Mini-atlas of the Marmoset Brain

http://marmoset-brain.org

Aya SenooTokyo University of Agriculture and Technology

Hironobu TokunoTokyo Metropolitan Institute of Medical Science

Charles WatsonCurtin University

Version 1.3Dec 8, 2014

All rights reserved

2

CEREBRAL CORTEX

CEREBELLUM

visual cortex

pyramidaldecussation

12N

solitarynucleus

sensorytrigeminal

occipital lobe

RHOMBENCEPHALON

deep cerebellarnuclei

4V

3

Level P 4.0

The hindbrain at the level of the pyramidal decussation This section shows the caudal end of the hindbrain, just before it joins the spinal cord. The hindbrain consists

of the rhombencephalon and a small segment called the isthmus which joins the rhombencephalon to the

mesencephalon. The cerebellum is also part of the hindbrain, because it grows out of the rhombencephalon and

the isthum. The cerebellum lies between the rhombencephalon and the occipital pole of the cerebrum. In the

center of the hindbrain is the prominent crossing of the pyramidal tract (pyramidal decussation). The fibers in

the pyramidal tract arise in the cerebral cortex and at this level they cross the midline to reach the opposite side

of the spinal cord. The large trigeminal nuclei, which receive touch, pain, and temperature sensations from the

face, are found in the lateral part of the hindbrain. This part of the trigeminal sensory complex is called the spinal

trigeminal nucleus because it extends into the cervical spinal cord. Most of the remainder of the green area in

this section is occupied by the reticular nuclei, which extend the whole length of the hindbrain. The large solitary

nucleus lies in the floor of the fourth ventricle (4V). It receives taste and other visceral sensations from the head and

internal organs of the thorax and abdomen. Just below is the hypoglossal nucleus (12N) that sends motor fibers

to the tongue. The ventricular system is represented here by the caudal end of the fourth ventricle. Cerebrospinal

fluid (CSF) can escape from the ventricular system via small holes in the roof of the fourth ventricle to reach the

subarachnoid space.

The cerebellum, which is very large in monkeys and other primates, lies dorsal to the fourth ventricle. In

developmental terms, the cerebellum grows out from the roof of the hindbrain. It consists of an outer layer of

cerebellar cortex and a core of white matter (fibers). The deep cerebellar nuclei are embedded in the white matter

of the cerebellum.

The occipital pole of the cerebrum sits above the cerebellum. The primary visual cortex lies on the medial side of

the occipital pole.

4

vestibularnuclei

CEREBRAL CORTEX

CEREBELLUM

visual cortex

pyramidal tract

inferior olive

icp

deep cerebellarnuclei

sp5sensory

trigeminal

4V

RHOMBENCEPHALON

cochlearnuclei

occipital lobe

5

Level P2.5

The hindbrain at the level of the vestibular and cochlear nuclei

This section shows the hindbrain (rhombencephalon) below and the cerebellum and cerebrum above. The large

trigeminal nuclei are found in the lateral part of the hindbrain. The large vestibular nuclei lie in the floor of the

fourth ventricle (4V) and the cochlear (auditory) nuclei are lateral to the vestibular nuclei. The inferior cerebellar

peduncle (icp) lies between the vestibular and cochlear nuclei. It contains fibers that travel from the spinal cord

and inferior olive to the cerebellum. Below the vestibular nuclei is the sensory trigeminal nucleus. This part of

trigeminal sensory complex is called the spinal trigeminal nucleus and the trigeminal nerve fibers lateral to it are

called the spinal trigeminal tract (sp5). A large fiber bundle, the pyramidal tract, lies on either side of the midline on

the ventral margin of the hindbrain. The fibers in the pyramidal tracts arise in the cerebral cortex and travel down

to cross to the opposite side of the spinal cord. Above each pyramidal tract is the inferior olive, which is functionally

connected with the cerebellum of the opposite side. Most of the remainder of the green area of the hindbrain

in this section is occupied by the reticular nuclei, which extend for the whole length of the hindbrain. The fourth

ventricle contains cerebrospinal fluid (CSF), which has flowed down from its origin in the lateral (cerebral) ventricles

through the third ventricle and aqueduct to reach the hindbrain.

