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Sensors (Basel, Switzerland) Jul 2022The development of auditory sensors and systems is essential in smart materials of robotics and is placed at the strategic category of mutual communication between...
The development of auditory sensors and systems is essential in smart materials of robotics and is placed at the strategic category of mutual communication between humans and robots. We designed prototypes of the rubber-made equilibrium and auditory sensors, mimicking hair cells in the saccule and the cochlea at the vestibule of the human ear by utilizing our previously proposed technique of electrolytic polymerization on the hybrid fluid rubber (HF rubber). The fabricated artificial hair cells embedded with mimicked free nerve endings and Pacinian corpuscles, which are well-known receptors in the human skin and have already been elucidated effective in the previous study, have the intelligence of equilibrium and auditory sensing. Moreover, they have a voltage that is generated from built-in electricity caused by the ionized particles and molecules in the HF rubber due to piezoelectricity. We verified the equilibrium and auditory characteristics by measuring the changes in voltage with inclination, vibration over a wide frequency range, and sound waves. We elucidated experimentally that the intelligence has optimum morphological conditions. This work has the possibility of advancing the novel technology of state-of-the-art social robotics.
Topics: Humans; Polymerization; Robotics; Rubber; Skin, Artificial; Smart Materials
PubMed: 35891135
DOI: 10.3390/s22145447 -
European Journal of Translational... Aug 2019The aim of this study was to characterize the microscopic structure and sensory nerve endings of the crural interosseous membrane (IM). 13 IMs from 7 cadavers were used...
The aim of this study was to characterize the microscopic structure and sensory nerve endings of the crural interosseous membrane (IM). 13 IMs from 7 cadavers were used to analyze the organization of the collagen fibers, IM's thickness, distribution of elastic fibers and nerve elements. The IM is mainly a two-layer collagen fascicle structure with the collagen fibers of adjacent layers orientated along different directions, forming angles of 30.5 +/- 1.7° at proximal and 26.6 +/- 2.1° at distal part (P>0.05). The percentage of elastic fibers between the two layers and inside the collagen fascicle layer is 10.1 +/- 0.5% and 2.2 +/- 0.1% (P<0.001). The IM's thickness at proximal, middle, and distal parts is 268.5 +/- 18.6μm; 293.2 +/- 12.5μm; 365.3 +/- 19.3 μm, respectively (Proximal vs Distal: P<0.001; Middle vs Distal: P<0.05). Nerve elements were present and located both inside and on the surface of the IM, whereas the mechanoreceptors are mainly located on the surface of the IM. Free nerve endings (33.3 +/- 5.0/cm) and Ruffini corpuscles (3.4 +/- 0.6/cm) were the predominant sensory elements, while Pacinian corpuscles (1.3 +/- 0.7/cm) were rarely found. The type of mechanoreceptors found suggests that the IM may play a role in proprioception.
PubMed: 31579480
DOI: 10.4081/ejtm.2019.8340 -
Annals of Anatomy = Anatomischer... Feb 2024Afferent innervation of shoulder joints plays a fundamental role in nociception and mechanoception and its alteration result in shoulder´s disease that course with pain...
BACKGROUND
Afferent innervation of shoulder joints plays a fundamental role in nociception and mechanoception and its alteration result in shoulder´s disease that course with pain and functional disability.
METHODS
Joints shoulder from healthy subjects (n = 20) and with chronic pain shoulder syndromes (n = 17) were analyzed using immunohistochemistry for S100 protein to identify nerve structures (nerve fibers and sensory corpuscles), coupled with a quantification of the sensory formations. Sensory nerve formations were quantified in 13 distinct areas in healthy joint shoulder and in the available equivalent areas in the pathological joints. Statistical analyses were conducted to assess differences between healthy shoulder and pathological shoulder joint (p< 0.05).
RESULTS
All analyzed structures, i.e., glenohumeral capsule, acromioclavicular capsule, the extraarticular structures (subcoracoid region and subacromio-subdeltoid bursa) and intraarticular structures (biceps brachii tendon and labrum articulare) are variably innervated except the extrinsic coracoacromial ligament, which was aneural. The afferent innervation of healthy human shoulder joints consists of free nerve endings, simple lamellar corpuscles and Ruffini's corpuscles. Occasionally, Golgi-Mazzoni's and Pacinian corpuscles were found. However, the relative density of each one varied among joints and/or the different zones within the same joint. As a rule, the upper half and anterior half of healthy glenohumeral capsules have a higher innervation compared to the lower and posterior respectably. On the other hand, in joints from subjects suffering chronic shoulder pain, a reduced innervation was found, involving more the corpuscles than free nerve endings.
