1. Can you please briefly summarize the paper?

This work introduces StimNET, an ultraflexible neural electrode that can perform both long-term electrophysiological recording and electrical stimulation. Due to its small form factor and flexibility, we are able to minimize tissue scarring that typically accompanies implantation of conventional rigid electrodes and can establish long-lasting, seamless electrode-tissue integration. We employed two-photon calcium imaging, electrophysiological recording, behavior, and histology to investigate how these tissueintegrated electrodes improve the efficacy of stimulation. Our electrode delivers tiny electrical pulses to excite neural activity in a very controllable manner. Since conventional electrodes are quite invasive and damage much of the tissue around the electrode, higher currents are needed to evoke sensation which can make neuron activation more diffuse and less specific. We show with the StimNET that we can reduce the current and provide a more focal activation. This can provide an avenue for future neural prosthetics that aim to restore natural sensation such as sight or touch using electrodes that can deliver higher-resolution stimulation.
 

2. Can you please tell us the main difficulties you had in the laboratory work and how you overcame them?

The first difficulty we had was learning how to train animals to report the sensation of microstimulation in a behavioral task. Fortunately, we had a collaborator, Dr. Nelson Totah from the University of Helsinki, who happened to be visiting our lab for a couple days and graciously helped develop a step-by-step behavioral training protocol. The second difficulty we had was constantly malfunctioning stimulator equipment ranging from broken cables to stimulating at a current 40 times the requested current which slowed much of the research. This required a lot of back-and-forth communication with the company and ultimately a new design of the stimulators. As a PhD student, you will be confronted with such problems and sometimes you will get lucky and these problems might be resolved quickly. Other times, you won’t be. Regardless, you are expected to find a solution to these problems and if you can’t because it is out of your control, if possible, spend your time working on a separate part of the project.

3. Please introduce your laboratory, university or organization to bio-researchers in Korea.

Though I am in the department of electrical and computer engineering, I am also affiliated with the NeuroEngineering Initiative at Rice University which is a collaborative multidisciplinary project working on developing cutting-edge neural interface technologies. I am a PhD student in Dr. Lan Luan’s lab which uses integrative neural interfaces to investigate neurological disorders and develop novel therapies. Our lab works closely with Dr. Chong Xie’s lab whose interests are in engineering high-density, large scale ultraflexible neural electrodes.

4. Future plan?

We are performing both two-photon calcium imaging and the behavioral task simultaneously to understand how neuronal firing patterns change in relationship to decreasing detection thresholds over a chronic period.

5. Do you have anything else that you would like to tell Korean scientists and students?

Neuroengineering is a highly multidisciplinary field. I work with bioengineers, electrical engineers, chemists and physicists who all bring something unique to the project. This means if you are in STEM, it is more than likely that there is something for you. More generally, as a PhD student, please bear in mind that you have a limited time window. The years go by quickly and so it is imperative that you understand that time is a precious resource. Carefully craft your experiments and process your resulting data immediately to get feedback as soon as possible. You don’t want to end up months down the road with data all processed realizing you should have setup the study differently from the start.