Advanced features

Experiment control and stimulus sequencing

The Spike2 output sequencer can run complex experiment control and stimulus sequencing protocols during data capture using up to 16 TTL and 8 waveform outputs. Timing is precise as it is controlled at the CED 1401 interface, not the host computer.

Output protocols can be set up in two ways. A graphical editor provides all the functionality most users require, allowing creation of multiple sets of pulse outputs including square pulses, sine waves, ramps, pre-recorded and user-defined waveforms. See a video demonstration. For more demanding applications, a text editor is available in which you can edit the sequencer steps directly. This makes it possible to control the sequence interactively through the script language by use of variables and tables.

The sequencer can access the incoming waveform and event data in real-time, enabling very fast response to changes in waveform levels and detection of events.

Spike2 graphical sequence editor showing different
outputs and additional control options

Spike detection and sorting

Spike2 identifies and sorts single and multi-unit activity both on- and off-line. It can mark events using simple threshold crossings or sort up to 32 channels on-line with whole wave spike shape template matching of single trace and n-trode data. See a video demonstration.

For multi-unit recordings, Spike2 contains tools for sorting spikes based on the spike waveform shape. All events crossing a threshold are captured. See a video demonstration. A combination of template matching and cluster cutting based on Principal Component Analysis (PCA), user-defined measurements correlations or errors is then used to sort spikes into different units. Spikes can also be sorted interactively by dragging a line through overdrawn spikes and classifying any which intersect. Spike Collision Analysis can separate unit collisions by comparing the current spike shape with pairs of existing templates.

Cluster cutting methods plot measured values into a 3D view that can be rotated and replayed to show the occurrence of the spikes through time. Clusters are formed by automatic algorithms or manually by placing ellipses or drawing polygons. Interactive features include INTHs for current cluster classes, tracking over time, and selection of an individual spike by clicking on its dot in the cluster.

Multi-unit spike discrimination using PCA clustering


The graphical sequence editor in Spike2 offers a user-friendly interface for the built-in output sequencer. This video tutorial gives an introduction to the graphical editor and how to use it to setup a range of outputs for use during sampling.


There are a number of parameters used to define how spike templates are formed and how incoming spikes are matched to templates. This video tutorial demonstrates how these settings can be modified using the Template Parameters dialog.


When setting up a new WaveMark channel, the two default horizontal cursors in the spike shape 'oscilloscope ' window are used to set the positive and negative trigger levels for spike detection. This video tutorial demonstrates the 'do 's ' and 'dont 's ' of setting up threshold triggers for spike sorting.

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Privacy policy

CED, through this site, does two things that relate to privacy. We would like to explain them.

Emails from down-loads

We offer free down-loads of many files on our site, from test programs to complete install files for updated versions of major packages like Spike2 and Signal.

When customers wish to take a down-load of a major package, we ask a few questions, including their name, email address, the serial number of the software for which they seek an upgrade and whether they would like an automatic email whenever we update the product. This information is emailed back to CED when they access the final down-load screen. Within this email, your browser transmits the type and version of browser you are using, and the screen resolution you are running.

The reasons why we take and keep this information are that it is useful for our software development team to know who has taken the latest versions, and it is useful for our web site development team to know which browsers people are using to view our site, and what resolution they have their screens set to.


When people down-load a major package, we try to write a cookie, a small file in your computer, that records your name, serial number of the software package, and the version you are down-loading. These files have a lifetime of one year.

The reasons for storing this information are firstly that if you ask for another down-load some other time, your details are read from the cookie and are pre-written into the form, to save you looking them up again. The other reason is that next time you access our site, your browser looks through your CED cookies and compares the versions down-loaded with the latest version numbers read from our site. If there is a later version of a product you have already down-loaded, we tell you on the home page screen, so you know that it is worth going to the down-load page again.

None of this information is ever given to anyone outside CED. ×