The cerebellum is concerned with coordination of movement. It consists of an outer layer of cerebellar cortex and a

core of white matter (fibers). The deep cerebellar nuclei are embedded in the white matter of the cerebellum. The

deep cerebellar nuclei receive input from the cerebellar cortex and send fibers to the brainstem and thalamus.

The occipital pole of the cerebrum sits above the cerebellum. The primary visual cortex lies on the medial side of

the occipital lobe.

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pyramidal tract

sp5Amb

sensorytrigeminal

mcp

icp

LV

scp

mediallemniscus

inferior olive

cochlearnuclei

vestibularnuclei

occipital lobe

4V

CEREBRAL CORTEX

RHOMBENCEPHALON

CEREBELLUM

visual cortex

7

Level P 1.5

The hindbrain at the level of the middle of the fourth ventricle

This section shows the hindbrain at the level of the middle of the fourth ventricle. The trigeminal nuclei (the spinal

trigeminal nuclei) are found in the lateral part of the hindbrain. Lateral to the trigeminal nuclei are the sensory

fibers of the trigeminal nerve, called the spinal trigeminal tract (sp5). A large fiber bundle, the pyramidal tract, lies

on either side of the midline on the ventral margin of the hindbrain. Above each pyramidal tract is the inferior

olive, which is functionally connected with the cerebellum of the opposite side via the inferior cerebellar peduncle

(icp). Medial to the inferior olive is the medial lemniscus, which is a fiber pathway carrying touch and position

sense information from the hindbrain and spinal cord to the thalamus. Above the lateral edge of the inferior olive

is a small motor nucleus which supplies the muscles of the pharynx, larynx, and palate. It is called the ambiguus

nucleus (Amb). Most of the remainder of the green area of the hindbrain in this section is occupied by the reticular

nuclei, which extend for the whole length of the hindbrain. The vestibular nuclei lie at the junction of cerebellum

and hindbrain in the floor of the fourth ventricle. They receive information from the position sense organs of the

inner ear. At the lateral edge of the hindbrain under the cerebellum are the cochlear nuclei, which receive auditory

sensations from hearing organ of the inner ear. Lateral and dorsal to the vestibular nuclei are three large fiber

bundles that connect with the cerebellum. The fibers of the middle cerebellar pedunclem (mcp) arise in the basilar

pontine nuclei and travel to the cerebellar cortex. The fibers of the inferior cerebellar peduncle (icp) arise in the

inferior olive and spinal cord and project to the cerebellar cortex. The fibers of the superior cerebellar peduncle (scp)

arise in the deep cerebellar nuclei and travel to the red nucleus and the thalamus.

As in the previous two levels, the cerebellum lies between the rhombencephalon and the occipital lobe of the

cerebrum, which contains the primary visual cortex and the caudal tip of the lateral ventricle (LV).

8

pyramidal tractmediallemniscus

LV

inferior olive

occipital lobe

scp

cochlearnuclei

vestibularnuclei

sensorytigeminal

7Ns5

6N4V

CEREBRAL CORTEX

RHOMBENCEPHALON

MESENCEPHALON

CEREBELLUM

inferior colliculus(auditory)

superior colliculus(visual)

parabrachialnuclei

mcp

dcw

9

Level P 0.5

The hindbrain at the level of the abducens and facial nuclei

This section shows the hindbrain at the level of two notable motor nuclei - the abducens (6N) and the facial (7N)

nuclei. The abducens nucleus lies below the floor of the fourth ventricle; it supplies the lateral rectus muscle of the

eye. The facial nucleus lies ventral to the sensory trigeminal nucleus; it supplies the muscles of facial expression.

