Chapter 14: Brain Control of Movement Flashcards
The( ) influences motor activity of the spinal cord -> Initiates voluntary movements
brain
Hierarchy of controls
Highest level: strategy (1) -> deciding what to do; deals with complex information to decide the course of action
Middle level: tactics (2) -> which muscles to use, how much force to use; how to move the muscles of the body to achieve the course of action
Lowest level: execution (3)
- Association area of neocortex, basal ganglia
- Motor cortex, cerebellum
- Brain stem, spinal cord
(): Sensory information used by all levels of the motor system
sensorimotor system
Axons from brain descend along two major pathways:
Lateral pathways
Ventromedial pathways
axon pathway from brain that mediates Voluntary movement— originates in cortex
lateral pathways
components of lateral pathways
- corticospinal (pyramidal) tract
- rubrospinal tract
lateral pathway component: Motor cortex neurons directly innervate spinal cord; originates directly from motor cortex
corticospinal stract (direct)
the corticospinal tract passes through (lateral/medial) side of midbrain and (2), where the decussation occurs
- lateral
- medulla
lateral pathway component: indirectly control spinal cord neurons; suggested purpose: controls fine fractionated movements of arms and hands (not present in monkeys)
rubrospinal tract
the rubrospinal tract originates from () in the midbrain, which are governed by neurons in the motor cortex
red nucleus neurons
The effects of experimental corticospinal lesions
Deficit in fractionated movement of arms and hands
Both lateral pathways can (1) for the other if the other has a lesion -> allows for recovery after some time; subsequent (2) in the other pathway reverses recovery
- compensate
- lesion
() in human can affect (cause lesions) in motor cortex or corticospinal tract -> causes paralysis on contralateral side, with possibility of recovery over time
strokes
() pathways mediate balance and posture; originate in the brain stem
ventromedial
4 components of ventromedial pathways
- vestibulospinal tracts
- tectospinal tract
3-4. pontine/medullary reticulospinal tract
ventromedial pathway component: manages muscles to maintain head balance and head turning
vestibulospinal tracts
ventromedial pathway component: manages muscles for the orienting response -> Turning your head and moving your eye when you focus on an object
tectospinal tract
vestibulospinal tracts originate from (), which is the projection site of info from vestibular organs in inner ear -> combines sensory (proprioception) and motor info
vestibular nucleus
the vestibular spinal tracts pass near the (ventral/dorsal) side of the spinal cord
ventral
the tectospinal tract originates from the (1) and receives info from the (2) -> processing center for visual info and motor execution
- superior colliculus (optic tectum)
- retina
reticulospinal tract: enhances antigravity reflexes -> muscles resist effect of gravity to maintain standing position
pontine reticulospinal tract
reticulospinal tract: liberates and relaxes antigravity muscles from reflex control
medullary reticulospinal tract
motor cortex comprises areas () of the frontal lobe
4 and 6
area 4 of motor cortex: ()
primary motor cortex, M1
(): “higher” motor area (Penfield)
Area 6
area 6 consists of ()
Lateral region -> premotor area (PMA)
Medial region -> supplementary motor area (SMA)
Body areas that require more sensitive motor movements correspond to (narrower/wider) areas in motor cortex
wider
the posterior parietal cortex consists of areas () of the frontal cortex
5 and 7