Chapter 5: Motor Systems: The Organisation of Action

Question 1

motor program

Answer 1

plan to produce a particular motor action, such as writing one’s name, that occurs independently of the effectors used to carry out the movement

Question 2

lower motor neuron/ primary motor neuron

Answer 2

motor neuron that directly innervates muscle

Question 3

interneuron/ local circuit neuron

Answer 3

neuron whose local connections contribute to processing circuitry

Question 4

upper motor neuron

Answer 4

neuron that gives rise to a descending projection that controls the activity of lower motor neurons in the brainstem and spinal cord

Question 5

primary motor cortex

Answer 5

major source of descending projections to motor neurons in the spinal cord and cranial nerve nuclei; located in the precentral gyrus (area 4) and essential for the voluntary control of movement

Question 6

premotol cortical area

Answer 6

cortical areas, including the premotor cortex, supplementary motor cortex, and parts of the parietal cortex, that provide motor programming signals to the primary motor cortex

Question 7

premotor cortex

Answer 7

part of the prefrontal cortex lying just anterior to the primary motor cortex; involved in planning movement

Question 8

supplementary motor area/ SMA/ area 6

Answer 8

premotor area, lying anterior to the primary motor cortex on the medial surface of the cerebral hemisphere, that plays an important role in movement planning

Question 9

medullary pyramids

Answer 9

longitudinal bulges on the ventral aspect of the medulla that signify the corticospinal tracts at this level of the nervous system

Question 10

frontal eye fields

Answer 10

region of the prefrontal cortex in human and non-human primates, often associated with area 8a, that plays a key role in voluntary visual orienting movements

Question 11

superior colliculus

Answer 11

paired structures that form part of the roof of the midbrain; important in orienting movements of the head and eyes

Question 12

saccade

Answer 12

ballistic eye movement that changes the point of binocular visual fixation; normally occur at a rate of about three to four per second

Question 13

readiness potential

Answer 13

electrical potential, recorded from the motor and premotor cortices with EEG electrodes, that signals the intention to initiate a voluntary movement well in advance of actual production of the movement

Question 14

anosognosia

Answer 14

lack of awareness of one’s own disability

Question 15

reward value

Answer 15

likelihood that a particular movement will yield a reward, multiplied by the amount of reward expected

Question 16

optic ataxia

Answer 16

neurological condition associated with damage to the dorsal parietal cortex and characterized by deficits in visually guided reaching

Question 17

basal ganglia

Answer 17

group of nuclei lying deep in the subcortical white matter of the frontal lobes that organize motor behavior. The caudate, putamen, and globus pallidus are major components of the basal ganglia; the subthalamic nucleus and substantia nigra are often included

Question 18

gating

Answer 18

allowing/ permitting
the basal ganglia, for example, gate movement initiation. Channels through the neuronal membrane are often gated, allowing the access of certain ions under certain conditions

Question 19

caudate

Answer 19

one of the three major nuclei that make up the basal ganglia in the cerebral hemispheres; together with the putamen, serves as the input structure for the globus pallidus. Damage to the caudate nucleus leads to hyperkinetic movement disorders such as Huntington’s disease

Question 20

putamen

Answer 20

one of the three major nuclei that make up the basal ganglia

Question 21

striatum

Answer 21

input nuclei of the basal ganglia, consisting of the caudate and the putamen. So called because of the striped appearance of these structures in brain sections

Question 22

globus pallidus

Answer 22

one of the three major nuclei that make up the basal ganglia in the cerebral hemispheres; relays information from the caudate and putamen to the thalamus

Question 23

substantia nigra pars reticulata/ SNr

Answer 23

component of the midbrain substantia nigra nucleus that plays a key role in the suppression and initiation of saccadic eye movements

Question 24

Parkinson’s disease

Answer 24

neurodegenerative process affecting the substantia nigra that results in a characteristic tremor at rest and a general paucity of movement

Question 25

Huntington’s disease

Answer 25

autosomal dominant genetic disorder in which a single gene mutation results in damage to the basal ganglia that causes personality changes, progressive loss of the control of voluntary movement, and eventually death

Question 26

choreiform movement

Answer 26

uncontrollable, dancelike (“choreiform”) writhing or twisting associated with damage to the basal ganglia, as occurs in disorders such as Huntington’s disease

Question 27

hemiballismus

Answer 27

neurological disorder resulting from unilateral damage to the basal ganglia; manifested by flinging movements of the limbs contralateral to the lesion

Question 28

cerebellum

Answer 28

prominent hindbrain structure that is concerned with motor coordination, posture, balance, and some cognitive processes; composed of a three-layered cortex and deep nuclei, and attached to the brainstem by the cerebellar peduncles

Question 29

intention tremor

Answer 29

tremor that occurs during performance of a voluntary motor act. Characteristic of cerebellar pathology