throughout the body or spinal cord?
what does this lead to?
Definition
no, swollen areas in the spinal cord
Term
where are motor neurons that innervate distal and proximal muscles located in the spinal cord?
Definition
cervical segment
lumbar-sacral segment
Term
where are motor neurons that innervate axial muscles located in the spinal cord?
Definition
found at all levels
Term
compare the ventral horns of the cervical, thoracic, and lumbar regions of the spinal cord.
Definition
cervical and lumbar segments have large ventral horns where thoracic segment has small ventral horns
Term
where is precision facilitated? large or small horns?
Definition
large
Term
what projects from the ventral horns?
Definition
axon cell bodies
Term
T/F sensory in, motor out
Definition
true
Term
where does all sensory information end?
Definition
the cerebellum
Term
T/F somatosensory information is largely unconscious.
Definition
true
Term
the information from muscle spindles is transmitted directly to where?
Definition
the cerebellum
Term
what are the 3 orders of processing?
Definition
1-sensory receptor to cord
2-cord to brain stem
3-from the thalamus to the cortex
Term
give an example of the spinocerebellar pathway.
Definition
stretch reflex, facilitated by the muscle spindle causing a contraction of muscles unconsciously
Term
the spinocerebellar pathway involves what orders of processing?
Definition
1st and 2nd
Term
the dorsal column-medial lemniscal pathway involves what order of processing?
Definition
3rd
Term
what would happen if there was a lesion in the pathway from the spinal cord to the cerebellum?
Definition
still respond (the reflex will still occur) but the information may not make it to the cerebellum
Term
what is the location of the 1st order neuron cell body in the dorsal spinocerebellar tract?
Definition
dorsal root ganglion
Term
what is the location of the 2nd order neuron cell body in the dorsal spinocerebellar tract?
Definition
dorsal horn
C8-L2,3
Term
what is the termination in the dorsal spinocerebellar tract?
Definition
ipsilateral cerebellar vermis
Term
what is the functions of the dorsal spinocerebellar tract?
Definition
relays proprioceptive input from the ipsilateral trunk and lower limb
coordination of movements for the lower limb muscles
posture maintenance
Term
what is the location of the 1st order neuron cell body in the cuneocerebellar tract?
Definition
dorsal root ganglion
Term
what is the location of the 2nd order neuron cell body in the cuneocerebellar tract?
Definition
accessory cuneate nucleus
Term
what is the termination in the cuneocerebellar tract?
Definition
ipsilateral anterior lobe of the cerebellum
Term
what is the function of the cuneocerebellar tract?
Definition
relays proprioceptive information from the ipsilateral neck and upper limb
movement of head and upper limb
Term
what is the location of the 1st order neuron cell body in the ventral spinocerebellar tract?
Definition
dorsal root ganglion
Term
what is the location of the 2nd order neuron cell body in the ventral spinocerebellar tract?
Definition
dorsal horn
Term
what is the termination of the ventral spinocerebellar tract?
Definition
ipsilateral cerebellar vermis
Term
what are the functions of the ventral spinocerebellar tract?
Definition
relays proprioceptive input from the ipsilateral trunk and lower limb
coordination of movements for the lower limb muscles
posture maintenance
Term
what is the location of the 1st order neuron cell body in the rostral spinocerebellar tract?
Definition
dorsal root ganglion
Term
what is the location of the 2nd order neuron cell body in the rostral spinocerebellar tract?
Definition
dorsal horn
Term
what is the termination of the rostral spinocerebellar tract?
Definition
cerebellum
Term
what are the functions of the rostral spinocerelbellar tract?
Definition
relays proprioceptive input primarily from the ipsilateral head and upper limb
movement of head and upper limb
Term
if sensory information gets to the cord, what is the next step?
Definition
stimulates a response via an Alpha Motor Neuron
Term
what are alpha motor neurons?
Definition
large lower motor neurons of the brainstem and spinal cord
Term
what do alpha motor neurons innervate?
what are they responsible for?
Definition
extrafusal muscle fibers of skeletal muscle
directly responsible for initiating skeletal muscle contraction
Term
1 AMN and all the muscle fibers it innervated is called what?
Definition
motor unit
Term
the cell bodies of alpha motor neurons are found in the _____, but they are also considered part of the ______.
Definition
CNS
somatic nervous system
Term
what is a motor neuron pool?
Definition
a collection of AMNs that innervate a single muscle
Term
what are lower motor neurons?
Definition
AMN come off the cord and unnerve muscles that facilitate reflex contraction
Term
what do AMN mediate?
Definition
reflex contractions
Term
what order of processing are AMN?
Definition
1st order
Term
where are AMNs that innervate the head and neck found?
Definition
in the brain stem
Term
where can you find interneurons?
Definition
in various sections of the spinal cord and synapses
Term
T/F you cannot have a direct sensory input to the AMN.
Definition
false you can but it is rare
Term
what are the three sources of input of the AMN?
Definition
muscle spindles
motor cortex
interneurons in the spinal cord
Term
what is the first source of input to the AMN?
Definition
the dorsal root ganglion cells with axons that innervate specialized sensory devices "muscle spindles" which are embedded in the muscle
Term
what is the second source of input to the AMN?
why is this important?
Definition
comes from the upper motor neurons in the motor cortex and brain stem

