Chapter 40: Motor Cortex Flashcards Preview

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Flashcards in Chapter 40: Motor Cortex Deck (69)
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1
Q

The frontal lobe of the cerebrum is separated from the temporal lobe by the _____.

A
  • Lateral fissure
2
Q

One can see that three sulci demarcate 2 vertical gyri at the interface of the _____ and _____ lobes.

A
  • Frontal

- Parietal

3
Q

From anterior to posterior, the sulci are the precentral sulcus, the _____, and the postcentral sulcus.

A
  • Central sulcus
4
Q

The central sulcus separates the _____ from the _____.

A
  • Frontal lobe

- Parietal lobe

5
Q

The precentral gyrus is between the _____ and the _____.

A
  • Precentral sulcus

- Central sulcus

6
Q

The primary motor cortex (Brodmann area 4) occupies the precentral gyrus which is the only vertical gyrus of the _____.

A
  • Frontal lobe
7
Q

The primary motor cortex (Brodmann area 4) contains the _____ neurons for voluntary motor activity.

A
  • Upper motor
8
Q

The giant motor neurons of the primary motor cortex (Brodmann area 4) are the same size as Purkinje cells (100 um across), but they are pyramidal instead of _____.

A
  • Oval (ellipsoidal)
9
Q

Giant pyramidal neurons (Betz cells) are found only in the _____.

A
  • Primary motor cortex
10
Q

Brodmann defined area _____ as the area of the cerebral cortex containing giant pyramidal neurons.

A
  • 4
11
Q

The axons of the giant pyramidal neurons descend in the lateral and anterior _____ tracts and synapse on lower motor neurons.

A
  • Corticospinal
12
Q

The only axons in the corticospinal tracts that synapse on the dendrites and bodies of lower motor neurons are the axons of _____.

A
  • Giant pyramidal
13
Q

The axons of the large (not giant) pyramidal neurons of the primary motor cortex also descend in the _____, but they synapse on internuncial neurons that synapse on lower motor neurons.

A
  • Corticospinal tracts
14
Q

The giant pyramidal neurons (100 um across) of Brodmann area _____ are almost twice as large as the large pyramidal neurons (60 um across).

A
  • 4
15
Q

The axons of giant pyramidal neurons synapse on _____, but the axons of the more numerous large pyramidal neurons synapse on _____.

A
  • Lower motor neurons

- Internuncial neurons

16
Q

Both kinds of _____ are somatotopically arranged with neurons controlling the larynx at the inferior end of the precentral gyrus.

A
  • Upper motor neurons
17
Q

The upper motor neurons controlling the tongue are superior to neurons controlling the larynx in the _____ gyrus.

A
  • Precentral
18
Q

Upper motor neurons controlling the facial muscles are superior to neurons controlling the tongue in the _____.

A
  • Precentral gyrus
19
Q

_____ controlling fingers are arranged in an ascending 1-5 sequence from the _____ for the facial muscles.

A
  • Upper motor neurons

- Upper motor neurons

20
Q

Upper motor neurons for the arm are _____ to the upper motor neurons for the fingers and _____ to upper motor neurons for the trunk. which occupy the peak of the precentral gyrus.

A
  • Superior

- Inferior

21
Q

Upper motor neurons for the _____ are in a descending thigh-calf-foot sequence on the part of the precentral gyrus inside the longitudinal fissure.

A
  • Lower extremity
22
Q

On the motor homunculus below, each body part of the homunculus is positioned next to the region of the precentral gyrus containing the _____ neurons controlling that part.

A
  • Upper motor
23
Q

The motor homunculus for a precentral gyrus has only half of a body because the left motor cortex controls only the _____ side of the body.

A
  • Right
24
Q

The disproportionate amount of space in the _____ devoted to the upper motor neurons for the _____ reflects number of neurons necessary to achieve fine motor control of the _____.

A
  • Precentral gyrus
  • Fingers
  • Fingers
25
Q

The motor homunculus is drawn next to a tilted coronal section of the cerebrum because the _____ gyrus is not perfectly vertical.

A
  • Precentral gyrus
26
Q

A _____ is a convenient mnemonic for the positions of the upper motor neurons controlling each body part.

A
  • Motor humunculus
27
Q

Upper motor neuron lesions cause _____.

A
  • Spastic paralysis of the hands
28
Q

The axons of the upper motor neurons pass between the thalamus and the lenticular nucleus to form the posterior limb of the _____.

A
  • Internal capsule
29
Q

The inferior to superior arrangement of the upper motor neurons becomes an anterior to posterior arrangement of the axons in the _____ limb of the _____.

A
  • Posterior limb

- Internal capsule

30
Q

The posterior limb of the internal capsule slants from _____ to _____ as it slants from anterior to posterior.

A
  • Medial

- Lateral

31
Q

The medial to lateral arrangement of the corticobulbar and corticospinal tracts is exaggerated as the axons pass from the posterior limb of the internal capsule to the _____ of the midbrain.

A
  • Crus cerebri
32
Q

The corticobulbar fibers that control the facial and laryngeal muscles part company with the _____ fibers in the pons and medulla.

A
  • Corticospinal
33
Q

The medial to lateral order of the corticospinal fibers is maintained through the base of the pons and the _____ of the medulla.

A
  • Pyramid
34
Q

When the corticospinal fibers cross in the _____, the most lateral fibers cross furthest.

