Sensory Functions
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Author(s):  
Elzbieta Jankowska ◽  
Ingela Hammar

The review surveys various aspects of the plasticity of nerve fibres, in particular the prolonged increase in their excitability evoked by polarization, focusing on a long-lasting increase in the excitability of myelinated afferent fibres traversing the dorsal columns of the spinal cord. We review the evidence that increased axonal excitability (i) follows epidurally applied direct current as well as relatively short (5 or 10 ms) current pulses and synaptically evoked intrinsic field potentials; (ii) critically depends on the polarization of branching regions of afferent fibres at the sites where they bifurcate and give off axon collaterals entering the spinal grey matter in conjunction with actions of extrasynaptic GABAA membrane receptors; and (iii) shares the feature of being activity-independent with the short-lasting effects of polarization of peripheral nerve fibres. A comparison between the polarization evoked sustained increase in the excitability of dorsal column fibres and spinal motoneurons (plateau potentials) indicates the possibility that they are mediated by partly similar membrane channels (including non-inactivating type L Cav++ 1.3 but not Na+ channels) and partly different mechanisms. We finally consider under which conditions trans-spinally applied DC (tsDCS) might reproduce the effects of epidural polarization on dorsal column fibres and the possible advantages of increased excitability of afferent fibres for the rehabilitation of motor and sensory functions after spinal cord injuries.


2021 ◽  
Vol 15 ◽  
Author(s):  
Yudong Cao ◽  
Ya Shi ◽  
Zhifeng Xiao ◽  
Xi Chen ◽  
Bing Chen ◽  
...  

Spinal cord injury (SCI) usually results in permanent functional impairment and is considered a worldwide medical problem. However, both motor and sensory functions can spontaneously recover to varying extents in humans and animals with incomplete SCI. This study observed a significant spontaneous hindlimb locomotor recovery in Sprague-Dawley rats at four weeks after post-right-side spinal cord hemisection at thoracic 8 (T8). To verify whether the above spontaneous recovery derives from the ipsilateral axonal or neuronal regeneration to reconnect the lesion site, we resected either the scar tissue or right side T7 spinal cord at five weeks post-T8 hemisected injury. The results showed that the spontaneously achieved right hindlimb locomotor function had little change after resection. Furthermore, when T7 left hemisection was performed five weeks after the initial injury, the spontaneously achieved right hindlimb locomotor function was dramatically abolished. A similar result could also be observed when T7 transection was performed after the initial hemisection. The results indicated that it might be the contralateral axonal remolding rather than the ipsilateral axonal or neuronal regeneration beyond the lesion site responsible for the spontaneous hindlimb locomotor recovery. The immunostaining analyses and corticospinal tracts (CSTs) tracing results confirmed this hypothesis. We detected no substantial neuronal and CST regeneration throughout the lesion site; however, significantly more CST fibers were observed to sprout from the contralateral side at the lumbar 4 (L4) spinal cord in the hemisection model rats than in intact ones. In conclusion, this study verified that contralateral CST sprouting, but not ipsilateral CST or neuronal regeneration, is primarily responsible for the spontaneous locomotor recovery in hemisection SCI rats.


Author(s):  
Elina S. Kangas ◽  
Elisa Vuoriainen ◽  
Xueqiao Li ◽  
Pessi Lyyra ◽  
Piia Astikainen

Abstract. Automatic deviance detection has been widely explored in terms of mismatch responses (mismatch negativity or mismatch response) and P3a components of event-related potentials (ERPs) under a predictive coding framework; however, the somatosensory mismatch response has been investigated less often regarding the different types of changes than its auditory counterpart. It is not known whether the deviance detection responses from different modalities correlate, reflecting a general prediction error mechanism of the central nervous system. Furthermore, interoceptive functions have been associated with predictive coding theory, but whether interoceptive accuracy correlates with deviance detection brain responses has rarely been investigated. Here, we measured ERPs to changes in somatosensory stimuli’s location and intensity and in sound intensity in healthy adults ( n = 34). Interoceptive accuracy was measured with a heartbeat discrimination task, where participants indicated whether their heartbeats were simultaneous or non-simultaneous with sound stimuli. We found a mismatch response and a P3a response to somatosensory location and auditory intensity changes, but for somatosensory intensity changes, only a P3a response was found. Unexpectedly, there were neither correlations between the somatosensory location deviance and intensity deviance brain responses nor between auditory and somatosensory brain responses. In addition, the brain responses did not correlate with interoceptive accuracy. The results suggest that although deviance detection in the auditory and somatosensory modalities are likely based on similar neural mechanisms at a cellular level, their ERP indexes do not indicate a linear association in sensitivity for deviance detection between the modalities. Furthermore, although sensory deviance detection and interoceptive detection are both associated with predictive coding functions, under these experimental settings, functional relationships were not observed. These results should be taken into account in the future development of theories related to human sensory functions and in extensions of the predictive coding theory in particular.


