Motor systems Flashcards
What is the Moravec´s paradox?
Discovery that, contrary to traditional assumptions, high-level reasoning (like chess) requires very little computation, but low-level sensorimotor skills (like movement) require many computational resources
which muscles are not under voluntary control?
Cardiac muscles & smooth muscles (like peristaltics)
What’s muscle antagonism?
Muscles can only pull, therefore every muscle needs an antagonist (relaxation and contraction, e.g. biceps & triceps)
What does a motor unit consist of?
lower motor neuron & muscle fiber(s) that is/are being innervated
What is the difference between monosynaptic & polysynaptic reflexes?
monosynaptic reflexes do not have an interneuron, polysynaptic reflexes have an interneuron and can be inhibited by conscious control
What are spinal “pattern generators”?
Neuronal circuits that when activated initiate very basic movements (walking, breathing) in the absence of sensory or descending inputs that carry specific timing information.
-> E.g. in animals when spinal cord is cut through between forelegs & hindlegs: Hindlegs will still initiate walking action
What is the pyramidal (voluntary) movement tract?
corticospinal (from brain to spinal cord) and corticobulbar (from brain to cranial nerves) tracts
What is the Georgopopoulos Model?
Populations of neurons code for one movement together (population vectors) –> Therefore, movement is precise even though tuning factors of cells are very broad
What brain areas are active in complex movement sequences?
motor cortex, somatic somatosensory cortex, medial premotor area
What is a ballistic loop system?
A loop system, which plans once in the beginning and does not implement a feedback loop (measuring element) along the way
input -> controller -> control signal -> process -> output (output doesn’t go back to the controller – open loop)
name the parts of the basal ganglia
dorsal striatum (caudate nucleus, putamen), ventral striatum (nucleus accumbens, olfactory tubercle), globus pallidus, subthalamic nucleus, substantia nigra
Does M1 code for directionality?
Yes. Motor neurons have a certain tuning width (like orientations in V1)
How can muscle tension be measured?
Electromyography (EMG)
what is an alpha motor neuron?
= lower motor neuron. Projects from synapse to muscle
