Thesis Committee

Solomon Diamond, Ph.D. (Chair)

Ryan Halter, Ph.D.

John Zhang, Ph.D.

Abstract

The study of human brain function is a challenging, multifaceted problem. Current technologies are limited in their ability to effectively record and stimulate neural circuits at the scale of hundreds to thousands of neurons with millisecond temporal precision as required to elucidate the precise function of these circuits and how they relate to behavior and disease. The objective of this thesis research is to investigate the feasibility of developing a minimally invasive, wireless method of recording neural activity and potentially stimulating them at the spatial scale and precision needed to study the connections between cortical minicolumns. This neural interface method involves introducing iron oxide nanoparticles to the cell to encode the magnetic field resulting from the electric neural activity. This would be done by exploiting the nonlinear magnetic properties of iron oxide nanoparticles when exposed to an external AC magnetic field for encoding of the magnetic field from the action potential from the neuron. To investigate the feasibility of this method, computer-based models were constructed to simulate an activated neuron with and without nanoparticles in an AC magnetic field. The signal from the neuron was simulated, as well as the change in AC encoded signal from the nanoparticles. In addition, a protocol was developed to record the magnetization behavior of nanoparticle samples in vitro using a particle property measurement system (PPMS) and to extract the material properties that are critical to the future success of the method.