Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27708, USA.
Addict Biol. 2010 Oct;15(4):480-90. doi: 10.1111/j.1369-1600.2010.00252.x.
Smoking withdrawal is associated with significant deficits in the ability to initiate and maintain attention for extended periods of time (i.e. sustained attention; SA). However, the effects of smoking abstinence on the temporal dynamics of neurocognition during SA have not been evaluated. Twenty adult smokers underwent functional magnetic resonance imaging scans following smoking as usual and after 24-hours abstinence. During scanning they completed a SA task with two levels of task difficulty, designed to measure both sustained (i.e. over the duration of the task) and transient (i.e. event-related) activation. Smoking abstinence significantly decreased task accuracy regardless of task difficulty. Compared to smoking as usual, abstinence resulted in decreased sustained activation in right inferior and middle frontal gyri but increased transient activation across dispersed cortical areas including precuneus and right superior frontal gyrus. Greater task difficulty was associated with even greater transient activation during abstinence in mostly right hemisphere regions including right inferior frontal gyrus. These findings suggest smoking withdrawal shifts the temporal and spatial dynamics of neurocognition from sustained, right prefrontal activation reflecting proactive cognitive control (Braver, Gray & Burgess 2009) to more dispersed and transient activation reflecting reactive control.
吸烟戒断与长时间（即持续注意力；SA）启动和维持注意力的能力显著下降有关。然而，吸烟戒断对 SA 期间神经认知的时间动态的影响尚未得到评估。20 名成年吸烟者在照常吸烟后和 24 小时戒断后接受了功能磁共振成像扫描。在扫描过程中，他们完成了一个具有两个任务难度水平的 SA 任务，旨在测量持续（即任务持续时间）和瞬态（即事件相关）激活。无论任务难度如何，吸烟戒断都会显著降低任务准确性。与吸烟时相比，戒断导致右侧下额和中额回的持续激活减少，但在包括楔前叶和右侧额上回在内的分散皮质区域的瞬态激活增加。更大的任务难度与在右半球区域（包括右侧额下回）的更大的瞬态激活相关，这些区域在戒断期间表现出更具反应性的控制。这些发现表明，吸烟戒断将神经认知的时间和空间动态从反映主动认知控制的持续、右侧前额激活（Braver、Gray 和 Burgess，2009）转变为更分散和瞬态的激活，反映出反应性控制。