2021 ◽  
Vol 14 ◽  
Author(s):  
Ronja Markworth ◽  
Mathias Bähr ◽  
Katja Burk

Charcot-Marie-Tooth disease (CMT), also known as motor and sensory neuropathy, describes a clinically and genetically heterogenous group of disorders affecting the peripheral nervous system. CMT typically arises in early adulthood and is manifested by progressive loss of motor and sensory functions; however, the mechanisms leading to the pathogenesis are not fully understood. In this review, we discuss disrupted intracellular transport as a common denominator in the pathogenesis of different CMT subtypes. Intracellular transport via the endosomal system is essential for the delivery of lipids, proteins, and organelles bidirectionally to synapses and the soma. As neurons of the peripheral nervous system are amongst the longest neurons in the human body, they are particularly susceptible to damage of the intracellular transport system, leading to a loss in axonal integrity and neuronal death. Interestingly, defects in intracellular transport, both in neurons and Schwann cells, have been found to provoke disease. This review explains the mechanisms of trafficking and subsequently summarizes and discusses the latest findings on how defects in trafficking lead to CMT. A deeper understanding of intracellular trafficking defects in CMT will expand our understanding of CMT pathogenesis and will provide novel approaches for therapeutic treatments.


2021 ◽  
Vol 22 (16) ◽  
pp. 8570
Author(s):  
Il-Sup Kim ◽  
Woong-Suk Yang ◽  
Cheorl-Ho Kim

Peptides present in foods are involved in nutritional functions by supplying amino acids; sensory functions related to taste or solubility, emulsification, etc.; and bioregulatory functions in various physiological activities. In particular, peptides have a wide range of physiological functions, including as anticancer agents and in lowering blood pressure and serum cholesterol levels, enhancing immunity, and promoting calcium absorption. Soy protein can be partially hydrolyzed enzymatically to physiologically active soy (or soybean) peptides (SPs), which not only exert physiological functions but also help amino acid absorption in the body and reduce bitterness by hydrolyzing hydrophobic amino acids from the C- or N-terminus of soy proteins. They also possess significant gel-forming, emulsifying, and foaming abilities. SPs are expected to be able to prevent and treat atherosclerosis by inhibiting the reabsorption of bile acids in the digestive system, thereby reducing blood cholesterol, low-density lipoprotein, and fat levels. In addition, soy contains blood pressure-lowering peptides that inhibit angiotensin-I converting enzyme activity and antithrombotic peptides that inhibit platelet aggregation, as well as anticancer, antioxidative, antimicrobial, immunoregulatory, opiate-like, hypocholesterolemic, and antihypertensive activities. In animal models, neuroprotective and cognitive capacity as well as cardiovascular activity have been reported. SPs also inhibit chronic kidney disease and tumor cell growth by regulating the expression of genes associated with apoptosis, inflammation, cell cycle arrest, invasion, and metastasis. Recently, various functions of soybeans, including their physiologically active functions, have been applied to health-oriented foods, functional foods, pharmaceuticals, and cosmetics. This review introduces some current results on the role of bioactive peptides found in soybeans related to health functions.


