Cognitive decline, cholinergic dysfunction

In humans, nicotine is reported to increase arousal and attention as well as decrease reaction time and prevent decline in efficiency over time (Wesnes and Warburton, 1983, 1985). In both animals and humans nicotine improves the subject s ability to withhold responses to inappropriate stimuli (Myrsten et al., 1972 Wesnes and War-burton, 1983 Newhouse et al., 1988). This may be relevant to AD because a cardinal feature of the cognitive disorder of AD and a possible marker of cholinergic dysfunction (Fuld et al., 1982) is the difficulty demented patients have in inhibiting inappropriate responses or in responding to inappropriate stimuli. This difficulty in response selection and/or suppression is one explanation of the liberal response bias seen in AD. Gray et al. (1996) have shown that nicotine enhances hippocampal synaptic transmission which may be critical for new learning to take place. 

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