Information transfer and 600 Hz oscillations in the brain



Electrical stimulation of peripheral somatosensory nerves evokes two types of early brain activity in two distinct frequency ranges that can be detected with electroencephalography (EEG) or magnetoencephalography (MEG). An oscillatory brain activity with a mean frequency around 650 Hz is overlaying the initial low frequency (up to 250 Hz) cortical responses at latencies of 18 to 30 ms after stimulus (N20, P25) (figures 1 & 2).

Using time-frequency analysis, we found that the frequency of the first oscillatory 600 Hz component increases in frequency over time (figure 3).

We could show that the 600 Hz oscillations consist of two parts (bifurcation of the dispersion curves in the time-frequency plane) and can be associated by means of source reconstruction to the Brodmann areas 3b and 1 (figure 4).

We analyzed the coupling between the active brain areas with the help of models described by a system of differential-algebraic equations. Comparing models with various degrees of coupling, we show that mutual information transfer can be distinguished from one-way information transfer for activated cortical areas estimated by source localization techniques (figure 5).

Figure 1: Fast oscillatory activity (around 600Hz) overlays low frequency (N20, P25) activity of the somato-sensory evoked field/potential (upper trace: band pass filter 0.1-1500Hz; lower trace: 450-750Hz)
Figure 2: Time-frequency representation of the low frequency components and the high frequency oscillations (top) and spectral representation at 20 ms after stimulation.
Figure 3: Dispersion curve in the time-frequency space for one volunteer (white dots; top) and dispersion curves for 12 volunteers (each curve corresponds to one subject; bottom). We observe for all volunteers an unexpected increase of frequency over time.
Figure 4: Source localization results for the tangential (right) and radial (left) dipolar activity of the 600 Hz oscillations. The reconstructed dipoles are indicated by yellow arrows and CS indicates the central sulcus. A 3D representation is show in figure 5.
Figure 5: Left: Source localization results in a 3D view of the head and the cortex for dipoles (arrows) in Brodmann area 3b (red) and 1 (blue) and corresponding activation curves (dipole strength over time). Right: Three models describing the coupling between Brodmann areas 3b and 1. An input impulse originating from the thalamus (Th, yellow) is delivered to cortical area 3b (red) and 1 (blue) for all three models (model 0: no coupling between 3b and 1; model 1: feed forward coupling between 3b and 1; model 2: mutual coupling between 3b and 1)..


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Publications & Patents

  • Milde,T., Haueisen,J., Witte,H., Leistritz,L.: Modelling of cortical and thalamic 600Hz activity by means of oscillatory networks. Journal of Physiology (P), 103(6):342-7, 2009
  • Jaros,U., Hilgenfeld,B., Lau,S., Curio,G., Haueisen,J.: Nonlinear interactions of high-frequency oscillations in the human somatosensory system. Clinical Neurophysiology, 119(11):2647-57, 2008
  • Haueisen,J., Leistritz,L., Süße, T., Curio,G., Witte,H.: Identifying mutual information transfer in the brain with differential-algebraic modeling: evidence for fast oscillatory coupling between cortical somatosensory areas 3b and 1, Neuroimage, 37:130-136, 2007
  • Leistritz,L., Putsche,P., Schwab,K., Hesse,W., Süße, T., Haueisen,J., Witte,H.: Coupled oscillators for modeling and analysis of EEG/MEG oscillations. Biomed. Tech. 52:83–89, 2007
  • Leistritz,L., Suesse,T., Haueisen,J., Hilgenfeld,B., Witte,H.:  Methods for parameter identification in oscillatory networks and application to cortical and thalamic 600 Hz activity. Journal of Physiology (Paris), 99, 58-65, 2006
  • Haueisen,J., Schack,B., Meier,T., Curio,G., Okada,Y.: Multiplicity in the high-frequency signals during the short-latency somatosensory evoked cortical activity in humans. Clinical Neurophysiology, 112, 1316 – 1325, 2001
  • Liepert,J., Haueisen,J., Hegemann,S., Weiller,C. Disinhibition of somatosensory and motor cortex in mitochondriopathy without myoclonus. Clinical Neurophysiology, 112(5):917-922, 2001
  • Haueisen,J., Heuer,T., Nowak,H., Liepert,J., Weiller,C., Okada,Y., Curio,G.: The influence of lorazepam on somatosensory evoked fast frequency (600 Hz) activity in MEG. Brain Research, 874, 10 – 14, 2000