Polar Biology ◽  
2021 ◽  
Author(s):  
Andrew W. Naslund ◽  
Brittany E. Davis ◽  
James A. Hobbs ◽  
Nann A. Fangue ◽  
Anne E. Todgham

AbstractThe combustion of fossil fuels is currently causing rapid rates of ocean warming and acidification worldwide. Projected changes in these parameters have been repeatedly observed to stress the physiological limits and plasticity of many marine species from the molecular to organismal levels. High latitude oceans are among the fastest changing ecosystems; therefore, polar species are projected to be some of the most vulnerable to climate change. Antarctic species are particularly sensitive to environmental change, having evolved for millions of years under stable ocean conditions. Otoliths, calcified structures found in a fish’s inner ear used to sense movement and direction, have been shown to be affected by both warming and CO2-acidified seawater in temperate and tropical fishes but there is no work to date on Antarctic fishes. In this study, juvenile emerald rockcod (Trematomus bernacchii) were exposed to projected seawater warming and CO2-acidification for the year 2100 over 28 days. Sagittal otoliths were analyzed for changes in area, perimeter, length, width and shape. We found ocean warming increased the growth rate of otoliths, while CO2-acidified seawater and the interaction of warming and acidification did not have an effect on otolith development. Elevated temperature also altered the shape of otoliths. If otolith development is altered under future warming scenarios, sensory functions such as hearing, orientation, and movement may potentially be impaired. Changes in these basic somatic abilities could have broad implications for the general capabilities and ecology of early life stages of Antarctic fishes.


2021 ◽  
pp. 135910452110372
Author(s):  
Onur O Demirci ◽  
Eser Sagaltici

Patients with functional neurological symptom disorder (FND) have many diverse symptoms including psychogenic nonepileptic seizures (PNES), positive movements such as tremor, dystonia, or gait abnormalities, loss of motor function such as leg or arm paresis, and loss of sensory functions, such as blindness, deafness, or loss of feeling in the limbs. Eye movement desensitization and reprocessing (EMDR) is a therapy method that includes some techniques arising from psychodynamic, cognitive, and behavioral approaches. EMDR is known as a proven psychotherapeutic approach in post-traumatic stress disorder, but there are also numerous studies reporting its efficacy in other psychiatric disorders and trauma-associated symptoms, in patients with comorbid psychiatric disorders. This article presents the outcome of EMDR treatment of two patients’ cases, a 13-year-old female and a 16-year-old male, who were diagnosed as FND with PNES, according to the DSM-5 diagnostic criteria. In both cases, there was a significant decrease in Adolescent Dissociative Experiences Scale scores and no pseudo seizures were found, even at the sixth-month follow-up visits. These case studies suggest that EMDR can be an effective method in the long-term treatment of FND with PNES and a useful alternative to other treatment methods.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
David Hickey ◽  
Andrej Vilfan ◽  
Ramin Golestanian

Cilia are hairlike organelles involved in both sensory functions and motility. We discuss the question of whether the location of chemical receptors on cilia provides an advantage in terms of sensitivity and whether motile sensory cilia have a further advantage. Using a simple advection-diffusion model, we compute the capture rates of diffusive molecules on a cilium. Because of its geometry, a non-motile cilium in a quiescent fluid has a capture rate equivalent to a circular absorbing region with ~4x its surface area. When the cilium is exposed to an external shear flow, the equivalent surface area increases to ~6x. Alternatively, if the cilium beats in a non-reciprocal way in an otherwise quiescent fluid, its capture rate increases with the beating frequency to the power of 1/3. Altogether, our results show that the protruding geometry of a cilium could be one of the reasons why so many receptors are located on cilia. They also point to the advantage of combining motility with chemical reception.


