Neural - Thalamus Development: Difference between revisions
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* '''Review - Development of the thalamus: From early patterning to regulation of cortical functions'''{{#pmid:31034163|PMID31034163}} "The thalamus is a brain structure of the vertebrate diencephalon that plays a central role in regulating diverse functions of the cerebral cortex. In traditional view of vertebrate neuroanatomy, the thalamus includes three regions, dorsal thalamus, ventral thalamus, and epithalamus. Recent molecular embryological studies have redefined the thalamus and the associated axial nomenclature of the diencephalon in the context of forebrain patterning. This new view has provided a useful conceptual framework for studies on molecular mechanisms of patterning, neurogenesis and fate specification in the thalamus as well as the guidance mechanisms for thalamocortical axons. Additionally, the availability of genetic tools in mice has led to important findings on how thalamic development is linked to the development of other brain regions, particularly the cerebral cortex. This article will give an overview of the organization of the embryonic thalamus and how progenitor cells in the thalamus generate neurons that are organized into discrete nuclei." | |||
* '''Thalamus Controls Development and Expression of Arousal States in Visual Cortex'''{{#pmid:30150360|PMID30150360}} "Two major checkpoints of development in cerebral cortex are the acquisition of continuous spontaneous activity and the modulation of this activity by behavioral state. Despite the critical importance of these functions, the circuit mechanisms of their development remain unknown. Here we use the rodent visual system as a model to test the hypothesis that the locus of circuit change responsible for the developmental acquisition of continuity and state dependence measured in sensory cortex is relay thalamus, rather than the local cortical circuitry or the interconnectivity of the two structures. We conducted simultaneous recordings in the dorsal lateral geniculate nucleus (dLGN) and primary visual cortex (VC) of awake, head-fixed male and female rats using linear multielectrode arrays throughout early development. We find that activity in dLGN becomes continuous and positively correlated with movement (a measure of state dependence) on P13, the same day as VC, and that these properties are not dependent on VC activity. By contrast, silencing dLGN after P13 causes activity in VC to become discontinuous and movement to suppress, rather than augment, cortical firing, effectively reversing development. Thalamic bursting, a core characteristic of non-aroused states, emerged later, on P16, suggesting these processes are developmentally independent. Together our results indicate that cellular or circuit changes in relay thalamus are critical drivers for the maturation of background activity, which occurs around term in humans.SIGNIFICANCE STATEMENT The developing brain acquires two crucial features, continuous spontaneous activity and its modulation by arousal state, around term in humans and before the onset of sensory experience in rodents. This developmental transition in cortical activity, as measured by electroencephalogram (EEG), is an important milestone for normal brain development and indicates a good prognosis for babies born preterm and/or suffering brain damage such as hypoxic-ischemic encephalopathy." | * '''Thalamus Controls Development and Expression of Arousal States in Visual Cortex'''{{#pmid:30150360|PMID30150360}} "Two major checkpoints of development in cerebral cortex are the acquisition of continuous spontaneous activity and the modulation of this activity by behavioral state. Despite the critical importance of these functions, the circuit mechanisms of their development remain unknown. Here we use the rodent visual system as a model to test the hypothesis that the locus of circuit change responsible for the developmental acquisition of continuity and state dependence measured in sensory cortex is relay thalamus, rather than the local cortical circuitry or the interconnectivity of the two structures. We conducted simultaneous recordings in the dorsal lateral geniculate nucleus (dLGN) and primary visual cortex (VC) of awake, head-fixed male and female rats using linear multielectrode arrays throughout early development. We find that activity in dLGN becomes continuous and positively correlated with movement (a measure of state dependence) on P13, the same day as VC, and that these properties are not dependent on VC activity. By contrast, silencing dLGN after P13 causes activity in VC to become discontinuous and movement to suppress, rather than augment, cortical firing, effectively reversing development. Thalamic bursting, a core characteristic of non-aroused states, emerged later, on P16, suggesting these processes are developmentally independent. Together our results indicate that cellular or circuit changes in relay thalamus are critical drivers for the maturation of background activity, which occurs around term in humans.SIGNIFICANCE STATEMENT The developing brain acquires two crucial features, continuous spontaneous activity and its modulation by arousal state, around term in humans and before the onset of sensory experience in rodents. This developmental transition in cortical activity, as measured by electroencephalogram (EEG), is an important milestone for normal brain development and indicates a good prognosis for babies born preterm and/or suffering brain damage such as hypoxic-ischemic encephalopathy." | ||
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Latest revision as of 10:16, 24 February 2020
Embryology - 28 Mar 2024 Expand to Translate |
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Introduction
Neural development is one of the earliest systems to begin and the last to be completed after birth. This development generates the most complex structure within the embryo and the long time period of development means in utero insult during pregnancy may have consequences to development of the nervous system.
The early central nervous system begins as a simple neural plate that folds to form a groove then tube, open initially at each end. Failure of these opening to close contributes a major class of neural abnormalities (neural tube defects).
Within the neural tube stem cells generate the 2 major classes of cells that make the majority of the nervous system : neurons and glia. Both these classes of cells differentiate into many different types generated with highly specialized functions and shapes. This section covers the establishment of neural populations, the inductive influences of surrounding tissues and the sequential generation of neurons establishing the layered structure seen in the brain and spinal cord.
