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At least 19 recordsLinked to original sources
PubMed1977

[The topography and cytoarchitectonic of the diencephalon of the cow (Bos taurus var. domesticus L.). II. The internal structure of the diencephalon of the cow (Bos taurus var. domesticus L.) (author's transl)].

The five parts of the diencephalon of the cow are distinctly separated by fibrous tractuses or plates. The three main tractuses (Fornix, Tractus mamillo-thalamicus and Fasciculus retroflexus) are very strongly developed. Regarding the essential fibrous structures and the cytoarchitectonic features 62 nuclei can be differentiated in either half of the diencephalon, of which the thalamus contains 28 and the hypothalamus 23 nuclei. Epithalamus, Metathalamus and Subthalamus possess 2 big nuclei on each side. The findings are briefly compared with the data on the diencephalic structures of cow, sheep goat, pig and dromedar given in literature.

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PubMed1993

The diencephalon of the Pacific herring, Clupea harengus: retinofugal projections to the diencephalon and optic tectum.

The pattern of retinofugal projections to nuclei in the diencephalon and to the optic tectum was analyzed with horseradish peroxidase and autoradiographic methods in Clupea harengus, a clupeomorph teleost, for comparison with osteoglossomorph, elopomorph, and euteleost teleosts and with non-teleost actinopterygians. Most retinal fibers decussate in the optic chiasm and project to nuclei in the preoptic area, ventral and dorsal thalamus, posterior tuberculum, synencephalon, and pretectum, as well as to the accessory optic nuclei and optic tectum. Some ipsilateral projections do not decussate in the optic chiasm, while others decussate and recross via the supraoptic (minor) and posterior commissures. The pattern of projections is similar to that seen in other actinopterygian fishes with several exceptions. The terminal field usually present lateral to nucleus anterior in the dorsal thalamus is extremely reduced despite the relatively large size of the nucleus. A dense terminal field lies within the cell plate of nucleus corticalis in the pretectum rather than dorsal to it. The tectal hemisphere is composed of two distinct lobules, and the dorsal optic tract projects to the more rostromedial lobule while the ventral optic tract projects to the more caudolateral lobule. The lack of a significant projection to nucleus anterior and the lobular morphology of the optic tectum appear to be apomorphic for Clupea. Other features of the pattern of retinal projections are also analyzed in actinopterygian fishes including Clupea, and several hypotheses are advanced as to which traits are plesiomorphic for actinopterygians and/or for teleosts.

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PubMed1977

[The topography and cytoarchitectonic of the diencephalon of the cow (Bos taurus var. domesticus L.) I. The topography of the diencephalon of the cow. (Bos taurus var. domesticus L.) (author's transl)].

The study contains a comprehensive review of the literature on the brain of the cattle, followed by notes on form and location of the brain in the skull of the cow and of the diencephalon. In addition we point to some possibilities for locating the brain by stereotaxic manipulations. Several structural particularities are discussed, where to a limited extent references to structures of the brains of other domestic artiodactyla are made.

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PubMed1996

Clones in the chick diencephalon contain multiple cell types and siblings are widely dispersed.

The thalamus, hypothalamus and epithalamus of the vertebrate central nervous system are derived from the embryonic diencephalon. These regions of the nervous system function as major relays between the telencephalon and more caudal regions of the brain. Early in development, the diencephalon morphologically comprises distinct units known as neuromeres or prosomeres. As development proceeds, multiple nuclei, the functional and anatomical units of the diencephalon, derive from the neuromeres. It was of interest to determine whether progenitors in the diencephalon give rise to daughters that cross nuclear or neuromeric boundaries. To this end, a highly complex retroviral library was used to infect diencephalic progenitors. Retrovirally marked clones were found to contain neurons, glia and occasionally radial glia. The majority of clones dispersed in all directions, resulting in sibling cells populating multiple nuclei within the diencephalon. In addition, several distinctive patterns of dispersion were observed. These included clones with siblings distributed bilaterally across the third ventricle, clones that originated in the lateral ventricle, clones that crossed neuromeric boundaries, and clones that crossed major boundaries of the developing nervous system, such as the diencephalon and mesencephalon. These findings demonstrate that progenitor cells in the diencephalon are multipotent and that their daughters can become widely dispersed.

Alkaline Phosphatase↗
PubMed1999

The posterior basal diencephalon of rats enhances expression of an activated state.

