Jacek Dmochowski

brain decoding; optimal electrotherapy; cost-sensitive learning

Brief Biography

After completing my Master's of Applied Science degree in Electrical Engineering under the supervision of Rafik Goubran at Carleton University (Ottawa, Canada), I continued my pursuit of array signal processing research as a doctoral student at the Universite du Quebec, where I worked on several aspects of acoustic signal processing under the tutelage of Jacob Benesty and Sofiene Affes. My dissertation was subsequently awarded the Governor General of Canada's Academic Gold Medal.  In the Fall of 2008, I transitioned into the biomedical domain as a post-doctoral research scholar at the City College of the City University of New York, where I have been engaged in neural engineering research: decoding brain state from functional magnetic resonance imagery (fMRI) and electroencephalography (EEG), and designing optimized non-invasive electrical brain stimulation paradigms.  My research is supervised by Lucas Parra and performed in close collaboration with Marom Bikson and Paul Sajda.      

Current Projects

Decoding Engagement during Film Viewing

In our most recent study, we have devised a novel machine learning algorithm, termed "correlated component analysis", to decode the level of viewer engagement during a short film clip.  This novel technique automatically extracts components of neural activity which are maximally correlated across multiple views.  We hypothesize that the amount of time-resolved correlation in these neural signals corresponds to the level of audience attention, affect, and memory encoding.  The clip below demonstrates the time course of these optimized correlation measures for three components in relation to the plot trajectory of the 1961 "Alfred Hitchcock Presents" episode "Bang! You're Dead."  Note that the peaks of the neural correlations occur in correpondence with momentous or arousing events in the narrative.      

 

Multi-Electrode Transcranial Electrical Stimulation

Communication in the nervous system is primarily carried out by propagating spikes termed "action potentials" --movements of ions within and across nerve cells.  Moreover, the pathological basis for a variety of neurological disorders is characterized by abnormalities in electrical activity.  One way to rectify these abnormalities is through psychotropic drugs, which act mainly to regulate neurotransmitter levels.  An alternative approach is to modulate the electrical activity directly through the application of external electric fields: electrical brain stimulation.  While invasive methods such as deep brain stimulation have achieved transformative benefits for Parkinsonian patients, for example, we focus on non-invasive techniques which are applicable to a much wider clinical population with less severe pathology.  To that end, we have recently leveraged advances in human brain mapping, beamforming, and optimization to develop a multi-electrode stimulation paradigm which is able to achieve unprecedented intensity and focality at cortical targets.    

 

Journal Publications
J. P. Dmochowski, P. Sajda, J. Dias, and L. C. Parra, “Brains synchronize when
viewers are engaged,” submitted to Proceedings of the National Academy of Sciences,
2011.
J. P. Dmochowski, M. Bikson, and L. C. Parra, “A theory for achieving focality in
transcranial electrical stimulation based on the spherical harmonic decomposition
of the applied current,” submitted to Brain Stimulation, 2011.
J. P. Dmochowski, A. Datta, M. Bikson, Y. Su, and L. C. Parra,“Optimized multielectrode
stimulation increases focality and intensity at target,” Journal of Neural
Engineering, 8(4): 046011, 2011.
J. P. Dmochowski, P. Sajda, and L. C. Parra, “Maximum likelihood in cost-sensitive
learning: model specification, approximations, and upper bounds,” Journal of Machine
Learning Research, 11: 3313-3332, 2010.
P. Sajda, E. Pohlmeyer, J. Wang, L. C. Parra, C. Christoforou, J. Dmochowski,
B. Hanna, C. Bahlmann, M. K. Singh, and S. F. Chang, “In a blink of an eye and
a switch of a transistor: cortically coupled computer vision,” Proc. IEEE, 98:462–
478, 2010.
2
E. A. P. Habets, J. Benesty, I. Cohen, S. Gannot, and J. Dmochowski, “New insights
into the MVDR beamformer in room acoustics,” IEEE Transactions on Audio,
Speech, and Language Processing, 18:157–180, 2010.
J. Dmochowski, J. Benesty, and S. Affes, “On spatial aliasing in microphone arrays”,
IEEE Transactions on Signal Processing, 57:1383–1395, 2009.
J. Dmochowski, J. Benesty, and S. Affes, “An information-theoretic view of array
processing”, IEEE Transactions on Audio, Speech, and Language Processing,
17:392–401, 2009.
J. Dmochowski, J. Benesty, and S. Affes, “Linearly constrained minimum variance
source localization and spectral estimation”, IEEE Transactions on Audio,
Speech and Language Processing, 16:1490–1502, 2008.
J. Dmochowski, J. Benesty, and S. Affes, “A generalized steered response power
method for computationally viable source localization”, IEEE Transactions on Audio,
Speech and Language Processing, 15:2510–2526, 2007.
J. Dmochowski, J. Benesty, and S. Affes, “Direction of arrival estimation using
the parameterized spatial correlation matrix”, IEEE Transactions on Audio, Speech
and Language Processing, 15: 1327–1339, 2007.
J. Benesty, J. Chen, Y. Huang, and J. Dmochowski, “On microphone-array beamforming
from a MIMO acoustic signal processing perspective”, IEEE Transactions
on Speech and Audio Processing, 15:1053–1065, 2007.
J. Dmochowski and R.A. Goubran, “Decoupled beamforming and noise cancellation:
an alternative to classical adaptive beamforming”, IEEE Transactions on
Instrumentation and Measurement, 56:80–88, 2007.

Journal Publications

J. P. Dmochowski, P. Sajda, J. Dias, and L. C. Parra, ``Brains lock to stimulus when viewers are engaged,'' under review, Journal of Neuroscience.  