The sensory trigeminal nucleus is found in the lateral part of the hindbrain. At this level we see the principal

trigeminal nucleus, closely applied to the sensory root of the trigeminal nerve (s5). Lateral to the trigeminal sensory

nuclei are the cochlear nuclei. A large fiber bundle, the pyramidal tract, lies on either side of the midline on the

ventral margin of the hindbrain. Above each pyramidal tract is the inferior olive, which is functionally connected

with the cerebellum. Medial to the inferior olive is the medial lemniscus, which is a fiber pathway carrying touch

and position sense information from the hindbrain and spinal cord to the thalamus. Most of the remainder of the

green area of the hindbrain in this section is occupied by the reticular nuclei. Lateral to the trigeminal nuclei are

the cochlear nuclei. The vestibular nuclei lie lateral to the abducens nucleus (6N). Above the vestibular nuclei is the

superior cerebellar peduncle (scp) which is surrounded by the parabrachial nuclei. Lateral to the superior cerebellar

peduncle is the middle cerebellar peduncle (mcp).

Dorsal to the fourth ventricle (4V) is the central part of the cerebellum. The cerebellum protrudes laterally to lie

dorsal to the vestibular and cochlear nuclei. Above the cerebellum, the dorsal parts of the mesencephalon (midbrain)

can be seen. These are the superior and inferior colliculi.

Above the mesencephalon and the cerebellum is the occipital lobe of the cerebrum, which in this section consists

of the cerebral cortex, deep cerebral white matter (dcw), and the lateral (cerebral) ventricle (LV).

10

cornu amm

onis

pyramidal tractmedial lemniscus

scp

LV

inferiorcolliculus(auditory)

superior colliculus(visual)

4V

5N

vestibular nuclei

parabrachialnuclei

ReIC

superior olive

periaqueductalgray

CEREBRAL CORTEX

RHOMBENCEPHALON

MESENCEPHALON

CEREBELLUM

4n

5n

mcp

11

Level A 0.5

The hindbrain at the level of the superior olive

Because this section is obliquely cut through the brain stem, both the hindbrain (below) and the midbrain (above)

can be seen in the same section. The rostral part of the fourth ventricle lies between the vestibular nuclei of the

hindbrain below and the periaqueductal gray of the midbrain above.

Just above the pyramidal tract is the medial lemniscus, a fiber bundle carrying touch information from the body

and face to the thalamus. Lateral to the pyramidal tract and the medial lemniscus is the superior olive, which is

a processing center for auditory information coming from the cochlear nuclei. Dorsal to the superior olive is the

motor trigeminal nucleus (5N), which controls the chewing (masticatory) muscles. The trigeminal nerve itself (5n)

attaches to the hindbrain at this level. Lateral to the motor trigeminal nucleus is the middle cerebellar peduncle

(mcp). The most dorsal part of the hindbrain in this section contains the vestibular nuclei medially and the superior

cerebellar peduncle (scp) and parabrachial nuclei laterally. The parabrachial nuclei receive input from the solitary

nuclei, which are concerned with taste and visceral sensation. The constricted rostral end of the fourth ventricle (4V)

is largely enclosed by the vestibular nuclei. In the roof of the fourth ventricle, the trochlear nerve (4n) of each side

crosses the midline. A small rostral part of the cerebellum likes lateral to the hindbrain at this level.

In this section the midbrain consists mainly of the superior colliculus, the inferior colliculus, and the periaqueductal

gray. In the center of the midbrain is the aqueduct, a small canal along which cerebrospinal fluid (CSF) flows from

the ventricles of the forebrain to the fourth ventricle of the hindbrain. The aqueduct is surrounded by a thick layer

of cells called the periaqueductal gray.

Each superior colliculus receives visual sensory information from the opposite eye. Each inferior colliculus receives

auditory information from the superior olive of both sides.

Within the cerebrum we can see the lateral ventricle (LV) and the most caudal part of the hippocampus, called the

cornu ammonis. The remaining parts of the hippocampus can be seen in the sections rostral to this level.

