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Medecine Sciences : M/S 2020The neuroretina is a functional unit of the central nervous system that converts a light signal into a nerve impulse. Of neuroectodermal origin, derived from the... (Review)
Review
The neuroretina is a functional unit of the central nervous system that converts a light signal into a nerve impulse. Of neuroectodermal origin, derived from the diencephalon, the neuroretina is a layered tissue composed of six types of neuronal cells (two types of photoreceptors: cones and rods, horizontal, bipolar, amacrine and ganglion cells) and three types of glial cells (Müller glial cells, astrocytes and microglial cells). The neuroretina lays on the retinal pigmentary epithelium, that together form the retina. The existence of the internal and external blood-retinal barriers and intra-retinal junctions reflects the fineness of regulation of the retinal exchanges with the circulation and within the retina itself. The central zone of the human retina, which is highly specialized for visual acuity, has anatomical specificities. Recent imaging methods make it possible now to enrich our knowledge of the anatomical and functional characteristics of the retina, which are still imperfectly described.
Topics: Animals; Choroid; Humans; Neuroglia; Retina; Retinal Cone Photoreceptor Cells; Retinal Pigment Epithelium; Retinal Rod Photoreceptor Cells; Retinal Vessels
PubMed: 32614310
DOI: 10.1051/medsci/2020094 -
Annual Review of Vision Science Sep 2021The outer retina is nourished from the choroid, a capillary bed just inside the sclera. O, glucose, and other nutrients diffuse out of the choroid and then filter... (Review)
Review
The outer retina is nourished from the choroid, a capillary bed just inside the sclera. O, glucose, and other nutrients diffuse out of the choroid and then filter through a monolayer of retinal pigment epithelium (RPE) cells to fuel the retina. Recent studies of energy metabolism have revealed striking differences between retinas and RPE cells in the ways that they extract energy from fuels. The purpose of this review is to suggest and evaluate the hypothesis that the retina and RPE have complementary metabolic roles that make them depend on each other for survival and for their abilities to perform essential and specialized functions.
Topics: Choroid; Energy Metabolism; Retina; Retinal Pigment Epithelium
PubMed: 34102066
DOI: 10.1146/annurev-vision-100419-115156 -
Nature Mar 2022Interoception, the ability to timely and precisely sense changes inside the body, is critical for survival. Vagal sensory neurons (VSNs) form an important body-to-brain...
Interoception, the ability to timely and precisely sense changes inside the body, is critical for survival. Vagal sensory neurons (VSNs) form an important body-to-brain connection, navigating visceral organs along the rostral-caudal axis of the body and crossing the surface-lumen axis of organs into appropriate tissue layers. The brain can discriminate numerous body signals through VSNs, but the underlying coding strategy remains poorly understood. Here we show that VSNs code visceral organ, tissue layer and stimulus modality-three key features of an interoceptive signal-in different dimensions. Large-scale single-cell profiling of VSNs from seven major organs in mice using multiplexed projection barcodes reveals a 'visceral organ' dimension composed of differentially expressed gene modules that code organs along the body's rostral-caudal axis. We discover another 'tissue layer' dimension with gene modules that code the locations of VSN endings along the surface-lumen axis of organs. Using calcium-imaging-guided spatial transcriptomics, we show that VSNs are organized into functional units to sense similar stimuli across organs and tissue layers; this constitutes a third 'stimulus modality' dimension. The three independent feature-coding dimensions together specify many parallel VSN pathways in a combinatorial manner and facilitate the complex projection of VSNs in the brainstem. Our study highlights a multidimensional coding architecture of the mammalian vagal interoceptive system for effective signal communication.