- Neural development beginnings quite early, therefore also look at notes covering Week 3- neural tube and Week 4-early nervous system.
- Development of the neural crest and sensory systems (hearing/vision/smell) are only introduced in these notes and are covered in other notes sections.
Some Recent Findings
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More recent papers |
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This table allows an automated computer search of the external PubMed database using the listed "Search term" text link.
More? References | Discussion Page | Journal Searches | 2019 References | 2020 References Search term: Thalamus Embryology <pubmed limit=5>Thalamus Embryology</pubmed> |
Embryonic Thalamus
Week 8
Human Stage 22 brain.
The basal part of the telencephalon forms the basal ganglia, a solid mass. Posteromedially these basal ganglia are in contact with the diencephalon. The large masses in either side of the diencephalon form the thalami.
Fetal Thalamus
Brain lateral view 13, 15, and 19 weeks the developing thalamus is shown in yellow.[5]
MRI three-dimensional reconstruction of the whole fetal brain (lower row; yellow - thalamus)
Development Overview
Neuralation begins at the trilaminar embryo with formation of the notochord and somites, both of which underly the ectoderm and do not contribute to the nervous system, but are involved with patterning its initial formation. The central portion of the ectoderm then forms the neural plate that folds to form the neural tube, that will eventually form the entire central nervous system.
- Early developmental sequence: Epiblast - Ectoderm - Neural Plate - Neural groove and Neural Crest - Neural Tube and Neural Crest
Neural Tube | Primary Vesicles | Secondary Vesicles | Adult Structures |
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week 3 | week 4 | week 5 | adult |
prosencephalon (forebrain) | telencephalon | Rhinencephalon, Amygdala, hippocampus, cerebrum (cortex), hypothalamus, pituitary | Basal Ganglia, lateral ventricles | |
diencephalon | epithalamus, thalamus, Subthalamus, pineal, posterior commissure, pretectum, third ventricle | ||
mesencephalon (midbrain) | mesencephalon | tectum, Cerebral peduncle, cerebral aqueduct, pons | |
rhombencephalon (hindbrain) | metencephalon | cerebellum | |
myelencephalon | medulla oblongata, isthmus | ||
spinal cord, pyramidal decussation, central canal |
Early Brain Vesicles
Primary Vesicles
Secondary Vesicles
References
- ↑ Nakagawa Y. (2019). Development of the thalamus: From early patterning to regulation of cortical functions. Wiley Interdiscip Rev Dev Biol , 8, e345. PMID: 31034163 DOI.
- ↑ Murata Y & Colonnese MT. (2018). Thalamus Controls Development and Expression of Arousal States in Visual Cortex. J. Neurosci. , 38, 8772-8786. PMID: 30150360 DOI.
- ↑ Mattes B, Weber S, Peres J, Chen Q, Davidson G, Houart C & Scholpp S. (2012). Wnt3 and Wnt3a are required for induction of the mid-diencephalic organizer in the caudal forebrain. Neural Dev , 7, 12. PMID: 22475147 DOI.
- ↑ Pyrgaki C, Trainor P, Hadjantonakis AK & Niswander L. (2010). Dynamic imaging of mammalian neural tube closure. Dev. Biol. , 344, 941-7. PMID: 20558153 DOI.
- ↑ Huang H, Xue R, Zhang J, Ren T, Richards LJ, Yarowsky P, Miller MI & Mori S. (2009). Anatomical characterization of human fetal brain development with diffusion tensor magnetic resonance imaging. J. Neurosci. , 29, 4263-73. PMID: 19339620 DOI.
Reviews
Nakagawa Y. (2019). Development of the thalamus: From early patterning to regulation of cortical functions. Wiley Interdiscip Rev Dev Biol , 8, e345. PMID: 31034163 DOI.
Greene ND & Copp AJ. (2009). Development of the vertebrate central nervous system: formation of the neural tube. Prenat. Diagn. , 29, 303-11. PMID: 19206138 DOI.
Articles
Saitsu H & Shiota K. (2008). Involvement of the axially condensed tail bud mesenchyme in normal and abnormal human posterior neural tube development. Congenit Anom (Kyoto) , 48, 1-6. PMID: 18230116 DOI.
Search PubMed
Search Pubmed: Thalamus Embryology | Thalamus Development
Additional Images
Quinlan R, Graf M, Mason I, Lumsden A & Kiecker C. (2009). Complex and dynamic patterns of Wnt pathway gene expression in the developing chick forebrain. Neural Dev , 4, 35. PMID: 19732418 DOI.
"Wnt4 expression in the thalamus is repressed by Shh from the ZLI we reveal an additional level of interaction between these two pathways and provide an example for the cross-regulation between patterning centres during forebrain regionalisation." |
Historic Images
Bailey FR. and Miller AM. Text-Book of Embryology (1921) New York: William Wood and Co.
Glossary Links
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Cite this page: Hill, M.A. (2024, March 28) Embryology Neural - Thalamus Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Neural_-_Thalamus_Development
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G