Electrocorticography (ECoG) strives to bridge the gap between traditional electroencephalography (EEG) and microneedle array recordings. While requiring a craniectomy, ECoG does not damage cortical tissue and is thus less invasive than microneedles. ECoG can achieve significantly higher spatiotemporal resolution than EEG because ECoG-electrodes are placed much closer to the signal sources in the brain. Commercially available ECoG arrays feature a small number of channels (<64) and a large electrode pitch (> 4 mm). Such coarse arrays likely undersample the signals available on the cortex surface. There is currently no agreement on the optimal inter-electrode pitch in the community and surprisingly little research has been published on the topic of optimal inter- electrode spacing for ECoG. I am designing, fabricating, packaging and testing a flexible, large-scale (>256 electrodes) high- density (pitch < 0.5 mm) ECoG array. Scaling-down an ECoG array and increasing the number of recording sites poses many engineering challenges in terms of SNR, interconnects complexity and device lifetime. Addressing these challenges lies at the heart of my project. Data collected from the array in vivo will allow conclusions about optimal electrode spacing and size. All devices will be optimized for decreased impedance resulting in better SNR.
Project end date: 01/29/14