Article: WM training

Question 1

goal of study

Answer 1

• investigate cognitive and neural effects of 8 week n-back training intervention in healthy middle aged participants
• evaluate potential transfer effects by cognitive testing and neuroimaging

Question 2

how did they control for expectancy and non-cognitive intervention techniques?

Answer 2

had active control group with low cognitive demand

Question 3

gaps in previous neuroimaging studies

Answer 3

• most have used task-related fMRI, focused on practice effects not transfer effects
• not many have looked at resting state functional connectivity changes
  (ones that did, didn’t look at whole brain or use active control group)
• only a few have looked at structural connectivity after WM training
• No PET studies

Question 4

what are transfer effects supposedly an index of?

Answer 4

effectiveness of WM training

Question 5

transfer effects

Question 6

How are transfer effects categorized?

Answer 6

• through similarity between training and transfer tasks
  improvement in highly similar WM tasks = nearest or direct transfer
  improvements in dissimilar WM tasks = near transfer
  improvements in related cognitive domains = far transfer

Question 7

what have meta-analyses shown?

Answer 7

• found significant greater effect sizes for nearest transfer compared to near transfer, suggesting training yields task-specific transfer not general improvement in WM
• inconsistent conclusion regarding far transfer

Question 8

what may have contributed inconsistent conclusions in past studies?

Answer 8

• presence or absence of active control group
• differences in classification of the different measures

Question 9

what does an active control group account for?

Answer 9

• non-specific training affects
  receives an alternative intervention or treatment rather than no intervention

Question 10

what were the 2 groups they could be assigned to?

Answer 10

single-blinded experimental and active control

Question 11

Working memory training

Answer 11

• Training in both the experimental and the active control group
  consisted of variants of visual and verbal n-back tasks
• participants were presented a sequence of stimuli and were asked to identify a target stimulus
• targets were stimuli matching the stimulus shown n positions back
• active control group performed a non-adaptive low-level training
  intervention
• X-back task, participants had to press the “A” key whenever a target
  shape was presented.

Question 12

two-sided Wilcoxon signed-rank test

Answer 12

• Tests whether the median difference between paired observations is significantly different from zero
• Comparing pre-treatment and post-treatment measurements on the same group of subjects
• they used this for all cognitive tests within the experimental and control group

Question 13

d prime

Answer 13

calculated as the
difference between the hit rate and the false alarm rate

Question 14

what was analyzed for the experimental group?

Answer 14

mean n-back level achieved in
each session (experimental group only) and the d prime (both training
groups

Question 15

what was used to assess practice effects?

Answer 15

two-sided Wilcoxon signed-rank test

Question 16

What does the Bayes Factor Statistic demonstrate?

Answer 16

quantify how much more (or less) likely the data are under one hypothesis compared to the other
- superscript a = favour of H1 over H0
- superscript b = favour of H0 over H1

Question 17

ANOVA

Answer 17

• analysis of Variance
• statistical method used to compare the means of three or more groups to determine if there are statistically significant differences between them

Question 18

Z statistic

Answer 18

• describe how far a data point is from the mean of a distribution, measured in standard deviations
  Positive Z-Statistic: The value is above the mean.
  Negative Z-Statistic: The value is below the mean

Question 19

T- value

Answer 19

• measures how far the sample statistic (e.g., sample mean) is from the null hypothesis
• larger the absolute t-value, the greater the evidence against the null hypothesis.
• A t-value near 0 suggests no significant difference

Question 20

What are the takeaways from this study?

Answer 20

• absence of near and far transfer effects
• no training-induced changes in resting state fMRI, DTI, and FDG-PET data
• argue that such pseudo-transfer effects do not reflect increases in WM capacity, reflect practice effects