Examining the relationships among adolescent health behaviours, prefrontal function, and academic achievement using fNIRS

Several adolescent health behaviours have been hypothesized to improve academic performance via their beneficial impact on cognitive control and functional aspects of the prefrontal cortex (PFC). The primary objective of this study is to examine the association between lifestyle behaviours and academic performance in a sample of adolescents, and to examine the extent to which activity within the PFC and behavioural indices of inhibition may mediate this relationship. Sixty-seven adolescents underwent two study sessions five days apart. Sleep and physical activity were measured using wrist-mounted accelerometry; eating habits, substance use and academic achievement were measured by self-report. Prefrontal function was quantified by MultiSource Interference Task (MSIT) performance, and task-related activity via functional near-infrared spectroscopy (fNIRS). Higher levels of physical activity predicted higher MSIT accuracy scores (β= .321, ρ= 0.019) as well as greater activation within the right dlPFC (β=.008, SE= .004, ρ =.0322). Frequency of fast-food consumption and substance use were negatively associated with MSIT accuracy scores (β= -.307, ρ= .023) and Math grades (β= -3.702, SE= 1.563, ρ= .022) respectively. Overall, the results of this study indicate the importance of lifestyle behaviours on cognition and academic achievement in youth.