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Current Topics in Developmental Biology 2024The primary senses-touch, taste, sight, smell, and hearing-connect animals with their environments and with one another. Aside from the eyes, the primary sense organs of... (Review)
Review
The primary senses-touch, taste, sight, smell, and hearing-connect animals with their environments and with one another. Aside from the eyes, the primary sense organs of vertebrates and the peripheral sensory pathways that relay their inputs arise from two transient stem cell populations: the neural crest and the cranial placodes. In this chapter we consider the senses from historical and cultural perspectives, and discuss the senses as biological faculties. We begin with the embryonic origin of the neural crest and cranial placodes from within the neural plate border of the ectodermal germ layer. Then, we describe the major chemical (i.e. olfactory and gustatory) and mechanical (i.e. vestibulo-auditory and somatosensory) senses, with an emphasis on the developmental interactions between neural crest and cranial placodes that shape their structures and functions.
Topics: Animals; Neural Crest; Humans; Sensation; Sense Organs; Vertebrates
PubMed: 38729675
DOI: 10.1016/bs.ctdb.2024.01.015 -
Acta Bio-medica : Atenei Parmensis Nov 2021Vernal keratocongiuntivitis (VKC) is a chronic inflammatory disease affecting the ocular conjunctiva and cornea. It is a rare and underestimated pathology, whose missed... (Review)
Review
Vernal keratocongiuntivitis (VKC) is a chronic inflammatory disease affecting the ocular conjunctiva and cornea. It is a rare and underestimated pathology, whose missed or delayed diagnosis can lead to the development of serious ocular complications. Moreover, despite VKC symptoms are well known, they can overlap and be mistaken with allergic conjunctivitis. In fact, diagnostic criteria and severity grading are not standardized yet. The pathogenesis of VKC is still controversial and it is difficult to identify a single mechanism underlying the chronic ocular inflammation. Different studies hypothesized both allergies and autoimmune diseases and also oxidative stress contribute significantly to the origin of the disease. However, the unclear pathogenesis and the lack of specific disease biomarkers make treatment a challenge. The standard therapy includes antihistamines, anti-inflammatory and immunosuppressant drugs and novel therapies are currently under investigation. However, considering treatment guidelines and recommendations are not well defined yet, therapy should be personalized on the clinical features of the patient. This paper provides an overview of the VKC and updates on the challenges that need to be addressed in the future to improve the management of the patient with this disease and improve his quality of life.
Topics: Anti-Inflammatory Agents; Conjunctiva; Conjunctivitis, Allergic; Histamine Antagonists; Humans; Quality of Life
PubMed: 34842588
DOI: 10.23750/abm.v92iS7.12419 -
Journal of Neurogenetics 2020has a simple nervous system of 302 neurons. It however senses environmental cues incredibly precisely and produces various behaviors by processing information in the... (Comparative Study)
Comparative Study Review
has a simple nervous system of 302 neurons. It however senses environmental cues incredibly precisely and produces various behaviors by processing information in the neural circuit. In addition to classical genetic analysis, fluorescent proteins and calcium indicators enable monitoring of protein dynamics and neural activity on either fixed or free-moving worms. These analyses have provided the detailed molecular mechanisms of neuronal and systemic signaling that regulate worm responses. Here, we focus on responses of against temperature and review key findings that regulate thermotaxis and cold tolerance. Thermotaxis of has been studied extensively for almost 50 years, and cold tolerance is a relatively recent concept in . Although both thermotaxis and cold tolerance require temperature sensation, the responsible neurons and molecular pathways are different, and uses the proper mechanisms depending on its situation. We summarize the molecular mechanisms of the major thermosensory circuit as well as the modulatory strategy through neural and tissue communication that enables fine tuning of thermotaxis and cold tolerance.
Topics: Adaptation, Physiological; Animals; Avoidance Learning; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Calcium Signaling; Cold Temperature; Dendrites; Interneurons; Mammals; Memory; Neural Pathways; Oxygen; Sense Organs; Sensory Receptor Cells; Species Specificity; Taxis Response; Thermoreceptors; Thermosensing
PubMed: 32316810
DOI: 10.1080/01677063.2020.1734001 -
Nature Communications Sep 2023Salient objects grab attention because they stand out from their surroundings. Whether this phenomenon is accomplished by bottom-up sensory processing or requires...
