The Human Brain During the Third Trimester

Lateral Lateral ventricleventricle

Lateral vLateral ventricleentricle

Temporal

lobe

Te mporal

lobe

FFornixornix

ChorChoroid plexusoid plexus

C

hor

oid plexus

C

hor

oi

d

p

lexu

s

CorCorpus callosum (body)pus callosum (body)

CA1CA1

Pontine

gray

Pontine

gray

CA3CA3

Granular laGranular layeyerr

Molecular laMolecular layeyerr

Hippocampal Commissure

Pyramidal laPyramidal layeyerr

Stratum orienStratum orienss

Stratum radiatumStratum radiatum

Stratum

lacunosum-

moleculare

Stratum

lacunosum-

moleculare

HilusHilus

PulvinarPulvinar

Internal

capsule

Internal

capsule

Cerebral

aqueduct

Cere bral

aqueduct

Subcom-

missural

organ

Subcom-

missural

organ

Central

gray

Central

gray

Superior colliculuSuperior colliculuss

Brachium of the

inferior colliculus

Brachium of the

inferior colliculus

Inferior

colliculus

Inferior

colliculus

Medial

longitudinal

fasciculus

Medial

longitudinal

fasciculus

Superior

cerebellar peduncle

(decussation)

Superior

cerebellar peduncle

(decussation)

Central

tegmental

tract

Central

tegmental

tract

Para-

subiculum

Para -

subiculum

Tectospinal

tract

Tectospinal

tract

Fi

m

bria

Fi

m

bria

Reticular

formation

Reticular

formation

Reticular

formation

Reticular

formation

Stria terminalisStria terminalis

Reticular tegmental

nucleus

Reticular tegmental

nucleus

Middle cerebellar

peduncle

Nerve V

Mesencephalic

nucleus of V

Mesencephalic

nucleus of V

Nucleus of the

lateral lemniscus

(dorsal)

Nucleus of the

lateral lemniscus

(dorsal)

Parabigeminal

nucleus (dorsal)

Parabigeminal

nucleus (dorsal)

Parabigeminal

nucleus (ventral)

Parabigeminal

nucleus (ventral)

Su

b

ic

ul

u

m

Su

b

ic

ul

u

m

Presubi

cu

lu

m

Presubi

cu

lu

m

A

m

m

o

n

's

h

or

n

A

m

m

o

n

's

h

or

n

M

ed

ia

ll

e

m

n

is

cu

s

M

ed

ia

ll

e

m

n

is

cu

s

L

a

te

ra

l

le

m

n

is

cu

s

L

a

te

ra

l

le

m

n

is

cu

s

Zonallay

er

Zonallay

er

O

pt

icn

erve

layer

O

pt

icn

erve

layer S

uperficialg

ray

la

ye

r

Superficialg

ray

la

ye

r

M

id

dl

eg

ray

layer

M

id

dl

eg

ray

layer M

id

d

le

w

h

it

e

la

ye

r

M

id

d

le

w

h

it

e

la

ye

De r

ep

gr

ay

la

ye

r

D

ee

p

gr

ay

la

ye

r

D

ee

p

w

hi

te

la

ye

r

D

ee

p

w

hi

te

la

ye

r

HippocampusHippocampus

Raphe

nuclear

complex

Raphe

nuclear

complex

THALAMUSTHALAMUS

POSTERIOR COMPLEXPOSTERIOR COMPLEX

PONSPONS

D

entateg

yr

D us

entateg

yr

us

HHIPPOIPPOCCAAMMPUPUSS

Subgranular

zone

Subgranular

zone

Subgranular

zone

Subgranular

zone

Temporal stratified

transitional field

Temporal stratified

transitional field

Temporal neuro-

epithelium and

subventricular

zone

Te mporal neuro-

epithelium and

subventricular

zone

Pa rahippocampal neuroepithelium,

subventricular zone, and

stratified transitional field

AlvAlve ar glioepitheliuear glioepitheliumm

Posterior striatal

neuroepithelium and

subventricular zone

Po sterior striatal

neuroepithelium and

subventricular zone

FFo rnical glioepitheliuornical glioepitheliumm

Parahippocampal

gyrus

Parahippocampal

gyrus

Subpial granular layer

Callosal glioepithelium Germinal and transitional structuGerminal and transitional structurres ines in italicsitalics

Fornical

glioepithelium

Fo rnical

glioepithelium

Strionuclear

glioepithelium

Strionuclear

glioepithelium

TTectuectumm

MIDBRAIMIDBRAINN

TTe gmentumegmentum

White

matter

Layer I

Cortical

plate

Caudate nucleus

(tail)

Caudate nucleus

(tail)

Mesencephalic

glioepithelium/ependyma

Mesencephalic

glioepithelium/ependyma

Transpontine corticofugal tract

(thick longitudinal bundles)

Pontocerebellar fibers

(thin transverse bundles)

Pontocerebellar fibers (decussation)

Oculomotor

nucleus (III)

Oculomotor

nucleus (III)

PLATE 40B