Vol. 49 (2018) ACTA PHYSICA POLONICA B No 12 MULTI-LEVEL EXPLANATIONS IN NEUROSCIENCE I: FROM GENES TO SUBJECTIVE EXPERIENCES * Wlodzislaw Duch Neurocognitive Laboratory, Center for Modern Interdisciplinary Technologies and Department of Informatics, Faculty of Physics, Astronomy and Informatics Nicolaus Copernicus University, Toruń, Poland (Received October 30, 2018) Brains are the most complex systems in the known Universe. Under- standing brain dynamics, control of behavior and mental processes is the ultimate challenge for science. It requires multi-level explanations, start- ing from evolutionary pressures, genes, proteins, cells, networks of neurons, psychophysics, subjective experiences at the mental level, and social inter- actions. Many branches of science contribute to this endeavor. Physics provides experimental and theoretical tools at the molecular and brain signal processing level, and mathematical tools at the level of neurody- namics. Inspirations from understanding brains are of great practical im- portance in many fields, including neuropsychiatry, neuropsychology and artificial intelligence. Neurodynamics provides the best language to link low-level molecular phenomena to high-level cognitive functions. Compu- tational simulations help to understand molecular dynamics and analyze real brain signals. This is a very fruitful area of research that requires global, interdisciplinary effort of experts from many branches of science. DOI:10.5506/APhysPolB.49.1981 1. Introduction In the XXI century, science has finally reached the stage at which we can start to understand complex systems, including connections between brain, behavior and mind. Physics of mind should describe processes that govern mental events. This idea 20 years ago seemed to be so far-fetched that an article in Computer Physics Communications was accompanied with editor’s remark: “We hope our readers will find inspiration in these more * Presented at the LVIII Cracow School of Theoretical Physics “Neuroscience: Machine Learning Meets Fundamental Theory”, Zakopane, Poland, June 15–23, 2018. (1981)