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cornu ammonis

dentategyrus

superiorcolliculus

(visual)

pulvinar

LV

scp

laterallemniscus

mediallemniscus

pyramidal tract

subiculum

fi

corpus callosum

RHOMBENCEPHALON

ISTHMUS

CEREBRAL CORTEX

4N

aqueduct

mcp

cingulatecortex

periaqueductalgray

MESENCEPHALO

N

13

Level A 2.0

The forebrain at the level of the caudal end of the corpus callosum.

The caudal end of the corpus callosum is present in this section. This very large fiber sheet connects symmetrical

parts of the two cerebral hemispheres. Above the corpus callosum is the cingulate cortex.

Below the corpus callosum, this section shows both the hindbrain and midbrain. It also reveals the first appearance

of the diencephalon, represented by the caudal tip of the pulvinar of the thalamus. Within the cerebrum, we see the

caudalmost part of the hippocampus, represented by the dentate gyrus, the cornu ammonis, and the subiculum.

The hippocampus is a part of the cerebral cortex that is vital for memory registration. The fibres projecting out of

the hippocampus are called the fimbria of the fornix (fi). Lateral to the fimbria is the lateral ventricle (LV).

As in more caudal sections, the pyramidal tract is found next to the ventral midline of the hindbrain

(rhombencephalon). The small rostral part of the superior olive is seen lateral to the pyaramidal tract, and the lateral

lemniscus (which consists of fibers connecting the superior olive to the inferior colliculus) can be seen above the

superior olive. The medial lemniscus between the pyramidal tract and the lateral lemniscus; it is a large fiber bundle

carrying touch information from the body and face to the thalamus.

In the center of the brain stem is the trochlear nucleus (4N), which supplies the superior oblique muscle of the

eye. This nucleus is an important landmark for the isthmus, a thin strip of rostral hindbrain that separates the

rhombencephalon from the mesencephalon. The territory of the isthmus is often mistakenly included in the

mesencephalon. Below and to the side of the trochlear nucleus is the superior cerebellar peduncle (scp).

In this section the midbrain consists mainly of the superior colliculus and the periaqueductal gray. In the center of

the midbrain is the aqueduct, a small canal along which cerebrospinal fluid (CSF) flows from the ventricles of the

forebrain to the fourth ventricle of the hindbrain. The aqueduct is surrounded by a thick layer of cells called the

periaqueductal gray.

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CEREBRAL CORTEX

parietal lobe

fi

temporal lobe

3V

caudate

caudate

LV

lateralgeniculate

medialgeniculate

VPM & VPL

3N

VTA

3Vsomatosensorythalamus

DIENCEPHALON

cornu ammonis

dentategyrus

basilar pons

substantia nigra

cp

subiculum

interpeduncularnucleus

rednucleus ml

corpus callosum

cingulatecortex

15

Level A 4.5

The forebrain at the level of the lateral geniculate nucleus

This section shows the junction of the midbrain (below) with the diencephalon above. The main features of the

midbrain at this level are the oculomotor nucleus (3N), the red nucleus, the substantia nigra, and the VTA (ventral

tegmental area). Each oculomotor nucleus (3N) supplies four of the six muscles that move the eye. In addition, the

oculomotor nerve supplies the main muscle of the upper eyelid and the muscles of the pupil and lens. Between

the oculomotor nucleus and the medial lemniscus (ml) is the red nucleus. This large group of cells gives rise to a

fiber bundle that travels down the spinal cord, called the rubrospinal tract. At this level, the pyramidal (corticospinal)

fibers and other descending fibers form a bundle called the cerebral peduncle on the ventral aspect of the

midbrain. At this level the pyramidal tract is embedded in the cerebral peduncle (cp). Coating the inside (medial)

border of the fibers of the cerebral peduncle (cp) is the substantia nigra, a large cell group that is important for

motor control. A large group of substantia nigra neurons contain dopamine; they project to the caudate and

putamen in the subpallial part of the cerebrum. On the medial side of the medial lemniscus is another group of

dopaminergic neurons, the ventral tegmental area (VTA); these neurons project to the accumbens nucleus in the

subpallium. Medial to the VTA is the midline interpeduncular nucleus.