Topics: Animals; Brain; Calcium; Mammals; Mice; Perception; Psychophysiology; Sensory Receptor Cells; Vagus Nerve; Vomeronasal Organ
PubMed: 35296859
DOI: 10.1038/s41586-022-04515-5 -
International Journal of Molecular... Jun 2017Dry eye can damage the ocular surface and result in mild corneal epithelial defect to blinding corneal pannus formation and squamous metaplasia. Significant progress in... (Review)
Review
Dry eye can damage the ocular surface and result in mild corneal epithelial defect to blinding corneal pannus formation and squamous metaplasia. Significant progress in the treatment of dry eye has been made in the last two decades; progressing from lubricating and hydrating the ocular surface with artificial tear to stimulating tear secretion; anti-inflammation and immune regulation. With the increase in knowledge regarding the pathophysiology of dry eye, we propose in this review the concept of ocular surface microenvironment. Various components of the microenvironment contribute to the homeostasis of ocular surface. Compromise in one or more components can result in homeostasis disruption of ocular surface leading to dry eye disease. Complete evaluation of the microenvironment component changes in dry eye patients will not only lead to appropriate diagnosis, but also guide in timely and effective clinical management. Successful treatment of dry eye should be aimed to restore the homeostasis of the ocular surface microenvironment.
Topics: Cellular Microenvironment; Conjunctiva; Cornea; Dry Eye Syndromes; Eye; Eyelids; Homeostasis; Hormones; Humans; Lacrimal Apparatus; Lubricant Eye Drops; Meibomian Glands; Microbiota; Tears
PubMed: 28661456
DOI: 10.3390/ijms18071398 -
Ophthalmology. Retina Jul 2020
Topics: Choroid; Humans; Retina; Retinal Detachment; Vitreous Body
PubMed: 32646560
DOI: 10.1016/j.oret.2020.02.005 -
Trends in Neurosciences Dec 2018Many internal organs change volume periodically. For example, the stomach accommodates ingested food and drink, the bladder stores urine, the heart fills with blood, and... (Review)
Review
Many internal organs change volume periodically. For example, the stomach accommodates ingested food and drink, the bladder stores urine, the heart fills with blood, and the lungs expand with every breath. Specialized peripheral sensory neurons function as mechanoreceptors that detect tissue stretch to infer changes in organ volume and then relay this information to the brain. Central neural circuits process this information and evoke perceptions (satiety, nausea), control physiology (breathing, heart rate), and impact behavior (feeding, micturition). Yet, basic questions remain about how neurons sense organ distension and whether common sensory motifs are involved across organs. Here, we review candidate mechanosensory receptors, cell types, and neural circuits, focusing on the stomach, bladder, and airways. Understanding mechanisms of organ stretch sensation may provide new ways to treat autonomic dysfunction.
Topics: Afferent Pathways; Animals; Humans; Interoception; Mechanoreceptors; Organ Size; Sensory Receptor Cells
PubMed: 30143276
DOI: 10.1016/j.tins.2018.07.008 -
Mucosal Immunology Jun 2022The eye is a sensory organ exposed to the environment and protected by a mucosal tissue barrier. While it shares a number of features with other mucosal tissues, the... (Review)
Review
The eye is a sensory organ exposed to the environment and protected by a mucosal tissue barrier. While it shares a number of features with other mucosal tissues, the ocular mucosal system, composed of the conjunctiva, Meibomian glands, and lacrimal glands, is specialized to address the unique needs of (a) lubrication and (b) host defense of the ocular surface. Not surprisingly, most challenges, physical and immunological, to the homeostasis of the eye fall into those two categories. Dry eye, a dysfunction of the lacrimal glands and/or Meibomian glands, which can both cause, or arise from, sensory defects, including those caused by corneal herpes virus infection, serve as examples of these perturbations and will be discussed ahead. To preserve vision, dense neuronal and immune networks sense various stimuli and orchestrate responses, which must be tightly controlled to provide protection, while simultaneously minimizing collateral damage. All this happens against the backdrop of, and can be modified by, the microorganisms that colonize the ocular mucosa long term, or that are simply transient passengers introduced from the environment. This review will attempt to synthesize the existing knowledge and develop trends in the study of the unique mucosal and immune elements of the ocular surface.