important for initiating and controlling voluntary movement
Term
what is the third source of input to the AMN?
Definition
comes from the interneurons in the spinal cord which may be excitatory or inhibitory and is responsible for generating spinal motor programs
Term
how are slow twitch fibers different from fast twitch?
Definition
produce energy over time
produce less force
Term
what muscle fibers do relaxes recruit?
Definition
fast twtich
Term
what is Henneman's size principle?
Definition
ordered recruitment of motor units
small slow units active during low force contraction (smooth control)
large fast units active during high force contraction (poor control)
Term
what does contracting more or less motor units depend on?
Definition
strength of contraction
Term
what two factors contribute to force production in muscle contraction?
Definition
numer and type of fiber
frequency
Term
how does number and type of muscle fiber affect force production?
Definition
the more muscle fibers within the unit the greater force producing potential
Term
how does frequency affect force production?
low to high frequencies?
Definition
the frequency with which the muscle fibers are stimulated by their innervating axon

single twitch contractions to frequencies high enough to produce a sustained contraction
Term
T/F the fiber will take on the characteristics of the neuron that innervates it.
Definition
true
Term
what types of fibers do large AMN innervate?
Definition
fast twitch
Term
what was found in the crossed-innervation experiment?
Definition
the fiber will take on the characteristics of the neuron that innervates it.
Term
what was found in the voluntary and reactive recruitment experiment?
Definition
a pool of specially fixed locomotor muscle synergies
can't produce movement without both reflexes and voluntary
collaboration of reflex contraction and voluntary control
Term
what is ALS?
Definition
amyotrophic lateral sclerosis
a disease of the nerve cells in the brain and spinal cord that control voluntary muscle movement
Term
what percent of cases of ALS are genetic?
Definition
10%
Term
what are the steps of ALS/ how does the disease work?
Definition
1-AP to terminal branch
2-voltage Ca2+ channels influx
3-release glutamate
4-binds to NMDA channels
5-glutamate not broken down=clogs receptors which makes it difficult to pass AP and also triggers excessive Ca2+
6-too much Ca2+ in the cell is toxic
Term
what is the resultant effect of excessive amounts of Ca2+ in the pre-synaptic cell?
Definition
toxic, causes mitochondria dysfunction
Term
what is the theoretical explanation of what causes ALS.
Definition
1-a genetic defect in superoxide dismutase SOD-1, which deactivate free radicals that can cause damage
2- they play an important role in maintaining the motor neuron
3-the disfunction of microglial cells leads to inflammation
4-too much inflammation leads to mitochondria initiating cell death
Term
what is the primary neurotransmitter of the nervous system?
Definition
glutamate
Term
in one sentence what its the cause of ALS?
Definition
excito-toxicity caused by excessive glutamate at the post synapse
Term
SOD-1 does what?
what happens with age?
Definition
deactivates free radicals that damage the cell membrane
decreases with age
Term
what is Myasthenia Graves?
Definition
an autoimmune disease where the individuals immune system generates antibodies against their own nicotinic Ach receptors
Term
in Myasthenia Graves, what is the action of the antibodies?
Definition
they bind to receptors interfering with normal Ach function
Term
what is a result of the antibodies binding to the receptor in Myasthenia Graves?
Definition
degenerative changes in the structure of the neuromuscular junction
Term
what are treatment options for Myasthenia Graves?
Definition
drugs inhibiting the enzyme acetylcholinesterase
drugs that suppress the immune system
Term
how would prolonging the life of Ach benefit a patient with Myasthenia Graves?
Definition
prolong the life of Ach to give it a greater chance to bind to the post synaptic receptor
Term
T/F Myasthenia Graves patients only make antibodies for the Ach receptors on the post synaptic cell.
explain.
Definition
false
they body can make antibodies for voltage-gates Ca2+ channels, muscle specific tyrosine kinase has been seen, VGKCs are all targets
Term
what is Muscular Dystrophy?
Definition
is an inherited disorder that is manifest as muscle weakness
Term
what is Duchenne MD?
age of death?
what do they lack?
Definition
Muscular Dystrophy that only affects boys and presents weakness in legs placing the child in a wheelchair at age 12
death by age 30

