Effects of phonetic processing and stimulus relevance on the auditory evoked response / by Dennis Alfred Silva.
Dennis Alfred Silva · 1977
There is a substantial body of research data, gathered from both clinical and nonclinical behavioral investigations, which support the phenomenon of specialization of function in the human brain.In addition, recent findings suggest that there are structural asymmetries in the cortex which parallel the functional differences. Results of recent electrophysiological investigations suggestthat the left hemisphere's specialization for language is reflected in auditory evoked responses to speech and nonspeech stimuli and during phonetic and nonphonetic processing of speech stimuli.Because of several inconsistencies in the existing data, however, the precise nature of the effect as well as the actual processing mechan- isms reflected in the reported asymmetries remain obscure.For example, the evoked potential asymmetries might be reflecting the activity of a lateralized neural center responsible for phonetic analysis of speech stimuli or they might be due to a lateralized cortical activation occurring in preparation for phonetic processing.the evoked potential was most sensitive to various conditions of stimulus relevance.The amplitude of the P3 component was largest when the evoking stimulus was most like the relevant stimulus, and smallest when the evoking stimulus was of the other class (i.e.speech or nonspeech) than the relevant stimulus.These findings support a "neural template" model of P 3 .