J. P. Dmochowski, M. Bikson, and L. C. Parra, ``A theory for achieving focality in transcranial electrical stimulation based on the spherical harmonic decomposition of the applied current,'' under review, Brain Stimulation.    

J. P. Dmochowski, A. Datta,  M. Bikson, Y. Su, and L. C. Parra,``Optimized multi-electrode stimulation increases focality and intensity at target,'' Journal of Neural Engineering, 8(4): 046011, 2011.  

J. P. Dmochowski, P. Sajda, and L. C. Parra, ``Maximum likelihood in cost-sensitive learning: model specification, approximations, and upper bounds,'' Journal of Machine Learning Research, 11: 3313-3332, 2010.

P. Sajda, E. Pohlmeyer, J. Wang, L. C. Parra, C. Christoforou, J. Dmochowski, B. Hanna, C. Bahlmann, M. K. Singh, and S. F. Chang, ``In a blink of an eye and a switch of a transistor: cortically coupled computer vision,'' Proc. IEEE, 98:462--478, 2010.  

E. A. P. Habets, J. Benesty, I. Cohen, S. Gannot, and J. Dmochowski,``New insights into the MVDR beamformer in room acoustics,'' IEEE Transactions on Audio, Speech, and Language Processing, 18:157--180, 2010.

J. Dmochowski, J. Benesty, and S. Affes, ``On spatial aliasing in microphone arrays'', IEEE Transactions on Signal Processing, 57:1383--1395, 2009.

J. Dmochowski, J. Benesty, and S. Affes, ``An information-theoretic view of array processing'', IEEE Transactions on Audio,Speech, and Language Processing, 17:392--401, 2009.  

J. Dmochowski, J. Benesty, and S. Affes, ``Linearly constrained minimum variance source localization and spectral estimation'', IEEE Transactions on Audio, Speech and Language Processing,16:1490--1502, 2008.

J. Dmochowski, J. Benesty, and S. Affes, ``A generalized steered response power method for computationally viable source localization'', IEEE Transactions on Audio, Speech and Language Processing, 15:2510--2526, 2007.

J. Dmochowski, J. Benesty, and S. Affes, ``Direction of arrival estimation using the parameterized spatial correlation matrix'', IEEE Transactions on Audio, Speech and Language Processing,15: 1327--1339, 2007.

J. Benesty, J. Chen, Y. Huang, and J. Dmochowski, ``On microphone-array beamforming from a MIMO acoustic signal processing perspective'', IEEE Transactions on Speech and Audio Processing, 15:1053--1065, 2007.

J. Dmochowski and R.A. Goubran, ``Decoupled beamforming and noise cancellation: an alternative to classical adaptive beamforming'', IEEE Transactions on Instrumentation and Measurement, 56:80--88, 2007.

 

Peer-Reviewed Conference Publications

J. P. Dmochowski, P. Sajda, and L. C. Parra, ``Examining Loss Functions in Cost-Sensitive Learning,'' in Proc. of the Computational and Biological Learning Society Learning Workshop, 2011.

J. P. Dmochowski, M. Bikson, and L. C. Parra, ``A Multiple Electrode Scheme for Optimal Non-Invasive Electrical Stimulation,'' in Proc. IEEE Engineering in Medicine and Biology Society Conference, 2011.

J. Dmochowski, J. Benesty, and S. Affes, ``Calibrated acoustic source localization,'' in Proc. IEEE Biennial Symposium on Communications, 2008.  

J. Dmochowski, J. Benesty, and S. Affes, ``On autoregressive modeling for the localization of speech,'' in Proc. IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM), 2008.

J. Dmochowski, Z. Liu, and P. A. Chou, ``Blind source separation in a distributed microphone meeting for improved teleconferencing,'' in Proc. IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), 2008.

J. Dmochowski, J. Benesty, and S. Affes, ``Fast steered response power source localization using inverse mapping of relative delays,'' in Proc. IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), 2008.

J. Dmochowski, J. Benesty, and S. Affes, ``Broadband MUSIC: challenges and opportunities for multiple source localization,'' in Proc. IEEE Workshop on the Applications of Signal Processing to Audio and Acoustics (WASPAA), 2007.

J. Dmochowski, J. Benesty, and S. Affes, ``The generalization of narrowband localization methods to broadband environments via parametrization of the spatial correlation matrix,'' in Proc. European Signal Processing Conference (EUSIPCO), 2007.

J. Dmochowski, J. Benesty, and S. Affes, ``Direction of arrival estimation using eigenanalysis of the parameterized spatial correlation matrix,'' in Proc. IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), 2007.  

W. Dmochowski and J. Dmochowski, ``Frequency dependent dynamic properties of tilting pad journal bearing: experimental results and uncertainty analysis,'' in Proc. World Tribology Congress, 2005.

J. Dmochowski and R.A. Goubran, ``Combined beamforming and noise cancellation,'' in Proc. of the IEEE Instrumentation and Measurement Technology Conference, 2005.

J. Dmochowski and R.A. Goubran, ``Noise cancellation using fixed beamforming,'' in Proc. of the IEEE Workshop on Haptic, Audio and Visual Environments and their Applications (HAVE), 2004.

 

Book Chapters

J. Dmochowski and J. Benesty, ``Microphone arrays: fundamental concepts'', Speech Processing in Modern Communication: Challenges and Perspectives, Berlin: Springer, 2010, pp. 199--223. 

J. Dmochowski and J. Benesty, ``Steered beamforming approaches to source localization'', Speech Processing in Modern Communication: Challenges and Perspectives, Berlin: Springer, 2010, pp. 307--337.

 

 

 

Full CV.

Last updated: 3 weeks ago