Nuclei/Tract Cross-Sections: Images from Semmelweis Flashcards
Midbrain
1
What type of nucleus is this?
- Edinger-Westphal Nucleus - Accessory Oculomotor
General Visceromotor (parasympathetic, performs pupil constriction)
Midbrain
2
What neurotransmitter is produced here?
- Substantia Nigra
Dopamine
Midbrain
3
Which funiculus of the spinal cord contains this pathway?
- Rubrospinal Tract - see it coming from Red Nucleus and crossing
Runs through Lateral Funiculus (with the lateral corticospinal tract)
Midbrain
4
What sensation is it involved in?
What type of nucleus?
What is the morphology of this neuron (multipolar, unipolar etc?)
- Mesencephalic Trigeminal Nucleus
Proprioception of Head/Face
General Somatosensory
Pseudounipolar morphology
Midbrain
5
Where do the central branches go?
What is unique about this tract?
- Mesencephalic Trigeminal Tract
Central branches descend into pons, and the fibers synapse with the trigeminal motoneurons innervating the masticatory muscles
Forms the only monosynaptic reflex arc in the brainstem, creating the jaw jerk reflex when the jaw is extended
Midbrain
6
What cranial nerves are involved in this pathway?
Between what places does it travel?
- Medial Longitudinal Fasciculus (MLF)
Primarily involved in the directing eye movement via cranial nerves III, IV, VI, connecting them with the vestibular nucleus, also involving CN VIII for head movement information
Travels from the Interstitial Nucleus of Cajal to the cervical spinal cord
Midbrain
7
What type of information does it carry, and to where?
- Brachium of Inferior Collicle
Carries auditory information to the Medial Geniculate Body (MGB) of the thalamus
8
What type of information does it receive?
- Medial Geniculate Body (MGB) of (meta)thalamus
Not part of midbrain, but must have been drawn this way to show a connection between midbrain and thalamus
An intermediate connection in the auditory pathway, between inferior collicle and auditory cortex
Midbrain
9
What tract(s) originate here?
What tract(s) terminate here?
- Red Nucleus
Rubrospinal Tract (#3) originates from here and crosses in midbrain, then goes to affect lower motor neurons. Has limited function in humans, most of voluntary control is from corticospinal tract
Some branches called the rubro-olivary tract also go to the inferior olive (uncrossed pathway)
Dentatorubro tract terminates here; it comes from dentate nucleus of cerebellum
Midbrain
10
What type of information do these fibers carry?
Where do these fibers originate from?
Where do these fibers decussate?
Where do these fibers go?
- Medial Lemniscus
Carries epicritic information from the body
Contains the afferent fibers coming from gracile and cuneate nuclei (Dorsal Column)
Decussate in the medulla
Goes to Thalamus VPL, then to sensory cortex
Midbrain
11
Which part of the internal capsule does this pass through?
- Türck Tract (temporo-parieto-occipito-pontine)
Passes through posterior limb of internal capsule
Midbrain
12
Which part of the internal capsule does this travel through?
- Corticospinal Tract
Posterior Limb of internal capsule
Midbrain
13
Which limb of the internal capsule does this pass through?
- Arnold Tract (fronto-pontine)
Anterior limb of internal capsule
Midbrain
14
- Oculomotor Nerve (CN III)
Midbrain
15
- Tectospinal Tract (see the tract originating from tectum)
upper medula
1
what type of nucleus?
What nerve(s) have fibers with this nucleus in this section?
Solitary nucleus and Solitary tract
Special Viscerosensory Nucleus (taste)
Nerves IX and X have afferent fibers to the solitary nucleus here in the medulla
Nerve VII has a connection more superiorly!
upper medulla
2
what type of nucleus is it?
which cranial nerve(s) have fibers here?
2 dorsal vagal nucleus
aka medial ala cinera nucleus
General Visceromotor (parasympathetic)
Only Vagus
upper medulla
3
What type of nucleus is it?
- Hypoglossal nucleus
Somatomotor nucleus
upper medulla
4
4 medial longitudinal fasciculus
upper medulla
5
5 tectospinal tract
upper medulla
unlabelled black line between 5 and 6
What cranial nerve(s) have fibers here?
What type of nucleus?
unlabelled line btwn 5 and 6
lateral ala cinerea nucleus
Glossopharyngeus and Vagus have sensory fibers that go here
General Viscerosensory (GVS) - the only nucleus like this!
upper medulla
6
6 area postrema
upper medulla
7
which order neuron is this?
7 nucleus gracilis
second order neuron
upper medulla
8
8 nucleus cuneate
upper medulla
9
9 inferior vestibular nucleus
upper medulla
10
What type of nucleus is here?
What pathway does the tract take, and to where?
10 Tract and nucleus of spinal trigeminal
General Somatosensory for protopathic information about the head
Travels via the Trigeminal Lemniscus to the Thalamus VPM
upper medulla
11
is this path crossed?
11 Posterior spinocerebellar tract
uncrossed
upper medulla
12
12 olivocerebellar tract
upper medulla
13
what type of nucleus is this?
what cranial nerve(s) have fibers here?
13 Nucleus Ambiguus
Branchiomotor/SVM
cranial nerves IX, X, XI
upper medulla
14
With what type of fibers does the pathway originating from here end in the cerebellar cortex?
14 Inferior Olivary nucleus
Ends in Climbing Fibers (IO means inferior olive in image below)
upper medulla
15
15 olivocerebellar fibers
upper medulla
16
16 internal arcuate fibers as they approach the lemniscal decussation, after which they become the medial leminiscus
upper medulla
17
What type of fibers run through here?
With what type of neurons do they synapse when they terminate?
