Brain Structure and Function

, Volume 218, Issue 1, pp 187–208

Common and distinct neural inputs to the medial central nucleus of the amygdala and anterior ventrolateral bed nucleus of stria terminalis in rats

Original Article

DOI: 10.1007/s00429-012-0393-6

Cite this article as:
Bienkowski, M.S. & Rinaman, L. Brain Struct Funct (2013) 218: 187. doi:10.1007/s00429-012-0393-6
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Abstract

The central nucleus of the amygdala (CEA) and lateral bed nucleus of stria terminalis (BST) are highly interconnected limbic forebrain regions that share similar connectivity with other brain regions that coordinate behavioral and physiological responses to internal and environmental stressors. Their similar connectivity is frequently referred to when describing the CEA and lateral BST together as a unified “central extended amygdala”. However, the CEA and BST reportedly play distinct roles in behavioral and physiological responses associated with fear, anxiety, and social defeat, presumably due to differences in connectivity. To identify common and unique sources of input to the CEA and lateral BST, we performed dual retrograde tracing. Fluorogold and cholera toxin β were iontophoresed into the medial CEA (CEAm) and the anterior ventrolateral BST (BSTvl) of adult male rats. The anatomical distribution of tracer-labeled neurons was mapped throughout the brain. Regions with overlapping populations of CEAm- and BSTvl-projecting neurons were further examined for the presence of double-labeled neurons. Although most regions with input to the mCEA also projected to the BSTvl, and vice versa, cortical and sensory system-related regions projected more robustly to the CEAm, while motor system-related regions primarily innervated the BSTvl. The incidence of double-labeled neurons with collateralized axonal inputs to the CEAm and BSTvl was relatively small (~2 to 13%) and varied across regions, suggesting regional differences in the degree of coordinated CEAm and BSTvl input. The demonstrated similarities and differences in inputs to CEAm and BSTvl provide new anatomical insights into the functional organization of these limbic forebrain regions.

Keywords

Limbic systemExtended amygdalaAxon collateralizationDual retrograde tracing

Abbreviations

ACBsh

Nucleus accumbens, shell division

aco

Anterior commissure

AI

Agranular insular cortex

amc

Amygdalar capsule

AP

Area postrema

AStr

Amygdala-striatal transition area

Aud

Auditory thalamus

BLAp

Basolateral amygdalar nucleus, posterior part

BMA

Basomedial amygdalar nucleus

BST

Bed nucleus of stria terminalis

pBST

Posterior subnuclei group of the bed nucleus of stria terminalis

BSTvl

Ventrolateral subnuclei group of the bed nucleus of stria terminalis

CA1

Field CA1, Ammon’s horn

cc

Corpus callosum

CEA

Central amygdalar nucleus

CEAm

Central amygdalar nucleus, medial part

CEAl

Central amygdalar nucleus, lateral part

CLI

Central linear nucleus raphé

cpd

Cerebral peduncle

DI

Dysgranular insular cortex

DMX

Dorsal motor nucleus of the vagus

DR

Dorsal nucleus raphé

dscp

Superior cerebellar peduncle decussation

ec

External capsule

fx

Fornix

ILA

Infralimbic area

IMD

Intermediodorsal nucleus thalamus

IPAC

Interstitial nucleus of the posterior limb of the anterior commissure

LHA

Lateral hypothalamic area

LS

Lateral septal nucleus

mcp

Middle cerebellar peduncle

MD

Mediodorsal nucleus thalamus

ml

Medial lemniscus

mlf

Medial longitudinal fascicle

mPFC

Medial prefrontal cortex

MPO

Medial preoptic area

MTN

Midline thalamic nuclei

NLOT

Nucleus of the lateral olfactory tract

NTS

Nucleus of the solitary tract

och

Optic chiasm

opt

Optic tract

PA

Posterior amygdalar nucleus

PAGvl

Periaqueductal gray, ventrolateral division

PB

Parabrachial nucleus

PBle

Parabrachial nucleus, external lateral part

PBlv

Parabrachial nucleus, ventral lateral part

PBm

Parabrachial nucleus, medial part

PBw

Parabrachial nucleus, waist part

PL

Prelimbic area

PPN

Pedunculopontine nucleus

PSTN

Parasubthalamic nucleus

PVN

Paraventricular hypothalamic nucleus

PVT

Paraventricular thalamic nucleus

py

Pyramid

scp

Superior cerebellar peduncle

SI

Substantia innominata

sm

Stria medullaris

SNc

Substantia nigra, compact part

SNr

Substantia nigra, reticular part

SPFpm

Subparafascicular nucleus thalamus, parvicellular part, medial division

st

Stria terminalis

STN

Subthalamic nucleus

TR

Postpiriform transition area

V4

Fourth ventricle

VLM

Ventrolateral medulla

VP

Ventral pallidum

VPMpc

Ventral posteromedial nucleus thalamus, parvicellular part

VTA

Ventral tegmental area

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  1. 1.Department of NeuroscienceUniversity of PittsburghPittsburghUSA