AI Insight
Researchers analyzed brain activity patterns in 781 participants ranging from 3 months to 53 years old to understand how neural complexity develops across different brain regions. They found that in adults, brain areas relevant to a specific task show higher-dimensional activity patterns than irrelevant regions, but this specialization is absent in infants and develops gradually through childhood and adolescence. The developmental process works primarily through selective compression of neural activity in task-irrelevant regions rather than expansion in task-relevant ones, progressing from broad, nonselective compression in infants to precise, localized compression in adults.
Why it matters
This research reveals a fundamental principle of brain development: functional specialization emerges not by making relevant brain regions more complex, but by strategically reducing complexity in irrelevant regions. Understanding this mechanism could inform interventions for developmental disorders and provide insights into critical periods for brain plasticity.
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⚠️ Preprint – Noch nicht peer-reviewed
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Neural representations vary in their complexity across brain regions and tasks. How this variation emerges over human development remains poorly understood. We estimated intrinsic dimensionality in five naturalistic fMRI datasets (N = 781 unique participants, aged 3 months to 53 years) with T-PHATE — a nonlinear manifold learning method robust to noisy, autocorrelated signals. In adults, brain regions relevant to a task had higher-dimensional activity than task-irrelevant regions across auditory, visual, and audiovisual stimuli. The modulation of representational complexity by tasks was absent in infants, emerged in early childhood, and strengthened logarithmically through adolescence. It reflected a selective collapse in dimensionality in task irrelevant regions, relative to a resting-state baseline, rather than an expansion of dimensionality in task-relevant regions. Such compression followed a trajectory from global and nonselective in infants to local and precise by adulthood. These results identify selective compression as a developmental engine of functional specialization: rather than adding complexity where it is needed, the brain dynamically pares it away where it is not.
Source: Developmental tuning of functional manifold dimensionality across the human brain