Ch. 7.2 Brain mechanisms of movement Flashcards
What aspect of brain anatomy facilitates communication between body sensations and body movements?
The motor cortex and the somatosensory cortex are adjacent, and the area of motor cortex devoted to a particular body structure is aligned with the somatosensory cortex area responsive to the same structure.
What evidence indicates that cortical activity represents the “idea” of the movement and not just the muscle contractions?
Activity in the motor cortex leads to a particular outcome,
such as movement of the hand to the mouth, regardless of what muscle contractions are necessary given the hand’s current location
How does the posterior parietal cortex contribute to movement?
The posterior parietal cortex is important for perceiving the location of objects and the position of the body relative to the environment. It is also active for planning of a movement.
How does the supplementary motor cortex, the premotor cortex and the the prefrontal cortex contribute to movement?
The supplementary motor cortex inhibits a habitual action when it is inappropriate.
The premotor cortex and supplementary motor cortex are also active in preparing a movement shortly before it occurs.
The prefrontal cortex stores sensory information relevant to a movement and considers possible outcomes of a movement.
When expert pianists listen to familiar, well-practiced music, they imagine the finger movements, and the finger area of their motor cortex becomes active, even if they are not mov- ing their fingers. If we regard those neurons as another kind of mirror neuron, what do these results imply about the origin of mirror neurons?
These neurons must have acquired these properties through experience. That is, they did not enable pianists to copy what they hear. They developed as
pianists learned to copy what they hear.
. What kinds of movements does the lateral tract control? The
medial tract?
The lateral tract controls detailed movements in the periphery on the contralateral side of the body. For exam- ple, the lateral tract from the left hemisphere controls
the right side of the body.
The medial tract controls trunk movements bilaterally
What kind of perceptual task would be most impaired by damage to the cerebellum?
Damage to the cerebellum impairs perceptual tasks that depend on accurate timing.
Also suprisingly perceptions like lifting a small ball that is unexpected heavy activates the cerebellum strongly
How are the parallel fibers arranged relative to one another and to the Purkinje cells?
The parallel fibers are parallel to one another and perpendicular to the planes of the Purkinje cells
If a larger number of parallel fibers are active, what is the effect on the collective output of the Purkinje cells?
As a larger number of parallel fibers become active,
the Purkinje cells increase their duration of response
Structures in the basal ganglia
Lays in the forebrain.
Caudate nucleus, putamen ( = dorsal striatum )
globus pallidus
What kind of learning depends most heavily on the basal
ganglia?
The basal ganglia are essential for learning motor habits that are difficult to describe in words.
In general, do the basal ganglia have more effect on responses to a stimulus or on self-initiated movements?
The basal ganglia have more influence on self- initiated movements, which are generally slower.
Which aspect of movement do the basal ganglia control?
The vigor (strength/energy) of movement
Explain the evidence suggesting that a conscious decision to move does not cause the movement.
Why are some researchers skeptical of this evidence?
Researchers recorded responses in people’s cortex that predicted the upcoming response. Those brain responses occurred earlier than the time people reported as “when they made the decision.
The studies assume that people accurately report the times of their intentions. However, people’s reports are influenced by events after the movement, and therefore we cannot be confident of their accuracy. Furthermore, a decision to make a voluntary movement is a gradual process
that cannot be pinpointed to a single instant
What is the route from the motor cortex to the muscles?
Axons from the motor cortex go to the brainstem and spinal cord, which have axons to the muscles.
