PSYCHOLOGY

Biological Psychology
Regions of the brain – Casey et al
CASEY, B. J., SOMERVILLE, L. H., GOTLIB, I. H., AYDUK, O., FRANKLIN, N. T., ASKREN, M. K., JONIDES, J., BERMAN, M.,
WILSON, N., TESLOVICH, T., GLOVER, G., ZAYAS, V., MISCHEL, W. and SHODA, Y. (2011)
Behavioural and neural correlates of delay of gratification 40 years later.
Proceedings of the National Academy of Sciences, 108, (36), 14998-15003.
6. Some key findings
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Experiment 2
• Reaction times (inside the scanner)
- The two delay groups did not differ significantly in reaction times in correct “go” trials: [t (24) = 0.81, P ≥ 0.4].
• Accuracy (inside the scanner)
- Overall accuracy rates for the “hot” go/no-go task were uniformly high for “go” trials (mean 98.2% correct hits) with more variable
performance to “no-go” trials (12.4% false alarm rate).
- Differences between the two delay groups in “no-go” accuracy were consistent with the observed differences in the “hot” task performance
in Experiment 1, with low delayers committing more false alarms than high delayers.
• Imaging results
- The “no-go” vs. “go” trials identified candidate regions of the brain differentially engaged as a function of cognitive control tasks.
- The right inferior frontal gyrus was involved in accurately withholding a response.
- Compared with high delayers, low delayers had diminished recruitment of the inferior frontal gyrus for correct “no-go” relative to “go” trials.
- The ventral striatum demonstrated significant difference in recruitment between high and low delayers. This reward-related region of the
brain showed a three-way interaction of group x trial x emotion, with elevated activity to happy “no-go” trials for low delayers relative to
high delayers.
- These results showed that the prefrontal cortex differentiated between “no-go” and “go” trials to a greater extent in high delayers. The
ventral striatum showed exaggerated recruitment in low delayers.
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