UNIT SORTING

To sort the signals within a channel, define the minimal and the maximal number of clusters, specify a penalty and click the SORT button in the Sorting part of the NEV2lkit GUI. (Use SORT ALL to classify the units on all electrodes of the actual opened file).

At least under MacOSX 10.3 it is possible to save the actual content of the DATA PLOTTING part of the NEV2lkit GUI into a vector-based PDF file using the system provided PRINT-Dialog (accessible from the NEV2lkit FILE-menu).

If you don't agree with the units that NEV2lkit has detected, try one of the following:

• change the upper and lower thresholds to choose the desired data
• change the time window of the spike events
• change the minimal or maximal number of cluster. Assign a penalty to reduce the total number of clusters.
• Change the PCA methods.

In principle the unit sorting is only as good as the input data. If the signal to noise ratio of this data is poor, consider trying to improve your experimental data acquisition.

NEV2lkit offers the option to sort the units of all NEV files in a directory using the SORT A DIRECTORY-command from the FILE-menu of the program. The unit classification spans over all files in the directory - if an ordained unit is classified for example on electrode 7, the unit identifier is used in all selected data files if signal waveforms of this unit are present in the electrode 7 data content. This just the most basic requirement for all further data analysis. A further remark on cross-experimental this unit sorting: when you sort units in all files of a directory please keep in mind that a LOT (!) of RAM might be needed. NEV2lkit sorted successfully units over several experiments, in which around 500000 spikes were present. Only spikes with the same time base can be sorted cross experiments. It might be needed to trim your data adequate.

Remember: The parameters for the unit sorting whether for single or for a bunch of files are always defined in the GUI.