Brain and Behavior Chapter 7.2 Brain Mechanisms of movements

If a large 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.

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 example, the lateral tract from the left hemishphere controls the right side of the body. The medial tract controls trunk movements bilaterally.

In what way does the brain anatomy facilitate communication between body sensations and body movements?

The motor cortex represents muscular control of body areas in close alignment to the way the somatosesnory cortex, just posterior to the motor cortex, represents sensations from those areas.

Premotor cortex

most active immediately before a movement. It recieves information about the target to which the body is directing its movement, as well as information about the body's current position and posture.

What evidence indicates that cortical activity represents the "idea" of 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.

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.

Which aspect of movement do the basal ganglia control?

The basal ganglia control the vigor of movements.

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.

On what basis are some researchers skeptical of this evidence?

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.

nuclei of the cerebellum

clusters of cell bodies in the interior of the cerebellum and the vestibular nuclei in the brainstem, which in turn send information to the midbrain and thalamus.

globus pallidus

component of the basal ganglia that connects to the thalamus which relays information to the motor areas and the prefrontal cortex

Purkinje cells

flat cells in sequential planes, in the cerebellar cortex, parallel to one another

Corticospinal tracts

paths from the cerebral cortex to the spinal cord

lateral corticospinal tract

pathway of axons from the primary motor cortex, surrounding areas, and the red nucleus

readiness potential

the increased motor cortex activity prior to the start of the movement

Primary Motor cortex

the precentral gyrus of the frontal cortex, just anterior to the central sulcus.

cerebellar cortex

the surface of the cerebellum

caudate nucleus

One of the basal ganglia; it has a long extension or tail.

Explain the evidence that someone's conscious decision to move does not cause the movement.

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"

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.

How does the posterior parietal cortex contribute to movement? The premotor cortex? The supplementary motor cortex? The prefrontal cortex?

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. The premotor cortex and supplementary motor cortex are also active in preparing a movement shortly before it occurs. The supplementary motor cortex inhibits a habitual action when it is inappropriate. The prefrontal cortex stores sensory information to a movement and considers possible outcomes of a movement.

When expert pianoissts 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 moving 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 after pianists learned to copy what they hear.

Vestibular nucleus

a brain area that receives input from the vestibular system

basal ganglia

a group of large subcortical structures in the forebrain.

Red nucleus

a midbrain area that is primarily responsible for controlling the arm muscles

Prefrontal cortex

also active during a delay before a movement, stores sensory information relevant to a movement. It is also important for considering the probable outcomes of possible movements. Damage to this area would disorganize movements such as showering with clothes on, pouring water on the tube of toothepaste.

medial corticospinal tract

axons from many parts of the cerebral cortex, not just the primary cortex and its surrounding areas.

parallel fibers

axons parallel to one another and perpendicular to the planes of the Purkinje cells

striatum or dorsal striatum

forebrain structure composed of the caudate nucleus and putamen, which are important for certain aspects of movement

supplementary motor cortex

important for planning and organizing a rapid sequence of movements. Organizes rapid sequence of movements in a specific order; inhibitory if necessary Active seconds before the movement

putamen

large subcortical structure, part of the basal ganglia

antisaccade task

looking away from a powerful attention-getter

Mirror Neurons

neurons in the brain that are activated when one observes another individual engage in an action and when one performs a similar action

pOSTERIOR PARIETAL CORTEX

one of the first areas to become active in planning a movement; monitors the position of the body relative to the world