8.2.1 Brain Mechanisms Of Movement 2

Question 1

____ of the lateral tract extend directly from the motor cortex to their target neurons in the spinal-cord.

Answer 1

Axons

Question 2

In bulges of the medulla called ____, the lateral tract crosses to the contralateral side of the spinal-cord. (For that reason, the lateral tract is also called the pyramidal tract). It controls movement in peripheral areas, such as the hands and feet.

Answer 2

pyramids

Question 3

In some children with ____ ____, the contralateral path fails to mature, and the ipsilateral path remains relatively strong. The resulting competition causes clumsiness.

Answer 3

cerebral palsy

Question 4

The medial corticospinal tract includes axons from many parts of the cerebral cortex, not just the primary motor cortex and surrounding areas. It also includes axons from the midbrain tectum, reticular formation, and the ____ ____, a brain area that receives input from the vestibular system.

Answer 4

vestibular nucleus

Question 5

Axons of the medial tract go to ____ sides of the spinal-cord, not just a contralateral site.

Answer 5

both

Question 6

The ____ ____ controls mainly the muscles of the neck, shoulders, and trunk and therefore such movements as walking, turning, bending, standing up, and sitting down.

Answer 6

medial tract

Question 7

Note that these movements of the medial tract are necessarily ____, you can move your fingers on just one side, but the movement of your neck or trunk must include both sides.

Answer 7

bilateral

Question 8

The ____ tract controls muscles in the lateral parts of the body, such as hands and feet. The ____ track controls muscles in the medial parts of the body, including trunk and neck.

Answer 8

lateral : medial

Question 9

The cerebellum. People with cerebellar damage do lose ____ and ____, but that description understates the importance of the structure.

Answer 9

balance and coordination

Question 10

The cerebellum contains more ____ than the rest of the brain combined and an enormous number of synapses.

Answer 10

neurons

Question 11

One effect of _____ damage is trouble with rapid movements that require aim, timing, and alternations of movements.

Answer 11

cerebellar

Question 12

People with cerebellar damage are normal at ____ motor activity.

Answer 12

continuous

Question 13

____ – ballistic eye movements from one fixation point to another – depend on impulses from the cerebellum and the frontal cortex to the cranial nerves.

Answer 13

Saccades

Question 14

Someone with cerebella damage has difficulty ____ the angle and distance of eye movements. The eyes make many short movements until, by trial and error, they eventually find the intended spot.

Answer 14

programming

Question 15

The symptoms of cerebellar damage resemble those of ____ ____: clumsiness, slurred speech, and inaccurate eye movements.

Answer 15

alcohol intoxication

Question 16

A police officer testing someone for drunkenness may use a finger-to-nose test or similar test because the ____ is one of the first brain areas that alcohol effects.

Answer 16

cerebellum

Question 17

The cerebellum is not only a motor structure. The cerebellum responds to sensory stimuli even in the ____ of movement.

Answer 17

absence

Question 18

Masao Ito (1984) proposed that a key role of the cerebellum is to establish new ____ ____ that enable one to execute a sequence of actions as a whole.

Answer 18

motor programs

Question 19

Richard Ivry and his colleagues emphasise the importance of the cerebellum for behaviours that depend on ____ ____ of short intervals.

Answer 19

precise timing

Question 20

Any sequence of rapid movements obviously requires ____. Many perceptual and cognitive tasks also require ____.

Answer 20

timing

Question 21

People who are ____ at one kind of timed movement, such as tapping a rhythm with a finger, tend also to be good at other timed movements.

Answer 21

accurate

Question 22

People with ____ ____ are impaired at all of these tasks but unimpaired at controlling the force of a movement or at judging which tone is louder. The cerebellum as important mainly for tasks that require timing.

Answer 22

cerebellar damage

Question 23

The cerebellum also appears critical for certain aspects of ____. Evidently, people with cerebellar damage need longer to shift their ____.

Answer 23

attention

Question 24

The cerebellum receives input from the spinal-cord, from each of the sensory systems by way of the cranial nerve nuclei, and from the cerebral cortex. That information eventually reaches the ____ ____, the surface of the cerebellum.

Answer 24

cerebellar cortex

Question 25

The term ____ ____ applies collectively to a group of large subcortical structures in the forebrain.

Answer 25

basal ganglia

Question 26

Included in that basal ganglia are the ____ ____, the ____, and the ____ ____.

Answer 26

caudate nucleus : putamen : globus pallidus

Question 27

Input comes to the caudate nucleus and putamen, mostly from the ____ ____.

Answer 27

cerebral cortex

Question 28

Output from the caudate nucleus and putamen goes to the ____ ____ and from there mainly to the thalamus, which relays it to the cerebral cortex, especially its motor areas and the prefrontal cortex.

Answer 28

globus pallidus

Question 29

Most of the output from the globus pallidus to the thalamus releases ____, an inhibitory transmitter, and neurons in the globus pallidus show much spontaneous activity.

Answer 29

GABA

Question 30

The globus pallidus is constantly inhabiting the ____.

Answer 30

thalamus

Question 31

Input from caudate nucleus and the putamen tells the globus pollidus which movements to ____ ____.

Answer 31

stop inhibiting

Question 32

With extensive damage to globus pallidus, as in people’s ____ ____, the result has decreased inhibition and therefore involuntary, jerky movements.

Answer 32

Huntington’s disease

Question 33

In effect, the basal ganglia select a movement by ______. This circuit is particularly important for self initiated behaviours.

Answer 33

ceasing to inhibit it

Question 34

Neurons in the motor cortex adjust their responses as a person or animal _________. At first, movements are slow and inconsistent. As movements become faster, relevant neurons in the motor cortex increase their firing rates.

Answer 34

learns a motor skill

Question 35

After prolonged training, the movement patterns become more consistent from trial to trial, and so do the patterns of activity in the motor cortex. In engineering terms, the motor cortex increases its __________.

Answer 35

signal-to-noise ratio

Question 36

The basal ganglia are critical for learning new ____.

Answer 36

habits

Question 37

People with basal ganglia damage are impaired at learning motor skills and at converting new movements into smooth, ____ ____.

Answer 37

automatic responses