Phase coding of information in the human brain

The exact mechanism of information transfer between different regions in the human brain to form an unitary experience is still not known. One of the widely accepted beliefs is that different brain areas, which are anatomically not necessarily connected, bind themselves together when needed to complete a certain task. This is also known as the binding theory. In the past, few contributions have been made suggesting that an important role in the theory of binding, concerning the information coding and transfer is played by the phase characteristics of the transmitted signals. Therefore, this study investigates a possibility to decode some of the information exchanged between the brain centers using the phase demodulation approach. The study has been made using the EEG signals obtained when the subjects performed two types of tasks; visual-motor task and working memory task. The presented study has revealed that even though EEG signals represent a superposition of all active neurons, it is possible to decode some information on the current activity of the brain centers. Thus, it can be concluded that phase coding in the brain signals seems to has an important role during the brain activity and information exchange.

[1]  J. Lisman,et al.  Hippocampal sequence-encoding driven by a cortical multi-item working memory buffer , 2005, Trends in Neurosciences.

[2]  G Pfurtscheller,et al.  Event-Related changes of band power and coherence: methodology and interpretation. , 1999, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[3]  Michio Sugeno,et al.  Fuzzy identification of systems and its applications to modeling and control , 1985, IEEE Transactions on Systems, Man, and Cybernetics.

[4]  W Singer,et al.  Visual feature integration and the temporal correlation hypothesis. , 1995, Annual review of neuroscience.

[5]  E. Fetz,et al.  Oscillatory activity in sensorimotor cortex of awake monkeys: synchronization of local field potentials and relation to behavior. , 1996, Journal of neurophysiology.

[6]  A. Schnitzler,et al.  Normal and pathological oscillatory communication in the brain , 2005, Nature Reviews Neuroscience.

[7]  A. Fingelkurts,et al.  Functional connectivity in the brain—is it an elusive concept? , 2005, Neuroscience & Biobehavioral Reviews.

[8]  O. Jensen,et al.  Maintenance of multiple working memory items by temporal segmentation , 2006, Neuroscience.

[9]  P. Nunez,et al.  Electric fields of the brain , 1981 .

[10]  J. Lisman The theta/gamma discrete phase code occuring during the hippocampal phase precession may be a more general brain coding scheme , 2005, Hippocampus.

[11]  G A Ivanitsky,et al.  Cortical connectivity during word association search. , 2001, International journal of psychophysiology : official journal of the International Organization of Psychophysiology.

[12]  J. J. Hopfield,et al.  Pattern recognition computation using action potential timing for stimulus representation , 1995, Nature.

[13]  M. Hallett,et al.  Task-related coherence and task-related spectral power changes during sequential finger movements. , 1998, Electroencephalography and clinical neurophysiology.

[14]  O. Jensen,et al.  Frontal theta activity in humans increases with memory load in a working memory task , 2002, The European journal of neuroscience.