Synchrony surfacing: Epicortical recording of correlated action potentials. (22nd October 2018)

• Record Type: Journal Article
• Authors: Bockhorst, Tobias; Pieper, Florian; Engler, Gerhard; Stieglitz, Thomas; Galindo‐Leon, Edgar; Engel, Andreas K.
• Is Part Of: European journal of neuroscience. Volume 48:Number 12(2018)
• Page Start: 3583
• Page End: 3596
• Publication Date: 2018-10-22
• Subjects: assembly‐coding -- auditory cortex -- brain‐machine interfaces -- electrocorticography -- synchronous spiking -- visual cortex; Nervous system -- Periodicals; 612.8
• DOI: 10.1111/ejn.14167
• Languages: English
• ISSNs: 0953-816X

Abstract

Abstract: Synchronous spiking of multiple neurons is a key phenomenon in normal brain function and pathologies. Recently, approaches to record spikes from the intact cortical surface using small high‐density arrays of microelectrodes have been reported. It remained unaddressed how epicortical spiking relates to intracortical unit activity. We introduced a mesoscale approach using an array of 64 electrodes with intermediate diameter (250 μm) and combined large‐coverage epicortical recordings in ferrets with intracortical recordings via laminar probes. Empirical data and modelling strongly suggest that our epicortical electrodes selectively captured synchronized spiking of neurons in the cortex beneath. As a result, responses to sensory stimulation were more robust and less noisy compared to intracortical activity, and receptive field properties were well preserved in epicortical recordings. This should promote insights into assembly‐coding beyond the informative value of subdural EEG or single‐unit spiking, and be advantageous to real‐time applications in brain‐machine interfacing. Abstract : We have compared spiking activity in simultaneous recordings from layers and the intact surface (ECoG) of sensory cortices in the ferret brain. Surface spiking reflected the truly representative activity of the cortical column, i.e. spikes fired in synchrony by several units. We show that this can sharpen tuning, reduce response variability and thus make single trial surface spiking data as informative as post hoc analyzed multi trial or population data from intracortical multi site recordings.