Control of movement Flashcards
What regions of the brain give information to the primary motor cortex in order to allow effective movement?
Prefrontal cortex
Premotor cortex
Supplementary motor cortex
What is the function of the prefrontal cortex in movement?
Planning of movement
Specifies goal of movement.
What is the function of the premotor cortex in movement?
Organises the sequence of movements
What is the function of the supplementary mortor cortex in movement?
Coordination of complex learned responses such as throwing or typing
Coordination of large muscles for typing
What is the function of the primary motor cortex in movement?
Intention produce outcomes,
Produce output to the spinal cord to cause the motor outcome.
What are the pyrimidal tracts?
Pass through the pyrimid of the medullar
Includes the corticospinal tract and the corticobular tract
Give an overview of the corticobular tract.
Corticobular tract originates in the primary motor cortex
innervates the cranial nerves, hence effects the head, neck and face
Axons for each cranial nerve pass through the brainstem until in level with the desired cranial nerve, where they synapse bilaterally with the target nerve
Tract is bilateral so is mirrored on the opposite side of thebody
Ends in the meduallary region
Before synapse is the UMN below synpase is the LMN
Give an overview of the corticospinal tract.
Originates in the primary motor cortex, descending white matter tract.
Innervates the limbs and trunk
Passess through the brain stem to te medulla, 80% of fibres cross the midline to the contralateral side, continue onwards to target
Fibres on the lateral side are called the lateral corticospinal tract, and fibres that continue on are called the anterior corticospinal tract.
Synpases with lower motor neurons in the ventral grey horn.
Note their are multiple upper and lower motor neurons in one spinal tract.
Is a bilateral structure
What are the signs of an upper motor neuron lesions?
Weakness
No atrophy
no fasiculations
increases reflexes
increased tone
What are the signs of a lower motor neurone lesion?
Weakness
Atrophy
Fasiculations
decreased reflexes
decreased tone
What is ankle clonus?
Involuntary and rhythmic muscle contractions caused by a permanent lower motor lesion
often seen when the foot is relaxed, rotate the ankle then suddenly dorsiflex, foot will repeatedly give small twtiching dorsiflexions, if more than twice this is a sign of clonus.
What does hemiplegic meaning?
Affecting one side of the body
often muscle weakness, wasting or flexion.
What does quadriplegia mean?
Affecting all limbs and trunks
What does paraplegia mean?
Paralysis of the lower legs and body, often due to spinal cord injury.
What are the different lobes of the cerebellum?
The anterior lobe
The posterior lobe
The flocculonodular lobe.
What is the purpose of the cerebellum?
Coordination
Maintains balance and posture
Tone of muscles
Motor learning
Maps original to intended position
All subconscious
*Note does not intiiate movement, uses sensory information and other inputs to fine tune motor activity.
What movement are indiactors of movement disorders caused by the cerebellum?
Impairment is ipsilateral to the lesion
Most apparent on movement not rest
No numbness or paralysis
Ataxia - coordination, balance and speech, affects force range and direction of movement
Past pointing - finger touch test
Intention tremor
Dysdiadochokinesis - difficulty with repetitive supination/pronation
Scanning speech - break or pause between sylables, not change in tone
What are the key features of an intention tremor in cerebellum damage?
Tremor starts small and becomes more noticeable just before action is complete
Tremor stops when the action is completed.
Give an overview of the structure of the cerebellum?
Inferior to the occipital and temporal lobes, seperated from them by the tentorium cerebelli.
Located within the posterior cranial fossa
Same level but posterior to the pons
Contains white and grey mater, white matter has deep nuclei.
What is dysmetria?
Inability to control the distance, speed and range of motion required for a co-ordinated task.
What are the key clinical signs to indicate a problem with the cerebellum?
Intention tremor
Loss of balance when walking heal to toe
What are the key clinical signs of a problem with the dorsal column?
Fall when eyes are shut