diff --git a/examples/cacoh.py b/examples/cacoh.py index 649e73c2..22a255a7 100644 --- a/examples/cacoh.py +++ b/examples/cacoh.py @@ -42,10 +42,13 @@ # that are present between only a small number of channels. # # Canonical coherency (CaCoh) is a multivariate form of coherency that uses -# spatial filters to extract the relevant components of connectivity in a -# frequency-resolved manner :footcite:`VidaurreEtAl2019`. It is similar to -# multivariate methods based on the imaginary part of coherency (MIC & MIM -# :footcite:`EwaldEtAl2012`; see :doc:`mic_mim` and +# eigendecomposition-derived spatial filters to extract the underlying +# components of connectivity in a frequency-resolved manner +# :footcite:`VidaurreEtAl2019`. This approach goes beyond simply aggregating +# information across all possible combinations of signals. +# +# It is similar to multivariate methods based on the imaginary part of +# coherency (MIC & MIM :footcite:`EwaldEtAl2012`; see :doc:`mic_mim` and # :doc:`compare_coherency_methods`). diff --git a/examples/compare_coherency_methods.py b/examples/compare_coherency_methods.py index 9c8e09fe..a823e8d4 100644 --- a/examples/compare_coherency_methods.py +++ b/examples/compare_coherency_methods.py @@ -47,7 +47,8 @@ # between two signals), advanced multivariate measures (i.e. between groups of # signals) have also been developed based on Cohy (CaCoh # :footcite:`VidaurreEtAl2019`; can take the absolute value for a multivariate -# form of Coh) or ImCoh (MIC & MIM :footcite:`EwaldEtAl2012`). +# form of Coh; see :doc:`cacoh`) or ImCoh (MIC & MIM :footcite:`EwaldEtAl2012`; +# see :doc:`mic_mim`). # # Despite their similarities, there are distinct scenarios in which these # different methods are most appropriate, as we will show in this example. diff --git a/examples/mic_mim.py b/examples/mic_mim.py index 511cc2a8..67c6e6d3 100644 --- a/examples/mic_mim.py +++ b/examples/mic_mim.py @@ -42,19 +42,32 @@ # A popular bivariate measure of connectivity is the imaginary part of # coherency, which looks at the correlation between two signals in the # frequency domain and is immune to spurious connectivity arising from volume -# conduction artefacts :footcite:`NolteEtAl2004`. However, depending on the -# degree of source mixing, this measure is susceptible to biased estimates of +# conduction artefacts :footcite:`NolteEtAl2004`. However, in cases where +# interactions between multiple signals are of interest, computing connectivity +# between all possible combinations of signals leads to a very large number of +# results which is difficult to interpret. A common approach is to average +# results across these connections, however this risks reducing the +# signal-to-noise ratio of results and burying interactions that are present +# between only a small number of channels. +# +# Additionally, this bivariate measure is susceptible to biased estimates of # connectivity based on the spatial proximity of sensors -# :footcite:`EwaldEtAl2012`. +# :footcite:`EwaldEtAl2012` depending on the degree of source mixing in the +# signals. +# +# To overcome this limitation, spatial filters derived from eigendecompositions +# allows connectivity to be analysed in a multivariate manner, removing the +# source mixing-dependent bias and increase the signal-to-noise ratio of +# connectivity estimates :footcite:`EwaldEtAl2012`. This approach goes beyond +# simply aggregating information across all possible combinations of signals, +# extracting the underlying components of connectivity in a frequency-resolved +# manner. # -# To overcome this limitation, spatial filters can be used to estimate -# connectivity free from this source mixing-dependent bias, which additionally -# increases the signal-to-noise ratio and allows signals to be analysed in a -# multivariate manner :footcite:`EwaldEtAl2012`. This approach leads to the -# following methods: the maximised imaginary part of coherency (MIC); and the -# multivariate interaction measure (MIM). These methods are similar to the -# multivariate method based on coherency (CaCoh :footcite:`VidaurreEtAl2019`; -# see :doc:`cacoh` and :doc:`compare_coherency_methods`). +# This leads to the following methods: the maximised imaginary part of +# coherency (MIC); and the multivariate interaction measure (MIM). These +# methods are similar to the multivariate method based on coherency (CaCoh +# :footcite:`VidaurreEtAl2019`; see :doc:`cacoh` and +# :doc:`compare_coherency_methods`). # # We start by loading some example MEG data and dividing it into # two-second-long epochs.