Chapter 38: Basal Motor Nuclei Flashcards Preview

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Flashcards in Chapter 38: Basal Motor Nuclei Deck (114)
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1
Q

The medial globus pallidus is lateral and inferior to the ventral anterior nucleus of the _____ to which it projects.

A
  • Thalamus
2
Q

The medial globus pallidus is lateral to the anterior end of the _____.

A
  • Thalamus
3
Q

Axons from the medial globus pallidus release GABA in the _____ of the thalamus to inhibit it and prevent the initiation of unwanted motor activity.

A
  • Ventral anterior nucleus
4
Q

The projections of the _____ to the ventral anterior nucleus of the thalamus are essential for the prevention of unwanted motor activity.

A
  • Medial globus pallidus
5
Q

The projections of the medial globus pallidus to the _____ of the _____ must cross or circumvent the white matter of the internal capsule that separates them.

A
  • Ventral anterior nucleus

- Thalamus

6
Q

The internal capsule that separates the medial globus pallidus from the ventral anterior nucleus of the thalamus is _____ matter.

A
  • White
7
Q

The projection tract of the medial globus pallidus that crosses the _____ to reach the ventral anterior nucleus of the thalamus is the fasciculus lenticularis.

A
  • Internal capsule
8
Q

The fasciculus lenticularis contains the axons of neurons in the _____.

A
  • Medial globus pallidus
9
Q

The _____ crosses the internal capsule to reach the ventral anterior nucleus of the thalamus.

A
  • Fasciculus lenticularis
10
Q

The projection tract of the medial globus pallidus that circumvents the _____ to reach the ventral anterior nucleus of the thalamus is the ansa lenticularis.

A
  • Internal capsule
11
Q

The _____ goes around behind the internal capsule to reach the ventral anterior nucleus of the thalamus.

A
  • Ansa lenticularis
12
Q

The projection tracts of the medial globus pallidus are the _____, which goes through the internal capsule, and the _____, which goes behind the internal capsule.

A
  • Fasciculus lenticularis

- Ansa lenticularis

13
Q

The fascicularis lenticularis and the ansa lenticularis join to form the fasciculus thalamicus before they enter the _____ of the _____.

A
  • Anterior nucleus

- Thalamus

14
Q

The projections of the medial globus pallidus meet and form the _____ before entering the ventral anterior nucleus of the thalamus.

A
  • Fasciculus talamicus
15
Q

The fasciculus lenticularis and the ansa lenticularis join on the medial side of the internal capsule to form the _____.

A
  • Fasciculus thalamicus
16
Q

The lateral globus pallidus is lateral to the _____, and the putamen is lateral to the lateral globus pallidus.

A
  • Medial globus pallidus
17
Q

The axons of many neurons in the putamen pass through the _____ to reach the medial globus pallidus.

A
  • Lateral globus pallidus
18
Q

Many GABAergic neurons in the putamen send their axons through the lateral globus pallidus to inhibit neurons in the _____.

A
  • Medial globus pallidus
19
Q

Inhibition of the medial globus pallidus by some of the GABAergic neurons in the _____ prevents excessive inhibition of the ventral anterior nucleus of the thalamus.

A
  • Putamrn
20
Q

The neurons in the _____ that inhibit the medial globus pallidus are called direct circuit neurons.

A
  • Putamen
21
Q

The circuit inhibiting the medial globus pallidus so that it will not inhibit the _____ of the _____, thus allowing the _____ to stimulate the premotor cortex (Brodmann area 6), is called the direct basal motor circuit.

A
  • Ventral anterior nucleus
  • Thalamus
  • Ventral anterior nucleus
22
Q

Direct circuit neurons in the _____ release GABA in the medial globus pallidus, thus preventing the medial globus pallidus from inhibiting the _____ of the _____.

A
  • Putamen
  • Ventral anterior nucleus
  • Thalamus
23
Q

When it is not inhibited by the _____ the ventral anterior nucleus of the thalamus stimulates the premotor cortex by releasing glutamate at synapses.

A
  • Medial globus palliduc
24
Q

The net effect of direct basal motor circuit activity is stimulation of the _____.

A
  • Premotor cortex
25
Q

The direct basal motor circuit is active when direct circuit neurons in the _____ are stimulated by dopaminergic neurons in the substantia nigra.

A
  • Putamen
26
Q

Dopaminergic neurons in the _____ release dopamine at synapses in the putamen.

A
  • Substantia nigra
27
Q

The direct circuit neurons have D1 receptors, which are _____ dopamine receptors.

A
  • Stimulatory
28
Q

The activity of the direct basal motor circuit is maintained by _____ neurons in the _____.

