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ENeuro 2021Feeding and breathing are two functions vital to the survival of all vertebrate species. Throughout the evolution, vertebrates living in different environments have... (Review)
Review
Feeding and breathing are two functions vital to the survival of all vertebrate species. Throughout the evolution, vertebrates living in different environments have evolved drastically different modes of feeding and breathing through using diversified orofacial and pharyngeal (oropharyngeal) muscles. The oropharyngeal structures are controlled by hindbrain neural circuits. The developing hindbrain shares strikingly conserved organizations and gene expression patterns across vertebrates, thus begs the question of how a highly conserved hindbrain generates circuits subserving diverse feeding/breathing patterns. In this review, we summarize major modes of feeding and breathing and principles underlying their coordination in many vertebrate species. We provide a hypothesis for the existence of a common hindbrain circuit at the phylotypic embryonic stage controlling oropharyngeal movements that is shared across vertebrate species; and reconfiguration and repurposing of this conserved circuit give rise to more complex behaviors in adult higher vertebrates.
Topics: Animals; Biological Evolution; Rhombencephalon; Vertebrates
PubMed: 33707205
DOI: 10.1523/ENEURO.0435-20.2021 -
BMJ Case Reports Dec 2023Chiari malformation (CM) is a group of complex deformities of the posterior fossa and hindbrain, of which CMIII is the rarest. We report a term neonate, with an...
Chiari malformation (CM) is a group of complex deformities of the posterior fossa and hindbrain, of which CMIII is the rarest. We report a term neonate, with an antenatal diagnosis of occipital encephalocele, who underwent resection of the encephalocele and ligation of vessels, with repair of a large scalp defect and dural reconstruction on day 4 of life. The parents of the child had been counselled for a guarded and poor prognosis on initial diagnosis. The child has had a good postoperative course without complications but suffers from cortical visual impairment and global developmental delay.
Topics: Humans; Infant, Newborn; Arnold-Chiari Malformation; Cerebellum; Encephalocele; Magnetic Resonance Imaging; Rhombencephalon
PubMed: 38087482
DOI: 10.1136/bcr-2023-255677 -
Nutrients Mar 2021The regulation of energy balance requires the complex integration of homeostatic and hedonic pathways, but sensory inputs from the gastrointestinal (GI) tract are... (Review)
Review
The regulation of energy balance requires the complex integration of homeostatic and hedonic pathways, but sensory inputs from the gastrointestinal (GI) tract are increasingly recognized as playing critical roles. The stomach and small intestine relay sensory information to the central nervous system (CNS) via the sensory afferent vagus nerve. This vast volume of complex sensory information is received by neurons of the nucleus of the tractus solitarius (NTS) and is integrated with responses to circulating factors as well as descending inputs from the brainstem, midbrain, and forebrain nuclei involved in autonomic regulation. The integrated signal is relayed to the adjacent dorsal motor nucleus of the vagus (DMV), which supplies the motor output response via the efferent vagus nerve to regulate and modulate gastric motility, tone, secretion, and emptying, as well as intestinal motility and transit; the precise coordination of these responses is essential for the control of meal size, meal termination, and nutrient absorption. The interconnectivity of the NTS implies that many other CNS areas are capable of modulating vagal efferent output, emphasized by the many CNS disorders associated with dysregulated GI functions including feeding. This review will summarize the role of major CNS centers to gut-related inputs in the regulation of gastric function with specific reference to the regulation of food intake.
