Fractal geometry predicts dynamic differences in structural and functional connectomes

Anca Rădulescu, Eva Kaslik, Alexandru Fikl, Johan Nakuci, Sarah Muldoon, Michael Anderson

arXiv

Abstract

Understanding the intricate architecture of brain networks and its connection to brain function is essential for deciphering the underlying principles of cognition and disease. While traditional graph-theoretical measures have been widely used to characterize these networks, they often fail to fully capture the emergent properties of large-scale neural dynamics. Here, we introduce an alternative approach to quantify brain networks that is rooted in complex dynamics, fractal geometry, and asymptotic analysis. We apply these concepts to brain connectomes and demonstrate how quadratic iterations and geometric properties of Mandelbrot-like sets can provide novel insights into structural and functional network dynamics. Our findings reveal fundamental distinctions between structural (positive) and functional (signed) connectomes, such as the shift of cusp orientation and the variability in equi-M set geometry. Notably, structural connectomes exhibit more robust, predictable features, while functional connectomes show increased variability for non-trivial tasks. We further demonstrate that traditional graph-theoretical measures, when applied separately to the positive and negative sub-networks of functional connectomes, fail to fully capture their dynamic complexity. Instead, size and shape-based invariants of the equi-M set effectively differentiate between rest and emotional task states, which highlights their potential as superior markers of emergent network dynamics. These results suggest that incorporating fractal-based methods into network neuroscience provides a powerful tool for understanding how information flows in natural systems beyond static connectivity measures, while maintaining their simplicity.

BibTeX

@article{RadulescuKaslikFiklNakuciMuldoonAnderson2025,
  title         = {
    Fractal geometry predicts dynamic differences in structural and functional
    connectomes
  },
  author        = {
    Anca R\u{a}dulescu and Eva Kaslik and Alexandru Fikl and Johan Nakuci and
    Sarah Muldoon and Michael Anderson
  },
  year          = 2025,
  month         = may,
  day           = 16,
  doi           = {10.48550/arXiv.2505.11477},
  url           = {https://arxiv.org/abs/2505.11477},
  eprint        = {2505.11477},
  archiveprefix = {arXiv},
  primaryclass  = {nlin.CD},
  abstract      = {
    Understanding the intricate architecture of brain networks and its
    connection to brain function is essential for deciphering the underlying
    principles of cognition and disease. While traditional graph-theoretical
    measures have been widely used to characterize these networks, they often
    fail to fully capture the emergent properties of large-scale neural
    dynamics. Here, we introduce an alternative approach to quantify brain
    networks that is rooted in complex dynamics, fractal geometry, and
    asymptotic analysis. We apply these concepts to brain connectomes and
    demonstrate how quadratic iterations and geometric properties of
    Mandelbrot-like sets can provide novel insights into structural and
    functional network dynamics. Our findings reveal fundamental distinctions
    between structural (positive) and functional (signed) connectomes, such as
    the shift of cusp orientation and the variability in equi-M set geometry.
    Notably, structural connectomes exhibit more robust, predictable features,
    while functional connectomes show increased variability for non-trivial
    tasks. We further demonstrate that traditional graph-theoretical measures,
    when applied separately to the positive and negative sub-networks of
    functional connectomes, fail to fully capture their dynamic complexity.
    Instead, size and shape-based invariants of the equi-M set effectively
    differentiate between rest and emotional task states, which highlights
    their potential as superior markers of emergent network dynamics. These
    results suggest that incorporating fractal-based methods into network
    neuroscience provides a powerful tool for understanding how information
    flows in natural systems beyond static connectivity measures, while
    maintaining their simplicity.
  },
}