Dr. Oren Shriki completed undergraduate studies in physics and doctoral studies in computational neuroscience at the Hebrew University (Jerusalem, Israel). After a postdoctoral period at the National Institute of Mental Health (Bethesda, MD, USA), he established the Computational Psychiatry Lab at Ben-Gurion University of the Negev in Israel. Research in his lab uses mathematical analyses of brain activity and machine learning techniques to develop novel diagnostic tools for neurological and psychiatric disorders. His lab investigates various neurofeedback and brain-computer interface paradigms. It also develops computational models of neuronal networks to gain insights into how changes in neural dynamics lead to brain disorders and how neural plasticity may assist in restoring healthy neural dynamics.
PhD
Oren Shriki
Critical Brain Dynamics: A Novel Framework for Assessing and Regulating Brain Dynamics
Oren Shriki, Dept. of Cognitive and Brain Sciences, Ben-Gurion University of the Negev, Israel
The critical brain hypothesis proposes that our brain is poised close to the border between two qualitatively different dynamical states. Whereas sub-critical dynamics are characterized by premature termination of activity propagation, super-critical dynamics are associated with runaway excitation. The talk will review evidence from recent years that supports this hypothesis and introduce the concept of neuronal avalanches, spatio-temporal cascades of activity whose sizes obey a power-law distribution. They are observed in a wide range of experiments from small-scale cortical networks to large-scale human EEG and are considered as evidence for critical brain dynamics.
The avalanche analysis provides novel qEEG measures which reflect the neural gain and are sensitive to changes in the balance of excitatory and inhibitory processes. Consequently, deviations from critical dynamics could serve as biomarkers for disorders associated with altered balance. For example, in sleep deprivation and in epilepsy the system tends towards super-critical dynamics, whereas in disorders of consciousness the system displays sub-critical dynamics. EEG-based measures of criticality can also be used as parameters for neurofeedback. In particular, our lab developed an EEG-based neurofeedback system that evaluates subject's neural gain using online avalanche analysis and reflects it by means of a video game. Our preliminary results indicate that subjects can regulate their neural gain.
References:
Shriki O., Alstott J., Carver F., Holroyd T., Henson R., Smith M. L., Coppola R., Bullmore E., and Plenz D., Neuronal Avalanches in the Resting MEG of the Human Brain, The Journal of Neuroscience 33: 7079-7090, 2013.
Arviv O., Medvedovsky M., Sheintuch L., Goldstein A., and Shriki O., Deviations from critical dynamics in inter-ictal epileptiform activity. The Journal of Neuroscience, 36: 12276-12292, 2016.
Fekete T., Omer D., Kazunori O., Grinvald A., van Leeuwen C., and Shriki O.. Critical dynamics, anesthesia and information integration: lessons from multi-scale criticality analysis of voltage imaging data. Neuroimage, 183: 919-933, 2018.