The diencephalon at this level mostly consists of thalamic nuclei. The somatosensory thalamic nuclei receive touch

and proprioception information from the medial lemniscus. They are called the ventroposterior medial (VPM) and

ventroposterior lateral (VPL) nuclei. The thalamic medial geniculate nucleus receives auditory information from

the inferior colliculus. Lateral to the medial geniculate is the huge lateral geniculate nucleus which receives input

from the eye. The lateral geniculate is so large in primates that it lies lateral to the main part of the thalamus. Each

thalamic nucleus projects to a specific part of the cerebral cortex: VPM and VPL project to the somaotosensory

cortex; the medial geniculate projects to the auditory cortex; and the lateral geniculate projects to the visual cortex.

Below and lateral to the lateral geniculate nucleus is the temporal lobe of the cerebrum. At this level it contains

the main parts of the hippocampus (dentate gyrus, cornu ammonis, and subiculum), the inferior horn of the lateral

ventricle (LV), and the tail of the caudate nucleus. The body of the caudate nucleus is seen above the lateral part of

the diencephalon, lateral to the body of the lateral ventricle. Because the caudate nucleus is C-shaped, it is possible

to cut it twice in the same section. The ventricle of the diencephalon is the third ventricle (3V), which at this level is

connected to the body of the lateral ventricle by the interventricular foramen.

The cerebral cortex at this level is represented by the temporal lobe cortex (including the hippocampus), the

parietal lobe cortex, and the cingulate cortex.

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CEREBRAL CORTEX

insularcortex

somatosensorycortex

internalcapsule

cornu ammonis

globuspallidus

opt

amygdaladentategyrus

subiculum

entorhinalcortex

fornix

corpus callosumLV

3V

ec

fi

3V

thalamus

VMH

cingulatecortex

claustrum

auditorycortex

caudate

temporal lobe

putamen

caudate

SUBPALLIUMHYPOTHALAMUS

lateral fissure

17

Level A 7.5

The forebrain at the level of the middle of the hypothalamus

This level shows all of the major elements of the forebrain - the diencephalon, the hypothalamus, the subpallium

(caudate, putamen, globus pallidus, and amygdala), and the cerebral cortex. Separating the thalamus from the

cerebrum is the internal capsule, a very large sheet of fibers that connects the cerebral cortex with the thalamus,

brainstem and spinal cord. The caudal end of the internal capsule forms the cerebral peduncle, which contains

the pyramidal tract. Between the internal capsule and the insular cortex are the globus pallidus, putamen, and

claustrum. The caudate nucleus is C shaped and appears twice in this section, once above the thalamus, and again

below the putamen. The caudate, putamen, and globus pallidus can be referred to collectively as the basal ganglia.

They are involved in motor control, particularly semi-automatic movements and locomotion.

The diencephalon in this section is mainly represented by the thalamus.

The hypothalamus lies ventral to the thalamus. The ventromedial hypothalamic nucleus (VMH) and the fornix are

prominent landmarks in the hypothalamus. Between the hypothalamus and the amygdala is the optic tract (opt),

a bundle of fibers running from the optic chiasm to the dorsal lateral geniculate nucleus of the thalamus. Part of

the third ventricle (3V) is in the midline in the hypothalamus; the dorsal recess of the third ventricle lies above the

thalamus. It is separated from the lateral ventricle (LV) by the fimbria.

