Suppose you have two populations of spike amplitudes in your recordings and wish to perform measurements only on those with the lower amplitude. Easiest is to use Spike Histogram. If Spike Histogram is not available, then there are two ways to achieve this:
The first hides the larger amplitude spikes utilizing the Threshold arithmetic function, similar to that found below.
Ch1/Threshold (Smoothsec (Window (Ch1, -1,1) , 0.02 ), 1)
However, the variables need to be adjusted for your recording. This article provides more information on each component of this arithmetic function.
The other method utilises several helper channels, as seen in this example file.
- Channel 1 (Raw) displays the unfiltered data.
- Channel 2 (All Spike Count) uses a cyclic measurement calculation to detect large and small spikes in the Raw channel. It has custom detection settings to try to select all the spikes without any false positives. These settings can be edited to control which spikes are detected.
- Channel 3 (Large Spike Event) is a copy of Channel 1 (Raw), which is required as subsequent calculations need to reference only the large spikes.
- Channel 4 (Large Spike Count) has a second custom cyclic measurement calculation that detects larger spikes in the Large Spike Event channel.
- Channels 2 and 4 are count cyclic measurements, so the step increase occurs each time they detect a spike.
- Channel 5 (Small Spike Events) differentiates between Channel 2 and 4. This means that only the smaller spikes remain, and Channel 5 shows spikes that line up with the position of the smaller spikes in the sampled data.
- Channel 6 is a simple cyclic measurement that calculates the frequency of the smaller spikes (referenced in the Small Spike Events channel).
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