Verb generation in Japanese - A multicenter PET activation study

Cerebral blood how (CBF) during silent verb generation was measured at four Japanese PET centers. To minimize the variance of the measurement, speaker s of a single language (Japanese) served as subjects and experimental condi tions at the four PET centers were controlled as much as possible. Two type s of activation patterns were observed: activations in the left dorsolatera l prefrontal cortices and the medial frontal cortex (at the two centers wit h a 2D PET scanner) and additional activation in the left posterior tempora l cortex (at the two centers with a 3D scanner). This suggests either a dif ference in the sensitivity of the two types of PET scanners (viz., a 3D sca nner is generally more sensitive than a 2D scanner) and/or subject bias due to the small number of subjects at the individual centers. The pooled acti vation pattern was fundamentally similar to activation patterns obtained in the previous studies for verb generation in English and other European lan guages, suggesting that regions for verb generation are independent of part icular languages. Regions relevant to verb generation are discussed. (C) 19 99 Academic Press.