16 Motor Cotices Flashcards
Describe the location/ organization of the motor cortices.
primary motor cortex is anterior to the central sulcus, association cortex is anterior to the primary motor cortex
What supplies blood to the primary and association motor cortex?
middle cerebral artery and anterior cerebral artery
What is the relative position of the SMA and PML premotor cortices?
SMA (supplementary motor association) is more medial to PML (lateral premotor area)
What is the PPC?
posterior parietal cortex receives information from the visual field for coordinated movements (lies posterior to the somatosensory cortices)
What is praxis?
ability to learned purposeful movements
What is the corona radiata?
superficial white matter that joins together as axons that descend from the cortex and continues on as internal capsule
Describe the path of corticospinal tract.
primary motor cortex, corona radiate, posterior limb of the internal capsule, cerebral peduncle of the midbrain, basis pontis, medullary pyramid, pyramidal decussation, lateral corticospinal tract
Describe the path of corticobulbar tract (supplies motor input to the face)
lateral primary motor cortex, corona radiate, genu of the internal capsule, mostly bilateral input to cranial nerve nuclei (except lower face and eyes)
Why is bilateral corticobulbar tract input important?
even if muscles work on both sides, coordination is very important and that is accomplished by bilateral input
Where does frontal eye field input from the cortex synapse?
on paramedic pontine reticular formation on the contralaterla side (BONUS: PPRF goes on to synapse on ipsilateral abducens and contra lateral MLF)
What is apraxia?
inability to perform learned purposeful movements, despite having the necessary motivation and basic motor and sensory functions (fundamental deficit in motor PLANNING, can result from damage to motor and/or parietal association cortices
Compare/ contrast paresis, plegia and palsy.
paresis is weakness while plegia/paralysis is zero volitional movement. palsy can mean paresis or plegia without specificity of severity
Contrast hemiparesis and paraparesis.
hemi (unilateral) para (bilateral legs)
Contrast ophthalmoparesis and gaze paresis.
ophthalmoparesis is nonspecific to any eye movement while gaze paresis includes movement of both eyes together
Describe some upper motor neuron PATTERNS
circumduction of the leg (arm is flexed, leg is extended, plantar flexion dominates) pronator drift and face disfunction of only the lower face
