Salivary and hair cortisol as biomarkers of emotional and behavioral symptoms in 6-9 year old children.

The aim of the present work is to investigate the association of salivary and cumulative cortisol levels with emotional and behavioral symptoms in a Franconian Cognition and Emotion Studies (FRANCES) general population cohort of 158 6- to 9 year old children. Salivary cortisol values were measured by one-day diurnal cortisol profile, whereas cumulative cortisol was estimated via one-month hair cortisol concentrations (rHCC). Nearly all significant associations of clinical symptoms with child cortisol indices were age dependent: We report emotional symptoms being associated with lower rHCC in younger children (6.06-7.54 years). In older children (7.55-9.41 years) behavioral problems were further associated with higher rHCC and lower salivary cortisol awakening responses. In summary, child clinical symptoms were stronger associated with markers of hair cortisol compared to salivary cortisol. To picture developmental mechanisms, we suggest longitudinal designs for cortisol measures of stress systems in children and adolescents.

Methylphenidate (MPH) promotes visual cortical activation in healthy adults in a cued visuomotor task.

Seeking for the mechanisms by which methylphenidate (MPH) improves behavior has demonstrated that MPH modulates excitability in the primary motor cortex. However, little is known about the influence of MPH on top-down controlled mechanisms in the sensory domain. The present study explored the effects of MPH on the activation of visual cortices in healthy adults who performed a cued visuo-motor task in a double-blind placebo-controlled crossover design. Two distinct measures, posterior alpha power and occipital slow cortical potentials (SCPs), were used to reflect raise in excitability and attention-based activation of visual cortical areas. According to the results, performance parameters (reaction time, response variance and error rate) were not affected by MPH. At the neurophysiologic level reflected by reduced alpha power, MPH increased the overall excitability of the occipital cortex, but not the parietal cortex. Before the cued response, MPH reduced alpha power and increased SCPs only before right hand responses, mostly at the right occipital location. It can be concluded that in visuo-motor tasks, MPH has the potency of adjusting the background excitation/inhibition balance of visual areas. Additionally, MPH may raise the attention controlled activation of visual cortical regions, especially during increased response control.