Topics: Afferent Pathways; Amygdala; Animals; Brain; Diabetes Mellitus; Eating; Efferent Pathways; Gastrointestinal Tract; Hippocampus; Humans; Hypothalamus; Inflammation; Nervous System Diseases; Obesity; Rhombencephalon; Vagus Nerve
PubMed: 33799575
DOI: 10.3390/nu13030908 -
Frontiers in Neural Circuits 2021Classically, the cerebellum has been thought to play a significant role in motor coordination. However, a growing body of evidence for novel neural connections between... (Review)
Review
Classically, the cerebellum has been thought to play a significant role in motor coordination. However, a growing body of evidence for novel neural connections between the cerebellum and various brain regions indicates that the cerebellum also contributes to other brain functions implicated in reward, language, and social behavior. Cerebellar Purkinje cells (PCs) make inhibitory GABAergic synapses with their target neurons: other PCs and Lugaro/globular cells via PC axon collaterals, and neurons in the deep cerebellar nuclei (DCN) via PC primary axons. PC-Lugaro/globular cell connections form a cerebellar cortical microcircuit, which is driven by serotonin and noradrenaline. PCs' primary outputs control not only firing but also synaptic plasticity of DCN neurons following the integration of excitatory and inhibitory inputs in the cerebellar cortex. Thus, strong PC-mediated inhibition is involved in cerebellar functions as a key regulator of cerebellar neural networks. In this review, we focus on physiological characteristics of GABAergic transmission from PCs. First, we introduce monoaminergic modulation of GABAergic transmission at synapses of PC-Lugaro/globular cell as well as PC-large glutamatergic DCN neuron, and a Lugaro/globular cell-incorporated microcircuit. Second, we review the physiological roles of perineuronal nets (PNNs), which are organized components of the extracellular matrix and enwrap the cell bodies and proximal processes, in GABA release from PCs to large glutamatergic DCN neurons and in cerebellar motor learning. Recent evidence suggests that alterations in PNN density in the DCN can regulate cerebellar functions.
Topics: Cerebellar Nuclei; Cerebellum; Extracellular Matrix; Neuronal Plasticity; Neurons; Purkinje Cells
PubMed: 34194302
DOI: 10.3389/fncir.2021.661899 -
Annual Review of Neuroscience Jul 2019The genetic approach, based on the study of inherited forms of deafness, has proven to be particularly effective for deciphering the molecular mechanisms underlying the... (Review)
Review
The genetic approach, based on the study of inherited forms of deafness, has proven to be particularly effective for deciphering the molecular mechanisms underlying the development of the peripheral auditory system, the cochlea and its afferent auditory neurons, and how this system extracts the physical parameters of sound. Although this genetic dissection has provided little information about the central auditory system, scattered data suggest that some genes may have a critical role in both the peripheral and central auditory systems. Here, we review the genes controlling the development and function of the peripheral and central auditory systems, focusing on those with demonstrated intrinsic roles in both systems and highlighting the current underappreciation of these genes. Their encoded products are diverse, from transcription factors to ion channels, as are their roles in the central auditory system, mostly evaluated in brainstem nuclei. We examine the ontogenetic and evolutionary mechanisms that may underlie their expression at different sites.
Topics: Animals; Auditory Pathways; Biological Evolution; Cochlea; Gene Expression Regulation, Developmental; Gene Ontology; Genes; Hair Cells, Auditory; Hearing Disorders; Humans; Ion Channels; Nerve Tissue Proteins; Neurogenesis; Rhombencephalon; Sensory Receptor Cells; Transcription Factors
PubMed: 30699050
DOI: 10.1146/annurev-neuro-070918-050428 -
NeuroImage. Clinical 2023To systematically investigate the topological organisation of morphological networks of the cerebellum using structural MRI and examine their clinical relevance in...
BACKGROUND
To systematically investigate the topological organisation of morphological networks of the cerebellum using structural MRI and examine their clinical relevance in chronic insomnia (CI).
METHODS
One hundred and one patients with CI and 102 healthy controls (HCs) were recruited in this study. Individual morphological networks of the cerebellum were constructed based on regional grey matter volume, and topologically characterised using weighted graph theory-based network approaches. Between-group comparisons were performed using permutation tests, and Spearman's correlation was used to examine the relationships between topological alterations and clinical variables.
