Motor system FINAL

Question 1

Motor control organisation

2 types

Answer 1

1) Functional segregation
2) Hierarchial organisation

1) Functional segregation: Organised in no of different areas that control different aspects of mvmt
2) Hierarchial organisation:

High order areas of hierarchy involved in more complex tasks (programme, coordinate)

Lower level areas- perform lower level tasks (Execution of mvmt)

Question 2

Function of brain stem in motor organisation

Answer 2

Passes commands from cortex to spinal cord

Question 3

Function of motor cortex in motor organisation

Answer 3

Receives info from other cortical areas and sends commands to brainstem and thalamus

Question 4

Which organs adjusts commands received from other parts of motor control

Answer 4

Function of basal ganglia and cerebellum in motor organisation

Question 5

Location of motor cortex

Function

Answer 5

Precentral gyrus, anterior to central sulcus

Control fine, discrete, precise VOLUNTARY mvmt

Question 6

Penfield motor hommunculus: where are legs and head

Answer 6

Legs at midline Head lateral

Question 7

Which artery supplies the medial part of brain

Lateral corticospinal tract:

Answer 7

Legs at midline (this part of brain in supplied by anterior cerebellar artery– stroke in this area=difficulty walking)

1) Betz cell project from primary motor cortex through internal capsule of basal ganglia
2) Pass through midbrain at cerebral peduncle
3) Through pons
4) Into pyramids of medulla, followed by decussation
5) Descend into lateral corticospinal tract
6) At appropriate level project to ventral horn of spinal cord
7) Synapse with alpha motor neuron which leaves through ventral root, out through spinal nerves to musculature

Question 8

Anterior corticospinal tract

what muscles

CN nuclei located where

Answer 8

Decussate at level of spinal cord
–> largely input to muscles of thorax, axial musculature

in brainstem

Question 9

Corticobulbar pathway

Answer 9

1) Head region of motor cortex (think of homonculus-lateral) fibres pass through internal capsule of basal ganglia
2) Synapse in brainstem at CN nucleus
3) CN nerve pass out

Question 10

Premotor cortex located at

Function

Answer 10

Frontal lobe anterior to M1 (Primary motor cortex)

Planning of movement
Regulates externally cued mvments
-Requires awareness of intrapersonal space and extrapersonal space

Question 11

Supplementary motor area

function

Answer 11

Frontal lobe, anterior to primary motor medially– closer to midline

• Planning complex movements and programming sequences of mvmts
• Regulates internally driven movements

Question 12

Association cortex

Which areas

Answer 12

Not strictly motor areas,

Question 13

Why is the association cortex not regarded as a motor area

Which areas

Answer 13

their activity doesn’t correlate with motor output

> Posterior parietal cortex: ensures movements are TARGETED ACCURATELY to objects in external space
Prefrontal cortex: Involved in SELECTION OF APPROPRIATE movements for a particular course of action

Question 14

Lower motor neurons refers to those in

Upper motor neurons refers to those in

Answer 14

Spinal cord and brainstem

corticospinal, corticolobular

Question 15

Pyramidal

Answer 15

Lateral cortcospinal tract

Question 16

Extra-pyramidal

Answer 16

Basal ganglia + Cerebellum – Adjust commands received from other parts of motor control

Question 17

Upper motor neuron lesions effects

Answer 17

Negative signs: LOSS OF FUNCTION

• Paresis:Graded weakness of movements
• Paralysis: Plegia

Postive signs: INCREASED ABNORMAL MOTOR FUNCTION
-Spasticity: increased muscle tone
-Hyper-reflexia: Exaggerated reflexes
-Clonus: Abnormal oscillatroy muscle contraction
:Babinski sign

Question 18

Apraxia

Lesions where result in this? what might these be caused by?

Answer 18

Disorder of skilled movements, not paretic but lost information how to perform

Lesions–STROKE+DEMENTIA of inferior parietal lobe, frontal (Premotor cortex, supplementary area)

Question 19

Lower motor neuron lesion effects

Answer 19

Weakness
Muscle wasting
Tongue fasciculations and wasting
Nasal speech
Dysphagia

Question 20

Motor neuron disease is what?

