RHYTHMOGENESIS, AMPLITUDE-MODULATION, AND MULTIPLEXING IN A CORTICAL ARCHITECTURE

In a network of excitatory and inhibitory neurons, hyperpolarization-a ctivated inward currents can help to produce population rhythms in whi ch individual cells participate sparsely and randomly. A shift in the activation curve of such a current changes the fraction of the cells p articipating in any given cycle of the population rhythm, thus changin g the amplitude of the field potential. Furthermore, the frequency of the population rhythm remains relatively fixed over a substantial rang e of amplitudes, allowing the population rhythm to play a separate pro cessing role from that of the individual components.