Brain : a journal of neurology
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Randomized Controlled Trial
Motor cortex stimulation for the treatment of refractory peripheral neuropathic pain.
Epidural motor cortex stimulation (MCS) has been proposed as a treatment for chronic, drug-resistant neuropathic pain of various origins. Regarding pain syndromes due to peripheral nerve lesion, only case series have previously been reported. We present the results of the first randomized controlled trial using chronic MCS in this indication. ⋯ Although the results of the crossover trial were slightly negative, which may have been due to carry-over effects from the operative and immediate postoperative phases, observations made during the open trial were in favour of a real efficacy of MCS in peripheral neuropathic pain. Analgesic effects were obtained on the sensory-discriminative rather than on the affective aspect of pain. These results suggest that the indication of MCS might be extended to various types of refractory, chronic peripheral pain beyond trigeminal neuropathic pain.
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Sensory capacity of reinnervated skin after redirection of amputated upper limb nerves to the chest.
Targeted reinnervation is a new neural-machine interface that has been developed to help improve the function of new-generation prosthetic limbs. Targeted reinnervation is a surgical procedure that takes the nerves that once innervated a severed limb and redirects them to proximal muscle and skin sites. The sensory afferents of the redirected nerves reinnervate the skin overlying the transfer site. ⋯ Mechanisms appear to be in place to maximize re-established touch input in targeted reinnervation amputees. It seems that sound sensory function is provided to the denervated skin of the residual limb when connected to afferent pathways once serving highly functionally relevant regions of the brain. This suggests that tactile interface devices could be used to give a physiologically appropriate sense of touch to a prosthetic limb, which would likely help with better functional utilization of the prosthetic device and possibly help to more effectively integrate the device with the user's self-image.
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Numerous studies have demonstrated that Huntington's disease mutation-carriers have deficient explicit recognition of isolated facial expressions. There are no studies, however, which have investigated the recognition of facial expressions embedded within an emotional body and scene context. Real life facial expressions are typically embedded in contexts which may dramatically change the emotion recognized in the face. ⋯ These findings suggest that, despite their impaired explicit recognition of facial expressions, Huntington's disease mutation-carriers display relatively preserved processing of the same facial configurations when embedded in context. The results also show intact utilization of the information elicited by contextual cues about faces expressing disgust even when the actually presented face expresses a different emotion. Overall, our findings shed light on the nature of the deficit in facial expression recognition in Huntington's disease mutation-carriers as well as underscore the importance of context in emotion perception.
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Pilocytic astrocytomas are WHO grade I gliomas that occur predominantly in childhood. They share features of both astroglial and oligodendroglial lineages. These tumours affect preferentially the cerebellum (benign clinical course) and the optic pathway, especially the hypothalamo-chiasmatic region (poor prognosis). ⋯ Of particular interest, NOTCH2, a gene expressed in radial glia and involved in gliomagenesis, was upregulated in hypothalamo-chiasmatic pilocytic astrocytomas. In order to find progenitor cells that could give rise to hypothalamo-chiasmatic pilocytic astrocytomas, we performed a morphological study of the hypothalamo-chiasmatic region and identified, in the floor of the third ventricle, a unique population of vimentin- and glial fibrillary acidic protein-positive cells highly suggestive of radial glia cells. Therefore, pilocytic astrocytomas of the hypothalamo-chiasmatic region should be considered as a distinct entity which probably originates from a unique population of cells with radial glia phenotype.
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Anterior temporal lobe resection is often complicated by superior quadrantic visual field deficits (VFDs). In some cases this can be severe enough to prohibit driving, even if a patient is free of seizures. These deficits are caused by damage to Meyer's loop of the optic radiation, which shows considerable heterogeneity in its anterior extent. ⋯ By applying a linear regression analysis we showed that both distance from the tip of Meyer's loop to the temporal pole and the size of resection were significant predictors of the postoperative VFDs. We conclude that there is considerable variation in the anterior extent of Meyer's loop. In view of this, diffusion tensor tractography of the optic radiation is a potentially useful method to assess an individual patient's risk of postoperative VFDs following anterior temporal lobe resection.