Simultaneous recording of ECoG and intracortical neuronal activity using a flexible multichannel electrode-mesh in visual cortex

Neuroimage. 2011 Jan 1;54(1):203-12. doi: 10.1016/j.neuroimage.2010.08.003. Epub 2010 Aug 7.


Electrocorticogram (ECoG) is a well-balanced methodology for stably mapping brain surface local field potentials (LFPs) over a wide cortical region with high signal fidelity and minimal invasiveness to the brain tissue. To directly compare surface ECoG signals with intracortical neuronal activity immediately underneath, we fabricated a flexible multichannel electrode array with mesh-form structure using micro-electro-mechanical systems. A Parylene-C-based "electrode-mesh" for rats contained a 6×6 gold electrode array with 1-mm interval. Specifically, the probe had 800×800 μm(2) fenestrae in interelectrode spaces, through which simultaneous penetration of microelectrode was capable. This electrode-mesh was placed acutely or chronically on the dural/pial surface of the visual cortex of Long-Evans rats for up to 2 weeks. We obtained reliable trial-wise profiles of visually evoked ECoG signals through individual eye stimulation. Visually evoked ECoG signals from the electrode-mesh exhibited as well or larger signal amplitudes as intracortical LFPs and less across-trial variability than conventional silver-ball ECoG. Ocular selectivity of ECoG responses was correlated with that of intracortical spike/LFP activities. Moreover, single-trial ECoG signals carried sufficient information for predicting the stimulated eye with a correct performance approaching 90%, and the decoding was significantly generalized across sessions over 6 hours. Electrode impedance or signal quality did not obviously deteriorate for 2 weeks following implantation. These findings open up a methodology to directly explore ECoG signals with reference to intracortical neuronal sources and would provide a key to developing minimally invasive next-generation brain-machine interfaces.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dominance, Ocular / physiology
  • Electrocardiography / methods*
  • Electrodes
  • Monitoring, Physiologic / instrumentation
  • Monitoring, Physiologic / methods
  • Neurons / physiology*
  • Photic Stimulation
  • Rats
  • Scalp / physiology
  • Signal Transduction
  • Visual Cortex / physiology*
  • Visual Fields