Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuroscience and NeuroAnatomy > 25 - NeuroAnatomy - Motor Pathways > Flashcards

25 - NeuroAnatomy - Motor Pathways Flashcards

1
Q

Which two structures regulate descending cortical and descending brainstem pathways?

A

Cerebellum

Basal Ganglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Cerebellum - In charge of what?

A

Controls pining and the patterns of muscles activated with eye movements, head movements, limb movements, body movements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Basal Ganglia - In charge of what?

A

Selection and initiation of specific motor programs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Cortical Motor Areas

A

Project to brainstem and spinal cord.

Important for skilled movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Brainstem

A

Important for posture, eye movements, eating, breathing, “that kind of thing”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the clinical consequences of the combined hierarchical and parallel organization of the motor pathways?

A

Alternate pathways for producing movement.

After a stroke, there are some back-up pathways that can contribute to partial functional recovery.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Three Primary Cortical Motor Pathways

A

Lateral Corticospinal Tract
Ventral Corticospinal Tract
Corticobulbar Tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Lateral Corticospinal Tract

A

Major component of the lateral pathway

Skilled limb movements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Ventral Corticospinal Tract

A

Major component of the medial pathway

Axial muscle control (the 10% of the fibers in the pyramids that don’t cross)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Corticobulbar Tract

A

Brainstem equivalent of Lateral & Ventral Corticospinal Tracts
Controls primarily cranial nuclei, facial muscles, jaw muscles, and muscles for swallowing & speaking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Four Brainstem Motor Pathways

A

Rubrospinal Tract
Tectospinal Tract
Reticulospinal Tract
Vestibulospinal Tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Rubrospinal Tract

A

Minor component of the Lateral Descending Pathway

Originates from Red Nucleus, involved in limb control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Tectospinal Tract

A

Medial Descending Pathway
Originates from Superior Colliculus
Head-eye coordination during gaze

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Reticulospinal Tract

A

Medial Descending Pathway

Automatic movements and posture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Vestibulospinal Tracts

A

Medial Descending Pathway

For posture and balance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Areas in which lobe are the primary source of descending cortical pathways?

A

Frontal Lobe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

From which cortical layer (and in which areas) do the three primary cortical motor pathways arise?

A

Projection Neurons (Layer V + a little bit of IV) in the following areas:
Primary Motor Cortex
Premotor Cortex
Supplementary Motor Cortex/Area (SMA, SMA medial surface)
Cingulate Motor Area (CMA, medial surface)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Primary Motor Cortex

A

Brodmann’s Area 4
Precentral Gyrus
Execution of Movements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Lesions in the Primary Motor Cortex produce

A

Weakness
Paralysis
Incoordination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Premotor Region

A

Brodmann’s Area 6
Contains Supplementary motor Area (SMA)
Planning of complex sequences of movements involving coordination of both limbs, especially the distal extremity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where within Brodmann’s Area 6 (Premotor Region) is the Supplementary Motor Area (SMA) located?

A

Dorsomedial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where within Brodmann’s Area 6 (Premotor Region) is the Premotor Cortex located?

A

Lateral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Premotor Cortex

A

The lateral portion of the Premotor Region (Brodmann’s Area 6)
Receives input from the “Where” pathways of both vision and auditory systems
Directs limb movements to targets of interest (reaching for thangs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Cingulate Motor Area (CMA)

A

Brodmann’s Area 31
Within cingulate sulcus and on cingulate gyrus
Receives input from areas involved in cognitive and emotional functions
May participate in emotionally-driven motor behaviors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Where do projections from the Primary Motor Cortex descend?

A

Through the Genu and Posterior Limb of the Internal Capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Where do projections from the SMA, CMA and Premotor Cortex descend?

A

Through the Anterior Limb of the Internal Capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Which is more important? Projections from the Primary Motor Cortex, or projections from the SMA, CMA and Premotor Cortex?

A

Primary Motor Cortex!
Damage to the Genu and Posterior Limb of the Internal Capsule can produce paralysis. Damage to the Anterior Limb does not!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Internal Capsule - From Genu through Posterior Limb, what is the somatotopic organization of descending motor fibers?

A

Face (Genu)
Arm
Trunk
Leg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

After the decussation of the pyramids, where are 90% of the descending motor fibers? This refers to the 90% that crossed over.

A

In the Lateral Pathways (the lateral column of the white matter in the spinal cord)

30
Q

What’s contained in the lateral column of the white matter of the spinal cord?

A

Lateral Corticospinal Tract

Rubrospinal Tract

31
Q

Which lateral descending systems go to the limbs, especially the hands and the feet?

A

Lateral Corticospinal Tract

Rubrospinal Tract

32
Q

Where do the Lateral Corticospinal Tract and the Rubrospinal tract project within the spinal cord?

A

Lateral Column on the ventral horn

Lateral aspects of the intermediate layer interneurons

33
Q

After the decussation of the pyramids, where are 10% of the descending motor fibers? This refers to the 10% that did not cross over.

A

They stay in the midline

In the Medial Pathway (the Ventral Corticospinal Tract)

34
Q

Where do Medial Descending Tract fibers project?

A

Medial Motor Neurons
Interneurons in the medial part of the intermediate zone
Most important: BILATERAL projections!!!!

35
Q

Which medial descending systems go to the axial and girdle musculature?

A

Ventral Corticospinal Tract

36
Q

Where does the Lateral Corticospinal Tract originate?

A 
Brodmann's Area 4 (Primary Motor)
Brodmann's Area 6 (Premotor Cortex)
Brodmann's Area 3 (Somatosensory)
Brodmann's Area 1 (Somatosensory)
Brodmann's Area 2 (Somatosensory)
37
Q

Lateral Descending Pathways

A

Lateral Corticospinal Tract

Rubrospinal Tract

38
Q

Where does the Lateral Corticospinal Tract decussate?