RESULTS
Compared with HCs, patients with CI exhibited a lower normalised clustering coefficient. Locally, CI patients exhibited lower nodal efficiency in the cerebellar lobule VIIb and vermis regions, but higher nodal efficiency in the right cerebellar lobule VIIIa regions. No correlations were observed between network alterations and clinical variables.
CONCLUSIONS
Individual morphological network analysis provides a new strategy for investigating cerebellar morphometric changes in CI, and our findings may have important implications in establishing diagnostic and categorical biomarkers.
Topics: Humans; Connectome; Sleep Initiation and Maintenance Disorders; Cerebellum; Cerebellar Vermis; Cerebral Cortex
PubMed: 37603949
DOI: 10.1016/j.nicl.2023.103492 -
Neuroscience May 2021Molecular layer interneurons (MLIs) play an important role in cerebellar information processing by controlling Purkinje cell (PC) activity via inhibitory synaptic... (Review)
Review
Molecular layer interneurons (MLIs) play an important role in cerebellar information processing by controlling Purkinje cell (PC) activity via inhibitory synaptic transmission. A local MLI network, constructed from both chemical and electrical synapses, is organized into spatially structured clusters that amplify feedforward and lateral inhibition to shape the temporal and spatial patterns of PC activity. Several recent in vivo studies indicate that such MLI circuits contribute not only to sensorimotor information processing, but also to precise motor coordination and cognitive processes. Here, we review current understanding of the organization of MLI circuits and their roles in the function of the mammalian cerebellum.
Topics: Animals; Cerebellum; Electrical Synapses; Interneurons; Purkinje Cells; Synaptic Transmission
PubMed: 33075461
DOI: 10.1016/j.neuroscience.2020.10.008 -
Journal of Anatomy Aug 2021Guinea pigs have proved useful as experimental animal models in studying cerebellar anatomical and structural alterations in human neurological disease; however, they...
Guinea pigs have proved useful as experimental animal models in studying cerebellar anatomical and structural alterations in human neurological disease; however, they are also currently acquiring increasing veterinary interest as companion animals. The morphometric features of the normal cerebellum in guinea pigs have not been previously investigated using stereology. The objective of the present work was to establish normal volumetric and quantitative stereological parameters for cerebellar tissues in guinea pigs, by means of unbiased design-based stereology. Cerebellar total volume, gray and white matter volume fractions, molecular and granular layers volume fractions, cerebellar surface area, Purkinje cellular and nuclear volumes, and the Purkinje cell total count were stereologically estimated. For this purpose, cerebellar hemispheres from six adult male guinea pigs were employed. Isotropic, uniform random sections were obtained by applying the orientator method, and subsequently processed for light microscopy. The cerebellar total volume, the white and grey matter volume fractions, and the molecular and granular layer volumes were estimated using the Cavalieri's principle and the point counting system. The cerebellar surface area was estimated through the use of test lines; Purkinje cellular and nuclear volumes were analysed using the nucleator technique, whereas the Purkinje cell total count was obtained by means of the optical disector technique. The mean ± standard deviation total volume of a guinea-pig cerebellar hemisphere was 0.11 ± 0.01 cm . The mean volumetric proportions occupied by the gray and white matters were, respectively, 78.0 ± 2.6% and 22.0 ± 2.6%, whereas their mean absolute volumes were found to be 0.21 ± 0.02 cm and 0.059 ± 0.006 cm . The volumes of the molecular and granular layers were estimated at 112.4 ± 20.6 mm and 104.4 ± 7.3 mm , whereas their mean thicknesses were calculated to be 0.184 ± 0.020 mm and 0.17 ± 0.02 mm. The molecular and granular layers accounted for 40.7 ± 3.9% and 37.4 ± 1.8% of total cerebellar volume respectively. The surface area of the cerebellum measured 611.4 ± 96.8 mm . Purkinje cells with a cellular volume of 3210.1 µm and with a nuclear volume of 470.9 µm had a higher incidence of occurrence. The mean total number of Purkinje cells for a cerebellar hemisphere was calculated to be 253,090 ± 34,754. The morphometric data emerging from the present study provide a set of reference data which might prove valuable as basic anatomical contribution for practical applications in veterinary neurology.
