Important relation between EEG and brain evoked potentials

In this study, we analyze the important relation between the spontaneous and evoked activities of the substructures of the cat brain, such as the reticular formation, hippocampus, inferior colliculus, medial geniculate nucleus and acoustical cortex, with an ensemble of systems theory methods consisting of the following steps: (1) single auditory and/or visual evoked potentials (EPs) and the spontaneous activities (EEG) just preceding the stimuli are recorded from the brain center under study; (2) selectively averaged evoked potentials (SAEPs) are obtained from the recorded EPs; (3) amplitude frequency characteristics are computed from the AAEPs by means of Fourier transform; (4) the single EEG-EP sweeps are theoretically pass-band filtered with adequate band limits determined according to the selectivities revealed by the amplitude characteristics; (5) the EEG and EP components obtained in this way are compared with regard to the amplification in the population response upon the application of the stimulus. The results of this analysis support quantitatively our prediction of various types of resonance phenomena in a number of nuclei in the cat brain and in a large scale of frequencies from 1 Hz to 1000 Hz and show that the amplification factor related to resonance phenomena has probabilistic nature. Therefore, the analogy which we have recently drawn between the behaviors of a neural population and a random-phase probabilistic harmonic oscillator is extended by assigning also the amplitude and the frequency of the oscillations as random variables. A working hypothesis for the dynamics of neuronal populations is elaborated accordingly.

[1]  J. S. Barlow,et al.  Comparative phase characteristics of induced and intrinsic alpha activity. , 1971, Electroencephalography and clinical neurophysiology.

[2]  L. Goldie,et al.  Paradoxical Blocking and Arousal in the Drowsy State , 1960, Nature.

[3]  S. Hillyard,et al.  Human auditory evoked potentials. I. Evaluation of components. , 1974, Electroencephalography and clinical neurophysiology.

[4]  S Zerlin,et al.  Acoustic relations of the human vertex potential. , 1966, The Journal of the Acoustical Society of America.

[5]  G Pfurtscheller,et al.  Frequency dependence of the transmission of the EEG from cortex to scalp. , 1975, Electroencephalography and clinical neurophysiology.

[6]  S. S. Fox,et al.  Functional Congruence: An Index of Neural Homogeneity and a New Measure of Brain Activity , 1968, Science.

[7]  P Ungan,et al.  Comparison of Wiener filtering and selective averaging of evoked potentials. , 1976, Electroencephalography and clinical neurophysiology.

[8]  T. Nogawa,et al.  Changes in amplitude of the EEG induced by a photic stimulus. , 1976, Electroencephalography and clinical neurophysiology.

[9]  I. Senitzky.  Incoherence, Quantum Fluctuations, and Noise , 1962 .

[10]  O. Grüsser,et al.  Neuronal Mechanisms of Visual Movement Perception and Some Psychophysical and Behavioral Correlations , 1973 .

[11]  Erol Başar,et al.  Biophysical and physiological systems analysis , 1976 .

[12]  J. S. Barlow,et al.  Rhythmic after-activity to flashes in relation to the background alpha which precedes and follows the photic stimuli. , 1972, Electroencephalography and clinical neurophysiology.

[13]  S Goldstein,et al.  Phase coherence of the alpha rhythm during photic blocking. , 1970, Electroencephalography and clinical neurophysiology.