This document is out of date and no longer maintained. I have left it here in the hope that some older information might still prove to be useful. As far as I know, there is no longer a spikesort mailing list.

Last update: Fri Aug 29 11:54:38 EDT 1997

The Spike Sorting FAQ

What am I looking at?

This is the SPIKESORT FAQ. It is a collection of information about spike sorting methods, papers and software, primarily derived from discussions on the SPIKESORT mailing list. In the fine tradition of usenet FAQs, it is arranged as a series of questions and their answers.

Whom is this document for?

The primary intended audience is extracellular neurophysiologists, or those considering doing extracellular neurophysiology. Other neuroscientists may find it interesting but it will probably not be at all useful to those with no interest in experimental neurobiology.

What questions are answered here?

Click on a question to jump to the answer:

What is spike sorting?

Neurophysiologists often record the currents flowing across cell membranes using an insulated wire probe whose exposed tip is placed in the extracellular medium near the soma or other spiking region of a cell. Any such probe will record currents passing across all sorts of physiological membranes close to its tip, but we can approximate this as a small number of close, high-amplitude sources imposed on a background of synaptic, somatic and axonal currents from more distant sources. Spike sorting, then, is the process of identifying the waveforms associated with action potentials in the foreground cell(s) and thereby detecting firing events.

Why is spike sorting important?

The short answer to this is that it is vital for extra-cellular recording from multiple cells. Obviously, sorting spikes from a single electrode can provide signals from more than one cell. But automatic recognition is also essential for any multiple electrode recording as achieving and maintaining an isolation on multiple probes simultaneously can be highly impractical.

What makes spike sorting difficult?

A number of issues make the problem non-trivial.

So, how do I do it?

A number of approaches have appeared in the
literature over the years. Some of these authors have made software available for general use. Finally, a few companies are selling tools that might be of use.

What academic papers are available on spike sorting?

Here is a list of papers published on the subject:

Where can I get software to sort spikes?

Various companies have commercial spike sorting products available. Some academics have also made their software available for free over ftp. Here are the packages that I know of:

Which companies provide spike sorting software or hardware?

How do I join the SPIKESORT mailing list?

SPIKESORT is a mailing list for developers, and users of spike sorting algorithms as well as any interested on-lookers. To join send a message to with the one word message body "subscribe".