STUDY OBJECTIVES: Various ablation studies have implicated the posterior basal diencephalon in the promotion of wakefulness. Although many studies have examined the role of this structure in promotion of cortical arousal, few investigations have attempted to examine its importance in regulation of motor activation (behavioral arousal). In the current study, recordings of freely moving decerebrate rats with and without a posterior basal diencephalon were performed. These studies allowed determination of the behavioral states expressed by the preparations and whether removal of the posterior basal diencephalon completely eliminated expression of both activated state with and activated state without limb movements. DESIGN: Muscle activity was recorded from limb and neck muscles. Eye movements and heart rate were also monitored. The percentage of time spent in various behavioral states and the proportion of limb movements expressed in each of these states were determined. MEASUREMENTS AND RESULTS: Rats with an intact posterior basal diencephalon cycled between all behavioral states. However, they spent most of the recording time in an activated state. In contrast, removal of the posterior basal diencephalon produced rats that spent most of the recording period in a quiescent state. Limb movements were expressed mainly by animals with an intact posterior basal diencephalon, and only when these animals were in the activated state. CONCLUSIONS: The results of this study suggest that the posterior basal diencephalon is required for expression of an activated state and specifically provide evidence for a descending projection from this region required for expression of this state and associated motor activation.

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PubMed1996

Spinothalamic and spinohypothalamic tract neurons in the sacral spinal cord of rats. I. Locations of antidromically identified axons in the cervical cord and diencephalon.

1. A goal of this study was to determine the sites in the diencephalon to which neurons in sacral spinal segments of rats project. Therefore, 95 neurons were recorded extracellularly in spinal segments L6-S2 of rats that were anesthetized with urethan. These neurons were activated initially antidromically with currents < or = 30 microA from a monopolar stimulating electrode placed into the contralateral posterior diencephalon. The mean +/- SE current for antidromic activation from these sites was 16 +/- 0.8 microA. These neurons were recorded in the superficial dorsal horn (4%), deep dorsal horn (89%), and intermediate zone and ventral horn (4%). 2. Systematic antidromic mapping techniques were used to map the axonal projections of 41 of these neurons within the diencephalon. Thirty-three neurons (80%) could be activated antidromically with currents < or = 30 microA only from points in the contralateral thalamus and are referred to as spinothalamic tract (STT) neurons. Eight neurons (20%) were activated antidromically with low currents from points in both the contralateral thalamus and hypothalamus, and these neurons are referred to as spinothalamic tract/ spinohypothalamic tract (STT/SHT) neurons. Three additional neurons were activated antidromically with currents < or = 30 microA only from points within the contralateral hypothalamus and are referred to as spinohypothalamic tract (SHT) neurons. The diencephalic projections of another 51 neurons were mapped incompletely. These neurons are referred to as spinothalamic/unknown (STT/ U) neurons to indicate that it was not known whether their axons ascended beyond the site in the thalamus from which they initially were activated antidromically. 3. For 31 STT neurons, the most anterior point at which antidromic activation was achieved with currents < or = 30 microA was determined. Fourteen (45%) were activated antidromically only from sites posterior to the ventrobasal complex (VbC) of the thalamus. Sixteen STT neurons (52%) were activated antidromically with low currents from sites at the level of the VbC, but not from more anterior levels. One STT neuron (3%) was activated antidromically from the anteroventral nucleus of the thalamus. 4. STT/SHT neurons were antidromically activated with currents < or = 30 microA from the medial lemniscus (ML), anterior pretectal nucleus (APt), posterior nuclear group and medial geniculate nucleus (Po/MG), and zona incerta in the thalamus and from the optic tract (OT), supraoptic decussation, or lateral area of the hypothalamus. No differences in the sites in the thalamus from which STT and STT/SHT neurons were activated antidromically were apparent. Five STT/SHT neurons (62%) were activated antidromically from points in the thalamus in the posterior diencephalon and from points in the hypothalamus at more anterior levels. Three STT/SHT neurons (38%) were activated antidromically with currents < or = 30 microA from sites in both the thalamus and hypothalamus at the same anterior-posterior level of the diencephalon. All three of these STT/SHT neurons projected to the intralaminar nuclei (parafascicular or central lateral nuclei) of the thalamus. 5. Seven STT/SHT neurons were tested for additional projections to the ipsilateral brain. Two (29%) were activated antidromically with currents < or = 30 microA and at longer latencies from sites in the ipsilateral diencephalon. One could only be activated antidromically from the hypothalamus ipsilaterally. The other was activated antidromically at progressively increasing latencies from points in the ipsilateral brain that extended as far posteriorly as the posterior pole of the MG. 6. Fifty-eight STT, STT/SHT, and STT/U neurons were classified as low-threshold (LT), wide dynamic range (WDR), or highthreshold (HT) neurons based on their responsiveness to innocuous and noxious mechanical stimuli applied to their cutaneous receptive fields.(ABSTRACT TRUNCATED)

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PubMed1990

The diencephalon of the channel catfish, Ictalurus punctatus. I. Nuclear organization.