the mRNA encoding dystrophin
Term
what is Etiology?
Definition
genetic disorder where defect is on the X chromosome where a area on the X chromosome does not contain the gene to produce dystrophin
Term
what is the muscle spindle?
Definition
a stretch receptor
primary proprioceptive mechanism for creating muscle contraction
Term
what type of motor neurons activate the intrafusal muscle fibers?
Definition
gamma
Term
how is 1a (primary) afferent of the muscle spindle arranged?
Definition
wrap around
dynamic
static
nuclear
Term
how is 2 (secondary) afferent of the muscle spindle arranged?
Definition
wrap static and nuclear fibers
Term
what do static intrafusal fibers facilitate?
Definition
response in a continuous way
Term
what do dynamic intrafusal fibers facilitate?
Definition
more responsive to change
Term
what is the 1a fiber of the muscle spindle?
Definition
the primary sensory fiber that tracts to the spinal cord
Term
what do gamma motor neurons do in relation to the muscle spindle?
Definition
stimulate the end of the spindle (terminate at the poles) causing the spindle to contract
Term
what is alpha-gamma coactivation?
Definition
gamma MN are activated in parallel with alpha MN to maintain the firing of spangle afferents with then extrafusal muscle shorten
Term
what is the myostatic reflex?
Definition
when the set point (desired muscle length) is altered 1a fibers detect a change in length, synapse in the spinal cord with an AMN which in turn initiates a reflex contraction of the muscle fibers that it innervates
Term
the magnitude of response from the stretch reflex depends on what?
Definition
the speed of the stretch
Term
what occurs during a static stretch?
Definition
change in the spindle length that caused a small reflex contraction
Term
what is the GTO?
Definition
sensory receptors located in series at the junction of the muscle and the tendon
Term
what does the GTO encode?
what does it need the help of?
Definition
muscle tension
1b fiber
Term
in the GTO what is the role of of 1b fiber?
Definition
enter the spinal cord and branches repeatedly synapsing on interneurons in the ventral horn
Term
what is the GTO also known as?
Definition
the reverse myotatic reflex
Term
what does the GTO do?
Definition
overrides the reflex contraction when the stretch is too great
Term
the coordination of AMN 1a and 1b assists in what?
Definition
fine motor acts and keeping a steady handing during very precise movements
Term
when muscle is slightly stretched or relaxed, muscle spindles are _____, while GTO are ______.
Definition
active
quiescent
Term
explain the combined muscle spindle and GTO functions during changes in muscle length (steps).
Definition
1-with contraction, tension is produced in the tendons which then compresses nerve terminals among the tendons
2-the nerve compression activates the GTO which in turn transmits proprioceptive info to the CNS
3-further stretching, produces tension on the tendons which actives the muscle spindle and GTO
4-GTO and spindles check with the CNS
Term
what information does the GTO provide to the CNS?
Definition
muscle activity info
avoids excessive forces on the muscle and tendon
Term
what does the GTO check?
Definition
amount of tension exerted on muscle regardless of whether tension is caused by a stretch or contraction
Term
what dos the muscle spindle check?
Definition
muscle fiber length and rate of changes of muscle length during stretch or contraction
Term
what are central pattern generators?
Definition
the spinal networks found in the upper thoracic and lumbar regions that can generate patterns of rhythmic activity for locomotion even without external feedback
Term
where are the central pattern generators?
Definition
spinal cord
Term
give an example of a central pattern generator.
Definition
a bird singing its song
there were some neurons that had the purpose to create a pause in the sound
Term
T/F central pattern generators are learned.
Definition
false
they come hardwired
Term
how do central generators function?
Definition
gravitational pull
give and take of muscles
Term
define central pattern generators.
Definition
small localized autonomous neural networks generating rhythmicity
Term
what begins the sequence of a CPG?
Definition
a reflex
Term
T/F each limb is controlled by a CPG.
Definition
true
Term
what is rhythmicity based on?
Definition
interactions among neurons
interactions among currents in individual neurons
Term
what is a fixed action pattern?
Definition
instinctive behavioral control sequence that is indivisible, runs to completion, produced by neural networks in response to an external sensory stimulus
Term
T/F Fixed action patterns are learned.
Definition
false
they appear to be hardwired
Term
what did Fritsch and Hitzig find?
Definition
that stimulation of the frontal cortex of the anesthetized dog produced movement on the contralateral side
Term
what did Ferrier and Sherrington find?
Definition
discovered the motor area in primates was in the perceptual gyrus.
Term
Campbell used Sherrington's work to find what?
Definition
identified cortical area 4 as the motor cortex and that motor area 6 was responsible for skilled voluntary movement
Term
what did Penfield find?
Definition
did experiments of patients with history of seizures to find areas that were important to movement
Term
voluntary movement is mediated by what structures?
Definition
PMC
cerebellum
basal ganglia
Term
T/F the basal ganglia can be excitatory and inhibitory at the same time.
Definition
true
Term
what is the neocortex?
Definition
the top layer of the cerebral hemispheres 2-4 mm thick and labeled 1 to 6
Term
T/F the neocortex consists of grey matter surrounding the deeper white matter of the cerebellum.
Definition
true
Term
what is the function of the grey matter of the neocortex?
Definition
to route sensory or motor stimulus to interneurons of the CNS for creation of response to stimulus through chemical synapse activity
Term
what higher processes is the neocortex involved in?
Definition
sensory perception
generation of motor commands
conscious thought
language in humans
Term
where is the PMC (primary motor cortex) located?
Definition
in the perceptual gyrus
Term
what is the function of the PMC?
Definition
the execution of very specific, defined motor activity of the contralateral side
Term
who mapped the motor cortex?
Definition
penfield
Term
where do the final instructions to move come from?
Definition
primary motor cortex
Term
how many layers are there of the PMC?
Definition
6
Term
what neurotransmitters influence the PMC?
Definition
glutamate and GABA
Term
where does the PMC fit in the sequence to move?
Definition
idea from front part of the brain->
basal ganglia->
PMC->
spinal cord to move
Term
T/F the PMC is responsible for precise movement of large muscle groups.
Definition
false
precise movement of specific muscles
Term
where does the PMC end?
why?
Definition
the cervical and lumbar areas

