Differences in brain activity during a verbal associative memory encoding task in high- and low-fit adolescents

Area of Science:

• Neuroscience
• Exercise Physiology
• Cognitive Psychology

Background:

• Aerobic fitness correlates with enhanced memory and brain structure in various age groups.
• The impact of aerobic exercise on the functional neural circuitry of learning and memory remains largely unexplored.

Purpose of the Study:

• To investigate how aerobic fitness influences brain activity during memory encoding in adolescents.
• To examine differences in functional connectivity between high-fit and low-fit adolescents during a memory task.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to assess brain activity in 17 high-fit (HF) and 17 low-fit (LF) adolescents.
• Participants underwent a subsequent memory encoding paradigm involving word pairs.
• Default mode network (DMN) and hippocampal activity were analyzed during successful versus forgotten memory encoding.

Main Results:

• Despite similar memory performance, HF and LF adolescents exhibited differential brain activation patterns.
• HF youth showed significant deactivation in DMN regions (e.g., ventral medial PFC, posterior cingulate cortex), unlike LF youth.
• LF youth displayed greater hippocampal and superior frontal gyrus activation during encoding of subsequently remembered items.

Conclusions:

• Aerobic fitness in adolescents may modulate functional connectivity between the hippocampus and DMN during memory encoding.
• This study provides novel insights into the influence of aerobic fitness on hippocampal function and neural circuitry, extending previous findings on brain structure.
• Findings suggest aerobic fitness impacts both the structure and function of memory-related brain networks in adolescents.