Theta rhythms associated with sucking, crying, gazing and handling in infants

In order to specify the locations and to clarify the electrophysiological significance of the transitory rhythmic theta activities detected on scalp electrodes in infants, we performed simultaneous EEG and video recording with power spectral map analysis in 29 normal infants of less than 1 year of age. The rhythmic theta activities appeared in posterior temporal regions with sucking or crying, in the parietal region with gazing, and in the frontal region with handling. Each specific location of the theta rhythm seemed to correspond to the functional localization in the infant's brain. We thus concluded that these rhythmic theta activities might originate from direct cortical activation, or from the cortical activation driven by the neuronal impulses from the limbic system through the connection between that system and the cortex.