because these are the swollen areas of the spinal cord that are responsible for precise movement of the upper and lower extremities
Term
where does the thalamus project?
Definition
the grey matter
Term
sensory information come to the thalamus and sends it where?
Definition
the cortical area that will handle the info
Term
in terms of modalities, where does the basal ganglia receive information from?
Definition
multiple modalities
Term
what is the basal ganglia?
Definition
a group of nuclei found at the forebrain
Term
the basal ganglia has a strong connection with what?
Definition
the cerebral cortex and the thalamus
Term
what are the basics of parkinson's disease?
Definition
limited availability of dopamine to produce voluntary movement
Term
what is the excitatory neurotransmitter of the nervous system?
Definition
glutamate
Term
what is the inhibitory neurotransmitter of the nervous system?
Definition
GABA
Term
what does the basal ganglia support the function of?
Definition
subconscious voluntary motor control and procedural learning
Term
T/F the basal ganglia also has been found to exert inhibitory influence of multiple motor systems
Definition
true
Term
the basal ganglia receives what kind of input from the spinal cord?
Definition
visual,
auditory,
vestibular,
somatosensory
Term
where does the basal ganglia send output?
Definition
prefrontal, premotor, and supplementary areas, all involved in high order processing of movement
Term
what are the main components of the basal ganglia?
Definition
striatum
globus pallidus
substantia nigra
subthalamic nucleus
Term
what is the inhibitory portion of the basal ganglia?
Definition
the striatum
Term
what does the striatum release?
Definition
GABA
Term
where does BG circuitry being?
Definition
in the cerebral cortex
Term
explain the circuitry of the basal ganglia.
Definition
1-the PMC sends axons to the striatum and releases glutamate
2-cells in the striatum project to the direct and indirect pathways
3-thalamus releases glutamate upon itself
4-
Term
what is important to know about the ability of the stratum?
Definition
it is inhibitory
Term
what two sectors of the cerebral cortex does the striatum receive input from?
Definition
caudate nucleus
putamen
Term
in terms of movement, the striatal connections of what pathway are critical?
Definition
nigrostriatal pathway
Term
where does the striatum project? (specific names)
Definition
external globes pallidus
pars compacta
pars reticulata
Term
the external globes pallidus, pars compacta, pars reticulate are inhibited by what neurotransmitter?
Definition
GABA
Term
the nigrastriatal pathway serves to what?
Definition
influence the activity of the striatum
Term
what is significant about the pars compacta?
Definition
it synthesizes dopamine to influence/excite the thalamus
Term
specifically what is happening in a patient with parkinson's disease?
Definition
there is a decrease in dopamine receptors
death of the pars compacta cells, which leads the not enough dopamine being synthesized
Term
what is the globus pallidus made up of?
Definition
the globus pallidus divided into the internal and external segments
Term
the GPi and GPe contain primarily what type of neurons?
Definition
GABAergic (inhibitory)
Term
the GPe receives input from where? projects it where?
Definition
from the striatum

