Waveform analysis in NeuroExplorer

NeuroExplorer version 5.005 released on November 15, 2014, introduces a new analysis – Waveform Comparison. This analysis was added at a request of one of the NeuroExplorer customers who needed to compare average waveforms from one interval to another. This is a standard requirement when one does optogenetical identification of neurons, i.e. spikes are triggered by light-induced activation. To make sure this manipulation does not dramatically change the waveform of the spike, one needs to compare shape of light-triggered spikes to spontaneously occurring spikes. When you run Waveform Comparison analysis, you can display average waveforms and waveform standard deviations (shown as a gray background around averages):

Waveforms1

 

You can also display waveforms in Principal Component space:

WaveformsPC

To compare  light-triggered spikes to spontaneously occurring spikes, you need to specify two interval filters – one for stimulation periods and one for the periods with no stimulation. You can compare waveforms side-by-side:

WaveformCompValues

In the graph above the left column shows waveforms that were recorded during stimulation, the right column shows waveform averages that were recorded in periods with no stimulation.

You can also overlay averages for each neuron:

WaveformsComp

 

as well as overlay PC projections:

WfPCOverlaid

and run MANOVA to evaluate differences in the waveform projections in principal component space:

WfManova

 

Exporting Data to Text Files

NeuroExplorer version 5.002 was released on September 8, 2014. Here is a summary of what’s new in this version:

  • Coherence, Spectrograms and PeriEvent Spectrograms analyses now have all the spectral calculation options available in other spectral analyses (selection of 3 types of data preprocessing, 6 types of windowing functions and multi-taper options).
  • Burst Analysis now saves properties of each burst in Numerical Results:

Burst Properties

  • When exporting data or numerical results to text files, a user can select what character is used to separate items in a line (comma, space or tab; previously only tab was available). The new comma-separated output (.CSV file format) is especially convenient when working with Excel since this file format is natively supported by Excel.
  • When exporting data to text files, a user can now export waveform variables and marker variables (previously, NeuroExplorer could only export neurons, events, intervals and continuous variables).
  • You probably know that you can open a .nex file in NeuroExplorer by double-clicking at the file in File Explorer. For some reason, Windows sends several open file commands to NeuroExplorer when you double click at a .nex file. You could see some files opened twice, and some files generating a “sharing violation” error. This problem is fixed in NeuroExplorer 5.002 (and while we are talking about opening files, note that you can also open a .nex file by dragging the file into NeuroExplorer).