Topics: Animals; Cerebellum; Guinea Pigs; Male; Microscopy; Purkinje Cells
PubMed: 33763861
DOI: 10.1111/joa.13434 -
Neuroscience May 2021Cerebellar development has a remarkably protracted morphogenetic timeline that is coordinated by multiple cell types. Here, we discuss the intriguing cellular... (Review)
Review
Cerebellar development has a remarkably protracted morphogenetic timeline that is coordinated by multiple cell types. Here, we discuss the intriguing cellular consequences of interactions between inhibitory Purkinje cells and excitatory granule cells during embryonic and postnatal development. Purkinje cells are central to all cerebellar circuits, they are the first cerebellar cortical neurons to be born, and based on their cellular and molecular signaling, they are considered the master regulators of cerebellar development. Although rudimentary Purkinje cell circuits are already present at birth, their connectivity is morphologically and functionally distinct from their mature counterparts. The establishment of the Purkinje cell circuit with its mature firing properties has a temporal dependence on cues provided by granule cells. Granule cells are the latest born, yet most populous, neuronal type in the cerebellar cortex. They provide a combination of mechanical, molecular and activity-based cues that shape the maturation of Purkinje cell structure, connectivity and function. We propose that the wiring of Purkinje cells for function falls into two developmental phases: an initial phase that is guided by intrinsic mechanisms and a later phase that is guided by dynamically-acting cues, some of which are provided by granule cells. In this review, we highlight the mechanisms that granule cells use to help establish the unique properties of Purkinje cell firing.
Topics: Cerebellum; Humans; Infant, Newborn; Interneurons; Neurogenesis; Neurons; Purkinje Cells
PubMed: 32554107
DOI: 10.1016/j.neuroscience.2020.06.010 -
Arquivos de Neuro-psiquiatria May 2020Transaxonal degenerations result from neuronal death or the interruption of synaptic connections among neuronal structures. These degenerations are not common but may be... (Review)
Review
UNLABELLED
Transaxonal degenerations result from neuronal death or the interruption of synaptic connections among neuronal structures. These degenerations are not common but may be recognized by conventional magnetic resonance imaging.
OBJECTIVE
The learning objectives of this review include recognition of the imaging characteristics of transaxonal degenerations involving cerebellar connections, the identification of potential encephalic lesions that can lead to these degenerations and correlation of the clinical manifestations with imaging findings that reflect this involvement.
METHODS
In this report, we review the neuroanatomical knowledge that provides a basis for identifying potential lesions that can result in these degenerations involving cerebellar structures.
RESULTS
Hypertrophic olivary degeneration results from an injury that interrupts any of the components of the Guillain-Mollaret triangle. In this work, we describe cases of lesions in the dentate nucleus and central tegmental tract. The crossed cerebellar diaschisis presents specific imaging findings and clinical correlations associated with its acute and chronic phases. The Wallerian degeneration of the middle cerebellar peduncle is illustrated by fiber injury of the pontine cerebellar tracts. A T2-hyperintensity in the dentate nucleus due to a thalamic acute lesion (in ventral lateral nuclei) is also described. Each condition described here is documented by MRI images and is accompanied by teaching points and an anatomical review of the pathways involved.
CONCLUSION
Neurologists and radiologists need to become familiar with the diagnosis of these conditions since their presentations are peculiar and often subtle, and can easily be misdiagnosed as ischemic events, degenerative disease, demyelinating disease or even tumors.
Topics: Brain; Cerebellum; Magnetic Resonance Imaging; Olivary Nucleus; Pons
PubMed: 32490959
DOI: 10.1590/0004-282x20200021