Cognitive Effects of Nicotine

Cigarette smoking is the primary cause of preventable death in developed countries, so there is a profound need to develop more effective treatments for nicotine addiction. The development of new treatments requires a better understanding of the individual factors that contribute to the initiation and maintenance of nicotine addiction. Accumulating evidence suggests that cognitive-enhancement may contribute to the reinforcing effects of nicotine, especially in individuals with cognitive deficits. Cognitive functions that are particularly improved following nicotine administration in humans include fine motor skills, attention, working memory, and episodic memory performance. Both the α4β2 and the α7 nicotinic acetylcholine receptors (nAChRs) participate in the cognitive-enhancing effects of nicotine. The α7 subunit modulates a sensory filtering function in the brain, and it has been implicated in the cognitive deficits associated with schizophrenia. Further, the β2 subunit appears to be essential for the attention, working memory, and behavioral flexibility functions of the prefrontal cortex. The modulation of neurotransmitter release by the α4β2 and α7 nAChRs in the prefrontal cortex may be one mechanism by which nicotine exerts its cognitive-enhancing effects. These receptors may modulate the release of neurotransmitters that contribute to the cognitive functions of the prefrontal cortex, including dopamine, glutamate, serotonin, norepinephrine, GABA, and acetylcholine. Poor cognitive performance predicts relapse among smokers who are attempting to quit smoking, which suggests that targeting cognitive-enhancement may be an effective treatment strategy. Receptor agonists that are selective for various nAChR subtypes, especially the α7 subtype, may be more effective cognitive-enhancers than nicotine.