Natalia Janson


I am a Senior Lecturer in Mathematics at Loughborough University, United Kingdom.

My research expertise is in nonlinear dynamical systems and their applications to medicine, biology, engineering and physics. I have been studying various self-organisation phenomena that can be described with dynamical systems, with relevant models involving autonomous dynamical systems, systems under deterministic and random forces, systems with time delay, and interacting oscillators. I am a co-author of the book "Synchronization: from simple to complex" (Springer, 2009).

Currently, my research is centered around mathematics of cognition. Recently I proposed a novel mathematics-based approach to explain the brain and artificial neural networks [Janson & Marsden (2017)]. The proposed framework could make the first draft of the unified brain theory and lead to brain-like explainable artificial intelligence.

The theory above suggests that, mathematically, the brain could be viewed as a dynamical system with a plastic self-organising vector field. In a dynamical model of the brain, the velocity vector field embodies both the rules governing the behavior, and the brain's physical structure, hence psychology and physiology can be directly connected via this field. Unlike in all previously known machines and organs, in the brain the vector field self-organises to reflect the self-organising brain plasticity, which required introduction of a previously unknown type of dynamical systems. Thus, it is proposed that to be intelligent, the system should have at least two levels of self-organisation as opposed to only one in all previously known dynamical systems. Namely, there should be conventional self-organisation of the observable behavior, and in addition self-organisation of the (not directly observable) rules governing the behavior and embodied in the vector field. The first theoretical analysis of the new systems has been done in [Janson & Kloeden (2020)], [Janson & Kloeden (2021)].

Among other things, the new theory offers an explicit answer to the question "What are memories and where can they be found in the brain?". It is proposed that memories are traces on the vector field of the brain, and just like this fied they exist in the phase space of the brain. The phase space is a well-known mathematical object, and although it is an abstract non-physicsl space, it can be reconstructed from detailed measurements of the physical parameters of the brain.

My other direction of research is optimisation based on mathematics of complex systems. Recently I proposed a mathematical principle for building an analogue optimising machine, which could potentially be faster than digital computers and much cheaper than quantum ones [Janson & Marsden 2021a, Janson & Marsden 2021b]. The idea is to utilise deterministic chaos instead of traditionally used random forces to make the system explore all available minima of the cost function. To achieve this in a reliable and robust manner not sensitive to the specifics of the problem, we introduced the time delay into the classical gradient descent setting. This is a highly counter-intuitive step given that normally the delay makes an already complex situation much more complex and unpredictable. However, we hypothesized and verified that for a certain broad class of the systems with delay, an increase of the delay can lead to quite predictable robust results, which would be largely independent of the specifics of the equations.

Researchgate | Google Scholar | ORCID

Key publications

COLLABORATORS

RESEARCH VIDEOS FOR GENERAL AUDIENCE BY NATALIA JANSON

TEDx 2016 talk by Natalia Janson: The question 'How is the mind related to the body?' has been intriguing people for centuries, but we have no definitive answer so far. Recent research highlights the need to study the mind with methods of natural sciences. We therefore need to know how mental processes are connected with measurable parameters of the brain along with a clear definition of the mind. However, different theories disagree on whether the mind is material or immaterial, observable or unobservable, distinct from the brain and its physical processes or coincident with them. This conflict of ideas makes it seem impossible to find an agreeable solution. But could all theories be correct? Is there an entity that possesses all key features expected of the mind, combines the features that look incompatible, and is directly connected to both the brain’s physical processes and its physical architecture? Such an entity appears to exist in mathematics. This talk proposes a mathematical solution to the mind-body problem.

This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at http://ted.com/tedx

(Watch from 15th minute) This talk describes how the brain and the mind could be understood with the help of dynamical systems theory, and explains why and how this theory needed to be upgraded in order to incorporate conginitve phenomena.


The talk is given at the Institute of Advanced Studies Workshop at Loughborough University (virtually) 27 January 2021.


This is a short video outlining the possibility to handle the mind mathematically.

EDUCATIONAL VIDEOS BY NATALIA JANSON: youtube lectures on "Dynamical Systems and Synchronization in Application to Biological Systems". Aimed at students and researchers interested in applying mathematics to understand living systems.

Dynamical Systems

Part 1: Definition of dynamical system. Mathematical modelling of physiological systems: Dynamical Systems.

This video lecture introduces the concept of a system evolving with time spontaneously, i.e. on its own and not thanks to any external rhythmic disturbance, such as a swinging pendulum or a beating heart. Such systems can be mathematically described as dynamical systems, i.e. as combinations of first-order ordinary differential equations, which are generally non-linear. Equations like this are usually impossible to solve analytically. To aid understanding and prediction of their behaviour, a special mathematical object called velocity vector field can be introduced. More explanation of a velocity vector field and its interpretation can be found here and here.