Salient objects grab attention because they stand out from their surroundings. Whether this phenomenon is accomplished by bottom-up sensory processing or requires top-down guidance is debated. We tested these alternative hypotheses by measuring how early and in which cortical layer(s) neural spiking distinguished a target from a distractor. We measured synaptic and spiking activity across cortical columns in mid-level area V4 of male macaque monkeys performing visual search for a color singleton. A neural signature of attentional capture was observed in the earliest response in the input layer 4. The magnitude of this response predicted response time and accuracy. Errant behavior followed errant selection. Because this response preceded top-down influences and arose in the cortical layer not targeted by top-down connections, these findings demonstrate that feedforward activation of sensory cortex can underlie attentional priority.
Topics: Animals; Male; Attention; Reaction Time; Parietal Lobe; Sensation; Sense Organs; Macaca; Visual Perception
PubMed: 37752171
DOI: 10.1038/s41467-023-41745-1 -
Journal of Neurophysiology Dec 2019Semicircular canal afferent neurons transmit information about head rotation to the brain. Mathematical models of how they do this have coevolved with concepts of how... (Review)
Review
Semicircular canal afferent neurons transmit information about head rotation to the brain. Mathematical models of how they do this have coevolved with concepts of how brains perceive the world. A 19th-century "camera" metaphor, in which sensory neurons project an image of the world captured by sense organs into the brain, gave way to a 20th-century view of sensory nerves as communication channels providing inputs to dynamical control systems. Now, in the 21st century, brains are being modeled as Bayesian observers who infer what is happening in the world given noisy, incomplete, and distorted sense data. The semicircular canals of the vestibular apparatus provide an experimentally accessible, low-dimensional system for developing and testing dynamical Bayesian generative models of sense data. In this review, we summarize advances in mathematical modeling of information transmission by semicircular canal afferent sensory neurons since the first such model was proposed nearly a century ago. Models of information transmission by vestibular afferent neurons may provide a foundation for developing realistic models of how brains perceive the world by inferring the causes of sense data.
Topics: Animals; Models, Biological; Neurons, Afferent; Semicircular Canals; Vestibule, Labyrinth
PubMed: 31693427
DOI: 10.1152/jn.00087.2019 -
PloS One 2019Proton conductivity is important in many natural phenomena including oxidative phosphorylation in mitochondria and archaea, uncoupling membrane potentials by the...
Proton conductivity is important in many natural phenomena including oxidative phosphorylation in mitochondria and archaea, uncoupling membrane potentials by the antibiotic Gramicidin, and proton actuated bioluminescence in dinoflagellate. In all of these phenomena, the conduction of protons occurs along chains of hydrogen bonds between water and hydrophilic residues. These chains of hydrogen bonds are also present in many hydrated biopolymers and macromolecule including collagen, keratin, chitosan, and various proteins such as reflectin. All of these materials are also proton conductors. Recently, our group has discovered that the jelly found in the Ampullae of Lorenzini- shark's electro-sensing organs- is the highest naturally occurring proton conducting substance. The jelly has a complex composition, but we proposed that the conductivity is due to the glycosaminoglycan keratan sulfate (KS). Here we measure the proton conductivity of hydrated keratan sulfate purified from Bovine Cornea. PdHx contacts at 0.50 ± 0.11 mS cm -1, which is consistent to that of Ampullae of Lorenzini jelly at 2 ± 1 mS cm -1. Proton conductivity, albeit with lower values, is also shared by other glycosaminoglycans with similar chemical structures including dermatan sulfate, chondroitin sulfate A, heparan sulfate, and hyaluronic acid. This observation supports the relationship between proton conductivity and the chemical structure of biopolymers.
Topics: Animals; Cattle; Cornea; Electric Conductivity; Glycosaminoglycans; In Vitro Techniques; Keratan Sulfate; Palladium; Protons; Sense Organs; Sharks
PubMed: 30849116
DOI: 10.1371/journal.pone.0202713 -
BMJ (Clinical Research Ed.) Apr 2020Head and neck structures govern the vital functions of breathing and swallowing. Additionally, these structures facilitate our sense of self through vocal communication,... (Review)
Review
Head and neck structures govern the vital functions of breathing and swallowing. Additionally, these structures facilitate our sense of self through vocal communication, hearing, facial animation, and physical appearance. Loss of these functions can lead to loss of life or greatly affect quality of life. Regenerative medicine is a rapidly developing field that aims to repair or replace damaged cells, tissues, and organs. Although the field is largely in its nascence, regenerative medicine holds promise for improving on conventional treatments for head and neck disorders or providing therapies where no current standard exists. This review presents milestones in the research of regenerative medicine in head and neck surgery.