A detailed cytoarchitectonic description of the diencephalon in the channel catfish reveals more than 40 distinct cell groups. Of these, 4 are located in the preoptic area, 8 in the hypothalamus, 7 in the thalamus, 2 in the epithalamus, 15 in the posterior tuberculum and 7 in the synencephalon. A comparison of the diencephalon of Ictalurus punctatus to that of goldfish, which has previously been described, indicates major differences in the diencephalon between these two species. Channel catfish lack the superficial pretectum and the nucleus 'glomerulosus' of goldfish, whereas the anterior tuberal nucleus of the hypothalamus, the paracommissural nucleus of the synencephalon and the nucleus lobobulbaris of the posterior tuberculum are all better developed in channel catfish than in goldfish. The nucleus electrosensorius in the synencephalon of channel catfish is probably homologous to the nucleus of the same name in gymnotoid teleosts, but it appears to have no homologue in the diencephalon of goldfish. An analysis of interspecific variation in the diencephalon among catfishes, goldfish and several other teleosts reveals that some areas of the diencephalon are more variable across species than others. Specifically, the migrated portions of both the posterior tuberculum and the synencephalon appear to be most variable, whereas the epithalamus and the preoptic area are the most conservative. It is hypothesized that the relatively conservative areas of the brain may have a greater number of afferent connections, and probably also a greater number of distinct behavioral functions, than the more variable areas.

Animals↗
PubMed1988

Cotransplantation of embryonic mouse retina with tectum, diencephalon, or cortex to neonatal rat cortex.

Retinae from embryonic mice were transplanted to the occipital cortex of neonatal rats together with their normal target regions, tectum or diencephalon, from embryonic mice or rats. In control experiments, retinae were cotransplanted with embryonic rat occipital cortex. In over 80% of the experimental animals, both transplants differentiated and grew. Ganglion cells in the retinae cotransplanted close to tectum or diencephalon survived for at least 15 weeks. Their survival was associated with the development of a distinct optic fiber layer and outgrowth of axons from the transplanted mouse retina. Specific innervation of distinct patches within the cotransplanted rat tectum or diencephalon was demonstrated by the use of an anti-mouse antibody. The innervated regions, which could be as far away as 1.3 mm from the retinae, were correlated with cytological features of the cotransplanted tectum or diencephalon. By contrast, the host cortex was never innervated by the transplanted retinae. In the control animals in which the retinae were cotransplanted with occipital cortex and in four animals in which the cotransplants lay more than 2.7 mm apart, no ganglion cells were identified and there was no evidence of an optic fiber layer, outgrowth of axons, or innervation. These results support the idea that in order to survive, retinal ganglion cells need to innervate an appropriate target region. Further, the specific innervation of regions within the cotransplanted tectum or diencephalon suggests that these target regions are able to exert a tropic influence on the axons of retinal ganglion cells, even in the absence of many of the normal structure cues.

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PubMed1999

Tissue interactions in the induction of anterior pituitary: role of the ventral diencephalon, mesenchyme, and notochord.

Rathke's pouch, the epithelial primordium of the anterior pituitary, differentiates in close topographical and functional association with the ventral diencephalon. It is still not known whether the ventral diencephalon acts as the initial inducer of pituitary development. The roles of the adjacent mesenchyme and notochord, two other tissues located in close proximity to Rathke's pouch, in this process are even less clear. In this report we describe an in vitro experimental system that reproduces the earliest steps of anterior pituitary development. We provide evidence that the ventral diencephalon from 2- to 4-day-old chick embryos is able to function as an inducer of pituitary development and can convert early chick embryonic head ectoderm, which is not involved normally in pituitary development, into typical anterior pituitary tissue. This induction is contact-dependent. In our experimental system, there is a requirement for the supporting action of mesenchyme, which is independent of the mesenchyme source. Transplantation of the notochord into the lateral head region of a six-somite chick embryo induces an epithelial invagination, suggesting that the notochord induces the outpouching of the roof of the stomodeal ectoderm that results in formation of Rathke's pouch and causes the close contact between this ectoderm and the ventral diencephalon. Finally, we demonstrate that the ventral diencephalon from e9.5-e11.5 mouse embryos is also an efficient inducer of anterior pituitary differentiation in chick embryonic lateral head ectoderm, suggesting that the mechanism of anterior pituitary induction is conserved between mammals and birds, using the same, or similar, signaling pathways.

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