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Inherent Noise Hidden in Nervous Systems’ Rhythms Leads to New Strategies for Detection and Treatments of Core Motor Sensing Traits in ASD
Published in Elizabeth B. Torres, Caroline Whyatt, Autism, 2017
This recent body of work has started to gain momentum, thus inviting the clinical community to reconsider motor deficits and quantify movement disorders of various kinds as core symptoms of ASD (Whyatt and Craig 2012, 2013). Throughout this book, we argue that despite the compilation of abundant evidence for neuromotor dysfunction across different cross sections of the population with a diagnosis of ASD, there has been a paucity of models with the potential to eventually connect neuromotor dysfunction with deficits in sensory processing, sensory transduction, and sensory transmission. An ability to augment these fields is particularly relevant, as impairments at these levels could prevent sensory-motor integration and transformation processes required for the neurodevelopment of sensory and motor maps.
Physiology of excitable cells
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2015
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Sensory receptors include exteroreceptors, interoreceptors and proprioceptors. In general, sensory transduction is accomplished by the production of a receptor potential and encode modality, spatial localization, intensity, duration and frequency of stimuli. Sensory receptors may show accommodation. Muscle spindles are sensory receptors in skeletal muscles that lie parallel to the regular extrafusal muscle fibres. They consist of nuclear bag and nuclear chain intrafusal fibres. Ia afferent fibres form primary nerve endings on both nuclear bag and chain fibres. Group II afferent fibres form a secondary ending, which is found chiefly on the nuclear chain fibres. Primary endings detect static (change in length) and dynamic (rate of change in muscle length) changes in muscle, whereas secondary endings detect only static responses. The γ efferent system controls the sensitivity of the muscle spindle. The muscle spindles also dampen jerky or oscillatory muscle contractions. The Golgi tendon organs, located in the tendons of the muscles, are arranged in series with the skeletal muscle. They are supplied by IIb afferent fibres and are stimulated by both stretch and contraction of the muscle. The stretch reflex includes a monosynaptic excitatory pathway from muscle spindle afferent (Ia and II) fibres to the α motor neurons to the same and synergistic muscle and a disynaptic inhibitory pathway to the motor neurons of the antagonist muscles.
Treadmill workouts alleviate neuropathic allodynia and scratching behavior in rats following thoracotomy
Published in Neurological Research, 2022
Siao-Yuan Wang, Chong-Chi Chiu, Jhi-Joung Wang, Yu-Wen Chen, An-Kuo Chou, Ching-Hsia Hung
Neuropathic pain syndromes are clinically characterized by spontaneous pain, mechanical allodynia, and thermal hyperalgesia [8]. Chronic neuropathic pain may be associated with inflammation and peripheral tissue damage when the pain pathway in the nervous system is still active [9]. Inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1beta (IL-1β), and interferon gamma (IFNγ) trigger the inflammatory reactions [10]. Pro-inflammatory cytokines, including TNF-α, IL-6, and IL-1β, play a role in initiating pathological pain [11]. Major anti-inflammatory cytokines such as IL-1 receptor antagonist and IL-10 regulate the proinflammatory cytokines [12]. After peripheral nerve lesions, cytokine overproduction and macrophage accumulation altered sensory transduction for nociceptors and subsequently caused peripheral sensitization and inflammatory reactions [13,14]. The critical role of anti-inflammatory (i.e. interleukin-10) and pro-inflammatory cytokines (e.g. interleukin-1β or tumor necrosis factor-α) was confirmed in subjects with various chronic neuropathic pain [15]. In our previous study, treadmill exercise could decrease neuropathic allodynia and heat hyperalgesia and cytokine expression in rats with injured sciatic nerve [16].
C. elegans: a sensible model for sensory biology
Published in Journal of Neurogenetics, 2020
Sensory neurobiology exists at the interface between biology, chemistry and physics. Our sensory processes mediate our interaction with the physical world. It is incredible that life has evolved to detect a vast array of forces and molecules present in our universe. Organisms as seemingly disparate as nematodes and humans have much in common in regard to their sensory processes. The relationship of an organism with its external and internal environments arguably begins with the sensory inputs and ends with behavioral output. Perception occurs via sensory neurons that activate in response to specific stimuli. These cues act upon sensory transduction machinery expressed by the sensory neuron itself or in specialized structures that communicate with the sensory neuron. Some of these sensory structures have evolved into large complex organs, such as the mammalian eye. However, such complexity incorporating large numbers of cells is not required for a sophisticated sensory system. Even a tiny one millimeter long organism with a compact nervous system of only 302 neurons can detect a surprisingly vast and varied array of physical stimuli, such as mechanical forces, chemicals, light, temperature, humidity and electromagnetic fields (Figure 1). The evolution of these sensory modalities confers numerous benefits to survival, including the ability to find food and mates and to avoid hazard.
Localization of melatonin and its receptors (melatonin 1a and 1b receptors) in the mouse inner ear
Published in Acta Oto-Laryngologica, 2019
The functional significance of melatonin in the inner ear remains still obscure. One possibility is that it plays an important role in the sensory transduction system. In the eye, melatonin is almost exclusively produced by the photoreceptor cells [8] and under some pathological conditions by other retinal cell types [9]. In addition, it has been reported that melatonin can also be produced – in smaller amounts – by ganglion cells in the chicken retina [10]. Melatonin may alter the sensitivity of photoreceptors and second-order neurons at night when photopic input is at its lowest level [11]. In Xenopus laevis, melatonin, acting through melatonin receptors on rod photoreceptor membranes, directly stimulates the responsiveness of rod photoreceptors to light [12]. This supports the hypothesis that melatonin acts both as an autocrine and a paracrine signal and binds to specific receptors in photoreceptors and other retinal cells to increase visual sensitivity [3].