17 Pyramids
Corticospinal tract
Terminates with synapse to alpha motor neurons
upper medulla
18
18 internal arcuate fibers
upper medulla
19
19 hypoglossal nerve
upper medulla
20
20 lemniscal decussation
and olivocerebellar decussation
upper medulla
21
21 spinothalamic tract
upper medulla
22
22 ventral spinocerebellar tract (gowers)
upper medulla
23
where are these nerve(s) coming from?
23 glossopharyngeus and vagus nerve
coming from the nucleus ambiguus
upper medulla
24
where are these nerve(s) coming from?
24 glossopharyngeal and vagus nerves
coming from lateral ala cinerea
Caudal Medulla
1
What type of nucleus is this?
- Hypoglossal Nucleus
A Somatomotor nucleus (hypoglossal nerve)
Caudal Medulla
2
What type of nucleus is this?
From what cranial nerves does it receive information?
To where does it send information?
- Solitary Nucleus
Special Viscerosensory Nucleus (taste)
Receives afferent fibers from CN VII, IX and X
Sends information to Thalamus VPM
Caudal Medulla
3
Which neurons are these in sequence?
What neurons terminate here?
What neurons start here?
- Gracile Nucleus
Second order neurons.
Gracile Fasciculus terminates here,
Internal arcuate fibers start here, then cross and become medial lemniscus.
Caudal Medulla
4
What type of information is carried here?
Where is it carried to?
- Cuneate Nucleus
Epicritic information from the cervical nerves (upper body)
Goes to Thalamus VPL via the medial lemniscus
Caudal Medulla
5
- Spinal Trigeminal Tract
Caudal Medulla
6
What is this type of nucleus?
What is the continuation of the nucleus when it goes inferiorly?
- Spinal Trigeminal Nucleus
General Somatosensory (GSS)
In the spinal cord, it becomes the Substantia Gelatinosa
(Rexed Lamina 2)
Caudal Medulla
7
What order are these neurons?
- Internal Arcuate Fibers
2nd order neurons
Caudal Medulla
8
Where does this pathway end?
What type of information does it carry?
Which neuron is it in sequence?
- Spinothalamic Tract
Ends at Thalamus VPL
Transmits protopathic sensation (pain, temperature, crude touch) for the body
2nd neuron in sequence
Caudal Medulla
9
What nerves does it join with?
- Nucleus Ambiguus
IX, X, XI nerves
Caudal Medulla
10
- Inferior Olivary Nucleus
Caudal Medulla
11
- Pyramidal Decussation
Caudal Medulla
12
- Decussation of Medial Lemniscus
Pons
1
- Superior Cerebellar Peduncle
2 & 11, what is this pathway?
Which peduncle does it travel through?
2 (and 11). Pontocerebellar Tract
Travels through middle cerebellar peduncle
3 (medial to the structure in #5)
What type of nucleus is this?
- Motor Trigeminal Nucleus
Branchiomotor / Special Visceromotor
4
Which information does this carry?
What type of fibers does this path end in?
Does it cross?
- Ventral Spinocerebellar Tract (Gowers)
Carries proprioceptive sensibility
Ends in mossy fibers
It crosses twice (once in the anterior commissure, once in the cerebellum) and so the cerebellum still receives information from the same side of body
5
hard to see, but it’s the one that’s lateral to #3 and covered by a giant arrow on that side of the picture
What type of information is carried?
Where does this nucleus send its fibers, and via what pathway?
Crossed or uncrossed?
- Chief Sensory Trigeminal Nucleus (Pontine/Principal)
Sends epicritic information from the head to the Thalamus VPM
via the Dorsal Trigeminal Lemniscus
(don’t confuse with the just Trigeminal Lemniscus!)
Crossed pathway
6
- Brachium Pontis
7
- Trigeminal Nerve (see its connections with the trigeminal nuclei)
8
- Medial Lemniscus
9: Which two types of tracts are seen?
Which part of the pons contains these fibers?
- Corticospinal tracts & Corticopontine tracts
Corticospinal tracts keep going through pons,
Corticopontine tracts synapse here with the pontine nuclei
Within the basis of the pons
10
- Pontine Nuclei, whose fibers go on to the pontocerebellar tract
12
- Spinothalamic Tract
13
Where do these fibers travel to?
- Lateral Lemniscus
Fibers go to Inferior Collicle
14
What type of neurotransmitter is produced here?
- Locus Ceruleus
Norepinephrine produced here (involved in stress)
15
what is the origin of these fibers?
where do these fibers end?
- Central Tegmental Fascicle / Tract
Comes from Red Nucleus
Goes to Inferior Olive
16
- Tectospinal Tract
17
- Medial Longitudinal Fascicle
Spinal Cord
1
- Lissauer Tract
2
- Posterior Spinocerebellar Tract
3
What system is this a part of?
- Cruciate (posterior) Corticospinal Tract
Part of pyramidal system
4
- Rubrospinal Tract
5
- Anterior Spinocerebellar Tract
6
- Spinothalamic Tract
(here shown as one, but normally there is an anterior and lateral branch of the spinothalamic tract within the spinal cord)
7
- Vestibulospinal Tract
8
- Tectospinal Tract
9
- Direct (anterior) Corticospinal Tract
10
- Medial Longitudinal Fasciculus
11: numbered twice to show it curving around
- Reticulospinal tract
12
- Olivospinal tract
(not even confirmed to exist in humans, thanks anatomy department)
13: What 2 tracts run through here?
Where are the perikarya of these fibers?
What is this whole region of white matter called?
- Gracile and Cuneate Fasciculus
Perikarya in the Dorsal Root Ganglion
Called Dorsal Column