CONCLUSIONS
Our findings report a global innervation map of the human shoulder joints, especially the glenohumeral one, and this knowledge might be of interest for arthroscopic surgeons allowing to develop more selective and unhurt treatments, controlling the pain, and avoiding the loss of afferent innervation after surgical procedures. To the light of our results the postero-inferior glenohumeral capsular region seems to be the more adequate to be a surgical portal (surgical access area) to prevent nerve lesions.
Topics: Humans; Shoulder Joint; Shoulder; Chronic Pain; Mechanoreceptors; Sensory Receptor Cells
PubMed: 38154784
DOI: 10.1016/j.aanat.2023.152206 -
Sensors (Basel, Switzerland) Jan 2023In order to advance engineering applications of robotics such as wearable health-monitoring devices, humanoid robots, etc., it is essential to investigate the tactile...
In order to advance engineering applications of robotics such as wearable health-monitoring devices, humanoid robots, etc., it is essential to investigate the tactile sensations of artificial haptic sensors mimicking bioinspired human cutaneous mechanoreceptors such as free nerve endings, Merkel's cells, Krause end bulbs, Meissner corpuscles, Ruffini endings, and Pacinian corpuscles. The generated receptor's potential response to extraneous stimuli, categorized as slow adaption (SA) or fast adaption (FA), is particularly significant as a typical property. The present study addressed the estimation of SA and FA by utilizing morphologically fabricated mechanoreceptors made of our proposed magnetically responsive intelligent fluid, hybrid fluid (HF), and by applying our proposed electrolytic polymerization. Electric circuit models of the mechanoreceptors were generated using experimental data on capacitance and inductance on the basis of the electric characteristics of impedance. The present results regarding equivalent firing rates based on FA and SA are consistent with the FA and SA findings of vital mechanoreceptors by biomedical analysis. The present investigative process is useful to clarify the time of response to a force on the fabricated artificial mechanoreceptor.
PubMed: 36772367
DOI: 10.3390/s23031327 -
Scientific Reports Mar 2020The function of the external ear canal in cetaceans is still under debate and its morphology is largely unknown. Immunohistochemical (IHC) analyses using antibodies...
The function of the external ear canal in cetaceans is still under debate and its morphology is largely unknown. Immunohistochemical (IHC) analyses using antibodies specific for nervous tissue (anti-S100, anti-NSE, anti-NF, and anti-PGP 9.5), together with transmission electron microscopy (TEM) and various histological techniques, were carried out to investigate the peripheral nervous system of the ear canals of several species of toothed whales and terrestrial Cetartiodactyla. This study highlights the innervation of the ear canal with the presence of lamellar corpuscles over its entire course, and their absence in all studied terrestrial mammals. Each corpuscle consisted of a central axon, surrounded by lamellae of Schwann receptor cells, surrounded by a thin cellular layer, as shown by IHC and TEM. These findings indicate that the corpuscles are mechanoreceptors that resemble the inner core of Pacinian corpuscles without capsule or outer core, and were labelled as simple lamellar corpuscles. They form part of a sensory system that may represent a unique phylogenetic feature of cetaceans, and an evolutionary adaptation to life in the marine environment. Although the exact function of the ear canal is not fully clear, we provide essential knowledge and a preliminary hypothetical deviation on its function as a unique sensory organ.
Topics: Animals; Axons; Ear Canal; Immunohistochemistry; Male; Microscopy, Electron, Transmission; Pacinian Corpuscles; Peripheral Nervous System; Phylogeny
PubMed: 32144309
DOI: 10.1038/s41598-020-61170-4 -
Sensors (Basel, Switzerland) Dec 2020It is known that humans experience a haptic illusion, such as the sensation of being pulled in a particular direction, when asymmetric vibrations are presented. A...
