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Tissue Structure and Function
Published in Joseph W. Freeman, Debabrata Banerjee, Building Tissues, 2018
Joseph W. Freeman, Debabrata Banerjee
The motor neurons exit the spinal cord in ventral rootlets that come together to form a ventral root. The sensory neurons are organized in a similar manner, from the spinal cord they split into dorsal rootlets and come together to form dorsal roots. A little further down the cell bodies of the sensory neurons come together to form the dorsal root ganglion. Further down the dorsal root and ventral root combine to form the spinal nerve.
Membrane Models
Published in Joseph D. Bronzino, Donald R. Peterson, Biomedical Engineering Fundamentals, 2019
Primary Afferents and Related Efferents A model comprising a fast sodium current, a delayed rectier potassium current, a calcium current, and a calcium-dependent potassium current was used to model primary aerents as well as interneurons and eerent neurons connected to the aerents by Saxena et al. (1997). A modication of the HH model was used in Amir et al. (2002) to model A-type dorsal root ganglion neuron cell bodies.
Effects of a 16-week Tai Chi intervention on cutaneous sensitivity and proprioception among older adults with and without sensory loss
Published in Research in Sports Medicine, 2021
Teng Zhang, Min Mao, Wei Sun, Li Li, Yan Chen, Cui Zhang, Xinyan Zhang, Qipeng Song
The significant interaction between the two groups in the heel supported our first hypothesis that TC improved cutaneous sensitivity at more sites among the older adults with sensory loss. PN, including sensory loss, caused a range of symptoms on the basis of the distribution and types of nerve fibres involved. In mammals, discriminative light touch perception was mediated by primary sensory neurons, namely, low-threshold mechanoreceptors (Fleming & Luo, 2013; Li et al., 2019). Cell bodies are located in the dorsal root ganglia and trigeminal ganglia, which extend a central projection innervating the spinal cord and brain stem and peripheral projection innervating the specialized mechanosensory end organs (Fleming & Luo, 2013). Among the older adults with sensory loss, peripheral nerves may have undergone morphological changes (Crone & Krarup, 2013). Major pathological changes in peripheral nerve fibres include axonal loss and demyelination. In most cases of demyelinating neuropathy, considerable axonal loss is found (Crone & Krarup, 2013). Therefore, the effects of TC intervention may be enhanced among the older adults with sensory loss. It is recommended the older adults begin TC exercises as early as possible.
Advanced methods of spinal stimulation in the treatment of chronic pain: pulse trains, waveforms, frequencies, targets, and feedback loops
Published in Expert Review of Medical Devices, 2019
Ankit Maheshwari, Jason E. Pope, Timothy R. Deer, Steven Falowski
The dorsal root ganglion houses primary sensory neurons of all modalities. It has been identified as an important site of aberrant activity in neuropathic pain. Electrical stimulation of the dorsal root ganglion has a potential to reduce neuronal excitability as well as modulating ectopic discharges. Since the time of our last review, there has been an increase in the application of dorsal root ganglion stimulation and clinical outcome studies have demonstrated its effectiveness for numerous chronic neuropathic pain conditions such as complex regional pain syndrome, post-herniorrhaphy groin pain, radicular pain (Table 6). Typically, this modality has been used for the treatment of distal neuropathic pain conditions which, in the past have been hard to treat with dorsal column stimulation.
Vibrotactile sensitivity testing for occupational and disease-induce peripheral neuropathies
Published in Journal of Toxicology and Environmental Health, Part B, 2021
The peripheral sensory system is used by humans and animals to investigate and identify objects in their environment. Changes or loss of peripheral sensory perception may indicate the presence of disease or injury to 1) cutaneous sensory receptors; 2) peripheral nerves that carry sensory information from the site of stimulation to the dorsal root ganglia and/or spinal cord; 3) spinal afferent pathways that carry sensory information to the brain; and/or 4) regions of the brain involved in sensory perception (Hendry, Hsiao, and Bushnell 1999). Tests examining sensory perception, including tests of thermal perception, touch, two-point tactile discrimination, manual dexterity, nerve conduction velocity, and perception of vibration, have been used to assess sensory loss in workers exposed to hand- or foot-transmitted vibrations (Cherniack et al. 2008, 1990; Cole et al. 1998; Poole, Mason, and Harding 2016; Seah and Griffin 2008) or workers exposed to various chemicals, such as pesticides (Dicka et al. 2001; Starks et al. 2012; Steenland et al. 1984) Other investigators also reported that sensitivity to vibrotactile stimuli is altered in the hands and feet as a result of aging (Brammer, Taylor, and Lundborg 1987; Peterson et al. 2020), and various diseases including diabetes (Ising, Dahlin, and Larsson 2018; Peterson et al. 2020) and stroke (Liu et al. 2002). In contrast, very low-amplitude vibration may be able to be used to improve sensory perception in subjects with balance problems and various movement disorders (Bao et al. 2019; Liu et al. 2002). This review summarizes how, and under which conditions, the vibrotactile perception threshold (VPT) test has been used to detect injury or dysfunction of the sensory nervous system (Brammer et al. 2010).