Control of movement Flashcards by Faith Taws

What are 3 major sensory inputs that control muscles?

-visual input (position)
-vestibular input (balance)
-proprioceptive input (position)

How well did you know this?

Not at all

Perfectly

Name some proprioceptors involved in the spinocerebellar pathway

-muscle spindles - muscle length and rate of length change
-golgi tendon organ- tension in muscles

How well did you know this?

Not at all

Perfectly

Name some proprioceptors involved in the dorsal column pathway

-skin
-Pacinian corpuscle-pressure and vibration
-ruffini endings- tension and stretch

-joints
-kinaesthetic receptors-Pacinian receptors,ruffini endings, limb position and rate of position change

How well did you know this?

Not at all

Perfectly

What are each of the spinal pathways in control of?

-spinocerebellar- unconscious proprioception

dorsal column- fine touch, vibration, conscious proprioception

spinothalamic- temp/ course touch/ pain

How well did you know this?

Not at all

Perfectly

Define proprioceptive deafferentation

process by which you loose the afferent proprioceptive info coming in from your body through your spine- you loose the info going into the CNS

How well did you know this?

Not at all

Perfectly

How might the immune system be involved in proprioceptive deafferentation?

-triggered autoimmune process
-viral infection
-target and destroy their own proprioceptive afferents
-immune system destroys and removes proprioceptive first order neurons
-info cant reach the CNS

How well did you know this?

Not at all

Perfectly

What are some targets for proprioceptive info?

1-somatosensory cortex and associated areas (early cognition)
2-primary motor cortex (initiation of motor control)
3-pre motor cortex (develops pattern of movement)
4-basal ganglia (scaling and action selection)
5-cerebellum ( refinement of motor control)
6-brain stem nuclei(refinement of motor control)
7-spinal cord (spinal reflex hoops)

How well did you know this?

Not at all

Perfectly

Where is the vestibular system?

-inner ear
-moves when the head moves- senses acceleration/movement

How well did you know this?

Not at all

Perfectly

What does an accelerometer do?

records motion, movement, acceleration

How well did you know this?

Not at all

Perfectly

What is the vestibular system comprised of?

3 semi circular canals
-otolith organs
-scarpa’s ganglion

fluid filled

How well did you know this?

Not at all

Perfectly

What is the function of the semi circular canals?

angular acceleration

How well did you know this?

Not at all

Perfectly

What is the function of the otolith organs?

utricle-horizontal acceleration
saccule-vertical acceleration

How well did you know this?

Not at all

Perfectly

What is the function of Scarpa’s ganglia?

-a series of sensory nerve cell bodies receiving info from the semi circular canals, utricle, saccule and carries the info via the vestibular nerve up to the brain stem.

How well did you know this?

Not at all

Perfectly

what is the difference between kinocilia and stereocilia?

kinocilia is tallest and stereocilia is shorter

embedded in a gel and attached apically to the hair cell
-want to move with the head
-move them away from each other hair cell hyperpolarises
-move them close together the hair cell with depolarise

How well did you know this?

Not at all

Perfectly

What are otoliths?

-dense made out of calcium carbonate
-like pebbles- embedded in gel
-Have inertia due to significant mass

How well did you know this?

Not at all

Perfectly

What is the ampullae?

-vectoral measurement
-swellings at the base of the semi-circular canal filled with endolymph
-contains hair cells which are embedded in gel called cupula

How well did you know this?

Not at all

Perfectly

Where are vestibular nuclei found?

brain stem
By nuclei we mean they are concentrations of nerve cells that act as computational areas

What are the 4 main outputs of the vestibular nuclei?

