A cytoarchitectonic study of the diencephalon of the tegu lizard, <i>Tupinambis nigropunctatus</i>

Cruce, Judith A.F.

doi:10.1002/cne.901530302

Cited by 75 publications

(42 citation statements)

References 23 publications

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“…Continuing caudally, the area between the lateral forebrain bundle and the third ventricle can be divided into three zones based on cellular density, with the densest zone being the most medial (the medial POA) and the sparsest the most lateral. The border between the intermediate (lateral POA) and more sparsely populated cell groups was traced [see Cruce, 1974. for divi sions of the dicncephalon of teiid lizards).…”

Section: Methodsmentioning

confidence: 99%

Sexually Dimorphic Areas in the Brain of Whiptail Lizards

1990

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The whiptail lizard species Cnemidophorus inornatus exhibits sexually dimorphic mating behaviors. We report that complementary sexual dimorphisms exist in two hypothalamic regions in male and female C. inornatus. The anterior hypothalamus-preoptic area (AH-POA), which is involved in male-typical mounting and intromission behaviors, is larger in males. The ventromedial hypothalamus (VMH), which controls female-typical receptivity, is larger in females. The all-female whiptail lizard Cnemidophorus uniparens, a direct descendant of C. inornatus, regularly and reliably displays both male-like mounting and female-like receptive (pseudosexual) behaviors. Rather than having a male-like AH-POA, however, the AH-POA as well as the VMH of C. uniparens resemble that of female C. inornatus. The biological basis of pseudosexual behavior in the parthenogen appears to be due to an unusual sensitivity to ovarian progesterone rather than to a difference in brain morphology.

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Section: Methodsmentioning

confidence: 99%

Sexually Dimorphic Areas in the Brain of Whiptail Lizards

1990

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“…Tracing was achieved first by using the interpolation function of the program Amira (Fischer 3D), followed by manual correction of every slice in all 3 dimensions, resulting in one 3D label for each subdivision of the tawny dragon MRI model (this process is called manual segmentation). There is no neuroanatomical atlas available for an agamid brain, so we analysed numerous available atlases for the brains of other lizards in order to accurately delineate the 6 subdivisions [ten Donkelaar, 1998;Del Corral et al, 1990;Medina et al, 1992;Greenberg, 1982;Smeets et al, 1986;Northcutt, 1967;Ulinski and Peterson, 1981;Butler and Northcutt, 1973;Cruce, 1974;Cruce and Newman, 1981;Schwab, 1979;Wolters et al, 1985;Wolters et al, 1984;ten Donkelaar et al, 2012]. Briefly, the telencephalon-diencephalon boundary is marked by the preoptic area and the epithalamus, the diencephalon-mesencephalon boundary by the pretectal nuclei, and the mesencephalon-rhombencephalon boundary by the isthmus.…”

Section: Calculating Brain Volumes With Magnetic Resonance Imagingmentioning

confidence: 99%

Evidence for Concerted and Mosaic Brain Evolution in Dragon Lizards

et al. 2017

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is unclear. Here, we examined the volumes of the 6 major neural subdivisions across 14 species of the agamid lizard genus Ctenophorus (dragons). These species have diverged multiple times in behaviour, ecology, and body morphology, affording a unique opportunity to test neuroevolutionary models across species. We assigned each species to an ecomorph based on habitat use and refuge type, then used MRI to measure total and regional brain volume. We found evidence for both mosaic and concerted brain evolution in dragons: concerted brain evolution with respect to body size, and mosaic brain evolution with respect to ecomorph. Specifically, all brain subdivisions increase in volume relative to body size, yet the tectum and rhombencephalon also show opposite patterns of evolution with respect to ecomorph. Therefore, we find that both models of evolution are occurring simultaneously in the same structures in dragons, but are only detectable when examining particular drivers of selection. We show that the answer to the question of whether concerted or mosaic brain evolution is detected in a system can depend more on the type of selection measured than on the clade of animals studied. AbstractThe brain plays a critical role in a wide variety of functions including behaviour, perception, motor control, and homeostatic maintenance. Each function can undergo different selective pressures over the course of evolution, and as selection acts on the outputs of brain function, it necessarily alters the structure of the brain. Two models have been proposed to explain the evolutionary patterns observed in brain morphology. The concerted brain evolution model posits that the brain evolves as a single unit and the evolution of different brain regions are coordinated. The mosaic brain evolution model posits that brain regions evolve independently of each other. It is now understood that both models are responsible for driving changes in brain morphology; however, which factors favour concerted or mosaic brain evolution

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“…These kinds of data are particularly lacking for the reptilian thalamus, yet an understanding of thalamic organization in reptiles is essential for testing theories about the evolution of the more complex avian and mammalian diencephalic patterns, and, further, for theories of telencephalic evolution. Apart from a few cytoarchitectonic studies on the reptilian diencephalon performed recently (Butler and Northcutt, 1973;Cruce, 1974;Senn, 1979;Hergueta et al, 1993), there has been only limited work on analyzing its structure (Pritz and Stritzel, 1986Díaz et al, 1994;Pritz, 1995Pritz, , 1997Pritz and Siadati, 1999). Moreover, most recent studies on the reptilian thalamus deal with the extrinsic connectivity of the dorsal thalamus and especially with the visual thalamus (Dacey and Ulinski, 1983;Pritz and Stritzel, 1992;Kenigfest et al, 1997;Martinez-Marcos et al, 1998), whereas other "thalamic" regions, such as the ventral thalamus, the epithalamus, or the pretectum, are not addressed in detail.…”

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confidence: 99%

Expression of calcium-binding proteins in the diencephalon of the lizardPsammodromus algirus

Dávila¹,

Guirado

Puelles

2000

J. Comp. Neurol.

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This work is a study of the distribution pattern of calbindin-D28k, calretinin, and parvalbumin in the diencephalic alar plate of a reptile, the lizard Psammodromus algirus, by using the prosomeric model (Puelles [1995] Brain Behav Evol 46:319-337), which divides the alar plate of the diencephalon into the caudorostrally arranged pretectum (p1), dorsal thalamus plus epithalamus (p2), and ventral thalamus (p3). Calbindin and calretinin are more extensively expressed in the dorsal thalamus than in the neighboring alar regions, and therefore these calcium-binding proteins are particularly suitable markers for delimiting the dorsal thalamus/epithalamus complex from the ventral thalamus and the pretectum. Conversely, parvalbumin is more intensely expressed in the pretectum and ventral thalamus than in the dorsal thalamus/epithalamus complex. Within the dorsal thalamus, calcium-binding protein immunoreactivity reveals a three-tiered division. The pretectum displays the most intense expression of parvalbumin within the diencephalon. Virtually all nuclei in the three sectors of the pretectum (commissural, juxtacommissural, and precommissural) present strong to moderate expression of parvalbumin. We compare the distribution of calcium-binding proteins in the diencephalon of Psammodromus with other vertebrates, with mammals in particular, and suggest that the middle and ventral tiers of the reptilian dorsal thalamus may be comparable to nonspecific or plurimodal posterior/intralaminar thalamic nuclei in mammals, on the basis of the calcium-binding protein expression patterns, as well as the hodological and embryological data in the literature.

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A cytoarchitectonic study of the diencephalon of the tegu lizard, Tupinambis nigropunctatus

Cited by 75 publications

References 23 publications

Sexually Dimorphic Areas in the Brain of Whiptail Lizards

Sexually Dimorphic Areas in the Brain of Whiptail Lizards

Evidence for Concerted and Mosaic Brain Evolution in Dragon Lizards

Expression of calcium-binding proteins in the diencephalon of the lizardPsammodromus algirus

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