[MRG] Add dPLI connectivity measure (#79)

* Add and document DPLIEst_ class in epochs.py

* Add DPLI parametrization to test_spectral_connectivity

* Fix citation

* Fix circleCI

* Adding fix

* Fixed pep

* Fix doc for sm_kernel and sm_freqs in spectral_connectivity_time

* Add wPLI/dPLI/PLI example

* Update whatsnew

* Update mne_connectivity/spectral/time.py

Co-authored-by: Adam Li <[email protected]>

* Update mne_connectivity/spectral/time.py

Co-authored-by: Adam Li <[email protected]>

* Add imaginary and heaviside definitions

* Define sgn

* Update mne_connectivity/spectral/time.py

* Fix lagging/leading plot

* Update doc/whats_new.rst

Co-authored-by: Adam Li <[email protected]>

Author: kenjimarshall

doc/authors.inc

@@ -4,4 +4,5 @@
 .. _Alexander Kroner: https://github.com/alexanderkroner
 .. _Richard Höchenberger: https://github.com/hoechenberger
 .. _Alex Rockhill: https://github.com/alexrockhill
-.. _Szonja Weigl: https://github.com/weiglszonja
+.. _Szonja Weigl: https://github.com/weiglszonja
+.. _Kenji Marshall: https://github.com/kenjimarshall

doc/references.bib

@@ -226,3 +226,16 @@ @article{ColcloughEtAl2015
   year = {2015},
   pages = {439--448}
 }
+
+ @article{StamEtAl2012,
+  title={Go with the flow: Use of a directed phase lag index (dPLI) to characterize patterns of phase relations in a large-scale model of brain dynamics},
+  volume={62},
+  ISSN={1053-8119},
+  DOI={10.1016/j.neuroimage.2012.05.050},
+  number={3}, 
+  journal={NeuroImage}, 
+  author={Stam, C. J. and van Straaten, E. C. W.}, 
+  year={2012}, 
+  month={Sep}, 
+  pages={1415–1428}
+}

doc/whats_new.rst

@@ -25,6 +25,7 @@ Enhancements
 ~~~~~~~~~~~~
 
 - Add ``node_height`` to :func:`mne_connectivity.viz.plot_connectivity_circle` and enable passing a polar ``ax``, by `Alex Rockhill`_ :gh:`88`
+- Add directed phase lag index (dPLI) as a method in :func:`mne_connectivity.spectral_connectivity_epochs` with a corresponding example by `Kenji Marshall`_ (:gh:`79`)
 
 Bug
 ~~~
@@ -39,7 +40,10 @@ API
 Authors
 ~~~~~~~
 
-
+* `Kenji Marshall`_
+* `Adam Li`_
+* `Alex Rockhill`_
+* `Szonja Weigl`_
 
 :doc:`Find out what was new in previous releases <whats_new_previous_releases>`