A
  • Dopaminergic

- Substantia nigra

29
Q

The direct circuit neurons have stimulatory receptors for both _____ and glutamate.

A
  • Dopamine
30
Q

The direct circuit neurons are stimulated by dopamine from the _____ and glutamate from the motor area (Brodmann area 4) and premotor area (Brodmann area 6) of the cerebral cortex.

A
  • Substantia nigra
31
Q

The motor and premotor areas of the cerebral cortex activate the direct basal motor circuit by releasing _____ on direct circuit neurons in the _____.

A
  • Glutamate

- Putamen

32
Q

The direct circuit inhibits the _____ so that it will not inhibit the _____ of the _____.

A
  • Medial globus pallidus
  • Ventral anterior nucleus
  • Thalamus
33
Q

Since the ventral anterior nucleus of the thalamus stimulates the _____, the direct basal motor circuit allows the _____ to stimulate itself and initiate an action.

A
  • Premotor cortex

- Premotor cortex

34
Q

The medial globus pallidus belongs to both the _____ and the indirect basal motor circuit.

A
  • Direct basal motor circuit
35
Q

The indirect basal motor circuit goes from the putamen to the lateral globus pallidus to the subthalamic nucleus to the _____ to the ventral anterior nucleus of the thalamus.

A
  • Medial globus pallidus
36
Q

The subthalamic nucleus is inferior to the _____ and medial to the medial globus pallidus to which it projects.

A
  • Thalamus
37
Q

The medial globus pallidus receives important projections from the _____ but not directly from the lateral globus pallidus.

A
  • Subthalamic nucleus
38
Q

The lateral globus pallidus projects to the subthalamic nucleus which projects to the _____.

A
  • Medial globus pallidus
39
Q

Axons from the subthalamic nucleus release glutamate in the _____ to stimulate its activity.

A
  • Medial globus pallidus
40
Q

Inhibition of the subthalamic nucleus by the lateral globus pallidus prevents it from overstimulating the _____.

A
  • Medial globus pallidus
41
Q

Axons from the lateral globus pallidus release GABA in the _____ to prevent it from overstimulating the medial globus pallidus.

A
  • Subthalamic nucleus
42
Q

Inhibition of the subthalamic nucleus by the _____ is necessary to prevent almost complete shutdown of the voluntary motor system.

A
  • Lateral globus pallidus
43
Q

Indirect circuit neurons in the putamen inhibit the lateral globus pallidus so that the _____ can be just active enough to prevent unwanted movement.

A
  • Subthalamic nucleus
44
Q

The lateral globus pallidus is attached to the lateral side of the _____, and the putamen is attached to the lateral side of the lateral globus pallidus to form the lenticular nucleus.

A
  • Medial globus pallidus
45
Q

The medial globus pallidus, lateral globus pallidus, and putamen comprise the _____.

A
  • Lenticular nucleus
46
Q

The direct basal motor circuit stays within the _____ nucleus, but the indirect basal motor circuit makes a detour through the _____ nucleus.

A
  • Lenticular

- Subthalamic

47
Q

The indirect circuit neurons in the putamen release GABA in the _____ to _____ it.

A
  • Lateral globus pallidus
48
Q

Inhibition of the lateral globus pallidus prevents inhibition of the _____.

A
  • Subthalamic nucleus
49
Q

An uninhibited subthalamic nucleus _____ the medial globus pallidus.

A
  • Stimulates
50
Q

Stimulation of the medial globus pallidus causes it to inhibit the _____.

A
  • Ventral anterior nucleus
51
Q

The net effect of indirect basal motor circuit activity is _____ of the initiation of movement.

A
  • Inhibition
52
Q

To recapitulate: The direct basal motor circuit goes through the putamen, _____, and the ventral anterior nucleus.

A
  • Medial globus pallidus
53
Q

The indirect basal motor circuit _____ the initiation of movement.

A
  • Inhibits
54
Q

The indirect basal motor circuit goes through the putamen, _____, _____, _____, and the ventral anterior nucleus.

A
  • Lateral globus pallidus
  • Subthalamic nucleus
  • Medial globus pallidus
55
Q

The direct basal motor circuit _____ the initiation of movement.

A
  • Facilitation (stimulation)
56
Q

The projection of the medial globus pallidus to the _____ is split into the fasciculus lenticularis which runs mediad in the coronal plane and the ansa lenticularis that loops around in the axial plane posterior to the globus pallidus and putamen.

A
  • Ventral anterior nucleus
57
Q

The _____ can be seen in a coronal section but the _____ cannot be seen.

A
  • Fasciculus lenticularis

- Ansa lenticularis

58
Q

The fasciculus lenticularis and ansa lenticularis join just above the medial end of the subthalamic nucleus to form the fasciculus thalamicus which runs laterad in the coronal plane before turning mediad to enter the _____ of the _____.