Example

Answer 20

Progressive neurodegenerative disease of the motor system

ALS

Question 21

Structures of basal ganglia include

Answer 21

Caudate nucleus
Lentiform nucleus (putamen + external globus pallidus)
Subthalamic nucleus
Substantia nigra
Ventral pallidum, claustrum, nucleus accumbens, nucleus basalis of Meynert

Question 22

Basal ganglia function

Answer 22

Elaborating associated movements (e.g. swinging arms when walking; changing facial expression to match emotions)

Moderating and coordinating movement (suppressing unwanted movements)

Performing movements in order

Question 23

Symptoms of Parkinsons

Answer 23

Cognitive decline
Bradykinesia
Hypomimic face
expressionless, mask-like (absence of movements that normally animate the face)
Akinesia
difficulty in the initiation of movements because cannot initiate movements internally
Rigidity
muscle tone increase, causing resistance to externally imposed joint movements
Tremor at rest
4-7 Hz, starts in one hand (“pill-rolling tremor”); with time spreads to other parts of the body so bilateral

Question 24

Neuropathology of parkinsons

Answer 24

neurodegeneration of the dopaminergic neurons that originate in the substantia nigra and project to the striatum

Question 25

Huntingdon’s disease what sort of disorder

Which chromosome
-issue?

Answer 25

Genetic neurodegenerative disorder

Chromosome 4, autosomal dominant
CAG repeat

Degeneration of GABAergic neurons in the striatum, caudate and then putamen

Question 26

Motor signs of huntingdons

Answer 26

Choreic movements (Chorea)
rapid jerky involuntary movements of the body; hands and face affected first; then legs and rest of body
Speech impairment
Difficulty swallowing
Unsteady gait
Later stages, cognitive decline and dementia

Question 27

Fold of dura that covers cerebellum

Answer 27

tentorium cerebelli

Question 28

structure connected to cerebellum

Answer 28

pons

Question 29

How many layers in cerebellum and names from outer
and contain

Connections

Answer 29

3

Molecular– few neurones
Piriform layer- Purkenje cells project to nuclei in white matter of cerebellum
Granular layer- Small neurones for processing

Inferior olive projects to Purkinje cells via climbing fibres
All other input to granule cells via mossy fibres and then onwards via parallel fibres
All output from Purkinje cells via deep nuclei

Question 30

Vestibulocerebellum function

Vestibulocerebellar Syndrome

Answer 30

Regulation of gait, posture and equilibrium
Coordination of head movements with eye movements

Damage (tumour) causes syndrome similar to vestibular disease leading to gait ataxia and tendency to fall (even when patient sitting and eyes open)

Question 31

Spinocerebellum

Spinocerebellar syndrome

Answer 31

Coordination of speech
Adjustment of muscle tone
Coordination of limb movements

Damage (degeneration and atrophy associated with chronic alcoholism) affects mainly legs, causes abnormal gait and stance (wide-based)

Question 32

Cerebrocerebellum

Cerebrocerebellar or Lateral Cerebellar Syndrome

Answer 32

Coordination of skilled movements
Cognitive function, attention,
processing of language
Emotional control

Damage affects mainly arms/skilled coordinated movements (tremor) and speech

Question 33

Main signs of cerebellar dysfunction

Answer 33

Deficits apparent only upon movement

Ataxia
General impairments in movement coordination and accuracy. Disturbances of posture or gait: wide-based, staggering (“drunken”) gait
Dysmetria
Inappropriate force and distance for target-directed movements (knocking over a cup rather than grabbing it)
Intention tremor
Increasingly oscillatory trajectory of a limb in a target-directed movement (nose-finger tracking)
Dysdiadochokinesia
Inability to perform rapidly alternating movements, (rapidly pronating and supinating hands and forearms)
Scanning speech
Staccato, due to impaired coordination of speech muscles