This technical paper on a study performed on nicotine’s effect on brain cognition is very interesting. Highlights below:
Nicotine administration, compared to placebo, significantly increased cost-integrated local efficiency of the network (Figure 4, t = 2.23, p = 0.043). A trend for cost-integrated global efficiency also was observed (Figure 5, t = 1.82, p = 0.091). Regional efficiencies also were examined to determine which areas of the brain contributed most to the changes in network efficiencies. Changes in cost-integrated regional efficiency for each region, averaged between hemispheres, are displayed in Figure 5.
In grouping regions as either prefrontal, sensorimotor, association, subcortical, or limbic/paralimbic (Mesulam, 1998); nicotine, as compared to placebo, was associated with a significant increase in cost-integrated regional efficiency for the limbic and paralimbic areas.
Nicotine administration improves cognitive, electrophysiological, and hemodynamic measures of neuronal function in many disease states, particularly Alzheimer’s disease (Festa et al., 2010) and schizophrenia (L. Adler et al., 1993; Barr et al., 2007). Attention, working memory, episodic memory and sensory gating are all fundamental cognitive functions that are disrupted in these diseases and improved by cholinergic agonists (L. Adler et al., 1993; Barr et al., 2007; Festa et al., 2010). All of these cognitive functions are mediated by networks of connected regions within the brain.
A main finding of this study was that nicotine increased local efficiency. A very similar network measure, clustering coefficient, has been shown to be associated with higher performance on many cognitive tests in healthy subjects: It positively correlates with measures of attention, working memory, verbal & spatial memory and psychomotor speed (Douw et al., 2011).