The lateral surface of the cerebral cortex seen in this section contains the somatosensory (touch and

proprioception) cortex. Below the somatosensory cortex is the lateral fissure, which encloses the insular cortex (taste

and visceral sensation). On the lower lip of the lateral fissure is the auditory cortex. The part of the cerebrum below

the lateral fissure is called the temporal lobe. The medial half of the temporal lobe at this level is occupied by the

hippocampus, which is made up of the dentate gyrus, cornu ammonis, subiculum, and entorhinal cortex. Lateral

to the hippocampus is the caudal end of the amygdala.

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entorhinalcortex

anterior comissure

lateral fissure

corpus callosum

3V

opt

preopticarea

septumec

ic

LV

bed nucleus of stria terminalis

caudate

globuspallidus

putamen

cingulatecortex

auditorycortex

somatosensorycortex

motorcortex

insularcortex

claustrumamygdala

CEREBRAL CORTEX

SUBPALLIUM

temporal lobe

19

Level A 9.5

The forebrain at the level of the anterior commissure

The anterior commissure lies immediately in front of the rostral pole of the thalamus. The anterior commissure is

a large bundle of crossing fibers, which connects the olfactory bulb and parts of the temporal lobe cortex with

symmetrical areas on the opposite side. The anterior commissure is in the center of this section, with the septum

above, the preoptic area below, and the bed nucleus of the stria terminalis applied to its dorsal and ventral margins.

In the midline of the preoptic region is the third ventricle (3V). Below the lateral part of the preoptic area is the very

large optic tract, indicating that the optic chiasm must be just rostral to this section.

The thin layer of white matter lateral to the putamen is called the external capsule. The lateral ventricle lies

between the septum and the caudate nucleus in this section. Between the insular cortex and the lateral ventricle

(LV) lie a number of components of the subpallium - the claustrum, putamen, globus pallidus and caudate nucleus.

Between the caudate nucleus and the putamen and globus pallidus is the rostral part of the internal capsule (ic).

The internal capsule is a large sheet of fibers that connects the cerebrum with the thalamus, brainstem, and spinal

cord. The superolateral surface of the cerebral cortex seen in this section contains the somatosensory cortex and

the motor cortex. Below the somatosensory cortex is the lateral fissure, which encloses the insular cortex (taste

and visceral sensation). On the lower lip of the lateral fissure is the auditory cortex. The part of the cerebrum below

the lateral fissure is called the temporal lobe. The medial half of the temporal lobe at this level is occupied by the

amygdala. Just ventral to the amygdala is an outlying part of the hippocampus, called the entorhinal cortex. The

medial surface of the cerebrum, above the corpus callosum, is represented by the cingulate cortex.

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lateral olfactory tract

rcc

corpus callosum

frontal lobe

dcw

ec

ic

cingulatecortex

caudateLV

putamenclaustrum

olfactorytubercle

ac

nucleusaccumbens

CEREBRAL CORTEX

SUBPALLIUM

21

Level A 12.5

The forebrain at the rostral end of the corpus callosum

This section passes through the frontal lobe of the cerebrum at the level rostral end of the corpus callosum. This

part of the corpus callosum is folded back on itself (see sagittal sections) to form the rostrum of the corpus callosum

(rcc). The cingulate cortex lies dorsal to the corpus callosum. The rostral part of the lateral ventricle (LV) separates

the rostrum of the corpus callosum from the head of the caudate nucleus. The caudate nucleus is separated from

the putamen by the internal capsule (ic). The caudate and putamen are continuous with the nucleus accumbens

ventrally. The accumbens is continuous with the olfactory tubercle.Together, these four entities (caudate, putamen,

accumbens, olfactory tubercle) form the largest of the subpallial groups, called the striatum. Lateral to the putamen

is the claustrum, which is separated from the putamen by the external capsule.

The anterior limb of the anterior commissure (ac) is prominent bundle of fibers between the olfactory tubercle and

the accumbens. Lateral to the olfactory tubercle is the lateral olfactory tract.