A

At the motor decussation (Spinal Cord)

39
Q

Where does the Rubrospinal Tract originate?

A

Magnocellular (caudal) part of the Red Nucleus

40
Q

Where does the Rubrospinal Tract Decussate?

A 
Red Nucleus (right at the start!!)
Decussation occurs at the Ventral Tegmental Area of the Midbrain
41
Q

Caudal part of the Red Nucleus

A

Magnocellular Part

Gives rise to the Rubrospinal Tract

42
Q

Medial Descending Pathways

A

Ventral Corticospinal Tract
Vestibulospinal Tract
Reticulospinal Tract

43
Q

Where does the Ventral Corticospinal Tract decussate?

A

Spinal Cord

44
Q

Purpose of Vestibulospinal and Reticulospinal Tracts

A

Automatic movements, some specific eye movements

45
Q

Lateral Pathways - Summary

A

Lateral Corticospinal Tract
Rubrospinal Tract
Limb motor neurons - Lateral ventral horn
Descending control - Lateral column of white matter
Crossed - Have consequences on movement by contralateral side of the body.
Lesions (even small ones) have profound effects

46
Q

Medial Pathways - Summary

A

Ventral Corticospinal Tract
Lateral Vestibulospinal Tract
Axial and proximal motor neurons - Medial Ventral Horn
Descending control - Medial Ventral column of white matter
Bilateral
Lesions have a less severe effect

47
Q

Corticospinal Tract - Origins

A

Originates from Arm, Trunk. Leg

48
Q

Corticobulbar Tract - Origins

A

Originates from Facial Area

49
Q

Corticobulbar Tract

A

Cranial Nerve Equivalent of Corticospinal Tract
Descending projections from the cortex (Face)
Genu of Internal Capsule
Cranial Nerve Nuclei of Pons and Rostral Medulla
These are the nuclei innervate striated muscle (except extraocular motor nuclei) - V, VII, Nucleus Ambiguus (projects to IX, X, XI), XI, XII

50
Q

Nucleus Ambiguus

A

Projects to Cranial Nerves IX, X, XI

51
Q

Corticobulbar System - Bilateral Control

A 
Jaw (V)
Larynx, Pharynx (Nucleus Ambiguus: IX, X, XI)
Tongue (XII)
Upper Facial Muscles (VII)
This control is bilateral and redundant
52
Q

Corticobulbar System - Contralateral Control

A

Lower Facial Muscles (VII)

53
Q

What do you see in a stroke affecting the Corticobulbar System?

A

No change to upper face, but lower face weakness/paralysis on the contralateral side

54
Q

Cortex to Trigeminal Motor Nucleus Path

A

Internal Capsule
Basis Pedunculi
Corticobulbar Portions of the Pons
Bilateral Projections to Trigeminal Motor Nucleus

55
Q

What is the most common cause of lesions in the posterior limb of the internal capsule?

A

Thrombosis or hemorrhage:
Anterior Choroidal Artery
Middle Cerebral Artery (above the level of the anterior commissure)

56
Q

What provides the blood supply for the Genu of the Internal Capsule?

A

Internal Carotid Artery

Branch of Heubner (off the ACA)

57
Q

Capsular infarcts commonly lead to

A

Total Hemiparesis (including lower face)

58
Q

Why is the upper face spared during a capsular infarct?

A

Redundancy!
Upper facial motor neurons are somewhat bilateral. They also receive strong projections from other areas besides the Primary Motor Cortex (The Cingulate Motor Area, for example). These other areas typically descend in the anterior limb (unaffected by most internal capsule strokes).

59
Q

Typical internal capsule stroke affects which parts?

A

Genu & Posterior Limb

60
Q

Ventral Anterior / Ventral Lateral Nuclear Complex

A

Thalamic Motor Nuclei
Receives projections from both cerebellum and basal ganglion
Projects to Premotor and Primary Motor Cortex

61
Q

From which structures does the Ventral Anterior / Ventral Lateral Nuclear Complex (Thalamic Motor Nuclei) receive its input?

A

Cerebellum

Basal Ganglia

62
Q

Where does the Ventral Anterior / Ventral Lateral Nuclear Complex (Thalamic Motor Nuclei) project out to?

A

Premotor Cortex

Primary Motor Cortex

63
Q

Basal Ganglion projects to

A

Ventral Anterior Nuclear Complex

64
Q

Cerebellum projects to

A

Ventral Lateral Nuclear Complex

65
Q

In the Basis Pedunculi, where do the fibers from the Genu and Posterior Limb of the Internal Capsule travel?

A

Middle 1/3

66
Q

Medial-to-Lateral, what order do we see the fibers within the basis pedunculi?

A

Face
Arm
Trunk
Limb

67
Q

Where does the Tectospinal Tract originate?

A

Superior Colliculus

68
Q

What does the Tectospinal Tract control?

A

Movement of the head and the eyes with conjugated gays

69
Q

Course of the Facial Motor Nucleus & Nerve

A

Fibers run dorsal and medial, then at the Genu, curve around and on top of the Abducens Nucleus at the area forming the Facial Colliculus

70
Q

Facial Colliculus

A

The bump on the anterior wall of the 4th Ventricle caused by the Genu Facial Nerve curving around and over the Abducens Nucleus.

71
Q

Input to Facial Motor Nucleus

A

Descending corticobulbar fibers
Bilateral for upper face
Unilateral for lower face

Neuroscience and NeuroAnatomy (41 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions