Angel's lectures Flashcards
Want to increase reflex gain to ..
ensure correct postural control
Want to decrease reflex gain to ..
prevent loss of balance
The stumble corrective response is mediated by
Skin afferents in the feet
Where does planned movement start?
In the premotor
In the Supplementary motor cortex
What is tone?
Resistance felt as you manipulate a joint passively
Spasticity is
Increased velocity-dependent tone
+
Exaggerated stretch reflexes (increased amplitude and briskness)
Clonus is
Rapid successions of stretch reflexes - best felt at ankle
What does pharmacological treatment of spasticity include?
Reducing transmission between the 1a afferent and motor neuron
Functions of the vestibulocerebellum
Balance, eye movement
Function of the spinocerebellum
Descending motor systems, regulate limb movement, posture and stance
Function of the cerebrocerebellum (dentate nucleus) projects to VL thalamus
To motor and premotor cortex - motor planning, learning and fine hand movement
The otolith organ (The saccule) detects linear motion how?
Up and down - in plane of gravity
The otolith organ (the utricle) detects linear motion how?
ACCELERATION, side to side, in horizontal plane
What detects angular velocity?
semi-circular canals
Both utricle and saccule contain…
CILIA as part of the receptor
and ottoconia on the top of the cilia
What do the otolith crystals do
Push against cilia, give a sense of gravity, respond to linear acceleration
What happens when hair cells bend towards the Kinocilium?
Increased firing of nerve 8, depolarization
What happens when hair cells bend away from the Kinocilium?
Decrease firing, hyper polarized receptor
Moving the head the left….. the left hair cells, and …. the right hair cells
Excites the left
inhibits the right
(fluid moves to the right)
Which cranial nerves are excited and how when head is turned to left - so left hair cells are excited?
IpsilateraL 3
Contralateral 6
In Nystagmus - the fast phase is in what direction of rotation
In the same direction - Slow phase an attempt to maintain visual fixation
What does the vestibulo, cortico, and reticulo spinal pathways do
Control reflex gain
Select motor program
Activate groups of motor neurons
Vestibulospinal pathway has bias towards what type of musculature?
Extensors
Hemiballism is due to
Lesion in contralateral subthalamic nulceus
1B afferents, do NOT make connections with alpha motor neurons….
They connect with inhibitory 1b interneurons
what are the hallmarks of the uMN syndrome>
- weakness
- Babinski
- hyperreflexia
- clasp knife
What is the first part of the clasp knife phenomenon due to?
- Exaggerated stretch reflex
2. Reverse flexion
For the basal ganglia what is the major output nucleus?
GP interna
