Longitudinal changes in behavioral approach system sensitivity and brain structures involved in reward processing...

Area of Science:

• Neuroscience
• Developmental Psychology
• Adolescent Psychiatry

Background:

• Adolescence involves significant changes and heightened risks for substance use, mood disorders, and injury.
• Increased reward sensitivity (Behavioral Approach System [BAS]) and emotional reactivity are proposed mechanisms for these adolescent phenomena.

Purpose of the Study:

• To longitudinally investigate changes in reward sensitivity (BAS) from ages 9 to 23 over a 2-year follow-up.
• To examine the relationship between reward sensitivity changes and brain structure, specifically nucleus accumbens (Nacc) and orbitofrontal cortex (OFC) volumes.

Main Methods:

• Longitudinal study tracking 9- to 23-year-olds over a 2-year period.
• Assessment of reward sensitivity (BAS) and threat sensitivity (Behavioral Inhibition System).
• Magnetic Resonance Imaging (MRI) to measure Nacc and OFC volumes at baseline.

Main Results:

• Reward sensitivity increased from early to late adolescence and declined in the early 20s.
• A decrease in left Nacc volume correlated with the decline in reward sensitivity in the early 20s.
• Increases in reward sensitivity were predicted by baseline Nacc and medial OFC volumes.
• Increases in threat sensitivity were observed only in females and predicted by lateral OFC volumes.

Conclusions:

• Reward sensitivity undergoes significant developmental changes during adolescence and early adulthood, linked to structural brain maturation.
• Individual differences in Nacc and OFC volumes predict sensitivity changes, highlighting their role in adolescent development.
• Sex differences in threat sensitivity development suggest distinct neurobiological pathways.