This research aims to achieve monolithic integration of full-color micro-LED arrays directly on silicon-based neural probes such that optical stimulation of single neurons can be specifically tailored by wavelength and intensity.
The objective of this work is to design, fabricate and test an implantable neural probe capable of simultaneous optical stimulation and chronic electrical recording in animals. Recent advancement in optogenetics (optical stimulation of neurons) promises new possibilities for selectively exciting or inhibiting individual neurons. However, to this date there is still an unmet need for reliable implantable tools to precisely deliver light to target neurons and simultaneously record from corresponding single neurons in a behaving animal. In the proposed work, we will develop an implantable probe with light emitting devices directly integrated on the lithographically defined probe shank. The size of light emitting devices and the recording electrodes have a dimension (~10 micrometers) similar to that of a neuron, offering unmatched resolution for single-cell manipulation. The outcome of this result will be significant because the developed probe can allow high precision, local stimulation of multiple, spatially distinct inputs to a single neuron. Also, it will mitigate tethering problems and minimize hindering to the animal movement as compared to the previous optical fiber approaches, allowing practical scaling of light sources for a behavioral study. To realize the monolithic integration of multiple light sources on the probe shank, we adapt the display device technologies developed for solid-state lighting. Wavelength of the light emitting devices can be tailored by implementing nanopillar structures on the emitting surface. This research will leads into the development of generic tools to access individual neurons in the target region of brain with high specificity for simultaneously recording and stimulation. The developed probes will open new windows into understanding the function and organization of the brain in the areas of brain mapping, memory storage, retrieval and plasticity in chronic behavioral neuroscience. There is good reason to hope that these advances will lead to dramatic improvements in our ability to treat some of mankind's most debilitating diseases such as Parkinson's disease, epilepsy and paralysis.
Recent advances in optogenetics provide a new capability to control action potential patterns by selectively exciting or inhibiting the targeted neurons by light at specific wavelengths. However, to date there is still an unmet need for reliable implantable tools to precisely deliver multiple wavelengths of light to manipulate neural activities at the cellular level and monitor the response of affected neurons simultaneously. This research aims to achieve monolithic integration of full-color micro-LED arrays directly on silicon-based neural probes such that optical stimulation of single neurons can be specifically tailored by wavelength and intensity. Monolithic integration allows precise alignment between the recording electrodes and the LED array with submicron accuracy. Multiple micro-LEDs in a cellular dimension (10 x15 micro-m2) allow precise local delivery of light to the target neurons at single cell resolution. The fabricate probe will be implanted in mice to perform a unique experiment that will elucidate how memories are formed and maintained.