Dynamical Systems

Part 2: Constructing a Dynamical System

This video lecture explains how a mathematical model of a spontaneously evolving system can be constructed, i.e. how to connect the physical architecture of a device or organ with its mathematical representation, usually in the form of the velocity vector field of a dynamical system. More explanation of a velocity vector field and its interpretation can be found here and here.

Dynamical Systems.

Part 3: Attractors in dynamical systems

This video lecture describes the features of real systems, i.e. those existing in the macroscopic world around us, which are dissipative, open, non-linear and often capable of oscillations. Self-organisation can be mathematically described as starting from randomly chosen initial conditions in the state space of the relevant dynamical system, and automatically converging to the same geometrical object , called attractor. There are four types of attractors, namely, fixed points, limit cycles, invariant tori and chaotic attractors. Usually, only fixed points can be found analytically, and it is demonstrated how this can be done using an example of the famous van der Pol oscillator. A lay introduction into the use of dynamical systems to understand living systems is given here.

Dynamical Systems

Part 4: Analyzing stability of fixed points: 1- dimensional case

This video lecture demonstrates how to find out whether the fixed point of a one-dimensional non-linear dynamical system is stable or not, following Lyapunov stability theory. The concepts of a small deviation from the fixed point, and of a linearisation of an originally non-linear system around this fixed point, are introduced.

Dynamical Systems

Part 5: Analyzing stability of fixed points: 2- dimensional case

This video lecture explains how the stability of a fixed point in non-linear two-dimensional dynamical systems can be analysed. The concepts of a small deviation from the fixed point, of linearisation of a non-linear system around the fixed point, and of eigenvalues, are introduced. It is shown how the analysis of eigenvalues of a fixed point can predict the behavior of the system in the vicinity of this point.

Dynamical Systems

Part 6: Bifurcations of fixed points.

This video lecture shows how drastic changes in the behavior of nonlinear systems can be explained and predicted from the analysis of bifurcations of their fixed points. In Parts 4-5 of this lecture series, the stability analysis and eigenvalues were introduced. Here it is shown how bifurcations can be deduced from the eigenvalues. Bifurcations considered here are saddle-node, Andronov-Hopf leading to the birth of a limit cycle (supercritical), and not leading to a limit cycle (subcritical). The change of the amplitude of the limit cycle with the increase of a parameter is described using the famous van der Pol oscillator as example. For periodic and chaotic oscillations, the concept of the Poincare section is introduced.

Synchronization

Part 1: Self-oscillations

This video lecture introduces the definition of a special class of oscillations, called self-oscillations. These can occur only in systems losing energy with time, called dissipative systems, which are also non-linear. To maintain oscillations, such systems need to be receiving energy from the outside world. A more detailed description of self-oscillations can be found here and here.

Synchronization

Part 2: Time-scales

This video lecture introduces the concept of a time scale in an oscillatory (self-oscillatory) process, which can occur in an electronic circuit, a pacemaker cell or a chemical reaction. It is explained how time scales can be extracted from experimental data, and how they are relevant to synchronization. A more detailed description of self-oscillations and synchronization can be found here and here.

Synchronisation

Part 3: Mechanisms of synchronization

This video lecture explains two most common mechanisms for synchronization, namely, phase (frequency) locking and suppression of natural dynamics. Both mechanisms are introduced for the simplest case of a forced synchronization, when a certain periodically self-oscillating system is being perturbed by an external periodically oscillating forcing. Each mechanism is illustrated with a numerically simulated example and with an electronic experiment. A more detailed description of self-oscillations and synchronization can be found here and here.

Synchronization

Part 4: Phase difference

This video lecture explains how synchronization can be interpreted in terms of phases (stages) of oscillations. The concepts of a simple and a generalized phase difference are introduced and illustrated with numerical simulations and with biological experiments. A more detailed description of self-oscillations and synchronization can be found here and here.

SYNCHRONIZATION

PHOTOS, VIDEOS AND ARTICLES FROM VARIOUS EVENTS

Forum of Neurosciences, Brussels,

10-12 June 2019

Natalia Janson gave a talk "How mathematics can inspire a new way to look at the brain and the mind" describing her brain-inspired theory of cognitive systems based on a dynamical system with plastic self-organising velocity vector field.

Natalia gave a talk about delayed feedback applied to human breathing at a conference "Model reduction across disciplines" 19-22 of August 2014, University of Leicester (UK) dedicated to the 60th birthday of Alexander Gorban.

Link to slides.

Relevant paper: Janson, Pototsky & Parkes "Delayed feedback applied to breathing in humans", The European Physical Journal 222 (10), 2623–2631 (2013).

EXTERNAL SITES discussing the idea of a cognitive system as a plastic dynamical system