New Phase Analysis Reveals Phase Relationship between Single-Cell Activity and Local Field Potentials

NeuroExplorer 5.017 released on July 22, 2015 has two new analyses: Find Oscillations analysis and Firing Phase analysis.

Find Oscillations analysis identifies episodes of oscillatory activity in the specified frequency band in recorded analog signals. The algorithm is described in Klausberger, Magill, Marton, Roberts, Cobden, Buzsaki and Somogyi. Brain-state- and cell-type-specific firing of hippocampal interneurons in vivo. Nature, 2003 Feb 20;421(6925):844-8

The user specifies two frequency bands (for example, theta band and delta band). NeuroExplorer finds the segments of LFP signal where theta to delta frequency power ratio exceeds a certain threshold. The LFP signal is then band-filtered and oscillation cycle start times are identified via Hilbert transform. This analysis adds several new variables to the data file. The data viewer screenshot below shows the results of analyzing variable LFP01. NeuroExplorer added three new variables: Theta_Epochs, Theta_Filtered and Theta_ZeroPhase:

FIndOsc1D

The LFP01_Theta_ZeroPhase event is than used in Firing Phase analysis that calculates probability of a neuron firing in a certain phase of theta cycle:

FiringPhase

By the way, I added these new analyses after several users asked me whether a phase-of-firing analysis is available in NeuroExplorer.

Do you need new analyses or new features in NeuroExplorer? Please send your requests to [email protected]