The Neurobiology of Reward Processing in Adolescence

Adolescence represents a time in development when the reward system undergoes substantial changes. Several studies suggest differences in reward processing amongst adolescents compared to adults and children. Abnormalities in reward processing also underlie many psychiatric disorders, such as attention deficit hyperactivity disorder (ADHD). The present research has the following objectives: 1) to investigate normal reward processing during reward anticipation and reward feedback in a large population based cohort of old adolescents. 2) to explore gender differences in reward processing and determine whether the association between reward processing and ADHD symptoms differs between boys and girls. 3) to determine whether the X-linked gene Monoamine Oxidase A (MAOA) is associated with ventral striatal brain activation during reward anticipation and 4) to investigate whether MAOA stratifies the relationship between ventral striatal activation and ADHD symptoms in boys. Objectives 1 and 2 were explored using the full IMAGEN dataset (n > 1200 adolescent), objective 3 was addressed using the first wave of IMAGEN, including both boys and girls (n = 411 adolescents) whereas objective 4 was investigated using only boys from the first wave (n = 190 adolescents). The results from random effects analyses and region of interest analyses suggested robust activation patterns during reward anticipation and feedback, particularly in the ventral striatum (VS) and orbitofrontal cortex. Gender differences were prominent during both phases of reward processing with boys showing significantly higher activation of a number of regions, including the VS, relative to girls. We also found that the X-linked gene MAOA significantly affected VS activation in boys, but not in girls. This gene also stratified the frequently reported relationship between VS activation and ADHD symptoms in adolescent boys.

Name dc:type.qualificationname

Doctor of Philosophy

Level dc:type.qualificationlevel

Doctoral Thesis

Grantor dc:publisher.institution

King's College London

Year dc:date.issued

2013

Author dc:creator

• Nymberg, Charlotte

Advisors dc:contributor.advisor

• Schumann, Gunter
• Loth, Eva

Language dc:language

eng

Identifier

oai:kclpure.kcl.ac.uk:studenttheses/e9ad0c43-b66b-4336-801d-d63c1b475914

OAI identifier oai:identifier

oai:kclpure.kcl.ac.uk:studenttheses/e9ad0c43-b66b-4336-801d-d63c1b475914