A
  • Pyramidal decussation
35
Q

The axons of the upper motor neurons for the muscles of the _____ do not cross.

A
  • Trunk (back)
36
Q

Because the most lateral fibers cross furthest, the fibers that were most lateral in the pyramids of the medulla remain the most lateral in the _____ of the spinal cord.

A
  • Lateral corticospinal tract
37
Q

The premotor cortex (Brodmann area 6) is just anterior to the primary motor cortex in the _____ lobe.

A
  • Frontal
38
Q

Brodmann area 6 abuts the anterior edge of area _____ because Brodmann numbers are based on cytoarchitecture rather than position.

A
  • 4
39
Q

The somatotopic arrangement of area 6 follows the _____ of area 4.

A
  • Somatotopic arrangement
40
Q

Because the premotor cortex instructs the primary motor cortex in the performance of skilled tasks, the premotor area for the _____ is larger than the other premotor areas.

A
  • Hand
41
Q

Damage to the premotor cortex causes apraxia, loss of a _____ one once had.

A
  • Skill
42
Q

The premotor cortex receives _____ input from the _____ nucleus of the _____.

A
  • Stimulatory
  • Ventral anterior
  • Thalamus
43
Q

Projections of the _____ of the thalamus assist the premotor cortex in the initiation and rapid execution of _____.

A
  • Ventral anterior nucleus

- Skilled tasks

44
Q

The primary motor cortex is assisted by direct input from the premotor cortex and the _____ of the _____.

A
  • Ventrolateral nucleus

- Thalamus

45
Q

The cerebellum influences the primary motor cortex through its projections to the _____ of the _____.

A
  • Ventrolateral nucleus

- Thalamus

46
Q

Damage to the pontocerebellum or the pontine part of the superior cerebellar peduncle causes _____ in the _____ extremities.

A
  • Clumsiness (apraxia)

- Ipsilateral

47
Q

Damage to or the ventrolateral nucleus of the thalamus causes _____ in the _____ extremities.

A
  • Clumsiness (apraxia)

- Contralateral

48
Q

Damage to the primary motor cortex causes _____ of the muscles whose upper motor neurons are damaged.

A
  • Spastic paralysis
49
Q

The lower motor neurons for the extraocular muscles are in the _____, _____, and _____ nuclei.

A
  • Oculomotor
  • Throchlear
  • Abducens
50
Q

The _____ for the extraocular muscles are in the frontal eye field (Brodmann area 8), a triangular region anterior to the arm and trunk regions of the premotor cortex.

A
  • Upper motor neurons
51
Q

Brodmann area 8 is anterior to the superior part of area _____.

A
  • 6
52
Q

The _____ are responsible for conscious tracking movements of the eyes.

A
  • Frontal eye fields
53
Q

The _____ are responsible for unconscious tracking movements of the eyes.

A
  • Superior colliculi
54
Q

Both the frontal eye fields and the superior colliculus depend on feedback from the _____ cortex in order to track a moving object accurately.

A
  • Parietal association
55
Q

The primary motor cortex depends on feedback from the _____ when working in the dark or out of the line of sight.

A
  • Parietal association cortex
56
Q

The intensity of muscular effort depends mostly on feedback through the _____, but the location of muscular effort depends mostly on feedback from the visual cortex and _____.

A
  • Cerebellum

- Parietal association cortex

57
Q

The frontal lobe is separated from the parietal lobe by the _____.

A
  • Central sulcus
58
Q

The inferior frontal gyrus is the gyrus of the _____ lobe just superior to the _____.

A
  • Frontal

- Lateral fissure (temporal lobe)

59
Q

Most of the _____ above the left lateral fissure is occupied by Broca’s motor speech area.

A
  • Inferior frontal gyrus
60
Q

The left Broca’s area in the left _____ is completely dominant in male speakers of Indo-European languages.

A
  • Inferior frontal gyrus
61
Q

A stroke in a man’s left Broca’s area causes mute aphasia, the complete _____ to _____.

A
  • Inability

- Speak

62
Q

A stroke in a woman’s left _____ causes severe loss of speaking ability because her left _____ is partially dominant.

A
  • Broca’s area

- Broca’s area

63
Q

Recovery from a stroke in the left Broca’s area requires teaching the right _____ to take over the task of programming spoken language.

A
  • Broca’s area
64
Q

Teaching a man’s _____ to control speech requires about 2 years; a woman’s _____ can learn in a year.

A
  • Right Broca’s area

- Right Broca’s area

65
Q

Brodmann area 8 is the _____, area 6 is the _____,

and area 4 is the _____.

A
  • Frontal eye field
  • Premotor cortex (area)
  • Primary motor cortex
66
Q

The primary motor cortex occupies the _____ gyrus.

A
  • Precentral
67
Q

The primary motor cortex gets instructions for skilled tasks directly from the _____ and indirectly from the _____ via the _____ of the _____.

A
  • Premotor cortex
  • Cerebellum
  • Ventrolateral nucleus
  • Thalamus
68
Q

Upper motor neurons are somatotopically arranged in the precentral gyrus from medial to lateral for muscles of the _____ through the _____.

A
  • Leg (or foot)

- Larynx

69
Q

The upper motor neuron axons are somatotopically arranged from anterior to posterior in the posterior limb of the internal capsule for muscles of the _____ through the _____.

A
  • Face

- Leg