Beyond correlation analysis: incremental mutual information

Incremental Mutual Information: A New Method for Characterizing the Strength and Dynamics of Connections in Neuronal Circuits is a 2010 paper by A. Singh and N. Lesica in PLoS Computational Biology that describes a method which can be used as an alternative to correlation analysis for some cases.*

What is the promise of Incremental Mutual Information (IMI), compared to correlation analysis and correlation functions? First, similar to mutual information, which I have discussed before, it also considers non-linear dependencies of neuronal activities. Second, “it has the potential to disambiguate statistical dependencies that reflect the connection between neurons from those caused by other sources (e.g. shared inputs or intrinsic cellular or network mechanisms) provided that the dependencies have appropriate timescales” (taken from the abstract). This sounds interesting, but we have to consider ‘appropriate timescales’ in more detail later.

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Beyond correlation analysis: mutual information

Last time, I mentioned a website which gives an overview of methods to analyze neuronal (and other) networks. Let’s have a closer look. Here’s a list of the methods:

  • Cross-correlation (the standard method)
  • Mutual Information
  • Incremental Mutual Information
  • Granger Causality
  • Transfer Entropy
  • Incremental Transfer Entropy
  • Generalized Transfer Entropy
  • Bayesian Inference
  • Anatomical Reconstruction

To be honest, I never heard of most of them. So let’s simply go into it and start with ‘Mutual Information’.

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Beyond correlation analysis

There are many papers out that use calcium imaging of a lot (tens to thousands) of neurons in animal brains. When I first encountered these kind of publications (roughly a year ago), it took me some hours to become familiar with the mode of presentation, which was very often a correlation matrix.

Yesterday, I was testing my 2-photon widefield microscope on C. elegans with nuclear GCamp5-labeled neurons. So I had the opportunity to do this kind of analysis on my own. Note that 1) I don’t know very much about these neurons 2) I don’t care really much; I’m more interested in the ways of analyzing this kind of data. Continue reading

Posted in Calcium Imaging, Data analysis, Neuronal activity | 2 Comments