Motor systems Flashcards
What are the different components of hierarchical control of movement?
N____ (conscious), b____ and s____ c____ (automatic)
Normally funcation ____ ____ ____
Neocortex, brainstem, spinal cord
Normally functions as a whole
What did Hughlings-Jackson (19th century) state about hierarchical control of movement?
The nervous system is organised in ____.
Since each nervous system had developed at ____ ____, each must have some ____ ____
layers.
(Spinal cord in worms, brainstem in fish, amphibians, reptiles, forebrain in birds and mammals;)
different times, functional independence
What was the 1930s concept of the forebrain and initiation of movement?
____ -> ____ (____ successful) ->____
Action -> feedback (action successful) -> action
What was the 1950s concept of the forebrain and initiation of movement? (Karl Lashley)
Movements for s____ a____ are performed q____ to rely on f____
Movement modules p____ by the brain and produced as a unit or as ‘m____ s____’
Complex behaviours require s____ and e____ multiple movement s____
As one sequence is e____, the next sequence is being p____
skilled actions, quickly, feedback
preprogrammed, ‘motor sequence’
selecting, executing, sequences
executed, prepared
The role of the frontal lobes in initiation of movement is to p____ movements, s____ the g____
Plan
specifying
goal
What is the role of the premotor cortex in movement?
O____ m____ s____
Organises motor sequences (select movements appropriate to the context of the action)
What is the role of the primary motor cortex in movement?
Produces s____, s____ m____
Produces specific, skilled movements
Fritsch and Hitzig (1870) found electrical stimulation of a dogs cortex produced what?
Movement of mouth, limbs and paws
What did Nudo and colleagues (1996) find when studying damaged part of motor cortex that controlled the hand in monkeys?
Without rehabilitation:
The hand area of the motor cortex became smaller whereas the elbow and shoulder area became larger
Monkeys lost most ability to move the hand
With rehabilitation:
The hand area of the motor cortex retained its size
Monkeys retained some ability to move hand
What is the corticospinal tract?
Bundle of n____ f____ directly connecting the c____ c____ to the s____ c____.
Branches at the b____ into opposite-side l____ tract that controls movement of l____ and d____, and a same-side v____ tract that informs movement of the t____
nerve fibres, cerebral cortex, spinal cord
brainstem, lateral, limbs, digits, ventral, trunk
What is the lateral corticospinal tract?
Branches at the ____ level, crossing over to the ____ side of the ____ and ____ ____
Moves the ____ and ____ on the ____ side of the body
brainstem, opposite, brain, spinal cord
digits, limbs, opposite
What is the ventral corticospinal tract?
Remains on the ____ side of the ____ and ____ ____
Moves the ____ of the ____ body (trunk) on the ____ side of the body
same, brain, spinal cord
muscles, midline, same
What are the two kinds of neurons located in the spinal column’s ventral horns?
I____
m____
Interneurons - project to motor neurons
Motor neurons - project to muscles of the body
What do the following neurons project to?
1. Laterally located motor neurons -> to m____ that control f____ and h____
2. Intermediately located motor neurons -> to m____ that control a____ and s____
3. The most medially located motor neurons -> to m____ that control the t____
- project to the muscles that control the fingers and hands
- project to muscles that control the arms and shoulders
- project to muscles that control the trunk
Limb muscles are arranged in pairs. What do these pairs consist of?
Extensor - moves (extends) the limb away from the trunk
Flexor - moves the limb toward the trunk
What are two consequences of spinal cord damage?
Quadriplegia - Paralysis of the legs and arms due to spinal cord injury
Paraplegia - Paralysis of the legs due to spinal cord injury
What are some key features of the basal ganglia?
Collection of s____ n____ within the f____.
Receives i____ from all areas of the n____ and l____ c____.
Project back to the m____ c____.
Allow us to adjust the f____ of our m____.
subcortical nuclei, forebrain
input, neocortex, limbic cortex
motor cortex
force, movements
What does the volume hypothesis state?
The i____ g____ p____ acts like a v____ d____ and projects to the t____, which projects to the m____ c____
internal globus pallidus
volume dial
thalamus
motor cortex
What are the two pathways within the basal ganglia?
1. D____ - I____ effect on GPi - too much acitvity leads to o____ in the t____ and a____ force of movement
2. I____ - E____ effect on GPi - too much acitvity leads to u____ in the t____ and r____ force of movement
- Direct, Inhibitory, overactivity, thalamus, amplified
- Indirect, Excitatory, underactivity, thalamus, reduced
Damage to the basal ganglia can produce what two main types of motor symptoms?
Hyperkinetic Symptom - Symptom of brain damage that results in excessive involuntary movements, as seen in Huntington’s Chorea
Hypokinetic Symptom - Symptom of brain damage that results in a paucity of movement, as seen in Parkinson’s disease
What is Huntington’s Chorea?
Genetic ____, affects m____ c____
Symptoms: excessive s____ movements, irregularly t____, randomly d____ and abrupt in c____
Atrophy of c____ n____ and putamen
Treatment - a____ that block d____ transmission
Anxiolytic/anticonvulsant GABAergic drugs that i____ i____ transmission
disorder, muscle coordination
spontaneous, timed, distributed, character
caudate nucleus (degeneration of indirect pathway, direct pathway spared)
Antipsychotics, dopamine, increase inhibitory
What is Parkinsons disease?
Slowly p____ disorder that affects m____, muscle c____ and b____
progressive, movement, control, balance.
*Symptoms: slowness of movement, resting tremor, stiffness of muscles, ‘gait’: small shuffling of steps
- Loss of substantia nigra that sends dopamine projections to putamen that controls movement and coordination.
Treatment is L-Dopa->dopamine precursor
*Boost dopamine levels and increase its transmission
*Loss of efficacy in many patients > 5 years
Dopamine normally increases activity in the direct pathway (D1R expressing) neurons, and decreases activity in the indirect pathway (D2R expressing neurons). What do Studies from MPTP treated monkeys show?
there is overactivity in the indirect pathway and underactivity in the direct pathway
What are some facts about the cerebellum?
To do with acquiring m____ skills
F____ - small but dense lobe involved in eye movements and balance, inputs from vestibular system
Two h____ - h____ organisation
L____ parts - controls movement of l____, h____, f____ and d____
M____ parts - controls movement of f____ and m____ of body
motor
Flocculus
hemispheres, Homuncular
Lateral, limbs, hands, feet, digits
Medial, face, midline
What are the two main motor functions of the cerebellum?
1. T____ of m____
2. Maintaining m____ a____
- timing of movements
- maintaining movement accuracy
What are the three key areas of the brain in the initiation of movement?
1. P____ cortex
2. P____ cortex
3. P____ m____ cortex
Prefrontal cortex, premotor cortex, primary motor cortex
What induces contraction of muscle fibres?
Acetylcholine