It is known that humans experience a haptic illusion, such as the sensation of being pulled in a particular direction, when asymmetric vibrations are presented. A pulling illusion has been used to provide a force feedback for a virtual reality (VR) system and a pedestrian navigation system, and the asymmetric vibrations can be implemented in any small non-grounded device. However, the design methodology of asymmetric vibration stimuli to induce the pulling illusion has not been fully demonstrated. Although the frequency of the asymmetric vibration is important, findings on the frequency have not been reported. In this study, we clarified the influences of the effects on the pulling illusion based on the investigation of asymmetric vibration frequency differences. Two psychophysical experiments that related to the frequency of asymmetric vibration were performed. Experiment I showed that the illusion occurs for specific vibration waveforms at 40 Hz and 75 Hz. As a result of Experiment II, the threshold was the lowest when the frequency was 40 Hz, and highest when the frequency was 110 Hz. This result supports the previous hypothesis that the Meissner corpuscles and the Ruffini endings contribute to the illusion, while the Pacinian corpuscles do not.
PubMed: 33321954
DOI: 10.3390/s20247086 -
Annals of Anatomy = Anatomischer... Feb 2024The cutaneous end organ complexes or cutaneous sensory corpuscles are specialized sensory organs associated to low-threshold mechanoreceptors. Mechano-gated proteins...
BACKGROUND
The cutaneous end organ complexes or cutaneous sensory corpuscles are specialized sensory organs associated to low-threshold mechanoreceptors. Mechano-gated proteins forming a part of ion channels have been detected in both the axon and terminal glial cells of Meissner corpuscles, a specific cutaneous end organ complex in the human glabrous skin. The main candidates to mechanotransduction in Meissner corpuscles are members of the Piezo family of cationic ion channels. PIEZO2 has been detected in the axon of these sensory structures whereas no data exists about the occurrence and cell localization of PIEZO1.
METHODS
Skin samples (n = 18) from the palmar aspect of the distal phalanx of the first and second fingers were analysed (8 female and 10 males; age range 26 to 61 26-61 years). Double immunofluorescence for PIEZO1 and PIEZO2 together with axonal or terminal glial cell markers was captured by laser confocal microscopy, and the percentage of PIEZOs positive Meissner corpuscles was evaluated.
RESULTS
MCs from human fingers showed variable morphology and degree of lobulation. Regarding the basic immunohistochemical profile, in all cases the axons were immunoreactive for neurofilament proteins, neuron specific enolase and synaptophysin, while the lamellar cells displayed strong S100P immunoreactivity. PIEZO1 was detected co-localizing with axonal markers, but never with terminal glial cell markers, in the 56% of Meissner corpuscles; weak but specific immunofluorescence was additionally detected in the epidermis, especially in basal keratinocytes. Similarly, PIEZO2 immunoreactivity was found restricted to the axon in the 85% of Meissner corpuscles. PIEZO2 positive Merkel cells were also regularly found.
CONCLUSIONS
PIEZO1 and PIEZO2 are expressed exclusively in the axon of a subpopulation of human digital Meissner corpuscles, thus suggesting that not only PIEZO2, but also PIEZO1 may be involved in the mechanotransduction from low-threshold mechanoreceptors.
Topics: Female; Humans; Male; Ion Channels; Mechanoreceptors; Mechanotransduction, Cellular; Merkel Cells; Pacinian Corpuscles; Skin; Adult; Middle Aged
PubMed: 38109982
DOI: 10.1016/j.aanat.2023.152200 -
Sensors (Basel, Switzerland) May 2023In order to advance the development of sensors fabricated with monofunctional sensation systems capable of a versatile response to tactile, thermal, gustatory,...
In order to advance the development of sensors fabricated with monofunctional sensation systems capable of a versatile response to tactile, thermal, gustatory, olfactory, and auditory sensations, mechanoreceptors fabricated as a single platform with an electric circuit require investigation. In addition, it is essential to resolve the complicated structure of the sensor. In order to realize the single platform, our proposed hybrid fluid (HF) rubber mechanoreceptors of free nerve endings, Merkel cells, Krause end bulbs, Meissner corpuscles, Ruffini endings, and Pacinian corpuscles mimicking the bio-inspired five senses are useful enough to facilitate the fabrication process for the resolution of the complicated structure. This study used electrochemical impedance spectroscopy (EIS) to elucidate the intrinsic structure of the single platform and the physical mechanisms of the firing rate such as slow adaption (SA) and fast adaption (FA), which were induced from the structure and involved the capacitance, inductance, reactance, etc. of the HF rubber mechanoreceptors. In addition, the relations among the firing rates of the various sensations were clarified. The adaption of the firing rate in the thermal sensation is the opposite of that in the tactile sensation. The firing rates in the gustation, olfaction, and auditory sensations at frequencies of less than 1 kHz have the same adaption as in the tactile sensation. The present findings are useful not only in the field of neurophysiology, to research the biochemical reactions of neurons and brain perceptions of stimuli, but also in the field of sensors, to advance salient developments in sensors mimicking bio-inspired sensations.
