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Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
From a functional point of view, the cerebral cortex can be divided into primary areas and association areas. The primary areas are those where sensory signals are first received by the cortex or from which output signals of the cortex directly emanate. Examples of primary sensory areas are the primary visual cortex in the occipital lobe (Figure 1.9), the primary auditory cortex in the temporal lobe, and the primary somatosensory cortex in the postcentral gyrus of the anterior portion of the parietal lobe (Figure 12.1). An example of a primary output area is the primary motor cortex in the precentral gyrus of the posterior portion of the frontal lobe, the primary motor cortex being separated from the primary somatosensory cortex by the central sulcus (Figure 12.1). The primary motor cortex is also referred to as the somatomotor cortex, M1, or Brodmann’s area 4. In contrast, association areas, which constitute a considerably larger area of the cortex, are those areas where signals from different sensory modalities are integrated, or areas associated with “higher mental functions”.
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 outcomes of this study supported our first hypothesis that a 16-week TC intervention could improve cutaneous sensitivity at the hallux and heel. The range of our results was consistent with previous studies (Unver & Akbas, 2018), in which TC intervention significantly improved cutaneous sensitivity among the older adults with PN by altering ring the plasticity of the sensory-motor system to increase the somatosensory information from the plantar mechanoreceptors (Li & Manor, 2010). This enhancement of cutaneous sensitivity might be attributed to an expanded representation of the primary somatosensory cortex (Liranisilva et al., 2017). Another study suggested the presence of underlying physiological changes, primarily in the form of increased plantar sensory function (Wang et al., 2001). This improvement was attributed to the increase in peripheral blood microcirculation and indicated that TC exercises could enhance endothelial and peripheral circulations and plasma nitric oxide levels (Wang et al., 2001). This finding might indicate that TC could augment endothelium-dependent dilation of skin vasculature by increasing acetylcholine-induced cutaneous perfusion (Wang et al., 2001). In this study, cutaneous sensitivity increased after TC intervention, indicating that TC is an effective intervention for improving cutaneous sensitivity among the older adults.
Anti-inflammatory mechanisms of fruits and by-products from Mauritia flexuosa, an exotic plant with functional benefits#
Published in Journal of Toxicology and Environmental Health, Part A, 2021
Vivianne Rodrigues Amorim, Débora Caroline do Nascimento Rodrigues, Jurandy do Nascimento Silva, Carla Lorena Silva Ramos, Lívia Maria Nunes Almeida, Antonia Amanda Cardoso Almeida, Flaviano Ribeiro Pinheiro-Neto, Fernanda Regina Castro Almeida, Marcia Santos Rizzo, Joilane Alves Pereira-Freire, Paulo Michel Pinheiro Ferreira
In view of the anti-edematogenic capacity, the writhing abdominal test was employed as a classic way to verify the presence of inflammation-based visceral pain produced by acetic acid. In such situations, the most important secreted local mediators are prostaglandins and bradykinin in addition to substance P, IL-1β, TNF-α, IL-8, and mediators from the nervous sympathetic system. Then, discharged mediators initiate pain by activation or sensitization of peripheral nociceptors adjacent to the injured tissue, and such stimulation takes the protopathic/spinothalamic afferent way to the primary somatosensory cortex mediated through nociceptive C fibbers (Koster, Anderson, and Debeer 1959; Ribeiro et al. 2010). Although pre-treatment with epicarp and mesocarp demonstrated anti-edematogenic properties and reduced TNF-α levels, only epicarp decreased abdominal contortions.
No change in foot soft tissue morphology and skin sensitivity after three months of using foot orthoses that alter plantar pressure
Published in Footwear Science, 2021
Joanna Reeves, Richard Jones, Anmin Liu, Leah Bent, Ana Martinez-Santos, Christopher Nester
Foot orthoses can alter the contact area at specific regions of the foot, like increase the contact area in the medial arch (Farzadi et al., 2015; McCormick et al., 2013), which could influence skin sensitivity. Skin sensitivity is comprised of both peripheral (alterations to the cutaneous mechanoreceptor activation or transmission) and central influences (cortical plastic changes based on input). Changes in contact area could alter, and potentially increase, the capacity for cutaneous mechanoreceptors to detect mechanical stimuli. There are four different classes of mechanoreceptors in glabrous skin, like on the foot sole, which respond to stretch, contact forces, vibration and pressure (Johansson et al., 1982; N. D. Strzalkowski et al., 2018). Cortical plasticity allows for the potential for increased skin sensitivity through increasing the relevant area in the primary somatosensory cortex (Björkman et al., 2009) and neurophysiological changes with training has been shown in primates following stroke (Plautz et al., 2016). Increased pressure in the medial arch could increase sensitivity due to the increases in the relative weighting given to receptors from that region, or skin sensitivity could decrease if the receptors become desensitised (Hao & Delmas, 2010). Altered stimulation of mechanoreceptors can modulate afferent feedback to the central nervous system, influencing muscle activity and movement of the lower and upper limbs (Bent & Lowrey, 2013; Fallon et al., 2005; Howe et al., 2015; Nurse & Nigg, 2001; Perry et al., 2008). Consequently, the skin’s contribution to gait and posture could be influenced with use of FOs through long term stimulation of mechanoreceptors (a response to mechanical load being elicited in mechanoreceptors repetitively over time).