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Cell Oct 2021Mammals use glabrous (hairless) skin of their hands and feet to navigate and manipulate their environment. Cortical maps of the body surface across species contain...
Mammals use glabrous (hairless) skin of their hands and feet to navigate and manipulate their environment. Cortical maps of the body surface across species contain disproportionately large numbers of neurons dedicated to glabrous skin sensation, in part reflecting a higher density of mechanoreceptors that innervate these skin regions. Here, we find that disproportionate representation of glabrous skin emerges over postnatal development at the first synapse between peripheral mechanoreceptors and their central targets in the brainstem. Mechanoreceptor synapses undergo developmental refinement that depends on proximity of their terminals to glabrous skin, such that those innervating glabrous skin make synaptic connections that expand their central representation. In mice incapable of sensing gentle touch, mechanoreceptors innervating glabrous skin still make more powerful synapses in the brainstem. We propose that the skin region a mechanoreceptor innervates controls the developmental refinement of its central synapses to shape the representation of touch in the brain.
Topics: Action Potentials; Animals; Animals, Newborn; Axons; Brain Stem; Ion Channels; Mechanoreceptors; Mice, Knockout; Neurons; Optical Imaging; Optogenetics; Skin; Synapses; Touch Perception; Mice
PubMed: 34637701
DOI: 10.1016/j.cell.2021.09.023 -
Current Opinion in Neurobiology Jun 2022The muscle spindle (MS) provides essential sensory information for motor control and proprioception. The Group Ia and II MS afferents are low threshold slowly-adapting... (Review)
Review
The muscle spindle (MS) provides essential sensory information for motor control and proprioception. The Group Ia and II MS afferents are low threshold slowly-adapting mechanoreceptors and report both static muscle length and dynamic muscle movement information. The exact molecular mechanism by which MS afferents transduce muscle movement into action potentials is incompletely understood. This short review will discuss recent evidence suggesting that PIEZO2 is an essential mechanically sensitive ion channel in MS afferents and that vesicle-released glutamate contributes to maintaining afferent excitability during the static phase of stretch. Other mechanically gated ion channels, voltage-gated sodium channels, other ion channels, regulatory proteins, and interactions with the intrafusal fibers are also important for MS afferent mechanosensation. Future studies are needed to fully understand mechanosensation in the MS and whether different complements of molecular mediators contribute to the different response properties of Group Ia and II afferents.
Topics: Action Potentials; Ion Channels; Mechanoreceptors; Muscle Spindles; Neurons, Afferent; Proprioception
PubMed: 35430481
DOI: 10.1016/j.conb.2022.102542 -
Current Biology : CB Feb 2012
Topics: Afferent Pathways; Animals; Epidermal Cells; Mammals; Mechanoreceptors; Pleasure; Touch
PubMed: 22321302
DOI: 10.1016/j.cub.2011.11.032 -
Philosophical Transactions of the Royal... Jul 1998Vision, audition and somatic sensation in the platypus are reviewed. Recent work on the eye and retinal ganglion cell layer of the platypus is presented that provides an... (Review)
Review
Vision, audition and somatic sensation in the platypus are reviewed. Recent work on the eye and retinal ganglion cell layer of the platypus is presented that provides an estimate of visual acuity and suggests that platypus ancestors may have used vision, as well as the bill organ, for underwater predation. The combined electroreceptor and mechanoreceptor array in the bill is considered in detail, with special reference to the elaborate cortical structure, where inputs from these two sensory arrays are integrated in a manner that is astonishingly similar to the stripe-like ocular dominance array in primate visual of cortex, that integrates input from the two eyes. A new hypothesis, along with supporting data, is presented for this combined mechanoreceptive-electroreceptive complex in platypus cortex. Bill mechanoreceptors are shown to be capable of detecting mechanical waves travelling through the water from moving prey. These mechanical waves arrive after the electrical activity from the same prey, as a function of distance. Bimodal cortical neurones, sensitive to combined mechanical and electrical stimulation, with a delay, can thus signal directly the absolute distance of the prey. Combined with the directional information provided by signal processing of the thousands of receptors on the bill surface, the stripe-like cortical array enables the platypus to use two different sensory systems in its bill to achieve a complete, three-dimensional 'fix' on its underwater prey.