Topics: Smell; Rubber; Touch; Mechanoreceptors; Thermosensing
PubMed: 37430506
DOI: 10.3390/s23104593 -
Journal of Anatomy Jul 2021Vibration is detected by mechanoreceptors, including Pacinian corpuscles (PCs), which are widely distributed in the human body including the adventitia of large blood...
Vibration is detected by mechanoreceptors, including Pacinian corpuscles (PCs), which are widely distributed in the human body including the adventitia of large blood vessels. Although the distribution of PCs around large limb vessels has been previously reported, there remains no consensus on their distribution in the adventitia of the human deep blood vessels in the upper arm. In addition, the physiological functions of PCs located around the deep limb blood vessels remain largely unknown. This study aimed to elucidate detailed anatomical features and physiological function of lamellar sensory corpuscles structurally identified as PCs using the immunohistochemical methods around the deep vessels in the upper arm. We identified PCs in the connective tissue adjacent to the deep vessels in the upper arm using histological analysis and confirmed that PCs are located in the vascular sheath of the artery and its accompanying vein as well as in the connective tissue surrounding the vascular sheath and nerves. PCs were densely distributed on the distal side of deep vessels near the elbow. We also examined the relationship between vascular sound and pulsating sensation to evaluate the PCs functions around deep arteries and veins and found that the vascular sound made by pressing the brachial arteries in the upper arm was associated with the pulsating sensation of the examinee. Our results suggest that PCs, around deep vessels, function as bathyesthesia sensors by detecting vibration from blood vessels.
Topics: Aged, 80 and over; Arm; Arteries; Female; Humans; Male; Pacinian Corpuscles; Pulsatile Flow
PubMed: 33527396
DOI: 10.1111/joa.13398 -
Frontiers in Human Neuroscience 2020In recent years, vibrotactile haptic feedback technology has been widely used for user interfaces in the mobile devices. Although functional neuroimaging studies have...
In recent years, vibrotactile haptic feedback technology has been widely used for user interfaces in the mobile devices. Although functional neuroimaging studies have investigated human brain responses to different types of tactile inputs, the neural mechanisms underlying high-frequency vibrotactile perception are still relatively unknown. Our aim was to investigate neuromagnetic brain responses to high-frequency vibrotactile stimulation, using magnetoencephalography (MEG). We measured 152-channel whole-head MEG in 30 healthy, right-handed volunteers (aged 20-28 years, 15 females). A total of 300 vibrotactile stimuli were presented at the tip of either the left index finger or the right index finger in two separate sessions. Sinusoidal vibrations at 150 Hz for 200 ms were generated with random inter-stimulus intervals between 1.6 and 2.4 s. Both time-locked analysis and time-frequency analysis were performed to identify peak responses and oscillatory modulations elicited by high-frequency vibrations. The significance of the evoked and induced responses for dominant and non-dominant hand stimulation conditions was statistically tested, respectively. The difference in responses between stimulation conditions was also statistically evaluated. Prominent peak responses were observed at 56 ms (M50) and at 100 ms (M100) for both stimulation conditions. The M50 response revealed clear dipolar field patterns in the contralateral side with significant cortical activations in the contralateral primary sensorimotor area, whereas the M100 response was not as prominent as the M50. Vibrotactile stimulation induced significant suppression of both alpha (8-12 Hz) and beta (20-30 Hz) band activity during the mid-latency period (0.2-0.4 s), primarily in sensorimotor areas contralateral to the stimulation side. In addition, a significant alpha enhancement effect in posterior regions was accompanied with alpha suppressions in sensorimotor regions. The alpha suppression was observed in a broader distribution of cortical areas for the non-dominant hand stimulation. Our data demonstrate that high-frequency tactile vibrations, which is known to primarily activate Pacinian corpuscles, elicit somatosensory M50 and M100 responses in the evoked fields and induce modulations of alpha and beta band oscillations during mid-latency periods. Our study is also consistent with that the primary sensorimotor area is significantly involved in the processing of high-frequency vibrotactile information with contralateral dominance.
PubMed: 33250728
DOI: 10.3389/fnhum.2020.576082