Afferent Projections to the Lateral and Dorsomedial Hypothalamus in a Lizard, &lt;i&gt;Gekko gecko&lt;/i&gt;

Bruce, Laura L.; Neary, Timothy J.

doi:10.1159/000113256

Cited by 51 publications

(37 citation statements)

References 14 publications

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“…Previous reports, using different neuroanatomical techniques, define a main amygdalo-hypothalamic pathway to the VMH (Hoogland, 1977;Voneida and Sligar, 1979;Halpern, 1980;Bruce and Neary, 1995a) and an additional descending projection to the lateral hypothalamus from the transition between the striatum and amygdala (Russchen and Jonker, 1988;Bruce and Neary, 1995b). Our results clearly define the origin and termination of these two projections and reveal the presence of two new amygdalo-hypothalamic pathways.…”

Section: Discussionsupporting

confidence: 72%

“…3) rules out the possibility that the hypothalamic labeling observed in this case had a cortical origin (Hoogland and VermeulenVanderZee, 1989). This view is reinforced by the presence of labeled cells in the VPA and VAA of the gecko after large injections in the tuberal hypothalamus (Bruce and Neary, 1995b).…”

Section: General Organization Of the Amygdalo-hypothalamic Projectionmentioning

confidence: 95%

“…11A). Moreover, Bruce and Neary (1995b) report labeling in the ventral half of the Naot after a WGA-HRP injection restricted to the lateral hypotalamic area at tuberal levels (see their Fig. 4).…”

Section: General Organization Of the Amygdalo-hypothalamic Projectionmentioning

confidence: 95%

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Amygdalo-hypothalamic projections in the lizardPodarcis hispanica: A combined anterograde and retrograde tracing study

et al. 1997

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The cells of origin and terminal fields of the amygdalo-hypothalamic projections in the lizard Podarcis hispanica were determined by using the anterograde and retrograde transport of the tracers, biotinylated dextran amine and horseradish peroxidase. The resulting labeling indicated that there was a small projection to the preoptic hypothalamus, that arose from the vomeronasal amygdaloid nuclei (nucleus sphericus and nucleus of the accessory olfactory tract), and an important projection to the rest of the hypothalamus, that was formed by three components: medial, lateral, and ventral. The medial projection originated mainly in the dorsal amygdaloid division (posterior dorsal ventricular ridge and lateral amygdala) and also in the centromedial amygdaloid division (medial amygdala and bed nucleus of the stria terminalis). It coursed through the stria terminalis and reached mainly the retrochiasmatic area and the ventromedial hypothalamic nucleus. The lateral projection originated in the cortical amygdaloid division (ventral anterior and ventral posterior amygdala). It coursed via the lateral amygdalofugal tract and terminated in the lateral hypothalamic area and the lateral tuberomammillary area. The ventral projection originated in the centromedial amygdaloid division (in the striato-amygdaloid transition area), coursed through the ventral peduncle of the lateral forebrain bundle, and reached the lateral posterior hypothalamic nucleus, continuing caudally to the hindbrain. Such a pattern of the amygdalo-hypothalamic projections has not been described before, and its functional implications in the transfer of multisensory information to the hypothalamus are discussed. The possible homologies with the amygdalo-hypothalamic projections in mammals and other vertebrates are also considered.

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Section: Discussionsupporting

confidence: 72%

Section: General Organization Of the Amygdalo-hypothalamic Projectionmentioning

confidence: 95%

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Amygdalo-hypothalamic projections in the lizardPodarcis hispanica: A combined anterograde and retrograde tracing study

et al. 1997

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“…It is likely that this afferent circuitry is present in all vertebrates, because the lateral hypothalamus and pallidum project to the habenula in fish, amphibians, and mammals (1,(48)(49)(50), but experiments are needed to confirm that these nuclei project selectively to the homologs of the LHb in fish and amphibians. Interestingly, our results suggest that the DPh is topographically distinct from the DP, the lamprey homolog of the GPi/EP (23).…”

Section: Discussionmentioning

confidence: 99%

Evolutionary conservation of the habenular nuclei and their circuitry controlling the dopamine and 5-hydroxytryptophan (5-HT) systems

