Task-dependent laterality for cue decoding during spoken... : NeuroReport (original) (raw)

Cognitive Neuroscience and Neuropsychology

Task-dependent laterality for cue decoding during spoken language processing

Imaizumi, Satoshi1,5; Mori, Koichi2; Kiritani, Shigeru1; Hosoi, Hiroshi3; Tonoike, Mitsuo4

1Departments of Speech and Cognitive Sciences, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113

2Departments of Speech Physiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113

3Department of Otolaryngology, School of Medicine, Kinki University, 377-2 Onohigashi, Osakasayama 589

4Life Electronics Research Center, Electrotechnical Laboratory, Ministry of International Trade and Industry, 11-46-3, Nakoji, Amagasaki, Hyogo, 661 Japan

5Corresponding Author: Satoshi Imaizumi

Received 17 December 1997;

accepted 11 January 1998

Abstract

THE task-dependent laterality of the auditory cortices was investigated by measuring the magnetic fields elicited by three forms of a Japanese verb, which differed in terms of prosodic and phonetic cues. Significant task- dependent magnetic fields were found in both hemispheres during a prosody-related task, but only in the left during a phoneme-related task. The latency was similar to the mismatch negatively which reflects the neural activity of automatic cue decoding. These results suggest that task-dependent schemata are activated at least partially in parallel with automatic cue-decoding processes such that those in the left hemisphere process linguistic information irrespective of acoustic cues whereas those in the right hemisphere process prosodic information.