to the sub thalamic nucleus
Term
the GPi receives input from where?
Definition
from the striatum from two pathways
Term
what are the two pathways that the GPi receives signals from?
Definition
direct and indirect pathways
Term
what does the substantia negra support? by what pathway?
Definition
supports movement in conduction with the striatum via the nigrastriatal pathway
Term
Nigra degeneration results in what?
Definition
parkinson's disease
Term
the substantia negra is essential in what?
Definition
producing precise voluntary movement
Term
what part of the striatum makes dopamine?
Definition
pars compacta
Term
what is the subthalamic nucleus?
Definition
a diencephalic gray matter portion of the basal ganglia
Term
T/F the subthalamic nucleus is the ONLY part of the basal ganglia that actually produces an excitatory neurotransmitter.
Definition
true
Term
what is the role of the subthalamic nucleus?
Definition
to stimulate the SNr-GPi complex
Term
what pathway is the subthalamic nucleus part of?
Definition
indirect pathway
Term
what is the main purpose of the indirect pathway?
Definition
inhibition, to reduce movement
Term
where does the indirect pathway begin?
Definition
the stiratum
Term
explain the indirect pathway.
Definition
1-cortex (stimulates)
2-stritatum (inhibits)
3-GPe (less inhibition of the STN)
4-STN (stimulates)
5-"SNr-GPi" complex (inhibits)
6-Thalamus (is stimulating less)
7-Cortex (is stimulating less)
8-Muscles
Term
what is a hypo kinetic state?
Definition
reduced movement
Term
if you have parkinson's disease, can you still move?
Definition
yes, but it is likely to influence the precision of the movement. because dopamine is not released. because the pars compacta cells are not synthesizing dopamine or the dopamine receptors are not receiving adequate dopamine
Term
the GPe is excitatory or inhibitory?
Definition
inhibitory
Term
what is the main purpose of the direct pathway?
Definition
excitatory, increase movement
Term
explain the direct pathway.
Definition
1-cortex (stimulates)
2-stritatum (inhibits)
3-"SNr-GPi" complex (less inhibition of thalamus)
4-Thalamus (stimulates)
5-Cortex (stimulates)
6-Muscle
Term
what is a hyperkinetic state?
Definition
increased movement
Term
how do you increase movement?
Definition
excite the thalamus
Term
what happens if you inhibit inhibition?
Definition
less inhibition
release less GABA
Term
as the motor cortex stimulates the striatum to inhibit the globus pallidus and pars reticulata, what is happening next?
Definition
less GABA is released at the Thalamus, which causes and increase in excitement of the thalamus
Term
the D1 receptors do what?
Definition
increase in dopamine activity
Term
the D1 receptors have a positive/negative influence on dopamine. what does this lead too?
Definition
positive

