Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Investigating the synchronization of hippocampal neural network in response to acute nicotine exposure | Akkurt et al. Journal of NeuroEngineering and Rehabilitation 2010 7 31 http content 7 1 31 J NER JOURNAL OF NEUROENGINEERING AND REHABILITATION RESEARCH Open Access Investigating the synchronization of hippocampal neural network in response to acute nicotine exposure David Akkurt 1 Yasemin M Akay2 and Metin Akay 1 2 Abstract Previous studies suggested that Y oscillations in the brain are associated with higher order cognitive function including selective visual attention motor task planning sensory perception working memory and dreaming REM sleep. These oscillations are mainly observed in cortical regions and also occur in neocortical and subcortical areas and the hippocampus. In this paper we investigate the influence of acute exposure to nicotine on the complexity of hippocampal Y oscillations. Using the approximate entropy method the influence of acute nicotine exposure on the hippocampal Y oscillations was investigated. The hippocampal Y oscillations have been generated in response to the 100 Hz stimulus and isolated using the visual inspection and spectral analysis method. Our central hypothesis is that acute exposure to nicotine significantly reduces the complexity of hippocampal Y oscillations. We used brain-slice recordings and the approximate entropy method to test this hypothesis. The approximate entropy complexity values of the hippocampal Y oscillations are estimated from the 14 hippocampal slices. Our results show that it takes at least 100 msec to see any hippocampal activities in response to the 100 Hz stimulus. These patterns noticeably changed after 100 msec until 300 msec after the stimulus Finally they were less prominent after 300 msec. We have analyzed the isolated hippocampal Y oscillations between 150 and 250 msec after the stimulus using the approximate entropy ApEn method. Our results showed that the ApEn complexity values of hippocampal Y oscillations during nicotine exposure were reduced compared to those of .
