Human auditory event-related processes in the time-frequency plane

Sensory stimuli produce phase-locked and non-phase-locked changes in brain activity as indexed by EEG and MEG. Time-frequency methods such as wavelets, when carefully applied, allow simultaneous analysis of both types of activity. Here we used wavelets of different time and frequency resolutions in combination with spatial mapping to identify these processes. We found that auditory stimulation leads to a pattern of large-magnitude power increases and small-magnitude power decreases. The power increases, ranging from the theta to the beta frequency band, were accounted for by the transient auditory responses P50m, N100m and P200m. Following these responses, we observed a power reduction of non-phase-locked activity which occurred 250–500 ms after stimulus onset in the 14–24 Hz frequency range and could be localized to the temporal and parietal brain areas. These results indicate that auditory event-related processes consist not only of the well-established transient responses but also of power reductions of ongoing, non-phase-locked brain processes.

[1]  R Parasuraman,et al.  Detection and recognition: Concurrent processes in perception , 1982, Perception & psychophysics.

[2]  B. MCA. SAVERS,et al.  The Mechanism of Auditory Evoked EEG Responses , 1974, Nature.

[3]  Hannu Tiitinen,et al.  Transient brain responses predict the temporal dynamics of sound detection in humans , 2004, NeuroImage.

[4]  G. Pfurtscheller,et al.  Functional brain imaging based on ERD/ERS , 2001, Vision Research.

[5]  Christo Pantev,et al.  MEG study of long-term cortical reorganization of sensorimotor areas with respect to using chopsticks , 2002, Neuroreport.

[6]  Werner Lutzenberger,et al.  Magnetic oscillatory responses to lateralization changes of natural and artificial sounds in humans , 2002, The European journal of neuroscience.

[7]  J. Kaiser,et al.  Dynamics of sensorimotor cortex activation to spatial sounds precueing ipsi- versus contralateral manual responses. , 2003, Brain research. Cognitive brain research.

[8]  G. Pfurtscheller,et al.  Evaluation of event-related desynchronization (ERD) preceding and following voluntary self-paced movement. , 1979, Electroencephalography and clinical neurophysiology.

[9]  G. Pfurtscheller.  Central beta rhythm during sensorimotor activities in man. , 1981, Electroencephalography and clinical neurophysiology.

[10]  D. McFarland,et al.  Spectral dynamics of electroencephalographic activity during auditory information processing , 2003, Hearing Research.

[11]  R. Ilmoniemi,et al.  Magnetoencephalography-theory, instrumentation, and applications to noninvasive studies of the working human brain , 1993 .

[12]  T. Sejnowski,et al.  Dynamic Brain Sources of Visual Evoked Responses , 2002, Science.

[13]  H. Yabe,et al.  Event-related desynchronization during an auditory oddball task , 2000, Clinical Neurophysiology.

[14]  S. Mallat.  A wavelet tour of signal processing , 1998 .

[15]  Alberto Labarga,et al.  Alpha and beta oscillatory changes during stimulus-induced movement paradigms: effect of stimulus predictability , 2003, Neuroreport.

[16]  C. Torrence,et al.  A Practical Guide to Wavelet Analysis. , 1998 .