-oculomotor complex- contribution to control of eye muscles
-Contribution to control of limb extensors- balance/posture
-to cervical spinal cord- adjustment of head
-Balance info sent to the cerebellum

Name some problems liked to vestibular apparatus damage

1-vertigo- deterioration of input to vestibular nuclei. False sensation of movement

2-Balance disorders-deterioration of input to vestibular nuclei. postural and tonal feed to LMN

3-Lack of coordination-deterioration of input to cerebellum via vestibular nuclei

4-bouncing vision-deterioration of input to oculomotor nuclei. Head/neck and eye coordination

Where is visual and proprioceptive info integrated?

posterior parietal cortex

What is the dorsal visual stream?

occipital lobe to sensory associative areas

What is the ventral visual stream?

insula and temporal lobe memory areas

What happens when there is a loss of visual sense?

1-loss of a major proprioceptive sense
2-reliance on other proprioceptive modalities
3-much more severe difficulties if other senses impaired

describe the control of movement model

1-descending pathways-UMN
2-motor cortex-planning, voluntary movements (basal ganglia)
3-brainstem motor pathways-basic movement and postural control (cerebellum)
4- interneurons-reflex coordination or lower alpha motor neurons

leads to skeletal muscles

What is the function of basal ganglia?

-interact in a 2 way manner -check and monitor and adjust the basic processes produced in motor areas of the cerebellum

Name some key structures in the basal ganglia

-caudate nucleus -putamen -Globus pallidus -subthalamic nucleus -substantia Nigra

What is the internal capsule ( in side the basal ganglia) ?

white brain matter- connectivity highway of axons these axons travel from higher brain centres through the internal capsule down to the brain stem into the spine to carry motor info. Sensory info is coming back the other way

What do the 5 nuclei in the basal ganglia work to control?

-scaling (how big our movements are) -action selection (selecting appropriate actions over inappropriate actions for the moment you are in)

What are the key inputs to basal ganglia and motor feedback loop?

-parietal association cortex -somatosensory cortex -primary motor cortex -frontal and prefrontal cortices receives sensory and a copy of the motor control plan to be executed

How does the basal ganglia talk to the other neurons to control movement?

-not directly -feedback loop from basal ganglia to motor areas -monitors sensory and motor info from the rest of the brain helps to make decisions on scaling and action selection

What is the function of the amygdala?

emotional dimension of movement control

what is the direct pathway of the basal ganglia model?

sustains and promotes desired behaviours

What is the indirect pathway of the basal ganglia model?

inhibits undesired behaviours

Describe the relevance of the substantia nigra

-heavily pigmented dark areas associated with the production of dopamine dopamine is released from the substantia nigra to certain areas of the basal ganglia -facilitates direct pathway-select appropriate motor commands -inhibits the indirect pathway - inhibits inappropriate motor commands

What are some impacts when there is a loss of dopamine from SN?

-Bradykinesia- action selection inhibited -festinating gait- scaling issue-parkinsonian gait -tremor- more distant relationship to action selection and scaling - rigidity- increased tone in LMNs

How do basal ganglia influence motor activity?

-action selection( facilitates/suppresses movements ) -establishes background patterns of movement, control, and adjust posture during voluntary movements -regulate scale/intensity of motor output

What are three functional divisions of the cerebellum?

-vestibulocerebellum -spinocerebellum -corticocerebellum

What is the function of the vestibulocerebellum?

-balance -connections with the vestibular system -connections with vestibular nuclei

What is the function of the spinocerebellum?

-posture -muscle tone -inputs from proprioceptors -outputs to motor centres in brainstem

What is the function of the corticocerebellum?

-coordination -motor learning -inputs from motor cortex -outputs to motor cortex via thalamus

Describe the link between the cerebellum and motor control

-compares actual movement with intended and predicted movement -reduces errors via output to motor cortex and brain stem cortical/reticular links- no direct links to LMNs

What are some consequences of cerebellar lesions?

-balance and posture problems -ataxia-abnormal/uncoordinated movements -asynergia-difficulty creating fluid movements -dysmetria-cant judge distance or scale -scanning speech- uncoordinated development of speech -decomposition of movements