title: Multi-scale analysis of neural activity in humans: Implications for micro-scale electrocorticography.
abstract: OBJECTIVE
  Electrocorticography grids have been used to study and diagnose neural pathophysiology for over 50 years, and recently have been used for various neural prosthetic applications. Here we provide evidence that micro-scale electrodes are better suited for studying cortical pathology and function, and for implementing neural prostheses.
  
  
  METHODS
  This work compares dynamics in space, time, and frequency of cortical field potentials recorded by three types of electrodes: electrocorticographic (ECoG) electrodes, non-penetrating micro-ECoG (μECoG) electrodes that use microelectrodes and have tighter interelectrode spacing; and penetrating microelectrodes (MEA) that penetrate the cortex to record single- or multiunit activity (SUA or MUA) and local field potentials (LFP).
  
  
  RESULTS
  While the finest spatial scales are found in LFPs recorded intracortically, we found that LFP recorded from μECoG electrodes demonstrate scales of linear similarity (i.e., correlation, coherence, and phase) closer to the intracortical electrodes than the clinical ECoG electrodes.
  
  
  CONCLUSIONS
  We conclude that LFPs can be recorded intracortically and epicortically at finer scales than clinical ECoG electrodes are capable of capturing.
  
  
  CONCLUSIONS
  Recorded with appropriately scaled electrodes and grids, field potentials expose a more detailed representation of cortical network activity, enabling advanced analyses of cortical pathology and demanding applications such as brain-computer interfaces.
authors.affiliation: Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT, USA.
authors.forename: Spencer
authors.initials: S
authors.lastname: Kellis
authors.affiliation: Department of Physics, University of Washington, Seattle, WA, USA.
authors.forename: Larry
authors.initials: L
authors.lastname: Sorensen
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle, WA, USA.
authors.forename: Felix
authors.initials: F
authors.lastname: Darvas
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle, WA, USA.
authors.forename: Conor
authors.initials: C
authors.lastname: Sayres
authors.affiliation: School of Biological & Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: O'Neill
authors.affiliation: Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT, USA; Department of Bioengineering, University of Utah, Salt Lake City, UT, USA; School of Computing, University of Utah, Salt Lake City, UT, USA.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Brown
authors.affiliation: Department of Neurosurgery, University of Utah, Salt Lake City, UT, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: House
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle, WA, USA; Center for Sensorimotor Neural Engineering, University of Washington, Seattle, WA, USA.
authors.forename: Jeff
authors.initials: J
authors.lastname: Ojemann
authors.affiliation: School of Biological & Health Systems Engineering, Arizona State University, Tempe, AZ, USA. Electronic address: bradley.greger@asu.edu.
authors.forename: Bradley
authors.initials: B
authors.lastname: Greger
mesh_terms: D000069280:Electrocorticography / Q000295:instrumentation* / Q000592:standards; D004567:Electrodes, Implanted / Q000592:standards; D006801:Humans; D008297:Male; D008839:Microelectrodes / Q000592:standards; D009044:Motor Cortex / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*
keywords: Brain computer interface (BCI); Human cerebral cortex; Micro-electrocorticography grid; Neural engineering; Neural microtechnology