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Morphology and axonal projection pattern of neurons in the telencephalon of the fire‐bellied toad Bombina orientalis : An anterograde, retrograde, and intracellular biocytin labeling study
Author(s) -
Roth Gerhard,
MühlenbrockLenter Sabine,
Grunwald Wolfgang,
Laberge Frédéric
Publication year - 2004
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.20265
Subject(s) - vomeronasal organ , cerebrum , biology , amygdala , biocytin , neuroscience , anatomy , olfactory tubercle , cytoarchitecture , stria terminalis , olfactory bulb , lateral hypothalamus , hypothalamus , tegmentum , olfactory system , central nervous system , midbrain
The connectivity and cytoarchitecture of telencephalic centers except dorsal and medial pallium were studied in the fire‐bellied toad Bombina orientalis by anterograde and retrograde biocytin labeling and intracellular biocytin injection (total of 148 intracellularly labeled neurons or neuron clusters). Our findings suggest the following telencephalic divisions: (1) a central amygdala–bed nucleus of the stria terminalis in the caudal midventral telencephalon, connected to visceral–autonomic centers; (2) a vomeronasal amygdala in the caudolateral ventral telencephalon receiving input from the accessory olfactory bulb and projecting mainly to the preoptic region/hypothalamus; (3) an olfactory amygdala in the caudal pole of the telencephalon lateral to the vomeronasal amygdala receiving input from the main olfactory bulb and projecting to the hypothalamus; (4) a medial amygdala receiving input from the anterior dorsal thalamus and projecting to the medial pallium, septum, and hypothalamus; (5) a ventromedial column formed by a nucleus accumbens and a ventral pallidum projecting to the central amygdala, hypothalamus, and posterior tubercle; (6) a lateral column constituting the dorsal striatum proper rostrally and the dorsal pallidum caudally, and a ventrolateral column constituting the ventral striatum. We conclude that the caudal mediolateral complex consisting of the extended central, vomeronasal, and olfactory amygdala of anurans represents the ancestral condition of the amygdaloid complex. During the evolution of the mammalian telencephalon this complex was shifted medially and involuted. The mammalian basolateral amygdala apparently is an evolutionary new structure, but the medial portion of the amygdalar complex of anurans reveals similarities in input and output with this structure and may serve similar functions. J. Comp. Neurol. 478:35–61, 2004. © 2004 Wiley‐Liss, Inc.