A different transmitter causes the muscle to relax
A different transmitter causes the muscle to move the other direction
Acetylcholine causes the extensor muscle to contract
A different transmitter causes the extensor muscle to contract
Because they are aerobic, they are subject to rapid fatigue
Because they are anaerobic, they are subject to rapid fatigue
Because they are aerobic, they do not fatigue rapidly
Because they are anaerobic, they do not fatigue rapidly
The receptor detects a muscle is stretched, and sends a signal to contract it reflexively
The receptor detects that a muscle is contracted, and sends a signal to stretch it reflexively
Isolated muscle twitches
Contraction of a particular combination of muscles
Contraction of whatever muscles are necessary to produce a particular outcome
Contractions of different muscles that vary unpredictably from one trial to another
During the second or two in preparation for a movement
During the movement itself
During the second or two after a movement
Peripheral movements on the contralateral side (relative to the side of the brain where the tract originated) / trunk movements bilaterally
Peripheral movements on the ipsilateral side / trunk movements bilaterally
Trunk movements bilaterally / peripheral movements on the contralateral side
Trunk movements bilaterally / peripheral movements on the ipsilateral side
From the primary motor cortex
From the primary motor cortex plus the red nucleus
From many parts of the cortex, plus the tectum, reticular formation, and vestibular nucleus
From the somatosensory cortex
It is active when the animal is at rest
It stimulates appropriate movements
It inhibits inappropriate competing movements
It produces imitation of other people's movements
Stimulus-triggered, and generally faster than self-initiated movements
Stimulus-triggered, and generally slower than self-initiated movements
Self-initiated, and generally faster than responses that a stimulus triggers
Self-initiated, and generally slower than responses that a stimulus triggers
People form an intention, then activity begins in the premotor cortex, and finally the movement starts
People form an intention at the same time that activity begins in the premotor cortex, and a bit later, the movement starts
Activity begins in the premotor cortex, and a bit later, people are aware of forming an intention, and finally the movement starts
Activity begins in the premotor cortex, and a bit later, people are aware of forming an intention, and simultaneously the movement starts
People inaccurately report the time of a sensory stimulus
An event shortly after the movement changes the reported time of the decision
People who are more highly motivated report earlier decision times
Dopamine / substantia nigra
GABA / basal forebrain
Norepinephrine / locus coeruleus
Serotonin / raphe nucleaus
Spontaneous voluntary movements
Movements in response to a stimulus
Movements when other people are around
Early childhood (3 to 7 years old)
Teenage years (13 to 19)
Middle age (30 to 50)
Old age (65 to 80)
Many different neurotransmitters.
Damage to dopamine-containing cells in the substantia nigra.
Damage to acetylcholine receptors at neuromuscular junctions.
Loss of cell bodies in the basal ganglia and cerebral cortex.
Damage to the myelin sheath that covers axons in the spinal cord.
Oxygen level in the muscle.
Acetylcholine concentration at the nerve-muscle junction.
Fatigue of the muscle.
Stretch of the muscle.
Increases in muscle tension.
Decreases in muscle tension.
Increases in muscle length.
Decreases in muscle length.
Contraction; inhibition of contraction.
Inhibition of contraction; contraction.
Inhibition of contraction; inhibition of contraction.
Contribute to the rhythmic patterns of movement.
Generate movement which is unresponsive to environmental stimulation.
Constrict the pupils in response to bright light.
Control all reflexes in adult humans.
Inferior temporal cortex.
Viewing reversed images.
Watching others perform movements.
Identifying ourselves in the mirror.
Playing the piano.
A heart attack.
Rapid fatigue of the muscles.
Loss of saccadic eye movements.
Difficulty initiating movements.
Inability to coordinate speech with movements.
Net decrease in the excitatory output from the globus pallidus.
Gradual, progressive death of neurons in the substantia nigra.
Immediate, mass death of neurons releasing acetylcholine.
Accumulation of amyloid-beta in neurons.