Peculiarities of frequency-phase filtering of signals at different stages of information processing in rat barrel cortex

Dependence of different components of evoked field potentials on frequency and phase of spontaneous waves was explored by microelectrode recording individual column activity in the rat barrel cortex. It was shown that the secondary bi- and poly-synaptic components of evoked potentials had a stronger frequency-phase dependence on spontaneous activity than monosynaptic primacy thalamocortical responses. Maximal suppression of the secondary intracortical evoked potentials has been observed during the downcoming phase of spontaneous waves of alpha and theta ranges. In addition to the transitory cyclic modulation of evoked potentials by cortical rhythms, a modification of focal responses of the barrels was shown after theta-burst stimulation pattern of the corresponding barreloids in the thalamus. Possible functional role and mechanisms of frequency-phase interaction between spontaneous and evoked activity in the columns of the rat barrel cortex are considered