The Human Brain During the Third Trimester

T

E

G

M

E

N

T

U

M

T

E

G

M

E

N

T

U

M

C

e

r

e

b

ra

l

p

e

d

u

n

cl

e

C

e

r

e

b

ra

l

p

e

d

u

n

cl

e

Choroid plexus

HIPPOCAMPUHIPPOCAMPUSS

Fimbria/fornix

Subiculum

Dentate gyrus

Ammon's horn

Caudate (head)Caudate (head)

Pu

ta

me

n

Pu

ta

me

n

Caudate (tail)Caudate (tail)

Claustr

um

Claustr

um

Lateral ventricle

Temporal

lobe

Te mporal

lobe

Frontal

lobe

Frontal

lobe

Lateral migratory stream

(infiltrating the claustrum and entering

the insular cortex and temporal cortex)

Insular gyrusInsular gyrus

Exter

nal^ c

apsu

le

Exter

nal^ cap

sule

Exter

nal capsule

Ex

ter

na

l^ ca

ps

ule

Lateral

fissure

Stria terminalisStria terminalis

I

n

t

e

r

n

a

l

c

a

p

s

u

l

e

I

n

t

e

r

n

a

l

c

a

p

s

u

l

e

A

nt

er

io

r

lim

b

A

nt

er

io

r

lim

b

P

O

S

T

E

R

IO

R

C

O

M

P

L

E

X

P

O

S

T

E

R

IO

R

C

O

M

P

L

E

X

B

A

S

A

L

G

A

N

G

L

IA

B

A

S

A

L

G

A

N

G

L

IA

Layer I

Cortical plate

White matter

T H A L A M U S

T H A L A M U S

SEPTUMSEPTUM

Lateral

septal nucleus

Lateral

septal nucleus

Inferior frontal gyrus

Mammillo-

thalamic tract?

Mammillo-

thalamic tract?

G

lo

bus pallidus

(exter

nal segm

ent)

G

lo

bu

s pallidus

(exter

nal segm

ent)

Third vThird ventricleentricle

Diencephalic (hypothalamic) glioepithelium/ependyma

Mesencephalic glioepithelium/ependyma

Subcommissural orga n

Zonal and optic nerve layers

Superficial gray layer

Superficial white layer

Middle gray layer

Middle white layer

Deep gray layer

Deep white layer

Be

d^ n

uc

leu

s^ o

f^ th

e

str

ia^

ter

min

ali

s

Be

d^ n

uc

leu

s^ o

f^ th

e

str

ia^

ter

min

ali

s

Glob

us pallidus

(inte

rnal segment

)

Glob

us pallidus

(inter

nal segment

)

M

ed

ul

la

ry

la

m

ina

M

ed

ul

la

ry

la

m

ina

MIDBRAIMIDBRAINN

TECTUMTECTUM

Superio

r

colliculu

s

Superio

r

colliculu

s

Lateral

geniculate

body

Lateral

geniculate

body

Corticofugal fiber s

(in internal capsule)

Tenia tecta (dorsal)

Medial septal nucleus

Median preoptic nucleus

Lateral ventricle

Corpus callosum

(rostrum)

Subcallosal area

Paraventricular

nucleus

Paraventricular

nucleus

FForel's field sorel's fields

Central grayCentral gray

Anterior commissuAnterior commissurree

Ansa

lenticularis?

Ansa

lenticularis?

Cere bral aqueduct

Zona incertaZona incerta

Medial

geniculate

body

Medial

geniculate

body

SU

BT

H

A

LA

M

US

SU

BT

H

A

LA

M

US

HYPO-

THALAMUS

HYPO-

THALAMUS

S

u

b

th

al

am

ic

nu

cl

eu

s

S

u

b

th

al

am

ic

nu

cl

eu

s

Parahippocampal

gyrus

Parahippocampal

gyrus

Subgranular zone

Fornical

glioepithelium

Fo rnical

glioepithelium

Rostral migratory stream

(source area)

Subpial granular layer

Fr ontal neuroepithelium

and subventricular zone

Pa rahippocampal neuroepithe-

lium and subventricular zone

Pa rahippocampal

stratified transitional field

Fr ontal stratified

transitional field

Callosal glioepithelium

Te mporal neuroepithelium

and subventricular zone

Te mporal stratified

Stem cells of transitional field

choroid plexus?

Stem cells of

choroid plexus?

FFornixornix

Germinal and transitional

structures in italics

Germinal and transitional

structures in italics

Me yer's loop (visual radiation)

P

osterior lim

b

P

osterior lim

b

Posterior striatal neuroepithelium

and subventricular zone

Po sterior striatal neuroepithelium

and subventricular zone

GlioepitheliuGlioepitheliumm

GlioepitheliuGlioepitheliumm

Strionuclear glioepitheliuStrionuclear glioepitheliumm

Superior temporal

gyrus

Superior temporal

gyrus

AlAlvve ar glioepitheliuear glioepitheliumm

Septal

glioepithelium/

ependyma

Septal

glioepithelium/

ependyma

Striatal neuroepithelium

and subventricular zone

Striatal neuroepithelium

and subventricular zone

AnterolateraAnterolaterall

AnteromedialAnteromedial

PLATE 233B