22

lateral olfactory tract

deep cerebralwhite matter

(dcw)

frontal lobe

CEREBRAL CORTEXcingulatecortex

23

Level A 14.5

The forebrain at the level of the frontal pole of the cerebrum

The section cuts through the rostral pole of the frontal lobe of the cerebrum. The center of the cerebrum is filled

with the deep cerebral white matter. The medial wall of the cerebral cortex is formed by the cingulate cortex. The

lateral olfactory tract lies against the ventral (orbital) surface of the frontal lobe.

24

4V

4V

pyramidal tract

basilarpontinenuclei

thalamus (p2)

ST

septum

fornix

ac

VMH och 2n

preopticarea

6N

RHOMBENCEPHALON

CEREBRAL CORTEX

DIENCEPHALON

HYPOTHALAMUSCEREBELLUM

inferiorcolliculus(auditory)

superiorcolliculus

(visual)

SUBPALLIUM

pretectum (p1)

corpus callosum occipital lobe frontal lobe

periaquaductalgray

ISTHMUSred nucleus

MESENCEPHALON

25

Sagittal Level L 1.75

Sagittal section close to the midline

This section shows all major regions of the marmoset brain. In the forebrain, we can see the occipital and frontal

lobes of the cerebral cortex and a number of subpallial areas (septum, bed nucleus of stria terminalis, and preoptic

area). Three forebrain commissures are present; the corpus callosum, the anterior commissure (ac), and the fornix

(hippocampal) commissure. The hypothalamus and diencephalon are present. Within the hypothalamus, the VMH

(ventromedial hypothalamic nucleus) is prominent and the optic chiasm is attached to the ventral border of the

hypothalamus. The diencephalon is made up of three segmental components - the prosomeres. Prosomere 2

(mainly thalamus - p2) and prosomere 1 (pretectum - p1) are seen here, but prosomere 3 (prethalamus - p3) is not

labeled.

The brain stem consists of the mesencephalon and the three parts of the hindbrain - the isthmus, the cerebellum

and the rhombencephalon. The mesencephalon includes the superior and inferior colliculi, the periaqueductal gray

and the red nucleus. The thin strip of isthmus separates the mesencephalon from the rhombencephalon. In the

rhombencephalon, the basilar pontine nuclei, the abducens nucleus (6N), and the pyramidal tract can be seen. The

fourth ventricle (4V) lies between the cerebellum and the rhombencephalon.

26

thalamus

deep cerebellar nuclei

corpus callosum

putamen

caudate

pret

halam

us

CEREBRAL CORTEX

DIENCEPHALON

SUBPALLIUM

CEREBELLUM

ac

inferior olive

sensory trigeminal

LV

4V

ic

cornu ammonis

pallidum

amygdaladentate

gyrussubiculum

inferiorcolliculus(auditory)

superiorcolliculus

(visual)

ISTHMUS

pretectum

27

Sagittal Level L 3.75

Sagittal section – 3.75 mm lateral to the midline

This section is some distance from the midline, but the major features are similar to those seen in the previous

section. In the forebrain, we can see the subpallium consisting of the caudate nucleus, putamen and pallidum.

Between the putamen and the pallidum is the anterior commissure (ac). At this level, the temporal lobe of the

cerebrum contains the main parts of the hippocampus (cornu ammonis, dentate gyrus, and subiculum) and the

amygdala. The diencephalon is made up of three segmental components (prethalamus, thalamus, and pretectum).

The brain stem consists of the mesencephalon (not labeled here) and the three parts of the hindbrain – the

isthmus, the cerebellum, and the rhombencephalon. Their dorsal surface is covered by the cerebral cortex. The

mesencephalon consists of the superior and inferior colliculi. The thin strip of isthmus separates the mesencephalon

from the rhombencephalon. In the cerebellum, we can see deep cerebellar nuclei. In the rhombencephalon, the

sensory trigeminal nucleus lies from anterior to posterior. Below the sensory trigeminal nucleus is the inferior olive.

The fourth ventricle (4V) lies between the cerebellum and the rhombencephalon.