Bursting Activity - Autocorrelation
(Time Triggered Average)

Bursting of the highest amplitude neuron in the crayfish 3rd nerve offshoot of the ventral cord ganglion was observed during the same experiment that produced the stimulus response example. Neuron 6 seemed to burst as many as 2-5 times and then silence. This example illustrates a detection of spikes and an autocorrelation to illustrate the behavior of the neuron as it bursts. It is designed to demonstrate the offline correlation features and creative use of threshold windows and window center.

Raw Data Files

• FinalPassive-4Burstofnum6.daq - 30 second recording of passive activity. -- .wav
• first-spike.txt - Extracted analysis values with threshold crosses corresponding to the first spike in each burst.

Extracting Burst Initiation Times

Note that spikes after the first in the burst seem to decrease in amplitude. Using a window of 0.005s, each of the bursts are detected.

Only the first spike is detected. Window width is set to trigger off threshold cross (include nothing before the threshold cross) and span a space longer than the entire burst.

1. Load FinalPassive-4Burstofnum6.daq
2. Activate threshold 1 and set it to approximately 6.5V
3. in the Analysis menu select the "Window Center on Threshold" option and set it to 0%
4. Set window width to 0.07s
5. Hit the calculate button
6. Select "Save All Analysis" from the "Results" menu. Save file as first-spike.txt

To Autocorrelate the bursting of Neuron 6 with each burst's initiation:

1. Have the data file loaded in the analysis interface
2. Choose "Correlate file With Extracted" from the "Analysis" menu.
3. Select "first-spike.txt"
4. Use the default window width of 0.05s
5. Locate window either fully after or centered on the extracted events
6. Use the threshold cross as the trigger point
7. Display all traces in the background

Note an decreasing degree of correlation from the first spike in the burst until the burst eventually ends. The amount of correlation is reflected in the size of signal in the mean (blue) trace of the correlation. The signal is highly correlated with itself at time zero as would be expected