Search results for "Hispanic"
showing 10 items of 77 documents
A Golgi study of the principal projection neurons of the medial cortex of the lizardPodarcis hispanica
1997
The medial cortex of lizards is a simple three-layered brain region displaying many characteristics that parallel the hippocampal fascia dentata of mammals. Its principal neurons form a morphologically diverse population, partly as a result of the prominent continuous growth of this nervous center. By using the classic Golgi impregnation method, we describe here the morphology of the principal neurons populating the medial cortex of Podarcis hispanica. These were projection neurons giving off descending axons. These axons displayed deep collateral branches provided with prominent axonal boutons, while the main axonal branch reached adjacent cortical areas and the bilateral septum. According…
Delayed postnatal neurogenesis in the cerebral cortex of lizards
1988
Labelled cells were consistently observed in the medial cortex of the lizard brain after i.p. injections of tritiated thymidine (5 microCi/g b. wt.), 1, 7, 18 or 28 days of survival and posterior autoradiographic evaluation. In 3 groups of specimens (postnatal, young and adult) of the species Podarcis hispanica, after one day of survival, labelled cells were located in the ependymal cell layer underlying the medial cortex. After intermediate survival times (7, 18 days), labelled cells were found in 3 zones: the ependymal layer, the inner plexiform layer and the granular layer. After one month of survival, most labelled cells were observed in the granular layer. In the granular layer, these …
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…
Laminar distribution and morphology of gamma-aminobutyric acid (GABA)-immunoreactive neurons in the medial and dorsomedial areas of the cerebral cort…
1988
The morphology and laminar distribution of immunolabeled neurons in the medial and dorsomedial telencephalic cortices of the lizard Podarcis hispanica were examined in vibratome sections after preembedding γ-aminobutyric acid (GABA)-immunocytochemistry. In both cortical areas and at all rostrocaudal levels, GABA-immunoreactive neurons were found in all cortical layers, with the largest number (74%) of GABA-positive cells in layer 3. GABA-positive neurons were classified into pyramidlike, vertical-fusiform, multipolar, and horizontal neurons. Cells that could be so classified were counted in each cortical lamina. In the medial cortex, multipolar and horizontal-bipolar cells dominated layer 1…
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…
Size variation and cell proliferation in chemosensory brain areas of a lizard (Podarcis hispanica): effects of sex and season
2008
Many lizards rely on chemoreception for crucial aspects of their biology, including exploration, prey and predator detection, and intraspecific communication. Here we investigate sex and seasonal variation in size and proliferative activity in chemosensory areas of the lizard brain. We captured adult Iberian wall lizards (Podarcis hispanica) of either sex in the breeding (April) and non-breeding (November) season, injected them with 5-bromo-2'-deoxyuridine (BrdU) and killed them 3 weeks later. We removed the brains, measured the length of the olfactory bulbs, and counted BrdU-labelled cells in the main and accessory olfactory bulbs (MOB, AOB), lateral cortex (LC) and nucleus sphericus (NS).…
County-level socioeconomic and crime risk factors for substantiated child abuse and neglect.
2019
Rates of substantiated child abuse and neglect vary significantly across counties. Despite strong cross-sectional support for links between social-contextual characteristics and abuse and neglect, few longitudinal studies have tested relations between these risk factors and substantiated rates of abuse/neglect. The goal of this study was to identify county-level socioeconomic and crime factors associated with substantiated abuse/neglect rates over 13 years (2004-2016). Annual county-level data for Tennessee, obtained from the KIDS COUNT Data Center, included rates of substantiated child abuse and neglect, children's race and ethnicity, births to unmarried women, teen birth rate, children in…
Chemosensory Recognition of Familiar and Unfamiliar Conspecifics by Juveniles of the Iberian Wall Lizard Podarcis hispanica
2002
Chemosensory recognition of familiar conspecifics has been reported in studies with members of several lizard families and may be advantageous to distinguish between intruders and neighbors or group members. However,few species have been studied and information on the ability to discriminate between familiar and unfamiliar conspecifics by chemosensory means is lacking for most lizard families. In this paper we ask whether juveniles of the Iberian wall lizard Podarcis hispanica (Lacertidae),can discriminate between chemical signals from familiar conspecifics with whom they have shared a terrarium for several months and those from unfamiliar conspecifics housed in a different terrarium. Exper…
Beyond ‘nasty neighbours’ and ‘dear enemies’? Individual recognition by scent marks in a lizard (Podarcis hispanica)
2008
True individual recognition (TIR), the ability to recognize conspecific individuals on the basis of identity cues, is required for the evolution of several social traits (e.g. the maintenance of dominance hierarchies). However, knowledge about the distribution and functional significance of TIR is scant in some vertebrate groups, such as reptiles. In this study we used a functional modification of a habituation-dishabituation paradigm to investigate the existence and adaptive significance of TIR in a territorial lizard (Podarcis hispanica, Lacertidae). Males discriminated between individual rivals of similar characteristics (e.g. size, weight, familiarity) solely on the basis of their scent…