Functional coupling between the central-autonomic and the cognitive systems is enhanced in states after optic neuritis and early multiple sclerosis.

We studied the relation between central-autonomic adaptability (largest Lyapunov exponent of heart rate dynamics) and visual learning capability (total net score in Kimura's Recurring-Figures-Test) in 15 healthy subjects and 35 patients with cerebral white matter diseases (12 with optic neuritis and 23 with multiple sclerosis), aged between 18 and 39 years. In optic neuritis patients and in those with very early, clinically asymptomatic multiple sclerosis, we found high correlations between these central-autonomic and cognitive functions (r = .66 and r = .86, respectively, p < .02). In contrast, in healthy subjects and in patients suffering from an already clinically symptomatic multiple sclerosis, there were no such significant correlations. These results are interpreted in terms of stochastic resonance within a postulated meta-system which integrates autonomic and cognitive functions.