Topographical organization of the afferent connections of area 24 from the insular and temporal cortices in the macaque monkey

S275

610

THE ORGANIZATION

OF THE INTRINSIC

YOSHIKO

HONDA’, 2, NOR10 ISIZUKAI

AND ENTORHINAL

CONNECTIONS

OF THE RAT

PRESUBICULUM.

l.Dept. of Cell Biology, Tokyo Metropolitan 2.Dept. of Physiology, The presubiculum

School of Medicine,

with the associational

the temporal half. The cells in the septal PreS projected

(MEA) and the anterior to MEA,

while the layer II

in the PreS including area 29e, and the majority were in

the association

cells were located densely in the mid and

but very few in the proximal part. As to the reciprocal topography

Tokyo 162-0054

far to the temporal PreS, while the cells in the temporal PreS

mostly within the temporal portion. Transversely,

and layer III of PreS, the following

cortex

Tokyo 183-8526,

Shinjuku-ku,

in PreS. In this study, further analysis was made using the WGA-HRP

cells were widely distributed

distal parts (far from the subiculum),

Fuchu-shi,

We reported that the layer III cells of PreS projected

connection

and PHA-L method. The association

terminated

2-6 Musashidai,

(PreS) plays a role of the interface between the medial entorhinal

thalamic nuclei as well as the subiculum. cells concerned

Institute for Neuroscience,

Tokyo Women’s Medical Univ., 8-l Kawada-cho

was observed:

connection

1) the septal PreS was connected

the temporal PreS with the medial MEA, and 2) the distal PreS connected

between

the MEA

with the lateral MEA, and

with the septal MEA and the proximal PreS with

the temporal MEA.

611

TOPOGRAPHICAL THE INSULAR

ORGANIZATION

AND TEMPORAL

OF THE AFFERENT

CORTICES

CONNECTIONS

IN THE MACAQUE

OF AREA 24 FROM

MONKEY

HIROKO SAKO and TOM10 ARIKUNI Dept. of Anatomy, This study in Japanese

Nihon Univ., School of Medicine,

analyzed ipsilateral

Macaque monkeys,

Itabashi-ku,

Tokyo 173-8610

inputs from the insular and temporal cortices into the anterior cingulate cortex (area 24)

using the WGA-HRP

tracer technique.

WGA-HRP

case 1, and into area 24d in case 2. In case 1, in the insular cortex, HRP-labeled agranular

insular cortex (Ia) and in the caudal part of the dysgranular

insular cortex (Ig). In case 2, HRP-labeled

cells were found concentrated

scattered

in Ia. In both cases, most of the labeled

dissecans

in Ia and in the supragranular

concentrated

cells were observed

was injected into areas 24a and 24b in cells were found concentrated

insular cortex

(Id), and scattered

in Ig and in the dorsal part of the caudal Id, and in the superficial

layer overlaying

layers in Id and Ig. In case 1, in the temporal cortex, HRP-labeled

in areas TPO, TAa, and Tsl, and less concentrated

in the

in the granular the lamina

cells were found

in areas Pro, PGa, and 1Pa. In case 2. labeled cells were

sparsely found in areas TPO, TAa, and Tsl. This suggests

that areas 24a and b receive inputs primarily

the insular cortex and from polymodal

areas in the temporal cortex. Area 24d receives inputs primarily

and auditory-related

from Ig and Id in the insular cortex and exiguously

612

from Ia and Id in

from the temporal cortex.

Direct synaptic contacts between axon terminals from the horizontal limb nucleus of the diagonal band and corticotectal neurons to the superior colliculus in the medial frontal cortex.

Kunio Murakami,

Shinji Takahashi,

2nd Dep. Anatomy,

Junko Yokofujita,

Toho Univ. School of Medicine,

Hiroaki Igarashi, Akiko Okada, Masaru Kuroda Ohta-ku, Tokyo 143-8540

A combined study of anterograde and retrograde tract-tracing technique was undertaken to identify synaptic connection between axon terminals from the horizontal limb of the diagonal band and corticotectal neurons in the medial frontal cortex (the anterior cingulate and medial precentral cortices) . Phaseolus vulgaris leucoagglutinin was used to anterogradely label fibers from medial part of the nucleus of the horizontal limb of the diagonal band to the medial frontal cortex, whereas a retrograde tracer dextran-biotin was injected into the superior colliculus to label corticotectal neurons in that cortex. Anterogradely labeled axon terminals directly formed symmetrical synaptic contacts with small and large dendritic shafts of apical dendrites of retrogradely labeled corticotectal pyramidal neurons within layer V of the medial frontal cortex. These results suggest that fibers from the the diagonal band nucleus exert their modulatory effects directly on pyramidal cells in the medial frontal cortex.