Fiber Connections of the Amygdaloid Formation of the Lizard <i>Podarcis hispanica</i>

Abstract

The amygdaloid formation of the lizard Podarcis hispanica can be divided into three main groups of nuclei on the basis of their input from the main and accessory olfactory bulbs: the vomeronasal amygdala, the olfactory amygdala and the dorsal amygdaloid group, the latter group receiving afferents from neither the main (MOB) or the accessory olfactory bulb (AOB). The vomeronasal amygdala has a centrifugal projection to the AOB, an important commissural connection to the contralateral vomeronasal amygdala, a minor projection to nucleus accumbens, and a bilateral projection to the lateral cortex. The olfactory amygdala displays a bilateral afferents from the MOB, receives a contralateral afferent, and is reciprocally connected with the lateral cortex. Moreover, it receives an important input from the vomeronasal amygdala. The dorsal amygdaloid group receives projections from the other two amygdaloid groups, multimodal inputs from the anterior dorsal ventricular ridge and the dorsal cortex, and a putative cholinergic input from the basal telencephalon. Moreover, it is the site of origin of a prominent bilateral amygdalo-striatal projection that extends to the bed nucleus of the stria terminalis and the so-called amygdalo-striatal transition area, through which it may control both visceral and motor activities. The main extratelencephalic output of the amygdala courses through the stria terminalis and terminates in the ventromedial hypothalamic nucleus. The extratelencephalic afferents of the amygdala arise from several hypothalamic and anterior thalamic nuclei, from the mesencephalic and rhombencephalic aminergic cell groups, and from the rhombencephalic parabrachial nucleus.

Efferents and Centrifugal Afferents of the Main and Accessory Olfactory Bulbs in the Snake <i>Thamnophis sirtalis</i>

“…It was called angulostriatal mass by Warner [1931] and Halpern [1980]. The name DLA was proposed by Martínez-García et al [1991], who later showed its strongly cholinergic character [Martínez-García et al, 1993]. The Thamnophis DLA also shows strong cholinesterase reactivity (unpubl.…”

Rapid neuroendocrine responses evoked at the onset of social challenge

“…These two regions have been shown previously to be involved in responses to different stress types [4,5,[26][27][28]. Accumbal samples comprised tissue homologous to mammalian NAc shell [35][36][37][38] while amygdalar samples correspond to the combined central, lateral and medial regions of the mammalian amygdaloid complex without inclusion of the basolateral nucleus homologue [23][24][25]39]. …”

“…The rapid increases in A. carolinensis amygdalar DA levels with social threat occurred in areas homologous with the central, lateral and medial nuclei of the mammalian amygdala [23][24][25]. Exposure to aversive conditioned stimuli is associated with increased DA levels in the central and lateral nuclei of the mammalian amygdala [53,54], and DA activity in the lateral amygdala is essential for inducing synaptic plasticity underlying acquisition of conditioned fear memories [55,56].…”

“…Specifically, we examined if acute social challenge would elicit changes both in systemic catecholamine release and in DA and 5-HT activity within the NAc and amygdala. We chose these limbic regions based on their known association with aggression and stress responses, their homology with mammalian systems [23][24][25], and our previous data demonstrating robust changes in DA and 5-HT activity in response to a range of stressors, including social stress [4,5,[26][27][28]. We also determined whether these neuroendocrine responses differed with the level of social threat, i.e., with the absence or presence of eyespots on the reflected opponent.…”

Proliferation, Migration, and Survival of Cells in the Telencephalon of the Ball Python, Python Regius

“…Following Curwen (1939), snake studies labeled the region lateral to the caudalmost NS as "pDVR" (Halpern, 1980;Krohmer and Crews, 1987b;Ulinski and Rainey, 1980). Subsequently, Martinez-Garcia et al (1991) labeled the region as DLA in lizards, and limited the PDVR to the caudal DVR region without this additional area (Martínez-García et al, 1993). This system has been implemented in many contemporary snake and squamate brain studies (Lanuza and Halpern, 1997b;Lanuza and Halpern, 1998;Martínez-García et al, 2007).…”