Chunk #11 — 2 Brain Function Responses to Acute Nicotine Administration and Cigarette Smoking — 2.2 Effect of Nicotine on Brain Activation During Cognitive Tasks
In examining brain mediation of the cognitive effects of smoking, several groups have performed functional imaging studies in subjects performing cognitive tasks during administration of nicotine (compared to a control condition) (Table 2). For most of these studies, subjects performed a cognitive task that involved visual recognition and working memory, such as the n-back task. Results of these studies have been somewhat mixed, showing both decreased (Ernst et al. 2001b; Ghatan et al. 1998) and increased (Jacobsen et al. 2004; Kumari et al. 2003) anterior cingulate cortex (ACC) activation in response to nicotine administration while performing the task. Brain activation responses to nicotine during cognitive tasks have been more consistent in other brain areas such as the thalamus (Jacobsen et al. 2004; Lawrence et al. 2002) and visual cortex (Ghatan et al. 1998; Lawrence et al. 2002), while nicotine had no effect on the visual cortex during photic stimulation (Jacobsen et al. 2002). This last finding indicates that nicotine activates the visual cortex only during demanding visual tasks, rather than on simple stimulation.
