Progress in brain research
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Biography Historical Article
Paul Wittgenstein's right arm and his phantom: the saga of a famous concert pianist and his amputation.
Reports of postamputation pain and problems linked to phantom limbs have increased in recent years, particularly in relation to war-related amputations. These problems are still poorly understood and are considered rather mysterious, and they are difficult to treat. In addition, they may shed light on brain physiology and neuropsychology. ⋯ The phantom movements of his right hand helped him develop the dexterity of his left hand. Wittgenstein played piano works that were written especially for him (the most famous being Ravel's Concerto for the Left Hand) and composed some of his own. Additionally, several famous composers had previously written for the left hand.
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The optic nerve head forms the interface between the intraocular compartment and the retrobulbar compartment. The former is characterized by what we term intraocular pressure (IOP) and the latter by orbital cerebrospinal fluid pressure (CSFP). The trans-lamina cribrosa pressure difference (TLCPD) is defined as the difference between the pressures in the two compartments. ⋯ In particular, glaucomatous optic neuropathy may be due to either an elevated IOP and/or an abnormally low orbital CSFP, or due to a change in the time-dependent relationship between the pulse-synchronous changes in IOP and orbital CSFP. Based on the triangular relationships between IOP, CSFP, and blood pressure, glaucoma may be described as an imbalance between these three pressure parameters, eventually leading to an increased TLCPD. Because the retinal and choroidal venous blood drains through the CSFP space, elevated CSFP may be associated with dilated retinal veins, increased incidence of retinal vein occlusions, higher prevalence and severity of diabetic retinopathy, and thicker choroid.
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Review Historical Article
Historical perspectives on music as a cause of disease.
The relationship between music and medicine is generally understood in the benign context of music therapy, but, as this chapter shows, there is a long parallel history of medical theories that suggest that music can cause real physical and mental illness. During the seventeenth and eighteenth centuries, the idea of music as an expression of universal harmony was challenged by a more mechanistic model of nervous stimulation. By the 1790s, there was a substantial discourse on the dangers of musical overstimulation to health in medicine, literature, and etiquette books. ⋯ This kind of psychological impact of music has meant it has been linked to a variety of culturally bound syndromes. Having said that, it is also clear that the most of the discourse on pathological music is basically fallacious. Over and over again, fundamentally moral objections to music relating to sexuality, gender, social order, and self-control have been clear beneath a veneer of medical language.
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The last decade of neuroscience research has revealed that the adult brain can undergo substantial reorganization following injury. Plasticity after stroke has traditionally been perceived as adaptive and supporting recovery, but recent studies have suggested that some plasticity may also be detrimental. In particular, increased activity in the unaffected (contralesional) hemisphere has been proposed to contribute to motor deficits of the paretic hand in some patients. ⋯ Ultimately, this knowledge will allow for the design of more effective treatments and will potentially lead to protocols adapted to the specific condition of each patient. In this chapter, we review the literature on the basic pathways that can support the effects of contralesional inhibition, interhemispheric interactions, and some of the changes that can occur in the sensorimotor network after stroke. Finally, we show work in rats that demonstrates how parameters of contralesional inactivation can affect postlesion recovery.
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Human bipedal gait requires supraspinal control and gait is consequently severely impaired in most persons with spinal cord injury (SCI). Little is known of the contribution of lesion of specific descending pathways to the clinical manifestations of gait deficits. Here, we assessed transmission in descending pathways using imaging and electrophysiological techniques and correlated them with clinical measures of impaired gait in persons with SCI. ⋯ Combination of different electrophysiological and anatomical measures using best subset regression analysis revealed improved prediction of gait ability, especially in the case of WISCI. These findings illustrate that lesion of corticospinal and vestibulospinal pathways makes different contributions to impaired gait ability and balance following SCI and that no single electrophysiological or anatomical measure provide an optimal prediction of clinical gait and balance disability. We suggest using a combination of anatomical and electrophysiological measures when evaluating spinal cord integrity following SCI.