Search results for "Cerebrum"
showing 10 items of 57 documents
Terminal nerve in the mouse-eared bat (Myotis myotis): ontogenetic aspects.
2006
As in other mammals, ontogenesis of the terminal nerve (TN) in the mouse-eared bat (Myotis myotis) starts shortly after the formation of the olfactory placode, a derivative of the ectoderm. During development of the olfactory pit, proliferating neuroblasts thicken the placodal epithelium and one cell population migrates toward the rostroventral tip of the telencephalon. Here they accumulate in a primordial terminal ganglion, which successively divides into smaller units. Initial fibers of the TN can be distinguished from olfactory fibers in the mid-embryonic period. The main TN fiber bundle (mfb) originates from the anteriormost ganglion in the nasal roof, whereas one or more inconstant sma…
Evolution of the Amygdala in Vertebrates
2007
The main aim of this article is to identify the homologues of the different components of the mammalian amygdala in the cerebral hemispheres of non-mammals using, primarily, a topological/embryological perspective. Thus, we first consider two main divisions of the amygdala of mammals, namely the pallial and subpallial (striatopallidal) amygdala. The pallial amygdala includes derivatives of both the lateral and ventral embryonic pallium that in the adult conform layered, superficial areas usually called cortical amygdala, and deep nuclei that conform the basolateral division of the amygdala plus the amygdalohippocampal area (AHA). The components of the subpallial amygdala are usually grouped…
Afferent and efferent projections of the dorsal anterior thalamic nuclei in the lizard Podarcis hispanica (Sauria, Lacertidae).
2002
The aim of this study was to investigate the afferent and efferent connections of the anterior thalamic nuclei in the lizard Podarcis hispanica. To identify potential sources of sensory inputs and to determine the fine organization of the projections of these thalamic nuclei to the telencephalon, we injected the sensitive tracer biotinylated dextran amine (BDA) into different nuclei of the anterior dorsal thalamus. We also injected BDA into several telencephalic areas in order to corroborate the results of thalamic injections. Our results show that the anterior thalamic nuclei receive projections from multiple areas and nuclei distributed throughout most of the brain, from rhombencephalon t…
Photoperiod-temperature and neuroblast proliferation-migration in the adult lizard cortex.
1997
The lizard medial cortex (a zone homologous to the mammalian fascia dentata) shows delayed postnatal neurogenesis throughout the lifetime of these animals. Experimental lesioning of this area is followed by neuronal regeneration, a unique phenomenon in the adult amniote telencephalon. The differential effects of temperature and photoperiod on postnatal neurogenetic activity were studied using tritiated thymidine pulses and posterior autoradiography as well as proliferating cell nuclear antigen (PCNA) immunostaining. Long (summer) photoperiods increased the number of proliferating neuroblasts in the ependymal neuroepithelium. Cold (winter) temperature prevented migration of the newly generat…
Calcium-binding proteins in the dorsal ventricular ridge of the lizardPsammodromus algirus
1999
The aim of the present work was to study further the intrinsic organization of the dorsal ventricular ridge of lizards. For that purpose, the morphology and distribution of cells and fibers containing the calcium-binding proteins calbindin-D28k, parvalbumin, and calretinin were investigated by using immunohistochemical methods. Colocalization of calcium-binding proteins with the neurotransmitter gamma-aminobutyric acid (GABA) was also studied because they are shown to coexist in many areas of the telencephalon where they define distinct subpopulations of GABAergic local circuit neurons. Neurons containing calcium-binding proteins are limited to the anterior part of the dorsal ventricular ri…
Distribution of CGRP-like immunoreactivity in the chick and quail brain
2000
Calcitonin gene-related peptide (CGRP)-containing neurones have been implicated in the transmission of visceral sensory information to the cortex and in the control of arterial blood pressure in mammals. However, little is known about its function in other vertebrates. As a first step toward investigating the function of CGRP in birds, its distribution was studied in the domestic chick and quail brain by means of immunocytochemistry, by using antibodies against rat CGRP. The distribution of CGRP immunoreactivity in the chick and quail central nervous system was found to be similar. CGRP-immunoreactive (CGRPi) perikarya were not present in the telencephalon. In the diencephalon, CGRPi perika…
Ontogeny of somatostatin immunoreactive neurons in the medial cerebral cortex and other cortical areas of the lizardPodarcis hispanica
1996
The ontogeny of somatostatin immunoreactive interneurons in the cerebral cortex of the lizard Podarcis hispanica has been studied in histological series of embryos, perinatal specimens, and adults. Somatostatin immunoreactive interneurons appear in the early stages of lizard cerebral cortex ontogeny, their number increases during embryonary development, reaches a peak in early postnatal life, and decreases in adult lizards. The first somatostatin immunoreactive somata in the lizard forebrain appeared on E36, and they were located in non cortical areas. Then, on E39 and later, somatostatin immunoreactive neurons were seen in the lizard cortex in a rostral-to-caudal spatial gradient, which pa…
Trigeminal Projections to the Dorsal Thalamus in a Lacertid Lizard, <i>Podarcis hispanica</i>
1998
Trigeminothalamic projections in the lizard <i>Podarcis hispanica </i>were investigated by means of biotinylated dextranamine (BDA) injections into different nuclei of the dorsal thalamus. Previous studies of lizards found a projection from the sensory trigeminal nuclei in the brainstem to the nuclei ventromedialis and ventrolateralis of the ventral thalamus. The present results show that, in addition to these projections to ventral thalamic nuclei, neurons of the nucleus of the descending tract and the principal sensory nucleus project contralaterally to the pretectal nucleus lentiformis thalami and bilaterally to the nucleus dorsolateralis anterior thalami of the dorsal thalam…
Organization of Zinc-Containing Terminal Fields in the Brain of the LizardPodarcis hispanica: A Histochemical Study
1988
The Timm method for the histochemical detection of metals defines accurately many terminal fields in the brain of mammals. This pattern is based on the presence of zinc within the synaptic vesicles of some boutons. The aim of this study was to use the Timm method for the anatomical description of the brain in a reptile. In the telencephalon, zinc staining was observed in the inner layer of the medial cortex, the inner and outer layers of both dorsomedial and dorsal cortices, the inner layer of the lateral cortex pars anterior ventralis, the lateral cortex pars profunda, the intermediate and caudal aspects of the anterior dorsal ventricular ridge, the marginal layer and hilus of the nucleus …
Olfacto-retinalis pathway in Austrolebias charrua fishes: A neuronal tracer study
2013
Abstract The olfacto-retinal centrifugal system, a constant component of the central nervous system that appears to exist in all vertebrate groups, is part of the terminal nerve (TN) complex. TN allows the integration of different sensory modalities, and its anatomic variability may have functional and evolutionary significance. We propose that the olfacto-retinal branch of TN is an important anatomical link that allows the functional interaction between olfactory and visual systems in Austrolebias . By injecting three different neuronal tracers (biocytin, horseradish peroxidase, and 1,1′-dioctadecyl-3,3,3′,3′tetramethyl-indocarbocyanine perchlorate (DiI)) in the left eye of Austrolebias ch…