EAGER: All-Optical Recording of Neural Activity by Excitonic Photoluminescence in 2D Optoelectronic Materials

Understanding the functions of brain circuits and how information is processed in the brain are instrumental for the development of effective treatments for neurological disorders such as epilepsy and Alzheimer’s disease. Recording of brain activity on very fast time scales with cellular level details is the “Holy Grail” for deciphering how the brain operates.

Electrical recording is the state-of-the-art for detection of fast brain activity. However, it is invasive for the brain tissue and lacks the required cellular level detail over large areas. Here, as an alternative, the research team proposes to explore voltage sensitive light emission from an emerging class of ultrathin semiconducting materials.

This transformative approach can potentially offer recording of very fast brain activity with cellular detail utilizing an optical microscope. If successful, the proposed work will help maintain the leadership of the US in neuroscience research. Over the course of the proposed work, doctoral and undergraduate students will be trained on this technology.

Furthermore, the results will be disseminated at national and international conferences. High school students from underrepresented groups and their families will be engaged through UCSD Science and Engineering with the Family programs. The project will also provide research internship opportunities for undergraduate students through the “Summer Internship" program at UCSD.

Understanding the functions of brain circuits and investigating information processing in the brain requires recording neural activity with high spatial and temporal resolution across large areas. Although electrophysiology has been the most widely used tool in neuroscience, it does not offer the spatial resolution and scalability to decipher information processing in distributed networks of the brain.

This proposal presents a transformative technology dubbed nanosheet voltage imaging for all-optical large-scale monitoring of electrical activity of neuron populations. The primary focus of the proposed research will be the comprehensive investigation of voltage sensitivity of quantum-confined photoluminescence in emerging low dimensional semiconductor materials.

Radiative emission lifetime of several picoseconds in these direct bandgap semiconductors, potentially enable optical detection of neural activity with an extraordinary temporal resolution while maintaining diffraction limited spatial resolution. If successful, this study will lay the groundwork for a radically new electrophysiology tool without the invasiveness of electrodes or electrical wires, by employing the noninvasiveness and practicality of optical imaging, to directly image voltages generated by single neurons and neuronal microcircuits at multiple spatial and temporal scales.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.