front matter 1

Spi

no

ce

ph

al

ic

tr

ac

ts

Spi

no

ce

ph

al

ic

tr

ac

ts

VVentral funiculusentral funiculus

VVentral grayentral gray

Intermediate grayIntermediate gray

Fasciculus cuneatus

Fasciculus gracilis

Dorsal root collateralization zone

Lateral

funiculus

Lateral

funiculus

Vestibulospinal tract?

Dorsal

gray

Dorsal

gray

Dorsal funiculus

Dorsal root

Central canal

surrounded by ependyma

Central canal

surrounded by ependyma

Lateral

corticospinal tract

Lateral

corticospinal tract

Myelinated terminals of

dorsal root collaterals Dorsal root bifurcation zone

Lissauer's tract

Int

raspina

lt

ra

c

ts

Int

raspina

lt

ra

c

ts

Sp

in

o

c

e

r

e

b

e

l

l

a r t r a c t

s

Sp

in

o

c

e

r

e

b

e

l

l

a r t r a c t

s

Subgelatinosal

plexus

Subgelatinosal

plexus

Reticulated areaReticulated area

Ventral corticospinal tract

Ventral white

commissure

Ventral white

commissure

VVentral gray commissureentral gray commissure

Dorsal intermediate septum

Dorsal median septum

Ventral median fissure

Rubrospinal tract?Rubrospinal tract?

Lateral

reticulospinal

tract?

Lateral

reticulospinal

tract?

See the matched cell body stained section in Plates 97A and B

The ventral commissure stains darkly in this section, even though there is a small ventral corticospinal tract. The still unmyelinated axons in the
ventral corticospinal tract may not have crossed the midline at this level, indicating a rostral (fi rst) to caudal (last) gradient of maturation.
The myelination gradient in the lateral corticospinal tract is not evident in this section, but note the lighter staining of the superfi cial fi bers in the
ventral and lateral funiculi compared to the darker staining of the deep fi bers.

Note the asymmetry in the size of the ventral corticospinal tract in

this section and in Plates 95 and 97.

PLATE 96B