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Cold Spring Harbor Protocols Apr 2023Gustatory systems sense chemicals upon contact and provide a model to investigate how these stimuli are encoded to inform various behavioral decisions including choice...
Gustatory systems sense chemicals upon contact and provide a model to investigate how these stimuli are encoded to inform various behavioral decisions including choice of foods, egg-laying sites, and mating partners. Multiple organs in the body house peripheral gustatory sensory neurons, the axons of which project to discrete regions in the subesophageal zone and ventral ganglion, representing both the location and quality of the taste stimulus. Taste neurons are broadly divided into subpopulations associated with either positive or negative behavioral valence, each expressing combinations of taste receptors-in some cases, more than 30 receptors-encoded by one or more chemosensory gene families that together determine their chemical response properties. provides a powerful model to study gustatory coding because a majority of the taste sensory units (sensilla) are present in external taste organs (labellum and legs) and are accessible for electrophysiological analysis of tastant-evoked responses. Moreover, a large body of work on the basic characteristics of individual taste neurons housed in a sensillum, as well as on functional surveys of entire taste organs, provides a foundation for investigating further questions about taste coding, adaptability, and evolution. This protocol describes how to perform recordings of stimulus-evoked activity from taste sensilla covering the basics of setting up the electrophysiology rig and stimulus-delivery device, sample preparation, and performing and analyzing the recordings.
Topics: Animals; Sensilla; Taste; Drosophila; Sense Organs; Neurons
PubMed: 36446534
DOI: 10.1101/pdb.prot108064 -
BioMed Research International 2015Stability and mobility in functional motor activities depend on a precise regulation of phasic and tonic muscular activity that is carried out automatically, without... (Review)
Review
Stability and mobility in functional motor activities depend on a precise regulation of phasic and tonic muscular activity that is carried out automatically, without conscious awareness. The sensorimotor control of posture involves a complex integration of multisensory inputs that results in a final motor adjustment process. All or some of the components of this system may be dysfunctional in Parkinsonian patients, rendering postural instability one of the most disabling features of Parkinson's disease (PD). Balance control is critical for moving safely in and adapting to the environment. PD induces a multilevel impairment of this function, therefore worsening the patients' physical and psychosocial disability. In this review, we describe the complex ways in which PD impairs posture and balance, collecting and reviewing the available experimental evidence.
Topics: Humans; Muscles; Parkinson Disease; Postural Balance; Posture; Sense Organs
PubMed: 25654100
DOI: 10.1155/2015/434683 -
International Journal of Molecular... Jun 2023Diabetic choroidopathy was first described on histopathological specimens of diabetic eyes. This alteration was characterized by the accumulation of PAS-positive... (Review)
Review
Diabetic choroidopathy was first described on histopathological specimens of diabetic eyes. This alteration was characterized by the accumulation of PAS-positive material within the intracapillary stroma. Inflammation and polymorphonuclear neutrophils (PMNs) activation are crucial elements in choriocapillaris impairment. The evidence of diabetic choroidopathy in vivo was confirmed with multimodal imaging, which provides key quantitative and qualitative features to characterize the choroidal involvement. The choroid can be virtually affected in each vascular layer, from Haller's layer to the choriocapillaris. However, the damage on the outer retina and photoreceptor cells is essentially driven by a choriocapillaris deficiency, which can be assessed through optical coherence tomography angiography (OCTA). The identification of characteristic features of diabetic choroidopathy can be significant for understanding the potential pathogenic and prognostic implications in diabetic retinopathy.
Topics: Humans; Diabetic Retinopathy; Retina; Choroid; Retinal Vessels; Angiography; Tomography, Optical Coherence; Fluorescein Angiography; Diabetes Mellitus
PubMed: 37373315
DOI: 10.3390/ijms241210167 -
Applied Optics Apr 2022Nodal points are defined using parallel object and image rays at very small angles to the optical axis, and Johann Listing described them when characterizing the eye in...
Nodal points are defined using parallel object and image rays at very small angles to the optical axis, and Johann Listing described them when characterizing the eye in 1845. They are only distinct from principal points when there is a refractive index difference, but Reginald Clay used the term "nodal slide" in 1904 for equipment that uses lens rotation when measuring a lens focal length in air. Over time, sketches of nodal rays at large angles have become common, and these perhaps appear to support observations that input angles to the eye match image angles measured to the nodal point. Raytrace calculations confirm that this is correct for very large angles, but the relationship comes from the cornea curving around, towards incoming light, angles being rescaled at the exit pupil by a constant factor, and then the retina curving around to meet the image rays. The eye has high linearity, with 1:1 angular scaling occurring at approximately the nodal point, but ray bundles passing through the pupil center, rather than paraxial nodal rays, define the optical properties.
