Fractal characterization of internally and externally generated conscious experiences

Although there is an extensive literature on the study of the neural correlates of consciousness (NCC) this is a subject that is far from being considered over. In this paper we present a novel experimental paradigm, based on binocular rivalry, to study internally and externally generated conscious experiences. We called this procedure bimodal rivalry. In addition, and assuming the non-linear nature of the EEG signals, we propose the use of fractal dimension to characterize the complexity of the EEG signal associated with each percept. Analysis of the data showed a significant difference in complexity between the internally generated and externally generated percepts. Moreover, EEG complexity was dissimilar for externally generated auditory and visual percepts. These results support fractal dimension analyses as a new tool to characterize conscious perception.

[1]  Christopher J. James,et al.  Semi-blind source separation and extraction techniques applied to multi-channel electroencephalogram and magnetoencephalogram signals , 2009 .

[2]  Rodrigo Quian Quiroga,et al.  Nonlinear multivariate analysis of neurophysiological signals , 2005, Progress in Neurobiology.

[3]  J. Röschke,et al.  The dimensionality of human's electroencephalogram during sleep , 1991, Biological Cybernetics.

[4]  D. Heeger,et al.  Neuronal activity in human primary visual cortex correlates with perception during binocular rivalry , 2000, Nature Neuroscience.

[5]  G. Shulman,et al.  Medial prefrontal cortex and self-referential mental activity: Relation to a default mode of brain function , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[6]  C. Koch,et al.  The Neural Correlates of Consciousness , 2008, Annals of the New York Academy of Sciences.

[7]  Jacques Martinerie,et al.  Unstable periodic orbits in human epileptic activity , 1997 .

[8]  D. Abásolo,et al.  Use of the Higuchi's fractal dimension for the analysis of MEG recordings from Alzheimer's disease patients. , 2009, Medical Engineering and Physics.

[9]  David A. Leopold,et al.  What is rivalling during binocular rivalry? , 1996, Nature.

[10]  M. Scherg,et al.  Neuromagnetic Correlates of Streaming in Human Auditory Cortex , 2005, The Journal of Neuroscience.

[11]  Arnaud Delorme,et al.  EEGLAB: an open source toolbox for analysis of single-trial EEG dynamics including independent component analysis , 2004, Journal of Neuroscience Methods.

[12]  Helmut Laufs,et al.  Where the BOLD signal goes when alpha EEG leaves , 2006, NeuroImage.

[13]  T. Higuchi.  Approach to an irregular time series on the basis of the fractal theory , 1988 .

[14]  J. Born,et al.  EEG complexity and performance measures of creative thinking. , 1999, Psychophysiology.

[15]  Andrea Mechelli,et al.  A report of the functional connectivity workshop, Dusseldorf 2002 , 2003, NeuroImage.

[16]  Kevin S. Brown,et al.  Cooperation between the default mode network and the frontal–parietal network in the production of an internal train of thought , 2012, Brain Research.

[17]  Gunnar Rätsch,et al.  An introduction to kernel-based learning algorithms , 2001, IEEE Trans. Neural Networks.

[18]  Terrence J. Sejnowski,et al.  An Information-Maximization Approach to Blind Separation and Blind Deconvolution , 1995, Neural Computation.

[19]  E. Formisano,et al.  Hearing an Illusory Vowel in Noise: Suppression of Auditory Cortical Activity , 2012, The Journal of Neuroscience.

[20]  H. Jasper,et al.  The ten-twenty electrode system of the International Federation. The International Federation of Clinical Neurophysiology. , 1999, Electroencephalography and clinical neurophysiology. Supplement.

[21]  Jaeseung Jeong.  EEG dynamics in patients with Alzheimer's disease , 2004, Clinical Neurophysiology.

[22]  Cornelis J Stam,et al.  Different EEG frequency band synchronization during nocturnal frontal lobe seizures , 2004, Clinical Neurophysiology.

[23]  Alfredo Brancucci,et al.  The Sound of Consciousness: Neural Underpinnings of Auditory Perception , 2011, The Journal of Neuroscience.

[24]  C. Stam,et al.  Nonlinear dynamical analysis of EEG and MEG: Review of an emerging field , 2005, Clinical Neurophysiology.

[25]  T. Hendler,et al.  Towards a Neuroscience of Mind-Wandering , 2011, Front. Hum. Neurosci..

[26]  T. Elbert,et al.  The scalp distribution of the fractal dimension of the EEG and its variation with mental tasks , 2005, Brain Topography.

[27]  Sophie M. Wuerger,et al.  Interactions between Auditory and Visual Semantic Stimulus Classes: Evidence for Common Processing Networks for Speech and Body Actions , 2011, Journal of Cognitive Neuroscience.

[28]  J. Smallwood,et al.  Counting the cost of an absent mind: Mind wandering as an underrecognized influence on educational performance , 2007, Psychonomic bulletin & review.

[29]  Roberto Hornero,et al.  Analysis of EEG background activity in Alzheimer's disease patients with Lempel-Ziv complexity and central tendency measure. , 2006, Medical engineering & physics.

[30]  A. Brancucci,et al.  “Binaural rivalry”: Dichotic listening as a tool for the investigation of the neural correlate of consciousness , 2011, Brain and Cognition.

[31]  V. Roychowdhury,et al.  Assessment of long-range correlation in time series: how to avoid pitfalls. , 2006, Physical review. E, Statistical, nonlinear, and soft matter physics.

[32]  C. Koch,et al.  Are we aware of neural activity in primary visual cortex? , 1995, Nature.

[33]  R. Nathan Spreng,et al.  The Common Neural Basis of Autobiographical Memory, Prospection, Navigation, Theory of Mind, and the Default Mode: A Quantitative Meta-analysis , 2009, Journal of Cognitive Neuroscience.

[34]  Abraham Z. Snyder,et al.  A default mode of brain function: A brief history of an evolving idea , 2007, NeuroImage.

[35]  Geraint Rees,et al.  Neural correlates of consciousness in humans , 2002, Nature Reviews Neuroscience.

[36]  Werner Lutzenberger,et al.  Dimensional analysis of the human EEG and intelligence , 1992, Neuroscience Letters.

[37]  Robert A. M. Gregson,et al.  Comparisons of the nonlinear dynamics of electroencephalograms under various task loading conditions: A preliminary report , 1990, Biological Psychology.

[38]  S. Makeig,et al.  Section: Behavioral/systems/cognitive Medial Prefrontal Theta Bursts Precede Rapid Motor Responses during Visual Selective Attention Introduction , 2022 .

[39]  J. Smallwood,et al.  The restless mind. , 2006, Psychological bulletin.

[40]  D. Braff,et al.  Sensory gating deficits in schizophrenia: can we parse the effects of medication, nicotine use, and changes in clinical status? , 2003, Clinical Neuroscience Research.

[41]  Leonidas D. Iasemidis,et al.  Dynamical resetting of the human brain at epileptic seizures: application of nonlinear dynamics and global optimization techniques , 2004, IEEE Transactions on Biomedical Engineering.

[42]  Claire Braboszcz,et al.  Lost in thoughts: Neural markers of low alertness during mind wandering , 2011, NeuroImage.

[43]  W. Klonowski.  Everything you wanted to ask about EEG but were afraid to get the right answer , 2009, Nonlinear biomedical physics.