What is the real shape of extracellular spikes?
We show that the standard filters used for on-line spike detection in most hardware acquisition systems introduce distortions in the recorded spike shapes. This is because on-line spike detection is done after band pass filtering the data with causal filters. As illustrated with three clusters of spike shapes from a real single cell recording in a human subject, causal filtering can create a spurious negative rebound and a smooth looking appearance of the spikes. We also show that these filtering distortions can make artifacts look similar to real spikes.
Quian Quiroga
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Department of Engineering, University of Leicester, LE1 7RH Leicester, UK. rqqg1@le.ac.uk
D000200:Action Potentials / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D005110:Extracellular Space / Q000502:physiology*; D006801:Humans; D013702:Temporal Lobe / Q000502:physiology; D013997:Time Factors