Topics: Cornea; Lens, Crystalline; Pupil; Retina; Vision, Ocular
PubMed: 35471355
DOI: 10.1364/AO.455464 -
Advances in Experimental Medicine and... 2020Sense organs (eyes, ears, nose, tongue, and skin) provide senses of sight, hearing, smell, taste, and touch, respectively, to aid the survival, development, learning,... (Review)
Review
Sense organs (eyes, ears, nose, tongue, and skin) provide senses of sight, hearing, smell, taste, and touch, respectively, to aid the survival, development, learning, and adaptation of humans and other animals (including fish). Amino acids (AAs) play an important role in the growth, development, and functions of the sense organs. Recent work has identified receptor-mediated mechanisms responsible for the chemosensory transduction of five basic taste qualities (sweet, sour, bitter, umami and salty tastes). Abnormal metabolism of AAs result in a structural deformity of tissues and their dysfunction. To date, there is a large database for AA metabolism in the eye and skin under normal (e.g., developmental changes and physiological responses) and pathological (e.g., nutritional and metabolic diseases, nutrient deficiency, infections, and cancer) conditions. Important metabolites of AAs include nitric oxide and polyamines (from arginine), melanin and dopamine (from phenylalanine and tyrosine), and serotonin and melatonin (from tryptophan) in both the eye and the skin; γ-aminobutyrate (from glutamate) in the retina; and urocanic acid and histamine (from histidine) in the skin. At present, relatively little is known about the synthesis or catabolism of AAs in the ears, nose, and tongue. Future research should be directed to: (1) address this issue with regard to healthy ageing, nasal and sinus cancer, the regulation of food intake, and oral cavity health; and (2) understand how prenatal and postnatal nutrition and environmental pollution affect the growth, development and health of the sense organs, as well as their expression of genes (including epigenetics) and proteins in humans and other animals.
Topics: Amino Acids; Animals; Humans; Sense Organs
PubMed: 32761578
DOI: 10.1007/978-3-030-45328-2_12 -
Journal of Immunology Research 2018Immune-mediated inner ear disease can be primary, when the autoimmune response is against the inner ear, or secondary. The latter is characterized by the involvement of... (Review)
Review
Immune-mediated inner ear disease can be primary, when the autoimmune response is against the inner ear, or secondary. The latter is characterized by the involvement of the ear in the presence of systemic autoimmune conditions. Sensorineural hearing loss is the most common audiovestibular symptom associated with systemic autoimmune diseases, although conductive hearing impairment may also be present. Hearing loss may present in a sudden, slowly, rapidly progressive or fluctuating form, and is mostly bilateral and asymmetric. Hearing loss shows a good response to corticosteroid therapy that may lead to near-complete hearing restoration. Vestibular symptoms, tinnitus, and aural fullness can be found in patients with systemic autoimmune diseases; they often mimic primary inner ear disorders such as Menière's disease and mainly affect both ears simultaneously. Awareness of inner ear involvement in systemic autoimmune diseases is essential for the good response shown to appropriate treatment. However, it is often misdiagnosed due to variable clinical presentation, limited knowledge, sparse evidence, and lack of specific diagnostic tests. The aim of this review is to analyse available evidence, often only reported in the form of case reports due to the rarity of some of these conditions, of the different clinical presentations of audiological and vestibular symptoms in systemic autoimmune diseases.
Topics: Autoimmune Diseases; Ear, Inner; Hearing Loss, Conductive; Hearing Loss, Sensorineural; Humans; Meniere Disease; Tinnitus
PubMed: 30211232
DOI: 10.1155/2018/5798103 -
Journal of Neurogenetics 2020Glia shape the development and function of the nervous system, especially its sense organs and central neuropil (nerve ring). Cell-type-specific promoters allow...
Glia shape the development and function of the nervous system, especially its sense organs and central neuropil (nerve ring). Cell-type-specific promoters allow investigators to label or manipulate individual glial cell types, and therefore provide a key tool for deciphering glial function. In this technical resource, we compare the specificity, brightness, and consistency of cell-type-specific promoters for glia. We identify a set of promoters for the study of seven glial cell types (, amphid and phasmid sheath glia; amphid sheath glia only; , amphid and phasmid socket glia; , cephalic (CEP) sheath glia; and , inner labial (IL) socket glia) as well as a pan-glial promoter (). We compare these promoters to promoters that are expressed more variably in combinations of glial cell types ( and ). We note that the expression of some promoters depends on external conditions or the internal state of the organism, such as developmental stage, suggesting glial plasticity. Finally, we demonstrate an approach for prospectively identifying cell-type-specific glial promoters using existing single-cell sequencing data, and we use this approach to identify two novel promoters specific to IL socket glia ( and ).
Topics: Adaptation, Physiological; Animals; Biomarkers; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Datasets as Topic; Gene Expression Regulation; Genes, Helminth; Neuroglia; Organ Specificity; Promoter Regions, Genetic; Single-Cell Analysis
PubMed: 32696701
DOI: 10.1080/01677063.2020.1781851 -
Documenta Ophthalmologica. Advances in... Oct 2021The purpose of this study was to assess eye movements during a multifocal ERG (mfERG) recording. This study evaluated the relationship between bivariate contour ellipse...
