What is meant by having a secure synapse?
Only one signal is required to active the post synaptic cell
What is the pattern of loss of innervation in UMN lesions of the face?
Loss of innervation to the bottom quadrant on the contralateral side
What is the difference between UM and LM lesion signs?
Babinski sign positive
Negative babinski sign
Signs of deinnervation - fasciculations and fibrillations
Most of the input from the brain to local spinal cord motor neurons is via what?
What is scanning speech due to?
Problems in the cerebellum
What are fasciculations?
Groups of muscles fibres activating spontaneously, probably due to signs for dying MNs/axons
Which tract has direct connections from the cortex to local motor neurons in the spinal cord?
The lateral corticospinal tract
What are some signs of faulty motor control?
- paralysis weakness
- increased reactivity
- ticks, twitches and jerks
- fibrillation and fasciculations
- loss of coordination and smoothness
- loss of the effectiveness of movements.
- speech problems.
What is Henneman's size principle?
In the recruitment of motor units for a movement, the smallest, least fatigable are recruited first while the biggest are recruited last
What is expressive aphasia?
Inability to formulate words despite being able to comprehend them, due to disconnection between the language and motor areas required for speech
The colliculospinal tract is for what?
Visual looming - eg falling
Why are there different patterns of innervation loss between upper and lower motor neuron injuries of the facial nerve?
Because the upper half of the face receives innervation from both sides of the face
T/F Lateral motor tracts control more lateral motor neurons
In which part of muscular control do you find very secure synapses?
Peripheral muscle synapses
What is the receptor at the neuromuscular cleft?
Motor control from the lateral vestibular nuclei is important for what?
Maintenance of posture
When does the motor cortex come into locomotor?
Modulating pattern generation in response to obstacles
What controls the initiation of swing in locomotion?
Feedback from receptors in extensor muscles
eg extension is still maintained while there is feedback from golgi tendon organs that a load is present
What is the purpose of post junctional folds at the neuromusclar cleft?
Increase the SA for ACh and nicotinic receptors
What is anticipation?
Learned movement that compensates for reflexes
eg When catching a ball, the muscle involved will contract in preparation and help with the reflexes to together control movement required for catching
What are UMNs?
Neuronal systems that influence the lower motor neuron
What are signs of de-activation of muscle?
Atropy and degeneration
What are fibrillations?
Tiny contraction of sinlge muscle fibres due to hyperreactivity or increased AChr expression
Gait abnormalities are good clinical signs because?
They correspond to specific CNS disorders
What does a change from decorticate to decerebrate sign tell you?
The lesion is spreading downwards towards to the reticular formation
What is the difference between decorticate and decerebrate signs?
In decerebrate the lesion has spread down to disrupt the rubrospinal tract of the red nucleus (that causes flexion) therefore you get extension of both limbs
Why do babies exhibit positive Babinski sign before they've learnt to walk?
The brain is yet to exert influence on the spinal cord
What does a decerebrate sign looks like?
Upper and lower limbs extended
What does a decorticate sign look like?
Extension of lower limb and flexion of upper limb
Where are the locomotion pattern generators?
In the spinal cord