Topics: Humans; Dry Eye Syndromes; Meibomian Glands; Lacrimal Apparatus; Conjunctiva; Mucous Membrane; Tears
PubMed: 36002743
DOI: 10.1038/s41385-022-00551-6 -
Current Opinion in Neurobiology Dec 2021Sensory systems evolve and enable organisms to perceive their sensory Umwelt, the unique set of cues relevant for their survival. The multiple components that comprise... (Review)
Review
Sensory systems evolve and enable organisms to perceive their sensory Umwelt, the unique set of cues relevant for their survival. The multiple components that comprise sensory systems - the receptors, cells, organs, and dedicated high-order circuits - can vary greatly across species. Sensory receptor gene families can expand and contract across lineages, resulting in enormous sensory diversity. Comparative studies of sensory receptor function have uncovered the molecular basis of receptor properties and identified novel sensory receptor classes and noncanonical sensory strategies. Phylogenetically informed comparisons of sensory systems across multiple species can pinpoint when sensory changes evolve and highlight the role of contingency in sensory system evolution.
Topics: Biological Evolution; Sensation; Sense Organs; Sensory Receptor Cells
PubMed: 34600187
DOI: 10.1016/j.conb.2021.08.005 -
Acta Oto-laryngologica Nov 2023At present, there are not international unified standards and reports on Congenital Ear Malformation (CEM) in the world, which makes it difficult to transfer information... (Review)
Review
BACKGROUND
At present, there are not international unified standards and reports on Congenital Ear Malformation (CEM) in the world, which makes it difficult to transfer information and compare the literature.
AIMS/OBJECTIVES
Through the statistical analysis of a large sample of CEM, a unified standard of all aspects of CEM is proposed and the data are provided for reference, which is convenient for the international work and literature comparison in this field.
MATERIALS AND METHODS
Based on the author's 30 years of clinical and scientific research work on CEM and the relevant cases of 3231 (4714 ears) in our hospital, and combined with literature, statistical analysis was made.
RESULTS
This paper summarizes the classification, definition, epidemiology, embryonic development, pathogenic factors of CEM and elaborates on the clinical manifestations, examination and sequence therapy of representative Congenital Malformation of the Middle and Outer Ear (CMMOE). We also introduce malformation of the auricle and inner ear, so as to cover the outer, middle and inner ear. At the same time, we introduce our achievements and contributions in this field.
CONCLUSIONS AND SIGNIFICANCE
This study provides reference to the international unified standard and treatment principle of the CEM.
Topics: Ear, Middle; Ear, External; Ear, Inner; Ear Auricle
PubMed: 38109200
DOI: 10.1080/00016489.2023.2279263 -
Experimental Physiology Jan 2024Proprioception is the sense that lets us perceive the location, movement and action of the body parts. The proprioceptive apparatus includes specialized sense organs... (Review)
Review
Proprioception is the sense that lets us perceive the location, movement and action of the body parts. The proprioceptive apparatus includes specialized sense organs (proprioceptors) which are embedded in the skeletal muscles. The eyeballs are moved by six pairs of eye muscles and binocular vision depends on fine-tuned coordination of the optical axes of both eyes. Although experimental studies indicate that the brain has access to eye position information, both classical proprioceptors (muscle spindles and Golgi tendon organ) are absent in the extraocular muscles of most mammalian species. This paradox of monitoring extraocular muscle activity in the absence of typical proprioceptors seemed to be resolved when a particular nerve specialization (the palisade ending) was detected in the extraocular muscles of mammals. In fact, for decades there was consensus that palisade endings were sensory structures that provide eye position information. The sensory function was called into question when recent studies revealed the molecular phenotype and the origin of palisade endings. Today we are faced with the fact that palisade endings exhibit sensory as well as motor features. This review aims to evaluate the literature on extraocular muscle proprioceptors and palisade endings and to reconsider current knowledge of their structure and function.
Topics: Animals; Oculomotor Muscles; Sensory Receptor Cells; Mechanoreceptors; Proprioception; Muscle Spindles; Mammals
PubMed: 36869596
DOI: 10.1113/EP090765