Padrões oscilatórios espontâneos no córtex somatossensorial em modelo de autismo

• Ano de defesa: 2017
• Autor(a) principal: Maciel, Suzyanne Xavier
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Brasil; UFRN; PROGRAMA DE PÓS-GRADUAÇÃO EM NEUROCIÊNCIAS
• Palavras-chave em Português: Oscilações corticais; Estados eletrofisiológicos; Córtex somatossensorial; Autismo; VPA; CNPQ::OUTROS::CIENCIAS: NEUROCIÊNCIAS
• Link de acesso: https://repositorio.ufrn.br/jspui/handle/123456789/25176

The rhythmic synchronization of neuronal excitability in neural populations is a crucial mechanism to integrate information between neural networks. In autism spectrum disorders (ASD), it is believed that there is a deficit in the ability to efficiently couple functional neural networks using this mechanism, collectively known as oscillations. In addition, sensory disturbances are one of the most prevalent symptoms in autism, which can be characterized as hyper-responsiveness or hypersensitivity, extending to multiple sensory systems, as well as sensorimotor integration. In the animal model of autism induced by prenatal exposure to valproic acid (VPA), it is observed behavioral and cellular alterations similar to those observed in patients with autism. However, there are still few studies evaluating cortical electrophysiological patterns with an emphasis on these oscillations. Therefore, the aim of this study was to evaluate the spontaneous oscillatory activity in local field potentials (LFP) recorded from the somatosensory cortex of rats exposed to VPA and controls. Experimental (n=04) and control (n=04) groups were generated by administration of VPA (500 mg / kg, i.p.) or saline in pregnant rats at E12.5 respectively. When adults, these were anesthetized with urethane and LFP recordings were obtained in the somatosensory cortex using arrays of microelectrodes. Data analysis evaluated the density of spectral power, the occurrence of discrepant events in neuronal activity and the global oscillatory dynamics. Our findings showed that VPA rats have a higher variability of electrophysiological states when evaluated by state-maps derived from spectral characteristics of LFPs in distinct behavioral states. Such variability is mainly influenced by frequencies above 20 Hz (20-55Hz). However, we did not find significant changes in the global analysis of power spectrum bands delta (0.5-4Hz), theta (4-12Hz), beta (12-30Hz) and gamma (30-100Hz). Finally, all VPA animals showed some form of epileptiform activity in the somatosensory cortex in contrast to controls.