A
  • Vental anterior nucleus

- Thalamus

59
Q

The fasciculus lenticularis crosses the white matter that separates the lenticular nucleus from the _____.

A
  • Thalamus
60
Q

The white matter separating the _____ from the thalamus is called the internal capsule of the lenticular nucleus, usually shortened to “internal capsule”.

A
  • Lenticular nucleus
61
Q

The corticospinal tract is called the posterior limb of the internal capsule where it passes between the _____ and the _____.

A
  • Thalamus

- Lenticular nucleus

62
Q

The activity of the indirect basal motor circuit is reduced when indirect circuit neurons in the _____ are inhibited by dopaminergic neurons in the substantia nigra.

A
  • Putamen
63
Q

The indirect circuit neurons in the putamen have D2 receptors, which are _____ dopamine receptors.

A
  • Inhibitory
64
Q

The activity of the indirect basal motor circuit is reduced by _____ neurons in the _____.

A
  • Dopaminergic

- Substantia nigra

65
Q

Since the indirect basal motor circuit _____ movement, the net effect of the release of dopamine on the indirect circuit neurons in the putamen is to _____ movement.

A
  • Inhibits

- Facilitate

66
Q

D1 receptors are _____, and D2 receptors are inhibitory.

A
  • Stiumlatory
67
Q

Because the direct circuit neurons in the putamen have _____ receptors and indirect circuit neurons have _____ receptors, activity of the substantia nigra facilitates movement through both circuits.

A
  • D1

- D2

68
Q

The net effect of dopamine on the basal motor nuclei is to _____ movement.

A
  • Facilitate
69
Q

Input to the putamen from the _____ and the _____ facilitates motor activity.

A
  • Substantia nigra

- Premotor cortex

70
Q

Neurons with _____ dopamine receptors are often called D1 neurons, and neurons with _____ dopamine receptors are often called D2 neurons.

A
  • Stimulatory

- Inhibitory

71
Q

Although direct circuit neurons have stimulatory _____ receptors, they have inhibitory acetylcholine receptors.

A
  • Dopamine
72
Q

Indirect circuit neurons have inhibitory _____ receptors and stimulatory acetylcholine receptors.

A
  • Dopamine
73
Q

Cholinergic neurons in the putamen _____ the direct circuit which _____ movement.

A
  • Inhibit

- Facilitates

74
Q

Cholinergic neurons in the putamen _____ the indirect circuit which _____ movement.

A
  • Stimulate

- Inhibits

75
Q

The net effect of acetylcholine on the basal motor nuclei is to _____ movement.

A
  • Inhibit
76
Q

The putamen, globus pallidus, and subthalamic nucleus, and also the caudate nucleus are collectively called the _____ nuclei.

A
  • Basal motor
77
Q

Because the medial globus pallidus projects to the _____ ventral anterior nucleus, the lenticular nucleus (putamen and globus pallidus) initiates movement on the _____ side of the body.

A
  • Ipsilateral

- Contralateral

78
Q

The putamen and lateral globus pallidus are fed by one or more lenticulostriate arteries that leave the _____ inside the lateral fissure.

A
  • Middle cerebral artery
79
Q

The lenticular nucleus gets most of its blood supply from the _____ arteries, but the medial globus pallidus gets its blood supply from the anterior choroidal branch of the internal carotid.

A
  • Lenticulostriate
80
Q

The putamen and lateral globus pallidus get their blood supply from _____ branches of the _____.

A
  • Lenticulostriate

- Middle cerebral artery

81
Q

Occlusion of a _____ usually produces unilateral difficulty in initiating movement on the contralateral side (“unilateral Parkinsonism”).

A
  • Lenticulostriate
82
Q

Occlusion of a _____ produces unilateral difficulty in initiating movement because the unaffected _____ continues to inhibit the ventral anterior nucleus.

A
  • Lenticulostriate

- Medial globus pallidus

83
Q

The subthalamic nucleus, like the anterior half of the thalamus superior to it, gets its blood supply from the _____ artery.

A
  • Thalamoperforating
84
Q

The subthalamic nucleus and the anterior half of the thalamus get their blood supply from the _____ branch of the _____ division of the _____.

A
  • Thalamoperforating
  • P1
  • Posterior cerebral artery
85
Q

The caudate nucleus is a circle of _____ matter in the parasagittal plane around the putamen.

A
  • Gray
86
Q

The caudate nucleus has a large head anterior to the putamen, a tapering body superior to the putamen, and a small tail _____ and _____ to the putamen.

