Abstract
Information theoretic metrics have proven useful in quantifying the relationship between behaviorally relevant parameters and neuronal activity with relatively few assumptions. However, these metrics are typically applied to action potential recordings and were not designed for the slow timescales and variable amplitudes typical of functional fluorescence recordings (e.g. calcium imaging). The lack of research guidelines on how to apply and interpret these metrics with fluorescence traces means the neuroscience community has yet to realize the power of information theoretic metrics. Here, we used computational methods to create mock action potential traces with known amounts of information. From these, we generated fluorescence traces and examined the ability of different information metrics to recover the known information values. We provide guidelines for how to use information metrics when applying them to functional fluorescence and demonstrate their appropriate application to GCaMP6f population recordings from mouse hippocampal neurons imaged during virtual navigation.
Significance Statement
Functional fluorescence imaging and information theoretic quantification could provide a powerful new combination of tools to study neural correlates of behavior, but functional fluorescence signals represent altered versions of the underlying physiological events. Therefore, it is unclear if or how information metrics can be applied to functional fluorescence imaging data. Here, we performed an in-depth simulation study to examine the application of the widely used bits per second and bits per action potential metrics of mutual information to functional florescence recordings. We provide guidelines for how to use information metrics when applying them to functional fluorescence and demonstrate their appropriate application to GCaMP6f population recordings from mouse hippocampal neurons imaged during virtual navigation.
Footnotes
Authors report no conflict of interest.
This work was supported by The McKnight Foundation, Northwestern University, The Chicago Biomedical Consortium with support from the Searle Funds at The Chicago Community Trust, The NIH (R01MH101297, T32AG020506) and NSF (CRCNS1516235).
The McKnight Foundation, Northwestern University, The Chicago Biomedical Consortium with support from the Searle Funds at The Chicago Community Trust, The NIH (R01MH101297, T32AG020506) and NSF (CRCNS1516235). Information theoretic approaches to deciphering the neural code with functional fluorescence imaging.
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
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