2021 ◽  
Author(s):  
Liam Sheehan

<p><b>The dominance of vision within the human sensory system, particularly in fields such as Architecture, has created an ocular-centric paradigm prevalent in Western architectural culture. “Experience” is an architectural design thesis that uses Virtual Reality (VR) design techniques to explore how we, as designers, can affect spatial presence by integrating other bodily senses within virtual environments. “Experience” integrates four senses, Vision, Audition, Kinaesthesia and Thermoception, as combined for exploration.</b></p> <p>The relationship between the human senses, in particular thermoception, and the spaces we experience is the particular focus of this thesis. Juhani Pallasmaa’s theories of sensory fragmentation have been applied as an important critical theoretical approach. This study aims to determine the extent to which our less commonly simulated sensory functions can be used within VR design to experience virtual spatial qualities. Specifically, it introduces a physical thermal atmosphere around the VR user to alter spatial and sensory perceptions and create virtual atmospheres. The development of a real ‘spatialised’ heating environment allows the thermal qualities of virtual space to be perceived by the user.</p> <p>In this context, space is defined as the experiential medium that situates itself within the bounds of a room. It is not of a fixed size, nor does it have fixed qualities. Instead, this research applies Henry Lefebvre’s ideas that the body creates space due to the relationship between the body’s deployment in space and its occupation of space.</p> <p>Through theoretical reviews and James Turrell and Olafur Eliasson’s artwork analysis’, ‘Experience’ generates an understanding of spatial perceptions, human sensory experience and space. These understandings were then applied to the virtual environment through a range of computational design means. </p> <p>The ideas of sensory fragmentation were then applied to a series of design experiments. Each sense was treated as its own sensory system fragment, which allowed a series of conceptual, and developed spatial, interventions to be created. Each spatial intervention provided unique insights into the independent sensory fragments, which eventuated in the design of the final holistic sensory experience.</p> <p>The final sensory design, titled Sensationalising VR, results showed how sensory balancing must be achieved before implementing new sensory experiences. Thermoception, the body’s ability to detect magnitude and direction of temperature changes, proved to be a fragile sensory fragment that requires careful balancing when being engaged with other sensory stimuli in a VR setting.</p> <p>The conclusions resulting from “Experience” suggests that the human sensory system’s visual bias can be usefully augmented; it can be shifted, altered and even removed by designers. The introduction of a spatial thermal atmosphere around VR users is shown to affect the perception of presence in that space.</p>


2021 ◽  
Author(s):  
Liam Sheehan

<p><b>The dominance of vision within the human sensory system, particularly in fields such as Architecture, has created an ocular-centric paradigm prevalent in Western architectural culture. “Experience” is an architectural design thesis that uses Virtual Reality (VR) design techniques to explore how we, as designers, can affect spatial presence by integrating other bodily senses within virtual environments. “Experience” integrates four senses, Vision, Audition, Kinaesthesia and Thermoception, as combined for exploration.</b></p> <p>The relationship between the human senses, in particular thermoception, and the spaces we experience is the particular focus of this thesis. Juhani Pallasmaa’s theories of sensory fragmentation have been applied as an important critical theoretical approach. This study aims to determine the extent to which our less commonly simulated sensory functions can be used within VR design to experience virtual spatial qualities. Specifically, it introduces a physical thermal atmosphere around the VR user to alter spatial and sensory perceptions and create virtual atmospheres. The development of a real ‘spatialised’ heating environment allows the thermal qualities of virtual space to be perceived by the user.</p> <p>In this context, space is defined as the experiential medium that situates itself within the bounds of a room. It is not of a fixed size, nor does it have fixed qualities. Instead, this research applies Henry Lefebvre’s ideas that the body creates space due to the relationship between the body’s deployment in space and its occupation of space.</p> <p>Through theoretical reviews and James Turrell and Olafur Eliasson’s artwork analysis’, ‘Experience’ generates an understanding of spatial perceptions, human sensory experience and space. These understandings were then applied to the virtual environment through a range of computational design means. </p> <p>The ideas of sensory fragmentation were then applied to a series of design experiments. Each sense was treated as its own sensory system fragment, which allowed a series of conceptual, and developed spatial, interventions to be created. Each spatial intervention provided unique insights into the independent sensory fragments, which eventuated in the design of the final holistic sensory experience.</p> <p>The final sensory design, titled Sensationalising VR, results showed how sensory balancing must be achieved before implementing new sensory experiences. Thermoception, the body’s ability to detect magnitude and direction of temperature changes, proved to be a fragile sensory fragment that requires careful balancing when being engaged with other sensory stimuli in a VR setting.</p> <p>The conclusions resulting from “Experience” suggests that the human sensory system’s visual bias can be usefully augmented; it can be shifted, altered and even removed by designers. The introduction of a spatial thermal atmosphere around VR users is shown to affect the perception of presence in that space.</p>


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