A
  • Posterior

- Inferior

87
Q

There is a break in the circle of the caudate nucleus where the anterior end of the _____ fails to touch the inferior end of the _____.

A
  • Tail

- Head

88
Q

The putamen and caudate nucleus are connected by many small stria of gray matter to form the striatum, a functional unit that regulates the _____ of simple and complex _____.

A
  • Initiation

- Movements

89
Q

The gray striae (stripes) that connect them give the putamen and caudate the collective name of the _____.

A
  • Striatum
90
Q

The principal role of the striatum is the _____ of movement.

A
  • Facilitation
91
Q

The head of the left caudate nucleus _____ activity in the _____ that create the sounds of speech.

A
  • Facilitates

- Muscles

92
Q

Infarction of the head of the _____ caudate nucleus causes poor pronunciation and erratic speech volume.

A
  • Left
93
Q

The head of the caudate nucleus gets its blood supply from the recurrent artery of Heubner (a.k.a. medial striate artery) which is branch of the A2 division of the _____.

A
  • Anterior cerebral artery
94
Q

The head of the caudate nucleus, which is part of the striatum, gets its blood supply from the _____ which is a branch of the _____.

A
  • Medial striate artery

- Anterior cerebral artery

95
Q

A stroke in the left recurrent artery or the anterior cerebral artery will severely affect _____ and _____ of _____.

A
  • Pronunciation
  • Volume
  • Speech
96
Q

The _____ of the _____ nucleus initiates production of the sounds of speech, but the head of the right caudate nucleus initiates actions that are conditional on a signal.

A
  • Head

- Left caudate

97
Q

Stopping or starting an action on an anticipated command is assisted by the _____ of the _____.

A
  • Head

- Right caudate nucleus

98
Q

The direct basal motor circuit in the caudate nucleus, like the direct basal motor circuit in the putamen is activated by _____ neurons in the substantia nigra and _____ neurons in the cerebral cortex.

A
  • Dopaminergic

- Glutaminergic

99
Q

The direct basal motor circuit in the head of the caudate nucleus is activated by _____ neurons in the ipsilateral executive area (Brodmann’s area 9) of the prefrontal cerebral cortex.

A
  • Glutaminergic
100
Q

Activation of the direct basal motor circuit neurons in the putamen depends more on the _____ and _____ areas of the _____ than on the executive area.

A
  • Motor
  • Premotor
  • Cerebral cortex
101
Q

Activation of the direct basal motor circuit neurons in the head of the caudate nucleus depends more on the _____ area of the ipsilateral cerebral cortex than on the motor and premotor areas.

A
  • Executive

- Ipsilateral

102
Q

The putamen, caudate nucleus, globus pallidus, and subthalamic nucleus are collectively the_____ nuclei.

A
  • Basal motor
103
Q

The term “basal nuclei” is usually just short for _____ but it is sometimes intended to include the amygdala, which is functionally a part of the _____ system.

A
  • Basal motor nuclei

- Limbic

104
Q

From medial to lateral, the 3 parts of the lenticular nucleus are: _____, _____, and _____.

A
  • Medial globus pallidus
  • Lateral globus pallidus
  • Putamen
105
Q

The lenticular nucleus is separated from the caudate nucleus and the thalamus by the _____.

A
  • Internal capsule
106
Q

A few neurons in the putamen release _____ which has the opposite effect of dopamine on other neurons in the putamen.

A
  • Acetylcholine
107
Q

Except for the cholinergic neurons in the putamen, all neurons in the lenticular nucleus release _____ at synapses and _____ their target neurons.

A
  • GABA

- Inhibit

108
Q

Neurons in the subthalamic nucleus and the ventral anterior nucleus of the thalamus release _____ at synapses to _____ their target neurons.

A
  • Glutamate

- Stimulate

109
Q

The medial globus pallidus _____ the _____ nucleus of the _____ which stimulates the premotor cortex.

A
  • Inhibits
  • Ventral anterior
  • Thalamus
110
Q

The medial globus pallidus inhibits the _____ nucleus of the _____ only if it is stimulated by the _____.

A
  • Ventral anterior
  • Thalamus
  • Subthalamic nucleus
111
Q

The _____ stimulates the medial globus pallidus unless it is inhibited by the lateral globus pallidus.

A
  • Subthalamic nucleus
112
Q

The lateral globus pallidus inhibits the _____ unless it is inhibited by _____ neurons in the putamen.

A
  • Subthalamic nucleus

- D2

113
Q

_____ neurons in the putamen inhibit the lateral globus pallidus unless they are inhibited by dopamine released by axon endings of neurons in the _____.

A
  • D2
114
Q

The _____ of the _____ facilitates the production of speech.

A
  • Head

- Left caudate nucleus