Progress in brain research
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Ischemia is a common problem after traumatic brain injury (TBI) that eludes detection with standard monitoring. In this review we will discuss four available techniques (SjVO2, PET, NIRS and PbrO2) to monitor cerebral oxygenation. We present technical data including strengths and weaknesses of these systems, information from clinical studies and formulate a vision for the future.
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Among the secondary events occurring after traumatic brain injury (TBI) pathologically increased intracranial pressure (ICP) correlates most closely with poor outcome. In addition to infusion of hypertonic solutions, e.g. mannitol, and other medical measures, decompression of the brain by surgical removal of a portion of the cranium (craniectomy) has been used for many decades as an intuitive strategy for the treatment of post-traumatic ICP increase. The lack of evidence-based clinical and controversial experimental data, however, resulted in decompressive craniectomy to be recommended by most national and international guidelines only as a third tier therapy for the treatment of pathologically elevated ICP. ⋯ The aim of the current review was therefore to summarize and discuss recent experimental data dealing with the use of decompression craniectomy following TBI. The present results suggest that surgical decompression effectively prevents secondary brain damage when performed early enough. Although caution should be taken when transferring conclusions drawn from experimental settings to the clinical situation, the current literature suggests that the timing of decompression may be of utmost importance in order to exploit the full neuroprotective potential of craniectomy following TBI.
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This chapter is focused on drug-induced hyperthermia with special regard to use of antipsychotics and antidepressants for the treatment of schizophrenia and major depression, respectively. Neuroleptic malignant syndrome (NMS) develops during the use of neuroleptics, whereas serotonin syndrome is caused mainly by serotoninergic antidepressants. Although both syndromes show various symptoms, hyperthermia is the main clinical manifestation. In this review we describe the historical background, clinical manifestations, diagnosis, and differential diagnosis of these two syndromes based on our observations on the experimental and clinical data.
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Case Reports Clinical Trial
Electrical stimulation of auditory and somatosensory cortices for treatment of tinnitus and pain.
The efficacy of electrical stimulation of the auditory cortex using extradural implanted electrodes for treatment of tinnitus was studied in 12 patients suffering tinnitus. The effect of similar stimulation of the somatosensory cortex for treatment of neuropathic pain was studied in five patients. ⋯ It is concluded that electrical stimulation of sensory cortices can be effective treatments of severe unilateral tinnitus and unilateral neuropathic pain in selected patients. The results suggest that similar pathophysiological mechanisms underlie some forms of these phantom sensations, and therefore, similar treatment such as electrical stimulation of the respective sensory cortices can suppress tinnitus and pain.
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Visual shape recognition--the ability to recognize a wide variety of shapes regardless of their size, position, view, clutter and ambient lighting--is a remarkable ability essential for complex behavior. In the primate brain, this depends on information processing in a multistage pathway running from primary visual cortex (V1), where cells encode local orientation and spatial frequency information, to the inferotemporal cortex (IT), where cells respond selectively to complex shapes. A fundamental question yet to be answered is how the local orientation signals (in V1) are transformed into selectivity for complex shapes (in IT). ⋯ Next, we found that responses to complex shapes were dictated by the curvature at a specific boundary location within the shape. Finally, using basis function decoding, we demonstrated that an ensemble of V4 neurons could successfully encode complete shapes as aggregates of boundary fragments. These findings identify curvature as a basis of shape representation in area V4 and provide insights into the neurophysiological basis for the salience of convex curves in shape perception.