A golgi study on the ventral lateral geniculate nucleus in the domestic hen, Gallus Domesticus

$209 A GOLGI STUDY ON THE V E N T R A L DOMESTICUS

LATERAL

NOBUHARU Nagasaki

of Anatomy,

IWAHORI, D e p a r t m e n t 852, Japan.

GENICULATE

NUCLEUS

Faculty

IN THE DOMESTIC

of Medicine,

HEN,

Nagasaki

GALLUS

University,

The i n t r a n u c l e a r o r g a n i z a t i o n of the v e n t r a l lateral g e n i c u l a t e nucleus (LGNv) was studied in the domestic hen using the rapid Golgi method. As seen in the frontal sections, the LGNv is an ovoid nucleus located dorsal to the optic tract in the ventral diencephalon. The LGNv neurons were seen m a i n l y in the internal region of the nucleus, w h e r e a s in the external region only a few cells were d i s s e m i n a t e d among the dense fiber plexus. The somata of the LGNv neurons were triangular, oval or stellate and g e n e r a t e d three to six dendrites. One to two of the dendrites extended v e n t r a l l y and d i v i d e d repeatedly to form tufted terminals in the external region of the nucleus. Other dendrites, however, p r o c e e d e d dorsally, d o r s o l a t e r a l l y or d o r s o m e d i a l l y to be d i s t r i b u t e d in the internal p o r t i o n of the nucleus. The axons of the LGNv neurons issued from the somata or from the proximal p o r t i o n of a dendrite, t r a v e l e d d o r s a l l y and could be traced to the dorsal region of the LGNv, b u t their terminal areas could not be determined. A few axons w e r e seen to give off short i n t r a n u c l e a r c o l l a t e r a l s or long c o l l a t e r a l s e x t e n d i n g dorsolaterally. The a f f e r e n t fibers to the LGNv w e r e d i v i d e d into two groups: a f f e r e n t s from the ventral aspect and fibers from the dorsal aspect. The afferents from the v e n t r a l aspect arose from fibers running v e n t r o m e d i a l l y in a deep region of the optic tract. These fibers e n d e d in tufted terminals in the external region of the nucleus and formed g l o m e r u l a r structures a s s o c i a t e d w i t h the tufted terminals of the dendrites. The a f f e r e n t fibers from the dorsal aspect reached the LGNv by w a y of two fiber bundles. One bundle ran along the lateral and ventral b o r d e r s of the nucleus rotundus to arrive at the dorsal aspect of the LGNv. The other bundle traveled ventrolaterally, b y p a s s i n g the medial border of the nucleus rotundus, and reached the LGNv from the d o r s o m e d i a l aspect. Upon arriving at the nucleus, fibers d e r i v e d from these two b u n d l e s e m i t t e d numerous c o l l a t e r a l s of v a r y i n g lengths w h i c h traveled v e n t r a l l y in the nucleus, b r a n c h i n g out into many terminal collaterals.

VISUAL P R E T E C T A L PULVINAR NUCLEUS

NEURONS PROJECTING IN THE CAT.

TO THE DORSAL

TOSHIAKI KUBOTA*, MASATOSHI M O R I M O T O Anatomy, Faculty of Medicine, Kyushu Fukuoka 812, JAPAN Cat visual

pretectal

olivary

pretectal

nucleus

(NPP).

the dorsal nuclei.

amount

given

anesthesia.

injections

and pulvinar labeled

was

were

superficial

large-sized

multipolar

cells

in the NPP.

cells

The somal

projecting

nucleus.

primarily

cells,

in the NTO, sizes

pretectal

neurons

and small-

nucleus

pretectal

and small-sized

fusiform

cells,

projecting

A small

and 7 were

to the LGNd nuclei.

multipolar

small-,

medium-

and m e d i u m - s i z e d

are not

ascending

cats under

into the LGNd,

Both the projections

to

thalamic

conjugated

nucleus.

18 adult

the pretectal

ascend

germ a g g l u t i n i n

into

in the visual

of neurons

to the pulvinar

nuclei

and other

injections

cells

include

nucleus

into the LGNd or pulvinar

of fusiform

horizontal

of wheat

AND

Department of Higashi-ku,

input,

pretectal

pulvinar

stereotaxically

NUCLEUS

(NTO) and posterior

of visual

cats were given

originate composed

in the NOL,

of neurons

injected

Eleven

of the visual

subtypes

retinal

nucleus

(LGNd),

GENICULATE

KANASEKI, Third 3-I-I Maidashi,

direct

tract

injections

(WGA-HRP)

into the pulvinar

nucleus

neurons

following

peroxidase

of 2.5% W G A - H R P

ketamine

nucleus

morphological

thalamus,

to h o r s e r a d i s h

optic

the axons

geniculate

We observed

that receive

(NOL),

In the cat,

lateral

to the dorsal

nuclei

nucleus

AND TAKESHI University,

LATERAL

The cells and

multipolar

to the LGNd and those

identical.