Control of neural activity is a powerful tool for studying circuits in the brain. Although optogenetics offers innovative approaches to achieve this in a cell-type specific manner with millisecond precision, there are still significant challenges. For example, it is still difficult to activate cell populations at high spatial resolution in vivo as well as to record responses from individual neurons in large groups both in vivo and in vitro. The present work covers the development and improvement of optoelectronic microdevices to this end, that can be divided into two categories:novel silicon probes using micro-scale light emitting diodes (μLEDs) for in vivo circuit manipulation and analysis, and in vitro electrode arrays for massively parallel recording. Compact penetrating needle probes have been designed to contain up to 96 independently controllable μLEDs, emitting up to 400 mW/mm2 of light at 450 nm.Standard operation regimes entail only a minimum rise in temperature. The devices allow coverage of brain structures, such as the the mouse cortex, at high spatial resolution and are capable of inducing rich spatiotemporal patterns of neural activity in vivo. The devices can also be extended to offer recording capabilities in the future, and prototype devices are shown. In order to demonstrate how electrode density is important for obtaining good recordings from single, densely-packed neurons, existing planar retinal recording devices have been adapted and fabricated, containing electrodes with a pitch as low as 15 μm. Versions with increased electrode counts have been designed and will be fabricated in the future, extending the toolbox for a better understanding of complex neural circuits.
|Date of Award||24 Feb 2017|
- University Of Strathclyde
|Supervisor||Keith Mathieson (Supervisor) & Erling Riis (Supervisor)|