A modular high-density μECoG system on macaque vlPFC for auditory cognitive decoding. (8th July 2020)

• Record Type: Journal Article
• Authors: Chiang, Chia-Han; Lee, Jaejin; Wang, Charles; Williams, Ashley J; Lucas, Timothy H; Cohen, Yale E; Viventi, Jonathan
• Is Part Of: Journal of neural engineering. Volume 17:Number 4(2020:Aug.)
• Publication Date: 2020-07-08
• Subjects: electrocorticography -- μECoG -- local field potentials -- ventrolateral prefrontal cortex -- hearing -- and non-human primate; Neurosciences -- Periodicals; Biomedical engineering -- Periodicals; 612.8
• DOI: 10.1088/1741-2552/ab9986
• Languages: English
• ISSNs: 1741-2560

Abstract

Abstract: Objective. A fundamental goal of the auditory system is to parse the auditory environment into distinct perceptual representations. Auditory perception is mediated by the ventral auditory pathway, which includes the ventrolateral prefrontal cortex (vlPFC). Because large-scale recordings of auditory signals are quite rare, the spatiotemporal resolution of the neuronal code that underlies vlPFC's contribution to auditory perception has not been fully elucidated. Therefore, we developed a modular, chronic, high-resolution, multi-electrode array system with long-term viability in order to identify the information that could be decoded from μ ECoG vlPFC signals. Approach. We molded three separate μ ECoG arrays into one and implanted this system in a non-human primate. A custom 3D-printed titanium chamber was mounted on the left hemisphere. The molded 294-contact μ ECoG array was implanted subdurally over the vlPFC. μ ECoG activity was recorded while the monkey participated in a 'hearing-in-noise' task in which they reported hearing a 'target' vocalization from a background 'chorus' of vocalizations. We titrated task difficulty by varying the sound level of the target vocalization, relative to the chorus (target-to-chorus ratio, TCr). Main results. We decoded the TCr and the monkey's behavioral choices from the μ ECoG signal. We analyzed decoding accuracy as a function of number of electrodes, spatial resolution, and time from implantation. Over a one-year period, we found significant decoding with individual electrodes that increased significantly as we decoded simultaneously more electrodes. Further, we found that the decoding for behavioral choice was better than the decoding of TCr. Finally, because the decoding accuracy of individual electrodes varied on a day-by-day basis, electrode arrays with high channel counts ensure robust decoding in the long term. Significance. Our results demonstrate the utility of high-resolution and high-channel-count, chronic µ ECoG recording. We developed a surface electrode array that can be scaled to cover larger cortical areas without increasing the chamber footprint.