Km. Petersson et al., Effective auditory-verbal encoding activates the left prefrontal and the medial temporal lobes: A generalization to illiterate subjects, NEUROIMAGE, 10(1), 1999, pp. 45-54
Recent event-related FMRI studies indicate that the prefrontal (PFC) and th
e medial temporal lobe ((MTL) regions are more active during effective enco
ding than during ineffective encoding. The within-subject design and the us
e of well-educated young college students in these studies makes it importa
nt to replicate these results in other study populations. In this PET study
, we used an auditory word-pair association cued-recall paradigm and invest
igated a group of healthy upper middle-aged/older illiterate women. We obse
rved a positive correlation between cued-recall success and the regional ce
rebral blood flow of the left inferior PFC (BA 47) and the MTLs. Specifical
ly, we used the cued-recall success as a covariate in a general linear mode
l and the results confirmed that the left inferior PFC and the MTL are more
active during effective encoding than during ineffective encoding. These e
ffects were observed during encoding of both semantically and phonologicall
y related word pairs, indicating that these effects are robust in the studi
ed population, that is, reproducible within group. These results generalize
the results of Brewer et al. (1998, Science 281, 1185-1187) and Wagner ct
al. (1998, Science 281, 1188-1191) to an upper middle aged/older illiterate
population. In addition, the present study indicates that effective relati
onal encoding correlates positively with the activity of the anterior media
l temporal lobe regions. (C) 1999 Academic Press.