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Neuropsychopharmacology : Official... Jan 2011As indicated by the profound cognitive impairments caused by cholinergic receptor antagonists, cholinergic neurotransmission has a vital role in cognitive function,... (Review)
Review
As indicated by the profound cognitive impairments caused by cholinergic receptor antagonists, cholinergic neurotransmission has a vital role in cognitive function, specifically attention and memory encoding. Abnormally regulated cholinergic neurotransmission has been hypothesized to contribute to the cognitive symptoms of neuropsychiatric disorders. Loss of cholinergic neurons enhances the severity of the symptoms of dementia. Cholinergic receptor agonists and acetylcholinesterase inhibitors have been investigated for the treatment of cognitive dysfunction. Evidence from experiments using new techniques for measuring rapid changes in cholinergic neurotransmission provides a novel perspective on the cholinergic regulation of cognitive processes. This evidence indicates that changes in cholinergic modulation on a timescale of seconds is triggered by sensory input cues and serves to facilitate cue detection and attentional performance. Furthermore, the evidence indicates cholinergic induction of evoked intrinsic, persistent spiking mechanisms for active maintenance of sensory input, and planned responses. Models have been developed to describe the neuronal mechanisms underlying the transient modulation of cortical target circuits by cholinergic activity. These models postulate specific locations and roles of nicotinic and muscarinic acetylcholine receptors and that cholinergic neurotransmission is controlled in part by (cortical) target circuits. The available evidence and these models point to new principles governing the development of the next generation of cholinergic treatments for cognitive disorders.
Topics: Acetylcholine; Action Potentials; Animals; Attention; Cholinergic Fibers; Cognition; Humans; Models, Neurological; Neural Pathways; Neurons; Perception; Prosencephalon
PubMed: 20668433
DOI: 10.1038/npp.2010.104 -
Cellular and Molecular Life Sciences :... Aug 2014Embryonic stem cells (ESCs) have been used extensively as in vitro models of neural development and disease, with special efforts towards their conversion into forebrain... (Review)
Review
Embryonic stem cells (ESCs) have been used extensively as in vitro models of neural development and disease, with special efforts towards their conversion into forebrain progenitors and neurons. The forebrain is the most complex brain region, giving rise to several fundamental structures, such as the cerebral cortex, the hypothalamus, and the retina. Due to the multiplicity of signaling pathways playing different roles at distinct times of embryonic development, the specification and patterning of forebrain has been difficult to study in vivo. Research performed on ESCs in vitro has provided a large body of evidence to complement work in model organisms, but these studies have often been focused more on cell type production than on cell fate regulation. In this review, we systematically reassess the current literature in the field of forebrain development in mouse and human ESCs with a focus on the molecular mechanisms of early cell fate decisions, taking into consideration the specific culture conditions, exogenous and endogenous molecular cues as described in the original studies. The resulting model of early forebrain induction and patterning provides a useful framework for further studies aimed at reconstructing forebrain development in vitro for basic research or therapy.
Topics: Animals; Embryonic Stem Cells; Humans; Neurogenesis; Prosencephalon; Signal Transduction
PubMed: 24643740
DOI: 10.1007/s00018-014-1596-1 -
Journal of Neuropathology and... Jul 2007Forebrain development is directed by secreted signaling molecules known as morphogens, and morphogen signaling defects often lead to failed midline induction and... (Review)
Review
Forebrain development is directed by secreted signaling molecules known as morphogens, and morphogen signaling defects often lead to failed midline induction and holoprosencephaly (HPE), the most common malformation of the human forebrain. Genetic studies in multiple organisms implicate 4 well-known morphogens or morphogen families--Nodal, Sonic hedgehog, Fibroblast growth factors, and Bone morphogenetic proteins--as causes of HPE. Here I review the roles of these morphogens in HPE and forebrain midline development. In particular, this review focuses on recent evidence for cross-regulatory interactions between morphogens, which lead to a signaling network model of forebrain development that can explain the distinctive HPE phenotypes seen in humans and animal models.
Topics: Animals; Body Patterning; Gene Expression Regulation, Developmental; Holoprosencephaly; Morphogenesis; Prosencephalon; Signal Transduction
PubMed: 17620982
DOI: 10.1097/nen.0b013e3180986e1b -
Annals of the New York Academy of... Jun 1999The concepts of the ventral striatopallidal system and extended amygdala have significantly improved our understanding of basal forebrain organization. As a result of... (Review)
Review
The concepts of the ventral striatopallidal system and extended amygdala have significantly improved our understanding of basal forebrain organization. As a result of these and other advances during the last twenty years, many of the most prominent basal forebrain structures, including the nucleus accumbens, olfactory tubercle, and amygdaloid body, have all but lost their relevance as independent functional anatomical units. In order to appreciate the distinct differences that exist between the ventral striatopallidal system and the extended amygdala, and as a way of explaining the choice of the terms ventral striatopallidal system and extended amygdala, we will review the discovery and subsequent elaboration of these two systems. On the background of these discussions, we will then proceed to dispel some recently published misgivings regarding the usefulness of the extended amygdaloid concept.
