Multi-Electrode Arrays (MEAs)

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Multi-Electrode Arrays (MEAs)

• March 25, 2005

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Introduction
Multi-electrode Arrays, or MEAs, are quickly
becoming a common tool to investigate patterns of
activity. Often see 4-, 8-, 16-, or even
60-channel array experimenters choice Made of
microwires (stainless steel, tungsten,
platinum/iridium) coated with nonconductive
polymers (Teflon or formvar), or silicon tip
diameter of 1-5 mm Horizontal array
inter-electrode separation of 400-500 mm
Vertical array interelectrode separation
250-300 mm
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Luo Katz, 2003recording in a behaving mouse

• Response of a neuron from a CBA male during
  investigation of anesthetized stimulus animals
  including BALBc male, CBA male, BALBc female, and
  CBA female, demonstrating excitation by a BALBc
  male and inhibition by a CBA female. Sound,
  playback of spiking activity. Colored bar on the
  right, the cells mean firing rate red,
  excitation blue, inhibition. Note the gradual
  increase of neuronal activity, strong excitatory
  response to its investigation of the face area of
  the BALBc male, and the inhibition following
  strong excitation.

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An economical multi-channel cortical electrode
array for extended periods of recording during
behavior

• Rennaker, R.L., Ruyle, A.M., Street, S.E. and
  A.M. Sloan. (2005)
• J. Neurosci Meth 14297-105.

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Figure 1 Rennaker et al.
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Figure 2 Rennaker et al.
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Figure 3 Rennaker et al.
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Figure 4 Rennaker et al.
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Figure 5 Rennaker et al.
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Figure 6 Rennaker et al.
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Figure 7 Rennaker et al.
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Multi-unit recordings reveal context-dependent
modulation of synchrony in odor-specific neural
ensembles

• Christensen, T.A., Pawlowski, V.M., Lei, H. and
  J.G. Hildebrand (2000) Nat Neurosci 3927-931.

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Christensen et al. - Introduction

• Studies in Manduca Sexta, a moth, that is a
  common model for insect olfaction.
• The antennal lobe (AL) is a structural and
  functional analogue of the mammalian olfactory
  bulb (OB)
• Glomerulus functional unit of the AL (and OB)
  that receives odor information from a single type
  of sensory neuron
• each glomerulus then sends odor-specific
  information out to higher level brain centers via
  the projection neurons (PNs)
• glomeruli are thought to be activated in
  stereotypical patterns that then make up an odor
  map of each odor

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Figure 1 Christensen et al.
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Figure 2 Christensen et al.
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Figure 3 Christensen et al.
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Figure 4 Christensen et al.
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Figure 5 Christensen et al.
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Recording spikes from a large fraction of the
ganglion cells in a retinal patch

• Segev, R., Goodhouse, J., Puchalla, J. and M.J.
  Berry II
• 2003 Nature Neurosci 71155-1162.

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Segev et al. - Introduction

• Why the retina?
• Promising for systematic study of large
  populations of neurons because of its modular
  organization recording from a small patch of
  ganglion cells should sample its full functional
  diversity
• Limitations of multielectrode arrays?
• Sorting the signals obtained into spike trains
  from individual neurons
• This paper
• Development of a new method of recording and
  spike sorting that uses a dense array and
  combines signals from up to 30 electrodes to sort
  spikes. Records from ganglion cells, output
  cells of retina.

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Segev et al. - Introduction

• How accomplished?
• Find the average voltage pattern on the array
  when a ganglion cell fires a spike
• Use an iterative algorithm to match multiple
  spike patterns to the raw data
• Because every ganglion cell occupies a unique
  position in space, and because extracellular
  signals decay rapidly with distance, each
  ganglion cell produces a unique pattern of
  activity on the dense array
• This unique pattern can be used to identify the
  source of overlapping spikes, which might appear
  ambiguous if using only one electrode.

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Figure 1 Segev et al.
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Figure 2 Segev et al.
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Figure 3 Segev et al.
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Figure 3 Segev et al.
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Figure 3 Segev et al.
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Figure 4 Segev et al.
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Figure 4 Segev et al.
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Figure 5 Segev et al.
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Figure 6 Segev et al.
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Figure 7 Segev et al.
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Figure 7 Segev et al.
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Figure 8 Segev et al.