front matter 1

Spin

oc

ep

ha

li

c

tr

a

c

ts

Spin

oc

ep

ha

li

c

tr

a

c

ts

VVentral funiculusentral funiculus

VVentral grayentral gray

Intermediate grayIntermediate gray

Dorsal root bifurcation zone

Fasciculus cuneatus

Fasciculus gracilis

Dorsal root collateralization zone

Lissauer's tract

Lateral

funiculus

Lateral

funiculus

Tectospinal tract?

Medial longitudinal fasciculus?

Vestibulospinal tract?

Dorsal grayDorsal gray

Dorsal funiculus

Myelinated ventral rootlets

myelinaionmyelinaiongradientgradient

Ventral corticospinal tract

Central canal

surrounded by ependyma

Central canal

surrounded by ependyma

Myelinated terminals of

dorsal root collaterals

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

Intraspinal tra

ct

s

Intraspinal tra

ct

s

myelination

gradient

myelination

gradient

Subgelatinosal pleSubgelatinosal plexusxus

Reticulated areaReticulated area

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?

Lateral

corticospinal

tract

Lateral

corticospinal

tract

This Plate has no matched cell body stained section

As in Plate 93, there is lighter staining of the ventral commissure

in this section, possibly due to the crossing of unmyelinated axons

from the ventral corticospinal tract.

There are two myelination gradients (straight arrows) in the ventral and lateral funiculi in this section and also in the section shown in Plate 93.
The arrow within the lateral corticospinal tract starts ventromedially in the area with a greater density of reactive glia and stops dorsolaterally in the
area with sparse reactive glia. Ventromedial fi bers enter the gray matter at rostral levels and will be the fi rst to myelinate. Dorsolateral fi bers enter
the gray matter at caudal levels and will be the last to myelinate. The arrow cutting across the intraspinal and spinocephalic tracts starts close to the
ventral gray in a region that contains many myelinating fi bers and stops in an area that contains sparse reactive glia just beneath the pial membrane.
Fibers in the intraspinal tract myelinate fi rst, then internal fi bers in the spinocephalic tracts, then outer fi bers in the spinocephalic tracts.

PLATE 95B