Hemisphere and stimulus differences as reflected in the cortical responses of newborn infants to speech stimuli

Auditory evoked potentials were recorded from the left and right temporal regions of 8 male and 8 female Caucasian full-term neonates in response to a series of CV syllables that varied in second formant structure. An early component of the brain's electrical response indicated the presence of a mechanism unique to the left hemisphere. This process is sensitive to second-formant transition differences. A second independent cortical component that occurred later in time appears to behave similarly to the first with the exception that it reflects a process common to both hemispheres. Hemisphere differences related to sex were also isolated. Early hemisphere differences appear in part to be due to the presence of lateralized perceptual mechanisms that are sensitive to specific acoustic cues. (26 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).