Points of view concerning forebrain morphology in lower vertebrates

Holmgren, Nils

doi:10.1002/cne.900340502

Cited by 196 publications

(199 citation statements)

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“…Once it was established by studies of chemoarchitectony and connectivity which are the homologues of the mammalian subpallium in sauropsids (comprising, basically, the striatum and pallidum; ¢gure 1b^d), it was obvious that the pallium of reptiles and birds contains massive nuclear areas within the ventricularly prominent formations called in reptiles thè anterior dorsal ventricular ridge' (ADVR) and the`basal dorsal ventricular ridge' (BDVR) (Ulinsky 1983;Kriegstein et al 1986). This conclusion agreed with earlier embryological conclusions regarding these ridges as being pallial, on topological grounds (Holmgren 1925;KÌlle¨n 1951aKÌlle¨n ,b,c, 1953KÌlle¨n , 1962. In birds, we unfortunately still use an obsolete nomenclature that erroneously attributes the su¤x`striatum' to the pallial DVR components, so that the reptilian BDVR equals the avian`archistriatum', and the ADVR homologue is subdivided into overlying parts called`neostriatum ' and`hyperstriatum ventrale' (¢gure 1c).…”

Section: The Pallium In Sauropsidssupporting

confidence: 92%

“…Holmgren's (1925) hypothesis agrees with modern gene-mapping data and is more parsimonious with ad hoc assumptions at all levels of analysis, independently of complexities introduced by the diverse palliopetal and palliofugal tangential cell migrations reported in recent years.…”

Section: Any Insights Into Cortical Evolution?supporting

confidence: 83%

“…Incidentally, such experiments should also examine whether some elements of the lateral pallium nuclear components may also migrate tangentially into the dorsal pallial cortex. Alternatively, if tangential migrations from the ventral and lateral pallium into the cortex are absent in mammals, then the ventropallial and lateropallial parts of the claustroamygdaloid complex represent the respective complete derivatives, strictly in agreement with Holmgren's (1925) hypothesis (see also Striedter 1997;Aboitiz 1999).…”

Section: The Claustroamygdaloid Complex and Its Connectionsmentioning

confidence: 54%

“…Accordingly, the complete hypopallium and the neighbouring dorsal pallium would represent two independent radially complete sectors of the telencephalic wall, and the same relationship applies for the medial pallium (and any areal subdivisions within them). The mammalian hypopallium was held by Holmgren (1925) to be ¢eld-homologous to the sauropsidian hypopallium, composed of the olfactory cortex (lateral pallium homologue) plus the DVR formations (held to be a claustroamygdaloid homologue). From the strictly topological point of view, this analysis seems sound, as corroborated by the respective patterns of radial glia and some hodological data (Ka¨lma¨n et al 1993;Bruce & Neary 1995;Striedter & Beydler 1997;Striedter 1997).…”

Section: The Pallium In Sauropsidsmentioning

confidence: 99%

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Thoughts on the development, structure and evolution of the mammalian and avian telencephalic pallium

Puelles

2001

Phil. Trans. R. Soc. Lond. B

175

207

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Various lines of evidence suggest that the development and evolution of the mammalian isocortex cannot be easily explained without an understanding of correlative changes in surrounding areas of the telencephalic pallium and subpallium. These are close neighbours in a common morphogenetic ¢eld and are postulated as sources of some cortical neuron types (and even of whole cortical areas). There is equal need to explain relevant developmental evolutionary changes in the dorsal thalamus, the major source of a¡erent inputs to the telencephalon (to both the pallium and subpallium). The mammalian isocortex evolved within an initially small dorsal part of the pallium of vertebrates, surrounded by other pallial parts, including some with a non-cortical, nuclear structure. Nuclear pallial elements are markedly voluminous in reptiles and birds, where they build the dorsal ventricular ridge, or hypopallium, which has been recently divided molecularly and structurally into a lateral pallium and a ventral pallium. A¡erent pallial connections are often simpli¢ed as consisting of thalamic ¢bres that project either to focal cell aggregates in the ventral pallium (predominant in reptiles and birds) or to corticoid areas in the dorsal pallium (predominant in mammals). Karten's hypothesis, put forward in 1969, on the formation of some isocortical areas postulates an embryonic translocation into the nascent isocortex of the ventropallial thalamorecipient foci and respective downstream ventropallial target populations, as speci¢c layer IV, layers II^III, or layers V^VI neuron populations. This view is considered critically in the light of various recent data, contrasting with the alternative possibility of a parallel, separate evolution of the di¡erent pallial parts. The new scenario reveals as well a separately evolving tiered structure of the dorsal thalamus, some of whose parts receive input from midbrain sensory centres (collothalamic nuclei), whereas other parts receive oligosynaptic`lemniscal' connections bypassing the midbrain (lemnothalamic nuclei). An ampler look into known hodological patterns from this viewpoint suggests that ancient collothalamic pathways, which target ventropallial foci, are largely conserved in mammals, while some emergent cortical connections can be established by means of new collaterals in some of these pathways. The lemnothalamic pathways, which typically target ancestrally the dorsopallial isocortex, show parallel increments of relative size and structural diversi¢cation of both the thalamic cell populations and the cortical recipient areas. The evolving lemnothalamic pathways may interact developmentally with collothalamic corticopetal collaterals in the modality-speci¢c invasion of the emergent new areas of isocortex.