Topics: Animals; Beak; Hair; Hearing; Mechanoreceptors; Platypus; Sensation; Sensory Receptor Cells; Vision, Ocular
PubMed: 9720115
DOI: 10.1098/rstb.1998.0276 -
Journal of the Royal Society, Interface May 2018Hair-like structures are prevalent throughout biology and frequently act to sense or alter interactions with an organism's environment. The overall shape of a hair is... (Review)
Review
Hair-like structures are prevalent throughout biology and frequently act to sense or alter interactions with an organism's environment. The overall shape of a hair is simple: a long, filamentous object that protrudes from the surface of an organism. This basic design, however, can confer a wide range of functions, owing largely to the flexibility and large surface area that it usually possesses. From this simple structural basis, small changes in geometry, such as diameter, curvature and inter-hair spacing, can have considerable effects on mechanical properties, allowing functions such as mechanosensing, attachment, movement and protection. Here, we explore how passive features of hair-like structures, both individually and within arrays, enable diverse functions across biology. Understanding the relationships between form and function can provide biologists with an appreciation for the constraints and possibilities on hair-like structures. Additionally, such structures have already been used in biomimetic engineering with applications in sensing, water capture and adhesion. By examining hairs as a functional mechanical unit, geometry and arrangement can be rationally designed to generate new engineering devices and ideas.
Topics: Arabidopsis; Biomimetic Materials; Biomimetics; Mechanoreceptors; Models, Biological; Trichomes
PubMed: 29848593
DOI: 10.1098/rsif.2018.0206 -
Science Advances Dec 2023Effective therapies for obesity require invasive surgical and endoscopic interventions or high patient adherence, making it challenging for patients with obesity to...
Effective therapies for obesity require invasive surgical and endoscopic interventions or high patient adherence, making it challenging for patients with obesity to effectively manage their disease. Gastric mechanoreceptors sense distension of the stomach and perform volume-dependent vagal signaling to initiate the gastric phase and influence satiety. In this study, we developed a new luminal stimulation modality to specifically activate these gastric stretch receptors to elicit a vagal afferent response commensurate with mechanical distension. We designed the Vibrating Ingestible BioElectronic Stimulator (VIBES) pill, an ingestible device that performs luminal vibratory stimulation to activate mechanoreceptors and stroke mucosal receptors, which induces serotonin release and yields a hormonal metabolic response commensurate with a fed state. We evaluated VIBES across 108 meals in swine which consistently led to diminished food intake (~40%, < 0.0001) and minimized the weight gain rate ( < 0.05) as compared to untreated controls. Application of mechanoreceptor biology could transform our capacity to help patients suffering from nutritional disorders.
Topics: Humans; Animals; Swine; Stomach; Obesity; Mechanoreceptors; Weight Gain; Vagus Nerve
PubMed: 38134286
DOI: 10.1126/sciadv.adj3003 -
Physiological Reviews Jul 1995Mechanical forces associated with blood flow play important roles in the acute control of vascular tone, the regulation of arterial structure and remodeling, and the... (Review)
Review
Mechanical forces associated with blood flow play important roles in the acute control of vascular tone, the regulation of arterial structure and remodeling, and the localization of atherosclerotic lesions. Major regulation of the blood vessel responses occurs by the action of hemodynamic shear stresses on the endothelium. The transmission of hemodynamic forces throughout the endothelium and the mechanotransduction mechanisms that lead to biophysical, biochemical, and gene regulatory responses of endothelial cells to hemodynamic shear stresses are reviewed.
