Theses Doctoral

Implantable Optoelectronics for Neural Interfaces

Pollmann, Eric Hiroshi

In neuroscience, optical techniques have become the leading method over electrophysiological techniques because of their ability to target defined populations upon tagging both for in vivo recordings using genetically encoded calcium or voltage indicators and stimulation using optogenetic opsins at the single neuronal level.

Additionally, optical imaging has a smaller tissue displacement factor, the ratio of displaced neuronal tissue to field of view (FoV), thus accelerating the ability to simultaneously record from a larger volumes of neurons whereas electrophysiology arrays are limited in the total number of recordable neurons by the amount of sustained tissue damage. Conventional optical approaches, however, typically rely on microscopy techniques which require the subject to be head-fixed thus limiting the applicability especially at the chronic setting, raising the need for fully implantable optical interfaces. As a result, multiple lens-based miniature microscopes have been developed in academia and industry.

Nevertheless, a truly implantable optical neurotechnology has remained intractable because traditional miniaturized fluorescence microscopes require an opening in the dura and skull that matches or exceeds the FoV and chronically extends outside the skull, resulting in a poor overall displacement factor. To overcome these limitations, I developed and characterized various implantable optoelectronic platforms designed to optically record from large neuronal FoVs in a minimally invasive implantable form factor. These works culminated in the SCOPe (Subdural CMOS Optical Probe) platform which was validated in multiple in vivo demonstrations involving mouse and nonhuman primate.

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More About This Work

Academic Units
Electrical Engineering
Thesis Advisors
Shepard, Kenneth L.
Degree
Ph.D., Columbia University
Published Here
April 19, 2023