Thursday, November 05, 2015
The human brain contains a distinct network that serves as its executive agent. This network is primarily based in the dorsolateral prefrontal, parietal, and cingulate cortices. It regulates the many “top down” neurobehavioral functions that are so characteristic of human brain (Banich et al. 2009). Deficiencies in the function of this network underlie numerous neuropsychiatric conditions (Beck, 2008). The ability to regulate emotions and direct rational actions is typically associated with success in life, and inability to do so often leads to dire consequences.
This network can be trained to develop more robust capacity for executive control. This, as we all experience, is what parenting and schooling are about. Such training is especially crucial in early childhood as the challenges of school are first encountered. Even so, such training takes many years and for most of us may never be completed.
The question arises: can such executive control training be expedited? One possibility has recently arisen from several studies showing that working memory capacity can be expanded by a relatively short training time, and in the process general intelligence may be improved. Since the same system that determines intelligence is also operative in executive control, Schweizer et al. (2013) reasoned that working memory training might also enhance executive control. To pursue this possibility in a specific context, the researchers hypothesized that inappropriate or maladaptive behaviors might be reduced by effective working memory training based on emotion-laded stimuli.
In this study, subjects in their early 20s were assessed for affective control before and after 20 training days of 20-30 minute sessions. The experimental groups received dual n-back training with a simultaneously presented face and a word that was either emotionally negative or neutral. After each picture-word pair, subjects were to press a button to indicate if either or both members of the pair matched the stimulus presented n-positions back. Tests began with n = 1 and increased as subjects gain proficiency.
Not surprisingly, errors in both trained and untrained subjects decreased at levels beyond n = 1, and the error rate was comparable for both groups. Results indicated that subjects reported less distress when they consciously willed to suppress it compared with the null state of just attending to negative stimuli. But this distress reduction occurred only in the emotional working memory training group.
No change in activity levels was indicated in fMRI scans as a result of placebo training, but significant increases occurred as a result of emotional working memory training irrespective of the level of n-back achievement in the executive control regions of interest.
The study also compared emotional responsivity before and after training. Subjects were asked to just pay attention or to pay attention and cognitively suppress their emotional reaction. Subjects rated their emotions on a numerical scale from negative to positive while viewing films that were emotionally neutral (such as weather forecasts) or that were emotionally disturbing (such as war scenes, accidents, etc.). Training caused no change in the group that viewed only neutral images, but in the groups viewing disturbing scenes, training decreased the perceived distress in a group told just to attend the scenes and was even more effective in the group told to suppress emotional reaction.
The affective working memory training produced benefits that transferred to the emotional response task. Trained subjects not only generated enhanced emotional regulation but also developed greater fMRI activity during the emotional task in the predicted brain regions of interest, the executive control loci. It seems that working memory training can do more than just expand the amount of information that can be held in working memory. Emotional working memory training improves the ability to suppress disturbing emotional responses and does so presumably because the executive control network is more activated. Thus, such training might also enhance many executive control functions, particularly responses to emotionally disturbing circumstances.
Banich, M. T., Mackiewicz, K. L., Depue, B. E., Whitmer, A. J., Miller, G. A. , Heller, W. (2009) Cognitive control mechanisms, emotions and memory: a neural perspective with implications for psychopathology. Neurosci. Biobehav. Rev. 33, 613-630.
Beck, A. T. (2008) The evolution of the cognitive model of depression and its neurobiological correlates. Am. J. Psychiatry. 165, 969-977.
Schweizer, S., Grahn, J., Hampshire, A., Mobbs, D., and Dalgleish, T. (2013). Training the emotional brain: improving affective control through emotional working memory training. J. Neurosci. 33(12), 5301-5311.