Topics: Animals; Blood Circulation; Endothelium, Vascular; Hemodynamics; Humans; Mechanoreceptors; Signal Transduction
PubMed: 7624393
DOI: 10.1152/physrev.1995.75.3.519 -
Acta Medica Portuguesa 1995The control system of breathing can be considered as a closed loop system, consisting of two subsystems: the controlling system and the controlled system. Both systems... (Review)
Review
The control system of breathing can be considered as a closed loop system, consisting of two subsystems: the controlling system and the controlled system. Both systems are defined by their input-output relationships. The controlling system is defined by the Respiratory Centers that are responsible for two separate, but overlapping, patterns: the automatic control pattern and the behavioral or voluntary control. In the controlling system the input is the blood gas value and the output is some parameters of ventilation. The controlled system is characterized by an input of ventilation and an output of blood gas values. In this closed loop system breathing is normally regulated by two anatomically distinct but functionally integrated elements, referred to as the metabolic and behavioral respiratory control systems. The metabolic control is concerned with blood gas homeostasis and the voluntary control relates with activities such as phonation and singing that use the ventilatory apparatus for purposes other than gas exchange.
Topics: Brain; Chemoreceptor Cells; Humans; Mechanoreceptors; Respiration
PubMed: 7484257
DOI: No ID Found -
Current Biology : CB Oct 2016The ability of animals to flexibly navigate through complex environments depends on the integration of sensory information with motor commands. The sensory modality most... (Review)
Review
The ability of animals to flexibly navigate through complex environments depends on the integration of sensory information with motor commands. The sensory modality most tightly linked to motor control is mechanosensation. Adaptive motor control depends critically on an animal's ability to respond to mechanical forces generated both within and outside the body. The compact neural circuits of insects provide appealing systems to investigate how mechanical cues guide locomotion in rugged environments. Here, we review our current understanding of mechanosensation in insects and its role in adaptive motor control. We first examine the detection and encoding of mechanical forces by primary mechanoreceptor neurons. We then discuss how central circuits integrate and transform mechanosensory information to guide locomotion. Because most studies in this field have been performed in locusts, cockroaches, crickets, and stick insects, the examples we cite here are drawn mainly from these 'big insects'. However, we also pay particular attention to the tiny fruit fly, Drosophila, where new tools are creating new opportunities, particularly for understanding central circuits. Our aim is to show how studies of big insects have yielded fundamental insights relevant to mechanosensation in all animals, and also to point out how the Drosophila toolkit can contribute to future progress in understanding mechanosensory processing.
Topics: Animals; Cues; Insecta; Locomotion; Mechanoreceptors; Sensation
PubMed: 27780045
DOI: 10.1016/j.cub.2016.06.070 -
Proceedings of the National Academy of... Oct 2022Low-threshold mechanoreceptors (LTMRs) and their cutaneous end organs convert light mechanical forces acting on the skin into electrical signals that propagate to the...
Low-threshold mechanoreceptors (LTMRs) and their cutaneous end organs convert light mechanical forces acting on the skin into electrical signals that propagate to the central nervous system. In mouse hairy skin, hair follicle-associated longitudinal lanceolate complexes, which are end organs comprising LTMR axonal endings that intimately associate with terminal Schwann cell (TSC) processes, mediate LTMR responses to hair deflection and skin indentation. Here, we characterized developmental steps leading to the formation of Aβ rapidly adapting (RA)-LTMR and Aδ-LTMR lanceolate complexes. During early postnatal development, Aβ RA-LTMRs and Aδ-LTMRs extend and prune cutaneous axonal branches in close association with nascent TSC processes. Netrin-G1 is expressed in these developing Aβ RA-LTMR and Aδ-LTMR lanceolate endings, and ablation experiments indicate that Netrin-G1 functions in sensory neurons to promote lanceolate ending elaboration around hair follicles. The Netrin-G ligand (NGL-1), encoded by , is expressed in TSCs, and ablation of partially phenocopied the lanceolate complex deficits observed in mutants. Moreover, NGL-1-Netrin-G1 signaling is a general mediator of LTMR end organ formation across diverse tissue types demonstrated by the fact that Aβ RA-LTMR endings associated with Meissner corpuscles and Pacinian corpuscles are also compromised in the and mutant mice. Thus, axon-glia interactions, mediated in part by NGL-1-Netrin-G1 signaling, promote LTMR end organ formation.
Topics: Animals; Mice; Axons; Ligands; Mechanoreceptors; Netrins; Schwann Cells; Skin
PubMed: 36252008
DOI: 10.1073/pnas.2210421119