The Tuned Cortex: Convergent Expertise-Related Structural and Functional Remodeling across the Adult Lifespan.

Bird identification experts showed lower mean diffusivity (MD) compared to novices in frontoparietal and posterior cortical regions.

• Regions with lower MD in experts included superior frontal gyrus (SFG), intraparietal sulcus (IPS), angular gyrus (AG), precuneus, lateral occipital cortex (LOC), and fusiform areas.
• Experts (n=29, ages 24-75, 15 female) were compared to matched novices (n=29, ages 22-79, 14 female).
• Lower MD indicates regionally specific increase in structural complexity.
• Diffusion-weighted MRI was used to assess cortical structure.

Experts showed a trend for more gradual age-related increases in mean diffusivity compared to novices.

• The trend suggests a potential attenuation of age-related structural decline in experts.
• The effect was observed across frontoparietal and posterior cortical areas.
• The sample spanned a wide age range: experts aged 24-75 and novices aged 22-79.
• The finding was described as a trend rather than a statistically significant effect.

Lower mean diffusivity in expert-related regions predicted higher bird identification accuracy in experts.

• The relationship between MD and accuracy was observed across frontoparietal (SFG, IPS) and posterior cortical (AG, precuneus, LOC, fusiform) regions.
• The behavioral measure was obtained during a delayed matching task requiring identification of local and nonlocal species.
• This finding links structural brain differences to expert behavioral performance.

Frontoparietal regions were selectively engaged in experts when judging less familiar nonlocal bird species compared to local species.

• Task-related BOLD timecourses revealed selective engagement of frontoparietal regions for the nonlocal > local contrast in experts.
• The magnitude of the nonlocal > local BOLD response tracked expert identification performance.
• The task was a delayed matching task requiring identification of both local and nonlocal species.
• Nonlocal birds were described as less familiar than local birds for the expert group.

The same frontoparietal regions showing structural differences (lower MD) in experts also showed selective functional engagement during expert performance.

• Convergence was observed between structural remodeling (lower MD) and functional tuning (selective BOLD response) in the SFG and IPS.
• The authors describe this as 'convergent structural remodeling and functional tuning in service of expert performance.'
• The multimodal approach combined diffusion-weighted MRI for structure and task-related BOLD for function.
• This convergence was interpreted as reflecting domain-specific reorganization driven by extensive practice.

The study used bird identification expertise as a domain for examining high-level perception, attention, and memory shaped through extensive practice.

• Bird identification expertise was chosen because high-level perception, attention, and memory are shaped through extensive practice in this domain.
• The sample included 29 skilled bird identification experts and 29 matched novices.
• A delayed matching task was used to assess identification of both local and nonlocal species.
• The study was designed to provide a multimodal view of cortical reorganization across the adult lifespan.