Functional neuroanatomy of movement disorders Flashcards
Monosynaptic reflex arc
- Sensory neurone detects muscle spindle → cord in dorsal root ganglion
- Dorsal root ganglion enters ventral horn
- Synapses with motor neurone in ventral horn → spinal nerve → muscle of interest
When you have a umn, what happens to your flexors and extensors?
Extensors are weaker, limbs in hyeprflexion
Signs of UMN lesion
- Attenuated knee jerk
- Ankle jerk
- Ankle clonus - sustained beating of foot by stretching gastrocnemius
- Positive babinski
Corticospinal tracts
Receive input from motor cortex -> internal capsule -> crus cerebri -> pons -> medulla -> tracts
What is your pre-central gyrus?
Primary motor cortex
How do the basal ganglia and cerebellum cooperate?
Basal ganglia starts movement, cerebellum makes it smooth
Function of posterior parietal cortex
Transforms visual info into motor commands - sends signals to premotor cortex and SMA
Function of premotor cortex
Sensory guidance of movement controlling proximal and trunk muscles
UMN lesion sx
Paralysis of movement rather than individual muscles
Hypertonic muscles
Hopping rabbit posture
Babinski
What happens when you have a LMN lesion?
Inhibits primitive reflex and causes massive response to stimulus - spasticity and exaggerated response
LMN lesion sx
Paralysis of individual muscles
Flaccid muscles
Absent tendon reflexes
Lentiform nucleus
Putamen + globus pallidus
Basal ganglia function
Initiates and terminates movement
Neuronal activity in putamen seen before body movements
Neuronal activity in caudate seen before eye movements
Function of limbic system
Fight/flight, smell, memory, reproductive behaviour and eating/feeding, emotion, survival, rewards
Which two structures does the fornix connect?
Cingulate gyrus to hippocampus
Wernicke’s encephalopathy
deficiency of vit B1 (thymin) - related to alcoholism - mammillary bodies shrivel up so break circuit of Papez so cam’t make memories - sx: amnesia, ataxia, confusion, opthalmoplegia
Function of circuit of papez
Emotional expression
Hippocampus - thalamus - hypothalamus - mammillary bodies - cingulate gyrus - fornix - hippocampu
Kluver-Bucy sundrome
Bilateral damage to amygdala
Wilson’s disease
Copper accumulation and motor disorder
3x peduncles in cerebellum
3x peduncle (top is efferent and bottom 2 are afferent)
BG dysfunction symptoms
- Chorea: involuntary dancing movements e.g. Huntington’s disease
- Ballismus: severe chorea with thrashing motions
- Athetosis: writhing movements of limb and neck
- Movement disorder contralateral to affected side of BG
Huntington’s
- Loss of GABA in corpus striatum
- Chorea
- Dementia, unsteadiness and speech problems
Function of cerebellum
Learning new actions - timing and coordination
DANISH
Dysdiadokokinesis Ataxia - uncoordinated, broad-based gait Nystagmus Intention tremor Speech disturbance Hypotonia
Symptoms of cranial nerve palsy
Nystagmus and dysarthria
Symptoms of palsy in the arms
Finger-nose ataxia, intention tremor, dyasiakokinesis
Symptoms of motor nerve palsy in legs
Heel-knee-shin ataxia, gait ataxia, falls
Path of superior cerebellar peduncles
Run from cerebellum to midbrain
Function of middle cerebellar peduncles
Voluntary motor signals from pontine nuclei to cerebellum
Function of inferior cerebellar peduncles
Sensory info from vestibular apparatus of ear and body proprioceptors