PURPOSE
The purpose of this study was to assess eye movements during a multifocal ERG (mfERG) recording. This study evaluated the relationship between bivariate contour ellipse areas (BCEAs), mfERG amplitudes (Amps) and mfERG implicit times (ITs) with repeat testing and experienced subjects.
METHODS
Thirty subjects were selected (15 experienced to ocular procedures and 15 novices). All were confirmed to have healthy retinas and at least 20/25 vision. MfERGs with a stimulus near 100% contrast and 4-min m-sequence were recorded on two different days using our common clinical technique, which did not constrain the head. VERIS with fundus monitoring system was used for recording with a Burian-Allen electrode. An external camera captured the fundus during each mfERG recording. The optic nerve head position was tracked in each video using a custom algorithm in order to determine BCEAs. Each subject performed one mfERG on two different days. MfERGs were analyzed for Amps and ITs for the fovea and whole eye.
RESULTS
There was no correlation between the mfERG metrics and BCEAs with repeat testing. There were also no differences between the experienced and novice subjects for mfERG Amps, ITs or BCEAs. Eye movements between visits were highly correlated (multiple r = 0.67). BCEAs were larger during mfERGs (1.04 ± 0.8 deg) than those observed in previous literature using brief viewing tasks (< 0.3 deg). The proportion of time spent fixating within 1.0 and 2.0 degrees of the central hexagon was 68 and 93%, respectively.
CONCLUSIONS
This study is the first to evaluate the stability of the retina while recording a mfERG in healthy subjects and indicates that the center of fixation during a mfERG stays within the central hexagon. Eye stability during an initial recording is the best indicator of stability on the second recording. The amount of movement during these recordings did not seem to affect the mfERG Amps or ITs. These data suggest clinical confidence with mfERGs when recording novice patients.
Topics: Electroretinography; Fovea Centralis; Fundus Oculi; Humans; Optic Disk; Retina
PubMed: 33713340
DOI: 10.1007/s10633-021-09829-9 -
Seminars in Neurology Feb 2020Recent advances in vestibular testing now permit functional testing of all peripheral vestibular sense organs (all three semicircular canals, utricle, and saccule). This... (Review)
Review
Recent advances in vestibular testing now permit functional testing of all peripheral vestibular sense organs (all three semicircular canals, utricle, and saccule). This makes it possible to identify patients with isolated dysfunction of the utricle or saccule, even though parallel pathways for vestibular information are ultimately integrated centrally. Selective, isolated unilateral loss of utricular function as measured by ocular vestibular-evoked myogenic potentials (VEMPs) has been observed in patients with normal semicircular canal function as measured by the video head impulse test of all six semicircular canals, and normal bilateral saccular function as determined by symmetrical cervical VEMPs. How these patients present clinically and how they recover is discussed and contrasted with acute vestibular neuritis. In some patients, the unilateral loss of otolith organ (utricle or saccule) function persists and yet the patient recovers functionally to their usual lifestyle. Until the testing of all peripheral vestibular sense organs is routine, the frequency of isolated loss of otolith function cannot be gauged.
Topics: Humans; Otolithic Membrane; Vestibular Diseases; Vestibulocochlear Nerve Diseases
PubMed: 31887751
DOI: 10.1055/s-0039-3402064 -
Nature Communications Mar 2024Insect antennae facilitate the nuanced detection of vibrations and deflections, and the non-contact perception of magnetic or chemical stimuli, capabilities not found in...
Insect antennae facilitate the nuanced detection of vibrations and deflections, and the non-contact perception of magnetic or chemical stimuli, capabilities not found in mammalian skin. Here, we report a neuromorphic antennal sensory system that emulates the structural, functional, and neuronal characteristics of ant antennae. Our system comprises electronic antennae sensor with three-dimensional flexible structures that detects tactile and magnetic stimuli. The integration of artificial synaptic devices adsorbed with solution-processable MoS nanoflakes enables synaptic processing of sensory information. By emulating the architecture of receptor-neuron pathway, our system realizes hardware-level, spatiotemporal perception of tactile contact, surface pattern, and magnetic field (detection limits: 1.3 mN, 50 μm, 9.4 mT). Vibrotactile-perception tasks involving profile and texture classifications were accomplished with high accuracy (> 90%), surpassing human performance in "blind" tactile explorations. Magneto-perception tasks including magnetic navigation and touchless interaction were successfully completed. Our work represents a milestone for neuromorphic sensory systems and biomimetic perceptual intelligence.
Topics: Animals; Arthropod Antennae; Mammals; Neurons; Sense Organs; Skin; Touch
PubMed: 38453967
DOI: 10.1038/s41467-024-46393-7