Authors

O'Leary DS. Andreason NC. Hurtig RR. Hichwa RD.

Watkins GL. Ponto LL. Rogers M. Kirchner PT.

Institution

Department of Psychiatry, University of Iowa Hospitals and Clinics, Iowa City 52242-1057, USA.

Title

A positron emission tomography study of binaurally and dichotically presented stimuli: effects of level of language and directed attention.

Source

Brain & Language. 53(1):20-39, 1996 Apr.

Abstract

Regional cerebral blood flow (rCBF) was measured using positron emission tomography with oxygen- 15 labeled water as 10 normal subjects listened to three types of auditory stimuli (environmental sounds, meaningless speech, and words) presented binaurally or dichotically. Binaurally presented environmental sounds and words caused similar bilateral rCBF increases in left and right superior temporal gyri. Dichotically presented stimuli (subjects attended to left or right ears) caused asymmetric activation in the temporal lobes, resulting from increased rCBF in temporal lobe regions contralateral to the attended ear and decreased rCBF in the opposite hemisphere. The results indicate that auditorily presented language and non-language stimuli activate similar temporal regions, that dichotic stimulation dramatically changes rCBF in temporal lobes, and that the change is due both to attentional mechanisms and to hemispheric specialization.