leads to movement
Term
the D2 receptors do what?
Definition
reduces dopamine sensitivity
Term
the motor cortex stimulates the striatum, which releases GABA to inhibit the GPi and pars reticulata, which in turn releases less GABA at the thalamus, which stimulates the motor cortex and leads to muscle movement is what pathway?
Definition
direct pathway
Term
the motor cortex stimulates the striatum to release GABA which inhibits the GPe, decrease the GABA released the the subthalamic nucleus, which increases the glutamate released to the GPi, which increases the GABA to the Thalamus, which sends a less excitatory signal to the motor cortex, which leads to decreased muscular movement is what pathway?
Definition
indirect pathway
Term
T/F there is a cure for parkinson's disease.
Definition
false
Term
parkinson's disease affects what percent of people over the age of 50?
Definition
1%
Term
what are the symptoms of parkinson's disease?
Definition
difficulty initiating willfull movements
increased muscle tone
tremors of hands and jaw
Term
what is akinesia?
Definition
difficulty initiating willfull movements
Term
what is rigidity?
Definition
increased muscle tone
Term
what does parkinson's disease result from?
Definition
the degeneration of the substantia negra inputs to the striatum
Term
would exercise be helpful for a parkinson's patient?
Definition
yes because it would increase neuroconnectivity and attempt to increase the affects of dopamine
Term
what is huntington's disease?
what are the characteristics?
Definition
progressive and lethal syndrom
abnormal movements
dementia
cognitive impairment
disorder of personality
Term
what is etiology?
Definition
loss of neurons in the caudate nucleus, putamen, and globus pallidus and cerebral cortex
Term
etiology results in what?
Definition
loss of inhibitory output to the thalamus
Term
would exercise be helpful for a patient with huntington's disease?
Definition
yes because it would increase the blood flow the those areas of the brain
Term
huntington's disease attacks what cells?
Definition
inhibitory cells
Term
why would a patient with huntington's disease have abnormal movements?
Definition
because the inhibitory influence is lost, which controls smooth movements
Term
the cerebellum contributes to what three things?
Definition
coordination
precision
accurate timing
Term
where does the cerebellum receive input information from?
Definition
spinal cord and other parts of the brain
Term
what does damage to the cerebellum cause?
Definition
disorders in fine movement, equilibrium, posture, and motor learning
Term
T/F damage to the cerebellum causes paralysis.
Definition
false
Term
where does the cerebellum project?
what does this allow it to act as?
Definition
the pre-frontal cortex

can acts as a comparator in that it compares intention with performance by shaping our motor plans and modify those plans for the future
Term
the cerebellum is involved in being able to adjust to changes in what?
which can also be called what?
Definition
sensorimotor relationships

synaptic plasticity
Term
T/F the cerebellum is involved in visually guided movements
Definition
true
Term
T/F the cerebellum is involved with the internal reference of correctness by internalizing a movement.
Definition
true
Term
What is the Marr-Albus theory?
Definition
the climbing fiber serves as a "teaching signal," which induces a long-lasting change in the strength of synchronously activated parallel fiber inputs

