Week 5 Gems Flashcards
Staring spells, sudden onset, no post ictal state, hyperventilation can induce spell, improve as patient ages
Absence seizures
Idiopathic or primary
No focal Sx. Seizures begins suddenly, post ictal state
Generalized tonic clonic seizures
Tend to be primary - inborn genetics or
Drug intoxication or withdrawal or
Metabolic abnormalities or
Encephalities
Focal lesion or disease affecting brain. Without alternation in state of awareness
Simple partial seizures
Focal lesion or disease affecting brain. With alternation in state of awareness.
Complex partial seizures
Sx of wilson’s disease
Movement disorders
psychiatric
Liver
Tx: zinc
2 basic types of neurons
UMN
- Control movement
- cerebral cortex
- brainstem
LMN
- control muscles
- brainstem
- spinal cord
Where is LMN in spinal cord and brainstem?
Ventral horn in spinal cord
Facial nucleus and oculomotor nuclei in brainstem
Where are UMN cell bodies
In cerebral Cortex: planning and initiating movement
- primary motor cortex
- premotor cortex
- posterior cingulate cortex
In brainstem: regulation of muscle tones, movements of eye, H&N
Initiation of movement - posterior cortex
Specifies movement goals
Send info to temporal cortex, prefrontal cortex and M1
Inititation of movement - prefrontal cortex
generate plans for movement
send info to premotor Cx
initiation of movement - premotor cortex
contains lexicon of movement
can recognize movement of others
can send info to motor Cx
initiation of movement - primary motor cortex
contains lexicon of more elementary movements
contributes to the recruitment of LMN
random motor system hierarchy
over 30% of CST are from premotor cx
some areas of premotor and SMA DON’T have direct connection with motor cx
areas in M1 can have higher cognitive functions
motor cx and some premotor cx can coordinate complex movement
2 proposed motor system hierarchy
- simple serial
2. several layer association with interconnection at each level
what does a intracortical microstimulation tell you?
organized movement is stimulated rather than individual muscles
e.g if you injure the thumb area of M1, you will get weakness of thumb as well as the other fingers and arm –> because it is affecting the movement (pincer grip) not only the thumb muscle
What is a muscle field?
the peripheral muscles controlled by a single UMN
what are the secondary motor cortexes?
premotor cx - ventrolateral
SMA - dorsalmedial
cingulate area - important for facial expression of emotions
SMA vs premotor cx
similarities:
mediate selection of movements, involvement with whole body movement
differences:
SMA - in response to external cues - closed loop
premotor - activated bilaterally, in response to internal cues - open loops
primary VS secondary motor cx
differences:
strength of direct connections to LMNs
primary - initiation of specific movements, lesions causes contralateral weakness
secondary - selection of movements, lesions impair ability to develop appropriate strategy (apraxia), no weakness
What is the function of Frontal Eye Fields (FEF)? clinical presentation if lesion?
for saccadic eye movement
in area 6 –whatever
lesion result in BOTH eyes deviating TOWARDS side of lesion
3 principles of descending pathways and their organization
- parallel functional organization - medial and lateral
- direct and indirect projections (via brainstem) from cortex
- monosynaptic and polysynaptic connections between descending pathways and LMNs (interneurons)
somatotropic organization of ventral horn
Dorsal MNs innervate flexor muscles
Ventral MNs innervate extensor muscles
Medial MNs innervate proximal/ axial muscles - trunk muscles
Lateral MNs innervate distal/ appendicular muscles - fingers
Medial Pathway of descending motor control
E.g. medial VST
for posture and balance
terminate bilaterally
long intersegmental interneurons within spinal cord with ipsilateral and bilateral connections
Lateral Pathway of descending motor control
e.g. CST
involve in skilled movement
terminate unilaterally
short intersegmental interneurons within spinal cords unilaterally ( intermediate zone of the spinal grey)
