EEG dynamics. Brain processing of sensory and cognitive information.

The EEG oscillations and resonances before sensory stimulation are variable; unstable frequencies and amplitudes. The EEG time-coherency is variable and tends to be incoherent preceding sensory stimulation. The phase angle of the EEG between brain structures tends to be random and coherence between various brain structures is low before the stimulus. Following sensory stimulation, the frequency is stabilized and the amplitude is greatly enhanced. These responses are considered to be related to coupling of neural oscillators and nuclear resonance. The shift to a time-coherent state is considered to be related to a probabilistic harmonic oscillators. The phase angle after the stimulus is zero-phase in the brain rhythm channels in all brain structures as noted in the phase spectra. In the post stimulation period there is a change to high coherency between brain structures in the inherent frequencies of their brain rhythms. Internal evoked potentials shown in all the brain nuclei studied. All the frequencies in the evoked potential responses are dependent on spontaneous EEG activities prior to the stimulus.