Topics: Bioengineering; Cell Transplantation; Cochlea; Ear Cartilage; Facial Bones; Humans; Intercellular Signaling Peptides and Proteins; Larynx; Nasal Cartilages; Otolaryngology; Plastic Surgery Procedures; Regenerative Medicine; Salivary Glands; Skull; Tissue Engineering; Tissue Scaffolds; Trachea; Tympanic Membrane
PubMed: 32349978
DOI: 10.1136/bmj.m718 -
Anatomical Record (Hoboken, N.J. : 2007) Jan 2020Here I review, compare, and contrast the neurobiology and behavior of the common, eastern mole (Scalopus aquaticus) and the star-nosed mole (Condylura cristata). These... (Review)
Review
Here I review, compare, and contrast the neurobiology and behavior of the common, eastern mole (Scalopus aquaticus) and the star-nosed mole (Condylura cristata). These two species are part of the same family (Talpidae) and have similar body size and general morphology. But they differ in sensory specializations, complexity of neocortical organization, and behavior. The star-nosed mole has an elaborate mechanosensory organ-the star-consisting of 22 epidermal appendages (rays) covered with 25,000 touch domes called Eimer's organs. This densely innervated structure is represented in the neocortex in three different somatosensory maps, each visible in flattened neocortical sections as a series of 11 modules representing the 11 rays from the contralateral body. The 11th ray is greatly magnified in primary somatosensory cortex (S1). Behavioral studies show the star is moved in a saccadic manner and the 11th ray is a high-resolution tactile fovea, allowing star-nosed moles to forage on small prey with unprecedented speed and efficiency. In contrast, common mole noses lack Eimer's organs, their neocortex contains only two cortical maps of the nose, and they cannot localize small prey. Yet common moles have exceptional olfactory abilities, sniffing in stereo to rapidly localize discrete odor sources originating from larger prey. In addition, common moles are shown to track odorant trails laid down by moving prey. These results highlight the surprising abilities of species once thought to be simple, and the usefulness of diverse species in revealing general principles of brain organization and behavior. Anat Rec, 2019. © 2019 American Association for Anatomy.
Topics: Animals; Behavior, Animal; Brain Mapping; Mechanoreceptors; Moles; Sense Organs; Smell; Touch; Touch Perception
PubMed: 30614659
DOI: 10.1002/ar.24057 -
Eye (London, England) Jun 2023Retinitis pigmentosa (RP) is the commonest inherited retinal dystrophy. It is characterized by progressive photoreceptor degeneration and cell death and ongoing neuronal... (Review)
Review
Retinitis pigmentosa (RP) is the commonest inherited retinal dystrophy. It is characterized by progressive photoreceptor degeneration and cell death and ongoing neuronal and vascular impairment. In recent years, pathophysiological alterations of the choroid have begun to be appreciated in RP. Thus, representing a potential diagnostic and therapeutic biomarker. In particular, choroidal thickness and the choroidal vascularity index can be used to understand the pathogenesis of disease and evaluate new therapeutic possibilities. Photoreceptor changes seen in eyes with RP are directly correlated to a decrease of choroidal flow, leading to a strong association between relative choroidal ischemia and visual impairment. In this review we analyse the literature on choroidal thickness and choroidal vascularity index in patients with RP and assess whether these markers may reflect progression of disease from an anatomical and functional point of view.
Topics: Humans; Tomography, Optical Coherence; Visual Acuity; Choroid; Retinitis Pigmentosa; Biomarkers
PubMed: 36207507
DOI: 10.1038/s41433-022-02270-5 -
Development (Cambridge, England) Oct 2022Placodes are embryonic structures originating from the rostral ectoderm that give rise to highly diverse organs and tissues, comprising the anterior pituitary gland,... (Review)
Review
Placodes are embryonic structures originating from the rostral ectoderm that give rise to highly diverse organs and tissues, comprising the anterior pituitary gland, paired sense organs and cranial sensory ganglia. Their development, including the underlying gene regulatory networks and signalling pathways, have been for the most part characterised in animal models. In this Review, we describe how placode development can be recapitulated by the differentiation of human pluripotent stem cells towards placode progenitors and their derivatives, highlighting the value of this highly scalable platform as an optimal in vitro tool to study the development of human placodes, and identify human-specific mechanisms in their development, function and pathology.
Topics: Animals; Cell Differentiation; Ectoderm; Ganglia, Sensory; Gene Expression Regulation, Developmental; Humans; Pluripotent Stem Cells; Sense Organs
PubMed: 36040061
DOI: 10.1242/dev.200831