long term potentiation
Term
based on the Marr-Albus theory each cerebellar purkinje cell receives input from what?
Definition
parallel fibers
single climbing fiber
Term
in the cerebellum what is a parallel fibers strength?
Definition
individually very weak
Term
in the cerebellum what is a climbing fiber's strength?
Definition
strong enough to cause the Purkinje cell to burst with APs
Term
how does the cerebellum help with fine tuning of motor skills? (steps)
Definition
receives information->
projects to the pre-frontal cortex->
informs the brain about sensory information which will increase the accuracy of the movement
Term
where is the cerebellum located?
Definition
underneath the cerebral hemispheres
Term
what is the cerebellum covered in?
what does it conceal?
Definition
finely spaced grooves that conceal a continuous layer of folded tissue
Term
what are the different types of neurons of the cerebellum?
Definition
purkinje cells and granule cells
mossy fibers
climbing fibers
deep nuclei
Term
where does all input to the cerebellum go to before it moves to the cortex?
Definition
one of the three deep nuclei
Term
where does all the output of the cerebellum go before going to the cerebral cortex and brainstem?
Definition
the deep nuclei
Term
all the layers of the cerebellum share information that leads to what?
Definition
signal processing
Term
explain the pathway when you move your head.
begin with activated cells
Definition
activate cells in the vestibule area->
to the cranial nerve->
to the spinal cord->
to the cerebellum
Term
what is the smallest subdivision of the cerebellum?
Definition
vestibulocerebellum
Term
what is the vestibulocerebellum involved in?
Definition
balance
spatial orientation
Term
what are the primary connections of the vestibulocerebellum?
Definition
vestibular nuclei
Term
what problems would you have if there were lesions to the vestibulocerebellum?
Definition
problems with balance and gait
Term
what are the three sub-divisions of the cerebellum?
Definition
vestibulocerebellum
spinocerebellum
cerebrocerebellum
Term
where does the spinocerebellum receive input from?
what kind of input?
Definition
the dorsal columns of the spinal cord, spinocerebellar tract, and trigeminal nerve, visual and auditory systems

proprioceptive
Term
what is the spinocerebellum involved in?
Definition
fine tune body movements
Term
T/F the spinocerebellum is the largest sub-division of the cerebellum.
Definition
false
cerebrocerebellum
Term
where does the cerebrocerebellum receive input from exclusively?

what lobe especially?
Definition
the cerebral cortex

parietal lobe
Term
where does the cerebrocerebellum send output?
Definition
the ventrolateral thalamus
Term
T/F the dorsal columns of the spine project on the cerebellum
Definition
true
Term
T/F the cerebellum projects to the front part of the brain to make a comparison between what you want to happen based on what actually occurred
Definition
true
Term
where does the mossy fiber project?
Definition
directly to the dee cerebellar nuclei
Term
where do the climbing fibers project?
Definition
to purkinje cells and collaterals to deep nuclei
Term
what are the dominant cells of the cerebellum?
Definition
purkinje and granule cells
Term
what are the dominant axons of the cerebellum?
Definition
mossy fibers and climbing fibers and parallel fibers
Term
where do the two main pathways through the cerebellar circuit originate?
Definition
mossy and climbing fibers
Term
where do the two main pathways through the cerebellar circuit terminate?
Definition
the deep cerebellar nuclei
Term
what type of cell is the bottom layer of the cerebellum made of?
Definition
granule cells
Term
what type of cells is the middle layer of the cerebellum made of?
Definition
purkinje cells
Term
what type of cell is the top layer of the cerebellum made of?
Definition
flattened dendritic trees of purkinje cells
Term
where are excitatory receptors located on the dendrite?
Definition
further from the cell body, distal ends of the dendrite
Term
where are inhibitory receptors located on the dendrite?
Definition
closer to the cell body
Term
how does information from the dorsal columns enter the cerebellum?
Definition
mossy fibers
Term
T/F the basal ganglia and the cerebellum are working simultaneously to make precise voluntary movement.
Definition
true
Term
Two groups of axons descend from the brain down the spinal cord along what two major pathways?
Definition
Lateral pathways
Ventromedial pathways
Term
what does the lateral pathway control?
Definition
voluntary movement
control of distal musculature
Term
what is in control of the lateral pathway?
Definition
direct cortical control
Term
T/F the ventromedial pathway has three descending tracts.
Definition
false
4
Term
where do the tracts of the ventromedial pathway originate?
terminate?
Definition
the brain stem

