John Griffiths

Dr. Griffiths is a cognitive and computational neuroscientist, with particular research interests in mathematical modelling of large-scale neural dynamics, multimodal neuroimaging data analysis methods, and brain stimulation in the context of neuropsychiatric and neurological disease. He is currently an Independent Scientist at the Krembil Centre for Neuroinformatics at CAMH, where he leads a team focused on whole-brain and multi-scale neurophysiological modelling. He is also an Assistant Professor in the University of Toronto Department of Psychiatry. Dr. Griffiths obtained his PhD in Cognitive Neuroscience from the University of Cambridge, and subsequently held postdoctoral positions at the University of Sydney School of Physics, and then in Toronto at the Rotman Research Institute (Baycrest Hospital) and Krembil Research Institute (UHN Toronto Western Hospital).

Research Synopsis

In the Whole Brain Modelling Group at the Krembil Centre for Neuroinformatics (KCNI), we take a “bird’s-eye” approach to understanding brain organization and how it is affected in neuropsychiatric and neurological disease. We work extensively with structural and functional neuroimaging data (sMRI, fMRI, DWI, MEG, EEG), employing the latest cutting-edge analysis methods to study connectivity, oscillations, and their modification by brain stimulation (esp. TMS) and drugs. This information is used to construct and constrain computational models of brain dynamics that combine meso-scale mathematical descriptions of neural population activity with whole-brain network structure. This framework strikes a balance between granularity (level of physiological detail) and coverage (number of brain regions included), that is well-matched to the type of information that can be obtained from modern in-vivo neuroimaging techniques. Together with colleagues in the KCNI microcircuit modelling and computational genomics groups, we are also developing multi-scale modelling approaches that bridge cellular-level and population-level descriptions of neural activity. Our long-term goal is the development simultaneously detailed and holistic in-silico computational and theoretical accounts of brain function, cognition, and their pathologies.

Recent Publications

Griffiths J D & Lefebvre J (2019). Shaping brain rhythms: dynamic and control-theoretic perspectives on
periodic brain stimulation for treatment of neurological disorders. (Chapter to appear in Vassilis et al. Eds. :
"Handbook of Multi-Scale Models of Brain Disorders: From Microscopic to Macroscopic Assessment of Brain
Dynamics. Springer. London.)

Park S, Griffiths J D, Longtin, A, & Lefebvre J (2018). Persistent entrainment in non-linear neural networks with memory. Frontiers in Applied Mathematics & Statistics 4:31

Hutt A, Griffiths J D, Herrmann C, & Lefebvre J (2018). Effect of Stimulation Waveform on the Nonlinear
Entrainment of Cortical Alpha Oscillations. Frontiers in Neuroscience 12

Zimmerman J, Griffiths J D, & McIntosh A R (2018). Subject-specificity of the correlation between large-scale
structural and functional connectivity. Network Neuroscience 3.

Robinson P A, Zhao X, Aquino K M, Griffiths J D, Sarkar S, & Panderjee, GM (2016). Eigenmodes of brain
activity: neural field theory and comparison with experiment. Neuroimage 142: 79-98

Griffiths J D (2015). Causal influence in neural systems: Reconciling mechanistic-reductionist and statistical
perspectives. Physics of Life Reviews, 15:130132.

Griffiths J D, Marslen-Wilson W D, Stamatakis E A, & Tyler L K (2013). Functional organization of the neural
language system: dorsal and ventral pathways are critical for syntax. Cerebral Cortex. 23(1):139-47
 

Appointments