Encoding and storage components of verbal working memory as revealed by a factorial design, an FMRI study

In this fMRI study, the contributions of frontal and posterior brain regions to verbal working memory were investigated. A two-factor design with low and high memory load (2 and 5 letters) and short and long delay (4 and 12 secs.) as factors were used. Based on reports in the literature, we expect activity in the following frontal and parietal brain regions of interest (ROIs): Brodmann areas (BA) 6, 9, 46, 44, 45, 7 and 40. The analysis of collected flvM data involved image processing and statistical analysis methods including realignment, spatial normalization, spatial smoothing, temporal filtering, intensity normalization, statistical tests, and thresholding of results. The design allowed for testing the interaction and main effects of the two factors. The interaction terms revealed involvement in the caudate and BA 6, 9, and 7. The main effects revealed activity in BA 6, 9, 32, 40, 44, cerebellum, thalamus, and caudate. The results of this study support the literature and offer more insight into previous findings