spinal interneurons controlling proximal and axial musculature
Term
what does the ventromedial pathway control?
Definition
posture
locomotion
Term
what is in control of the ventromedial pathway?
Definition
the brain stem
Term
where does the corticospinal tract originate?
Definition
pyramidal cell layer 5 of the motor cortex
Term
pyramidal cells of the corticospinal tract release what neurotransmitter?
Definition
glutamate
Term
85-90% of the axons in the corticospinal tract do what?
Definition
decussate in the caudal medulla
Term
How does the corticospinal tract descend, where does it innervate?
Definition
travels down the spinal cord and innervate in opposite hemispheres
Term
the lateral corticospinal tract is about what?
Definition
distal musculature
Term
a dense population of interneurons in the spinal cord allows for what?
Definition
multidirectional connection of movement
Term
the lateral corticospinal tract mediates the execution of what?
Definition
movements of the distal musculature of the upper and lower limbs, especially the hands and feet
Term
if you have a stroke, results in not being able to move the left hand, where did the stroke occur in the brain?
Definition
right hemisphere
Term
the upper motor neurons of the corticospinal tract descend via what?
terminate where?
Definition
the anterior funiculus

anterior horn gray matter of cervical and upper thoracic spinal cord levels
Term
the anterior corticospinal tract innervates what?
Definition
the axial and proximal limb (girdle) muscles
shoulder girdle and hips
Term
where are the cortionuclear tract fibers derived from?
Definition
the PMC(brodman's area 4), pre-motor(area 6,8) and somatosensory(area 1,2,3) cortex
Term
where does the corticonucelar tract project?
Definition
the cranial nerves
Term
where do corticonuclear tract also terminate?
Definition
sensory relay nuclei
Term
what corticonuclear tract supports what?
Definition
cranial muscle activity
reflexive eye movements
facial
mastication
tongue, palate, larynx, pharynx
trapezius and sternocleidomastoid
(voluntary movement)
Term
what occurs in lesions to the corticospinal tract?
Definition
can sit up and maintain balance, but if you hand them food they cannot make the connection
Term
strokes in the corticospinal tract result in what?
Definition
paralysis on the contralateral side
Term
what occurred in lesion only to the corticospinal tract?
was there recovery?
Definition
severe loos of movement
function occurred after several months with some loss of fine motor control of fingers
Term
what ventromedial pathway uses sensory information about body position, balance, and the visual environment to do what?
Definition
REFLEXIVELY maintain balance and body posture
Term
what does the medial vestibulospinal tract control?
regulate?
Definition
mainly extensors

posture, balance, particularly head stability
Term
what is activated when i move my head?
Definition
vestibular apparatus
Term
the lateral vestibulospinal tract receives excitatory input from where?
inhibitory input?
Definition
vestibular organs and deep cerebellar nuclei

purkinje cells of the cerebellar cortex
Term
where is the lateral vestibulospinal tract located?
Definition
brain stem and spinal cord area
Term
the vestibular apparatus uses cranial nerves to send axons where?
Definition
the spinal cord
Term
the lateral vestibulospinal tract as what innervation to wherE?
Definition
ipsilateral innervation of interneurons that excited motor neurons
Term
T/F the medial vestibulospinal tract excites motor neurons mainly to the arms, neck and back muscles.
Definition
false
inhibits
Term
what does the lateral vestibulospinal tract regulate?
Definition
regulation of posture and balance
Term
where does the pontine resticulospinal tract get input from?
Definition
both cortices and ascending sensory input from spinoreticular tract neurons
Term
what does the pontine reticulospinal tract support?
Definition
reflexive movement
Term
the pontine reticulospinal strict has ipsilateral innervation of interneurons that EXCITE/INHIBIT motor neurons to the limb and trunk muscles.
Definition
excite
Term
where does the tectospinal tract originate?
Definition
superior colliculus of the midbrain
Term
where does the superior colliculus receive input from?
Definition
retina
visual cortex
somatosensory and auditory info
Term
the tectospinal tract mediates what?
Definition
reflexive movements of the eyes, and the cervical and thoracic region of the trunk
Term
where is the tectospinal tract located?
Definition
above the brainstem
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