Stephenson-Jones

Floros

Robertson

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

129

153

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The medial (MHb) and lateral (LHb) habenulae are a small group of nuclei that regulate the activity of monoaminergic neurons. Disruptions to these nuclei lead to deficits in a range of cognitive and motor functions from sleep to decision making. Interestingly, the habenular nuclei are present in all vertebrates, suggesting that they provide a common neural mechanism to influence these diverse functions. To unravel conserved habenula circuitry and approach an understanding of their basic function, we investigated the organization of these nuclei in the lamprey, one of the phylogenetically oldest vertebrates. Based on connectivity and molecular expression, we show that the MHb and LHb circuitry is conserved in the lamprey. As in mammals, separate populations of neurons in the LHb homolog project directly or indirectly to dopamine and serotonin neurons through a nucleus homologous to the GABAergic rostromedial mesopontine tegmental nucleus and directly to histamine neurons. The pallidal and hypothalamic inputs to the LHb homolog are also conserved. In contrast to other species, the habenula projecting pallidal nucleus is topographically distinct from the dorsal pallidum, the homolog of the globus pallidus interna. The efferents of the MHb homolog selectively target the interpeduncular nucleus. The MHb afferents arise from sensory (medial olfactory bulb, parapineal, and pretectum) and not limbic areas, as they do in mammals; consequently, the "context" in which this circuitry is recruited may have changed during evolution. Our results indicate that the habenular nuclei provide a common vertebrate circuitry to adapt behavior in response to rewards, stress, and other motivating factors.basal ganglia | neuromodulator T he habenular complex, a small group of nuclei in the epithalamus, links the limbic forebrain to mid-and hind-brain regions involved in adapting the internal cerebral state (1-4). Lesion and genetic inactivation studies have implicated the habenula in a range of functions from control of the circadian rhythm to adapting the behavioral response to fear and reward, as well as to higher cognitive functions, such as attention and value-based decision making (5-8). The habenula is present in all classes of vertebrates, including those that seemingly lack highlevel cognitive functions (9). This suggests that it regulates processes crucial to survival through a basic neural mechanism common to all vertebrates. To unravel the neural basis for the habenula's basic and complex functions, it will be important to elucidate the basic circuitry and determine how this has evolved to regulate higher cognitive functions.In mammals, the habenula is subdivided into two nuclei: the medial habenula (MHb) and lateral habenula (LHb) (10). The LHb receives value-related signals from the basal ganglia [globus pallidus interna/entopeduncular nucleus (GPi/EP)] as well as inputs from the diagonal band of Broca and the lateral hypothalamus (1, 11). The LHb projects to the GABAergic rostromedial mesopontine tegmental nucleus (RMTg), a...

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“…Corticohypothalamic projections were reported to originate from the mCx in pond turtles [Hall et al, 1977], from the mCx and dmCx in lizards [Bruce and Butler, 1984a], from the dCx in the lizard Gekko [Bruce and Neary, 1995], and from dmCx and dCx in Tegu lizards [Lohman and Mentink, 1972;Lohman and Van Woerden-Verkley, 1976]. Although direct corticorubral projections in mammals are well documented, the existence of corticohypothalamic pathways in reptiles might be functionally significant because it has been determined that in turtles descending inputs to the red nucleus, a major decending pathway controlling movement, arise from the suprapeduncular nucleus (nSP) of the hypothalamus, which lies just lateral to the periventricular nucleus of the hypothalamus [nPH; Sarrafizadeh and Houk, 1994;Herrick and Keifer, 1997;Keifer and Lustig, 2000].…”

Section: Introductionmentioning

confidence: 99%

Thalamocortical Connections in the Pond Turtle <i>Pseudemys scripta elegans</i>

Zhu¹,

Lustig²,

Bifulco³

et al. 2005

Brain Behav Evol

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Thalamocortical connections are a neuroanatomical feature shared among vertebrates, although the extent and organization of these connections vary among species. From an evolutionary standpoint, reptiles represent early stages of the pattern of connectivity between the thalamus and cortex, and elucidation of these pathways may help to reveal the biological significance of these projections. The present tract tracing study was performed to examine the organization of thalamocortical projections in the pond turtle, Pseudemys scripta elegans. All experiments were carried out using in vitro brain preparations. Injections of neurobiotin into the medial cortex resulted in labeled neurons in the ipsilateral dorsomedial anterior nucleus of the thalamus, those in the dorsomedial cortex labeled neurons in the dorsolateral anterior nucleus, and injections into the dorsal cortex resulted in labeled neurons in the dorsal lateral geniculate nucleus of the thalamus. Injections of neurobiotin into these thalamic nuclei confirmed the projections to the cortex. Finally, neurobiotin injections primarily into the medial cortex resulted in bilateral label of axons and terminals in the suprapeduncular nucleus of the hypothalamus. The results of the neurobiotin injections revealed a topographic pattern of thalamocortical connections such that medial cortical regions connect with medial thalamic nuclei and lateral cortical regions connect with lateral nuclei. These findings suggest that the presence of functionally segregated thalamocortical projections is a conserved feature of brain organization among amniotes. Moreover, this work describes a descending pathway linking cortical regions with the red nucleus via the hypothalamus thereby providing indirect cortical control of the reptilian rubrospinal system.

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Afferent Projections to the Lateral and Dorsomedial Hypothalamus in a Lizard, <i>Gekko gecko</i>

Cited by 51 publications

References 14 publications

Amygdalo-hypothalamic projections in the lizardPodarcis hispanica: A combined anterograde and retrograde tracing study

Amygdalo-hypothalamic projections in the lizardPodarcis hispanica: A combined anterograde and retrograde tracing study

Evolutionary conservation of the habenular nuclei and their circuitry controlling the dopamine and 5-hydroxytryptophan (5-HT) systems

Thalamocortical Connections in the Pond Turtle <i>Pseudemys scripta elegans</i>

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