Q2. Why did the authors expect task by region interactions in left parietal cortex?
because maintenance load increases primarily during the Sternberg (two to seven items in their version, compared to one to three for the n-back), the authors also expected task by region interactions in left parietal cortex, in view of its putative role in phonological storage.
Q3. What is the main effect of the conjunction analysis?
Main effects for task load, as well as the results of the conjunction analyses, are reported at P 0.05 corrected for multiple comparisons.
Q4. What is the effect of the WM on the left posterior DLPFC?
In the present study, load-associated activity in left posterior DLPFC and L VLPFC occurred during both encoding and responding, but significant interaction effects were found in bilateral middle DLPFC for responding encoding.
Q5. In what study did Postle et al. (1999) find activation in L?
In the study by Postle et al. (1999), DLPFC activation during a manipulation task was found in all of their subjects, but only in a minority (two of five) during a maintenance task.
Q6. What was the MRI procedure used to obtain the axonal multislice images?
Axial multislice T2*weighted images were obtained with a gradient-echo planar sequence (TE 60 ms, TR 3.48 s, 64 64 matrix, 32 slices, 3 3-mm in-plane resolution, slice thickness 3 mm with a 1-mm interslice gap), covering the entire brain.
Q7. What is the role of the VLPFC in the Sternberg?
it has been assumed that VLPFC is primarily responsible for retrieval of information and organization of responses (Stern et al., 2000), this may entail considerable executive demands at higher task loads.
Q8. What is the reason for the DLPFC being involved during encoding?
In these latter two studies, it was concluded that the DLPFC was primarily involved during encoding, either due to changes in encoding strategy at higher task loads, or due to cognitive operations usually associated with complex tasks, such as monitoring the contents of WM, or updating and coordinating multiple memory buffers.
Q9. What areas of the Sternberg were found for encoding and responding?
Common areas for loadrelated activity during encoding and responding were foundto be bilateral DLPFC, L VLPFC, bilateral parietal cortex, motor cortex, and cerebellum (Table 4, left).
Q10. Why did the authors not select correct responses post hoc?
The authors also did not select correct responses post hoc, which, however, the authors felt was justified because the overall error rate was very low.
Q11. What is the reason why the n-back was aspecific?
it was conceivable that the workload task interactions in favor of the n-back were aspecific, resulting from a steeper increase in task difficulty, rather than a maintenance/manipulation difference.
Q12. What is the argument for a processing model of functional specialization within PFC?
the fact that manipulation activated L DLPFC to a greater extent was considered evidence for a processing model of functional specialization within PFC by these authors.