My lab is interested in the biophysics of the brain. It is an exciting time to be studying the brain, as we are just entering a vast, unexplored frontier. How do the 86 billion neurons of the human brain collectively generate the ability to run, talk, read, love, do physics, and think about themselves? What are the biophysical underpinnings of pathologies such as epilepsy, Parkinson's disease, schizophrenia, and certain forms of autism? Can we "hack" the brain to improve memory, creativity, and even morality? Scientists are making progress toward answering these questions every day. In my lab we take a physicist's approach to understanding the brain, viewing it as a highly-coupled dynamical system, in which each neuron may act as an oscillator. This approach is particularly fruitful in studying brain rhythms and "dynamical diseases" such as epilepsy and Parkinson's disease. Below are a few examples of projects we are currently working on.
Synchronous neural activity is an important mechanism of information transfer in the brain, and is therefore essential to healthy brain dynamics. Too much synchrony can be harmful, however, leading to pathologies such as epilepsy and Parkinson's disease. It is therefore important that we understand the factors (such as network structure and cellular properties) that determine the degree of neuronal network synchronization. We use tools from physics, dynamical systems, and network theory to describe and predict how networks of neurons synchronize their firing.
Brain rhythms (as measured by EEG recordings, for instance) are pervasive in the brain, with different frequency bands associated with various mental states (for example, 0.5-4 Hz rhythms are most prominent during sleep, while 40+ Hz rhythms are associated with directed attention). Manifold biophysical mechanisms underpin these rhythms, but most rely in some way on synchronous neural activity. We are currently investigating the possibility that completely asynchronous neural activity may generate brain rhythms, particularly in pathological states related to epilepsy.
High-Frequency Oscillations (HFO's) and Epilepsy
One brain rhythm which has recently attracted much interest is the so-called ''high-frequency oscillation,'' or HFO. These rhythms have peak power above 100 Hz, and are often found in parts of the brain that generate seizures. They therefore hold promise as a biomarker of epileptic tissue, which would help clinicians better identify which part of the brain to remove in order to cure patients with epilepsy. Unfortunately, HFO's are not always pathological--they are also often observed under completely normal conditions, with one variety known to be associated with memory consolidation, for instance. We are working to distinguish normal from pathological HFO's by comparing results of large-scale brain simulations with clinical data, obtained in collaboration with Dr. William Stacey and Dr. Stephen Gliske at the University of Michigan. This project is funded by NIH grant number R01-NS094399.