Department of Radiology, Lausanne University Hospital and University of Lausanne (CHUV-UNIL), Rue du Bugnon 46, 1011 Lausanne, Switzerland; Corresponding author
Morten L. Kringelbach
Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford OX3 7JX, UK; Center of Music in the Brain (MIB), Clinical Medicine, Aarhus University, Universitetsbyen 3, 8000 Aarhus C, Denmark
Gustavo Deco
Center of Brain and Cognition, Universitat Pompeu Fabra, Ramon Trias Fargas, 25-27, 08005 Barcelona, Spain; ICREA, Institució Catalana de Recerca i Estudis Avancats (ICREA), Passeig Lluís Companys 23, 08010 Barcelona, Spain; Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstraße 1A, 04103 Leipzig, Germany; School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton Campus, Clayton 3800, VIC, Australia
Patric Hagmann
Department of Radiology, Lausanne University Hospital and University of Lausanne (CHUV-UNIL), Rue du Bugnon 46, 1011 Lausanne, Switzerland
Joel Pearson
School of Psychology, Mathews Building, University of New South Wales, Sydney 2052, NSW, Australia
Selen Atasoy
Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford OX3 7JX, UK; Center of Music in the Brain (MIB), Clinical Medicine, Aarhus University, Universitetsbyen 3, 8000 Aarhus C, Denmark
Summary: The human brain consists of specialized areas that flexibly interact to form a multitude of functional networks. Complementary to this notion of modular organization, brain function has been shown to vary along a smooth continuum across the whole cortex. We demonstrate a mathematical framework that accounts for both of these perspectives: harmonic modes. We calculate the harmonic modes of the brain’s functional connectivity graph, called “functional harmonics,” revealing a multi-dimensional, frequency-ordered set of basis functions. Functional harmonics link characteristics of cortical organization across several spatial scales, capturing aspects of intra-areal organizational features (retinotopy, somatotopy), delineating brain areas, and explaining macroscopic functional networks as well as global cortical gradients. Furthermore, we show how the activity patterns elicited by seven different tasks are reconstructed from a very small subset of functional harmonics. Our results suggest that the principle of harmonicity, ubiquitous in nature, also underlies functional cortical organization in the human brain.
