Department of Psychology/Institute of Neuroscience, Carleton University, Ottawa, ON, Canada.
Brain Res. 2010 Feb 8;1313:162-71. doi: 10.1016/j.brainres.2009.12.002. Epub 2009 Dec 21.
Both smoking and nicotine can facilitate cognitive efficiency in humans, however the exact mechanism underlying this improvement in cognitive performance is unclear. Nicotine-related improvements in visual task performance may stem from facilitation of the identification and encoding of rare deviant stimuli at early sensory levels. Visual processes at these early levels are thought to be indexed by the visual mismatch negativity (vMMN), an event-related potential (ERP) measure of pre-conscious deviant detection. In order to contribute to our understanding of the neural mechanisms underlying nicotinic modulated cognition, the current study investigated the acute effects of nicotine on vMMN in a non-smoking sample. Twenty-seven volunteers (7 males, 20 females) were treated with nicotine gum (6 mg) in a double-blind randomized, placebo-controlled repeated measures design. ERPs (vMMN; visual N100 and P200) and motor indices of performance were extracted from an intermodal task, requiring participants to attend selectively to auditory targets presented within concurrent, non-overlapping oddball sequences of visual standard and deviant stimuli. Behavioural performance was unaffected by nicotine, however nicotine was found to enhance vMMN and P200 amplitude. The findings are discussed in relation to attentional and neurobiological theories of nicotine dependence and of cognition in general.
吸烟和尼古丁都可以促进人类的认知效率，但这种认知表现改善的确切机制尚不清楚。尼古丁对视觉任务表现的改善可能源于早期感觉水平上对稀有异常刺激的识别和编码的促进。这些早期水平的视觉过程被认为是视觉失配负波（vMMN）的指标，这是一种对潜意识异常检测的事件相关电位（ERP）测量。为了促进我们对尼古丁调节认知的神经机制的理解，本研究在非吸烟样本中调查了尼古丁对 vMMN 的急性影响。27 名志愿者（7 名男性，20 名女性）在双盲随机、安慰剂对照的重复测量设计中接受了尼古丁口香糖（6 毫克）治疗。从一个需要参与者选择性地注意听觉目标的多模态任务中提取了 ERPs（vMMN；视觉 N100 和 P200）和运动表现的指标，听觉目标呈现在同时呈现的、不重叠的视觉标准和异常刺激的奇数序列中。行为表现不受尼古丁影响，但发现尼古丁增强了 vMMN 和 P200 的振幅。该发现与尼古丁依赖的注意力和神经生物学理论以及一般认知理论有关。
