3 - Motor Systems II Flashcards
What does the frontal lobe control?
Motor control
What area is the primary motor cortex
4
Local lesions in primary motor cortex
Paralysis of specific muscle groups
What area is the premotor cortex
6
What area is the supplementary motor cortex
8
Damage to premotor/supplementary motor cortex
Apraxia - normal refelxes but difficulty in complex motor tasks
What is Oculomotor Apraxia
difficulty moving eyes horizontally and quickly
caused by damage to frontal eye fields
Frontal eye fields function
motor control of extraocular eye muscles
Damage to brocas area
Motor aphasia - difficulty constructing meaningful word sentences
What areas are the dorsolateral prefrontal cortex
9 and 10
What is the function of the dorsolateral prefrontal cortex
Planning and movement
Lesion in the dorsolateral prefrontal cortex
Personality changes
lack of ability to plan or sequence actions or tasks
Test for frontal lobe function
Wisconsin Card Sorting Test
What area is the orbitofrontal cortex
11
Function of the orbitofrontal cortex
Inhibition of motor responses associated with the lmbic system
Lesion in orbitofrontal cortex
Impulsiveness
Sexual disinhibition
Lack of concern
Stroke in motor thalamus
Severe paralysis
Occlusion of the MCA
all of one side of the frontal lobe
Severe motor disability in all parts of the contralateral body except the lower limb
Blood supply to basal ganglia
MCA via leticulostriate arteries
What does the cortcobulbospinal tract run through
Internal capsule
Where does the corticobulbar component terminate
Pontine nuclei
Reticular formation
Red nucleus
CN nuclei
Where is the red nuclei
Midbrain
Where is the motor decussation of the corticobulbospinal tract
Upper Spinal Cord + Medullary Pyramids
Origin of lateral vestibulospinal tract
Vestibular nuclei in upper medulla/lower pons
Function of lateral vestibulospinal tract
Posture and balance
tonically active when upright
Origin of reticulospinal tract
Reticular formation of pons and medulla
Function of reticulospinal tract
Autonomic control and respiration
Rubrospinal/vestigal spinal tract origin
Red nucleus in midbrain
Function of rubrospinal tract
Carries cerebellar commands to SC
Tectospinal tract
Co-ordinates voluntary head and eye movements
Medial vestibulospinal tract
Continuation of MLF
Maintains objects in view despite movements
coordination of head and neck with extraocular eye muscles
Which UMN act directly on LMN
Those driving the muscles of the thumb and fingers
Spasticity
Abnormally increased muscle tone
Upper motor neuron lesion
Clonus
Series of (jerky) contractions of a particular muscle following sudden stretching of the muscle
Hyperreflexia
abnormally (pathologically) brisk tendon reflex is seen in one or more muscles.
Decorticate posturing
More favourable
Arms adducted and flexed
Legs internally rotated and stiffly extended
Decerebrate posturing
Arms adducted and extended
Legs internally rotated
Severe injury to brain at the level of the brainstem
Unconscious patients
Can the cortex recover from a lesion?
Yes if acute - after paralysis
due to plasticity in the cortex
Larger lesions - slower recovery/permanent loss of movement
What is hemiplegic dystonia
Persistent flexion of the arms
Extension of the legs
occurs with chronic spasticity
Paralysis/weakness of voluntary movement
Corticospinal tract
Loss of bladder/bowel control
Reticulospinal tract
Loss of ability to stand up straigh/balance
Vestibulospinal tract
