front matter 1

Floor plateFloor plate

Ventral

corticospinal

tract

Ventral

corticospinal

tract

Ventral horn

motoneurons

Ventral horn

motoneurons

Lateral horn

motoneurons

(autonomic)

Ventral horn

interneurons

Ventral horn

interneurons

Intermediate

interneurons

Intermediate

interneurons

Dorsal root bifurcation zone

Fasciculus cuneatus

Deep fasciculus gracilis

Superficial fasciculus gracilis

Dorsal root collateralization zone

Lissauer's tract

Dorsal funiculus

Dorsal

horn

Substantia

gelatinosa

Substantia

gelatinosa

Lateral

funiculus

Lateral

funiculus

EpendymaEpendyma

Central

autonomic area

Central

autonomic area

Laminae

IV-V

Laminae

IV-V

Lateral

corticospinal

tract

Lateral

corticospinal

tract

Vestibulospinal tract?

Clarke's column?

Lamina I

VVentral funiculusentral funiculus

Roof plateRoof plate

Central canalCentral canal

trunk?trunk?

VVentral white commissureentral white commissure

VVentral gray commissureentral gray commissure

Dorsal median septum

Dorsal intermediate septum

I

n

tr asp

i

n

a

l

t

r

a

c

t

s

?

I

n

tr asp

i

n

a

l

t

r

a

c

t

s

?

Sp

in

o

c

e

p

h

a

l

ic

tr

a

c

ts

?

Sp

in

o

c

e

p

h

a

l

ic

tr

a

c

ts

?

Spi

no

c

e

r

e

b

e

l

l

a

r

tr

a

c

st

?

Spi

no

c

e

r

e

b

e

l

l

a

r

tr

a

c

st

?

Ventral median fissure

The fi ne lines in the lateral and ventral funiculi segregate regions of dif-

fering densities of proliferating glia, not the borders of fi ber tracts.

PLATE 41B

See Table III B-1 for the list of glial densities in each fi ber tract.

Examples of glial densities in each category are labeled in the lower

left corner of Plate 39B.