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Section: The Pallium In Sauropsidssupporting

confidence: 92%

Section: Any Insights Into Cortical Evolution?supporting

confidence: 83%

Section: The Claustroamygdaloid Complex and Its Connectionsmentioning

confidence: 54%

Section: The Pallium In Sauropsidsmentioning

confidence: 99%

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Thoughts on the development, structure and evolution of the mammalian and avian telencephalic pallium

Puelles

2001

Phil. Trans. R. Soc. Lond. B

175

207

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“…1). Interestingly, this interpretation had been previously made by some early comparative neuroanatomists (Holmgren 1922). Additional studies in mammals evidenced a strong auditory and visual projection from posterior thalamic nuclei to amygdalar components, further supporting a relationship between this structure and at least part of the claustroamygdalar system (Doron & LeDoux 1999, 2000.…”

Section: Case Study: the Origin Of The Mammalian Neocortexsupporting

confidence: 52%

A developmental approach to homology and brain evolution

Aboitiz

2010

Rev. chil. hist. nat.

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Although homology is central to evolutionary interpretations, establishing it has become a highly disputed issue in some instances. Here I argue for a developmental understanding of evolution, where modifications of the developmental programs are a key source of evolutionary novelty. Although this perspective is not new, in comparative neurobiology it has remained controversial. Specifically, the evolutionary origin of the mammalian neocortex has been a particularly debated point. I propose a perspective that could help reconcile a long standing controversy: either the mammalian neocortex corresponds as a whole to the dorsal hemisphere of reptiles and birds, or alternatively its lateral aspect corresponds to the lateral cerebral hemisphere and is partly homologous to the dorsal ventricular ridge (DVR), a brain mass that receives the bulk of sensory input in reptiles and birds. Genetic and embryonic evidence strongly favor a dorsal origin for the whole neocortex, while the DVR derives from the lateral hemisphere. Nevertheless, the phylogenetically new elements of both the neocortex and the avian DVR derive largely from intermediate progenitor cells located in the embryonic subventricular zone (SVZ), a zone of late proliferating activity located deep to the ventral, the lateral and the dorsal hemisphere. I suggest that, despite originating in different embryonic regions (lateral vs. dorsal hemisphere), the evolutionary new cellular elements in both the avian brain and in the mammalian neocortex derive from the activation of a similar genetic pathway, possibly activated by the gene Pax-6, that induces the late proliferation of embryonic neural progenitors. This pathway can be ancestral to amniotes, reflecting genetic homology. In mammals and birds independently, this precursor proliferative activity differentiated into an SVZ, recruiting neuronal precursors from different parts of the cerebral hemisphere in each group, to contribute to brain expansion.Key words: dorsal ventricular ridge, neocortex, pallium, subventricular zone, ventricular zone. RESUMENSi bien la homología es central en las interpretaciones evolutivas, en algunos casos su determinación ha sido causa de fuertes discusiones. Aquí propongo un enfoque evolutivo basado en la embriología, donde las modificaciones de los programas de desarrollo son una fuente crucial de novedad evolutiva. Si bien esta propuesta no es nueva, ha sido controversial en la neurobiología comparada. Específicamente, el origen de la neocorteza de los mamíferos es un tópico altamente debatido. Sugiero una perspectiva que podría ayudar a reconciliar dos antiguas posiciones en conflicto: la neocorteza deriva ya sea del hemisferio dorsal de los reptiles y aves, o alternativamente parte de ella deriva del hemisferio lateral y es homóloga a una estructura llamada cresta dorsoventricular (DVR) del cerebro de los reptiles y aves, que recibe la mayor parte de las proyecciones sensoriales. La evidencia embriológica y genética apoya fuertemente un origen dorsal de toda la neocorteza...

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Distribution of radial glia in the developing telencephalon of chicks

Striedter

Beydler

1997

J. Comp. Neurol.

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Radial glia are known to have a sparse and uneven distribution in the telencephalon of adult birds. The present study utilizes antibodies against vimentin to reveal a more extensive, and more clearly radial, set of radial glia in the chicken telencephalon during the first half of embryogenesis. This initially extensive radial glial fiber system becomes distorted and reduced between 10 and 14 days of incubation. This reduction coincides with the cytoarchitectural differentiation of the telencephalon into its major adult subdivisions. Because developing neurons tend to migrate along radial glial fibers in both birds and mammals, a topological projection of these major subdivisions onto the embryonic ventricular zone along the radial glial fibers suggests hypotheses about lineage relationships that can be tested by subsequent experimental methods. This analysis suggests that the major components of the avian dorsal ventricular ridge, i.e., the ventral hyperstriatum, the neostriatum with its various subdivisions, part of the archistriatum, and probably also the piriform cortex, all derive from overlapping portions of the lateral pallial ventricular zone. Staining with antibodies against neurofilament suggests that this developmental parcellation of the lateral pallial complex is associated with the development of neuronal fiber systems.

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Points of view concerning forebrain morphology in lower vertebrates

Cited by 196 publications

References 0 publications

Thoughts on the development, structure and evolution of the mammalian and avian telencephalic pallium

Thoughts on the development, structure and evolution of the mammalian and avian telencephalic pallium

A developmental approach to homology and brain evolution

Distribution of radial glia in the developing telencephalon of chicks

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