Altered processing of sensory stimuli in patients with migraine

Migraine is a cyclic disorder, in which functional and morphological brain changes fluctuate over time, culminating periodically in an attack. In the migrainous brain, temporal processing of external stimuli and sequential recruitment of neuronal networks are often dysfunctional. These changes reflect complex CNS dysfunction patterns. Assessment of multimodal evoked potentials and nociceptive reflex responses can reveal altered patterns of the brain's electrophysiological activity, thereby aiding our understanding of the pathophysiology of migraine. In this Review, we summarize the most important findings on temporal processing of evoked and reflex responses in migraine. Considering these data, we propose that thalamocortical dysrhythmia may be responsible for the altered synchronicity in migraine. To test this hypothesis in future research, electrophysiological recordings should be combined with neuroimaging studies so that the temporal patterns of sensory processing in patients with migraine can be correlated with the accompanying anatomical and functional changes

Validation of a Brazilian quantitative sensory testing (QST) device for the diagnosis of small fiber neuropathies

Quantitative sensory testing (QST) is defined as the determination of thresholds for sensory perception under controlled stimulus. Our aim was to validate a new QST device for Brazilian sample. In 20 healthy adults, thermoalgesic thresholds were assessed using a QST prototype (Heat Pain Stimulator-1.1.10; Brazil). A 30 × 30 mm² thermode with a 1°C/s stimulus change rate were applied. Thresholds of three consecutive stimuli were averaged in two different sessions separated by at least two weeks. Additionally long thermal heat pain stimulus was performed. To evaluate the consistency of our method we also analyzed 11 patients with small fiber neuropathy. Results showed good reproducibility of thermal perception thresholds in normal individuals and plausible abnormal thresholds in patients. We conclude that our QST device is reliable when analyzing the nociceptive pathway in controls and patients

Parkinson Phenotype in Aged PINK1-Deficient Mice Is Accompanied by Progressive Mitochondrial Dysfunction in Absence of Neurodegeneration

BackgroundParkinson's disease (PD) is an adult-onset movement disorder of largely unknown etiology. We have previously shown that loss-of-function mutations of the mitochondrial protein kinase PINK1 (PTEN induced putative kinase 1) cause the recessive PARK6 variant of PD.Methodology/principal findingsNow we generated a PINK1 deficient mouse and observed several novel phenotypes: A progressive reduction of weight and of locomotor activity selectively for spontaneous movements occurred at old age. As in PD, abnormal dopamine levels in the aged nigrostriatal projection accompanied the reduced movements. Possibly in line with the PARK6 syndrome but in contrast to sporadic PD, a reduced lifespan, dysfunction of brainstem and sympathetic nerves, visible aggregates of alpha-synuclein within Lewy bodies or nigrostriatal neurodegeneration were not present in aged PINK1-deficient mice. However, we demonstrate PINK1 mutant mice to exhibit a progressive reduction in mitochondrial preprotein import correlating with defects of core mitochondrial functions like ATP-generation and respiration. In contrast to the strong effect of PINK1 on mitochondrial dynamics in Drosophila melanogaster and in spite of reduced expression of fission factor Mtp18, we show reduced fission and increased aggregation of mitochondria only under stress in PINK1-deficient mouse neurons.ConclusionThus, aging Pink1(-/-) mice show increasing mitochondrial dysfunction resulting in impaired neural activity similar to PD, in absence of overt neuronal death

Promising treatments for neuropathic pain

In the last few years the understanding of mechanisms and, consequently, the diagnosis of neuropathic pain (NP) has becoming progressively clearer in clinical practice. However, the treatment of such condition remains challenging so far. One of the reasons for such difficulty is the diversity of mechanisms involved in NP generation and its persistency. In the present review we discuss several treatment modalities for NP that are scantily applied in daily clinical practice. For that, we collected positive clinical evidence of unusual and SECS (Safe, Easy, Cheap, and Sensible) approaches for NP. The aim of this review is not to establish the “state of the art” or rigid guidelines for NP treatment. In a different way, we only want bring new possibilities of treatment to the readers and also to motivate investigators to confirm those positive preliminary but promising results for NP reliev

Exposição a radiações eletromagnéticas não ionizantes da telefonia celular e sintomas psiquiátricos

Resumo O objetivo desse estudo foi investigar a associação entre exposição a radiações eletromagnéticas não ionizantes da estação radiobase de telefonia celular e sintomas à saúde. Em um estudo transversal realizado em Salvador, Bahia, Brasil, entrevistaram-se 440 indivíduos. Queixas e diagnósticos psiquiátricos constituíram as variáveis dependentes e a distância do domicílio para estação radiobase foi considerada a variável independente principal. Realizou-se análise de regressão logística hierarquizada para avaliação de confundimento e efeito. Observou-se associação entre sintomas psiquiátricos e residir próximo à estação radiobase e formas de uso do telefone celular (sinal de cobertura fraco, perto do corpo, dois ou mais chips e nunca desligar o celular quando dorme) e com uso de outros eletroeletrônicos. Concluiu-se que a exposição à radiação eletromagnética não ionizante de telefonia celular e a outros eletroeletrônicos foi associada aos sintomas psiquiátricos independente do sexo, escolaridade e tabagismo. Recomenda-se a adoção de medidas precaucionárias no sentido de se reduzir este tipo de exposição