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Head and neck
Published in Tor Wo Chiu, Stone’s Plastic Surgery Facts, 2018
The sural nerve (S1,2) supplies sensation to the lateral and posterior third of the lower leg and the lateral ankle/foot/heel (little toe). The sensory loss improves over time (continuing for up to 5 years) due to collateral sprouting/regeneration from surrounding nerves and cortical remapping.
Medical matters
Published in Roslyn Rogers, Anita Unruh, Managing Persistent Pain in Adolescents, 2017
Studies in the adult research literature show cortical changes such as increased synaptic efficiency that means less stimulus is required to activate pain mechanisms, and pain that fluctuates with sensory and non-sensory (psychosocial) inputs; imagined movement is sufficient to cause an increase in pain, with reduced distance between cortical representation of the affected area and adjacent areas, similar to findings in phantom limb pain (remapping). Adult CRPS I studies have demonstrated signs of neglect with human and animal studies suggesting that disuse of a limb can generate signs and symptoms of CRPS I. New theories propose a mismatch between motor commands and appropriate sensory feedback (possibly caused by cortical remapping), the conflict resulting in pain.8 Differences in outcome and treatment exist between adult populations with CRPS I and adolescent populations, with outcomes for adolescents better than those for adult populations. The use of TENS machines is more effective in adolescents than in adults.9
Chronic pain after surgery
Published in Peter R Wilson, Paul J Watson, Jennifer A Haythornthwaite, Troels S Jensen, Clinical Pain Management, 2008
Neuronal plasticity after injury occurs not only at the periphery and the spinal cord, but also in the brain. Pons et al.26 first described remapping of the sensory cortex after deafferentation. Cortical remapping is now known to occur in humans after limb amputation27 and may be evident soon after injury.28 It has been shown to change with time.29 Plasticity can also occur in the thalamus.30 In an interesting case described by Halligan et al.,31 a patient developed the sensation of a third arm following a stroke, suggesting that this may be a two-way process – injury to the brain can cause misperceptions at the periphery. The changes in the brain after amputation contribute to the reason why amputees have phantom sensations and pain.
Phantom Penis: Extrapolating Neuroscience and Employing Imagination for Trans Male Sexual Embodiment
Published in Studies in Gender and Sexuality, 2020
In contemporary neuroscience, the assertion of a hard-wired brain does not preclude brain plasticity. Ramachandran and colleagues have also contributed salient research regarding cortical remapping, which supports an understanding of the brain as changeable. That is, the brain adapts in response to its environment, whether that be the rest of the body or the outer world. To dichotomize hard-wired and plastic modes is to oversimplify both theoretical avenues. As Pitts-Taylor (2016) states in a considered discussion of neuroplasticity, with critical attention to social factors, the sexing of brains, new materialism, nonhuman agency, and material performativity: “How can [plasticity’s] promise be understood when plasticity so neatly coincides with dominant ideologies and practices, or when it threatens the body-subject with techniques of governmentality?” (p. 18) “The specificity of matter must be explored without accepting the naïve position that what neuroscience research uncovers is given by nature alone” (p. 41).
Passive accessory joint mobilization in the multimodal management of chronic dysesthesia following thalamic stroke
Published in Disability and Rehabilitation, 2019
Kristina Griffin, Michael O’Hearn, Carla C. Franck, Carol A. Courtney
Interventions have been proposed to normalize body schema and thereby decrease pain and improve function. These interventions include graded motor imagery, which initially involves hand recognition, termed laterality training [44]. Laterality deficits were demonstrated in this case and a home program issued, although the patient admitted almost complete noncompliance. Accordingly, her laterality deficits were unchanged, even though symptoms had remitted. In the amputee population where phantom limb sensations are common, the phantom limb is reported to become shorter and shorter; retracting into the stump. This shrinkage of aberrant sensations is called telescoping [45], and is purported to occur due to cortical remapping. It is possible this may be the mechanism underlying the treatment outcomes in this case, though graded motor imagery measures, as measured by laterality testing, did not capture this change.
Arterial Spin Labeling Perfusion Magnetic Resonance Imaging Reveals Resting Cerebral Blood Flow Alterations Specific to Retinitis Pigmentosa Patients
Published in Current Eye Research, 2019
Handong Dan, Yin Shen, Xin Huang, Fuqing Zhou, Yiqiao Xing
Recent studies have increasingly shown that in addition to causing retinal degeneration, RP causes damage to post-retinal vision-related structures, including the visual pathway and visual cortices. Progressive atrophy of visual pathway structured has been observed in RP patients. Zhang et al. reported lower fractional anisotropy (FA) and higher eigenvalue values of optic nerves in RP patients, related to sighted controls.3 Furthermore, Ohno et al. reported that RP patients had decreased FA values in the bilateral optic radiation, compared with sighted controls.4 A voxel-based morphometry study demonstrated that RP patients showed significant reduction in gray matter volume (GMV) in the primary visual cortices; this correlated with the degree of visual loss in RP.5 Sanda et al. found that RP patients exhibited reduced cortical thickness in early visual cortex and ventral area V4.6 In addition, RP patients showed vision and vision-related cerebral functional changes. Ferreira et al. reported that primary visual cortical remapping occurred in RP patients.7 Notably, our previous study of RP patients revealed significant reduction in the amplitudes of low-frequency fluctuation (ALFF) in V1 and V2, compared with those of sighted controls.8 Moreover, RP patients with late blindness showed cross model plasticity in the visual cortex, which was activated by tactile stimulation.9,10 The aforementioned studies focused on brain functional and structural architecture changes in RP patients. However, it is largely unknown whether CBF alterations occur in RP patients.