54 research outputs found

    Right hemisphere control of visuospatial attention in near space

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    Traditionally, the right cerebral hemisphere has been considered to be specialized for spatial attention and orienting. A large body of research has demonstrated dissociable representations of the near space immediately surrounding the body and the more distance far space. In this study, we investigated whether right hemisphere activations commonly reported for tasks involving spatial attention (such as the line bisection and landmark tasks) are specific to stimuli presented in near space. In separate blocks of trials, participants judged either whether a vertical transector was to the left or right of the centre of a line (landmark task) or whether the line was red or blue (colour task). Stimuli were seen from four distances (30, 60, 90, 120 cm). We used EEG to measure an ERP component (the ‘line-bisection effect) specific to the direction of spatial attention (i.e., landmark minus colour). Consistent with previous results, spatial attention produced a right-lateralized negativity over occipito-parietal channels. The magnitude of this negativity was inversely related to viewing distance, being largest in near space and reduced in far space. These results suggest that the right occipito-temporal cortex may be specialized not just for the orientation of spatial attention generally, but specifically for orienting attention in the near space immediately surrounding the body

    Spatial sensory organization and body representation in pain perception

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    Pain is a subjective experience that protects the body. This function implies a special relation between the brain mechanisms underlying pain perception and representation of the body. All sensory systems involve the body for the trivial reason that sensory receptors are located in the body. The nociceptive system of detecting noxious stimuli comprises two classes of peripheral afferents, Aδ and C nociceptors, that cover almost the entire body surface. We review evidence from experimental studies of pain in humans and other animals suggesting that Aδ skin nociceptors project to a spatially-organised, somatotopic map in the primary somatosensory cortex. While the relation between pain perception and homeostatic regulation of bodily systems is widely acknowledged, the organization of nociceptive information into spatial maps of the body has received little attention. Importantly, the somatotopic neural organization of pain systems can shed light on pain-related plasticity and pain modulation. Finally, we show that the neural coding of noxious stimuli, and consequent experience of pain, are both strongly influenced when cognitive representations of the body are activated by viewing the body, as opposed to viewing another object — an effect we term ‘visual analgesia’. We argue that pain perception involves some of the representational properties of exteroceptive senses, such as vision and touch. Pain, however, has the unique feature that the content of representation is the body itself, rather than any external object of perception. We end with some suggestions regarding how linking pain to body representation could shed light on clinical conditions, notably chronic pain

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    Castration; The eunuchs of Qing dynasty China; A Medical and Historical Review

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    During the Qing dynasty (1644-1912), eunuchs worked in Peking’s Imperial Palace as servants for the Imperial Family. Typically the emperor would have 2000 eunuchs in his service. They would symbolically and physically protect the emperor from the common man. By presenting themselves to be castrated, young boys and adult men in China openly showed disrespect to the traditional Confucian rules and were thus despised by Chinese society. The term “chujia”, by which eunuchs were colloquially known, actually translates as “leaving home” and they were thus called because once they became eunuchs it was too shameful to the family for them ever to return. The last eunuch, Sun Yaoting, who died in 1996, was castrated in 1910 at the age of 8 to save his father, a pancake seller, from bankruptcy
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