Topics: Amygdala; Animals; Corpus Striatum; Globus Pallidus; Humans; Neural Pathways; Prosencephalon
PubMed: 10415640
DOI: 10.1111/j.1749-6632.1999.tb09258.x -
Trends in Neurosciences Sep 2003The prosomeric model attributes morphological meaning to gene expression patterns and other data in the forebrain. It divides this territory into the same transverse... (Review)
Review
The prosomeric model attributes morphological meaning to gene expression patterns and other data in the forebrain. It divides this territory into the same transverse segments (prosomeres) and longitudinal zones in all vertebrates. The axis and longitudinal zones of this model are widely accepted but controversy subsists about the number of prosomeres and their nature as segments. We describe difficulties encountered in establishing continuity between prosomeric limits postulated in the hypothalamus and intra-telencephalic limits. Such difficulties throw doubt on the intersegmental nature of these limits. We sketch a simplified model, in which the secondary prosencephalon (telencephalon plus hypothalamus) is a complex protosegment not subdivided into prosomeres, which exhibits patterning singularities. By contrast, we continue to postulate that prosomeres p1-p3 (i.e. the pretectum, thalamus and prethalamus) are the caudal forebrain.
Topics: Animals; Gene Expression; Humans; Hypothalamus; Models, Neurological; Prosencephalon; Telencephalon
PubMed: 12948657
DOI: 10.1016/S0166-2236(03)00234-0 -
Annals of Neurology May 2001
Topics: Cardiovascular Physiological Phenomena; Functional Laterality; Humans; Prosencephalon
PubMed: 11357943
DOI: No ID Found -
Progress in Brain Research 2000The subventricular zone (SVZ) is a major germinal zone which persists in the adult brain. The SVZ contains cells that self renew and continuously produce new neurons and... (Review)
Review
The subventricular zone (SVZ) is a major germinal zone which persists in the adult brain. The SVZ contains cells that self renew and continuously produce new neurons and glia. In this chapter we discuss the development, architecture and function of the adult SVZ, as well as the fate of SVZ cells after transplantation. We focus on identification of neural stem cells, factors which regulate neurogenesis and mechanisms for neuronal migration through the adult brain. Detailed understanding of these processes is necessary to utilize the SVZ as a source of neuronal and glial precursors for genetic manipulation, transplantation or brain self repair.
Topics: Age Factors; Animals; Brain Injuries; Cell Differentiation; Cell Division; Cell Movement; Humans; Neurons; Prosencephalon; Stem Cell Transplantation; Stem Cells
PubMed: 11142024
DOI: 10.1016/s0079-6123(00)27002-7 -
The Journal of Comparative Neurology Jul 2004
Comparative Study Review
Topics: Animals; Biological Evolution; Cerebral Cortex; Fishes; Gene Expression Regulation, Developmental; Mammals; Models, Animal; Neural Pathways; Prosencephalon
PubMed: 15211457
DOI: 10.1002/cne.20183 -
BioEssays : News and Reviews in... Aug 2014Fezf1 and Fezf2 are highly conserved transcription factors that were first identified by their specific expression in the anterior neuroepithelium of Xenopus and... (Review)
Review
Fezf1 and Fezf2 are highly conserved transcription factors that were first identified by their specific expression in the anterior neuroepithelium of Xenopus and zebrafish embryos. These proteins share an N-terminal domain with homology to the canonical engrailed repressor motif and a C-terminal DNA binding domain containing six C2H2 zinc-finger repeats. Over a decade of study indicates that the Fez proteins play critical roles during nervous system development in species as diverse as fruit flies and mice. Herein we discuss recent progress in understanding the functions of Fezf1 and Fezf2 in neurogenesis and cell fate specification during mammalian nervous system development. Going forward we believe that efforts should focus on understanding how expression of these factors is precisely regulated, and on identifying target DNA sequences and interacting partners. Such knowledge may reveal the mechanisms by which Fezf1 and Fezf2 accomplish both independent and redundant functions across diverse tissue and cell types.
Topics: Animals; Body Patterning; Evolution, Molecular; Gene Expression Regulation, Developmental; Humans; Neural Stem Cells; Neurogenesis; Olfactory Cortex; Prosencephalon; Repressor Proteins; Transcription Factors
PubMed: 24913420
DOI: 10.1002/bies.201400039 -
Brain Structure & Function Sep 2008The neuroanatomical research by Heimer and colleagues has focused on the structure of, and connectivity between, basal forebrain regions as well as on the translational... (Review)
Review
The neuroanatomical research by Heimer and colleagues has focused on the structure of, and connectivity between, basal forebrain regions as well as on the translational significance of this research. By outlining several pressing research themes and questions concerning the neuroanatomy of the basal forebrain, as seen from a biopsychologist's perspective, the importance of continuing and expanding neuroanatomical research on the basal forebrain is illustrated.
Topics: Animals; Basal Ganglia; Cerebral Cortex; Cholinergic Fibers; Humans; Neural Pathways; Prosencephalon; Substantia Innominata; Synaptic Transmission
PubMed: 18183419
DOI: 10.1007/s00429-007-0165-x