Ventromedial prefrontal theta activity during rapid eye movement sleep is associated with improved decision-making on the Iowa Gambling Task.

Recent research is beginning to reveal an intricate relationship between sleep and decision-making. The Iowa Gambling Task (IGT) is a unique decision-making task that relies on the ventromedial prefrontal cortex (vmPFC), an area that integrates and weighs previous experiences with reward and loss to select choices with the highest overall value. Recently, it has been demonstrated that a period of sleep can enhance decision-making on this task. Our study investigated the sleep mechanisms (sleep stages and cortical activity) that underlie this improvement. We recorded electrophysiology for 3 consecutive nights: a habituation, baseline, and acquisition night. On acquisition night participants were administered either a 200-trial IGT (IGT group; n = 13) or a 200-trial control (IGT-control group; n = 8) version of the task prior to sleep. Compared with baseline, the IGT group had a significant increase in theta frequency (4 Hz-8 Hz) on cites located above vmPFC and left prefrontal cortex during REM sleep. This increase correlated with subsequent performance improvement from deck B, a high reward deck with negative long-term outcomes. Furthermore, presleep emotional arousal (measured via skin conductance response) toward deck B correlated to increased theta activity above the right vmPFC during REM sleep. Overall, these results suggests that insight into deck B may be enhanced via vmPFC theta activity during REM sleep and REM sleep may have distinct mechanisms for processing decision-making information. (PsycINFO Database Record

Post learning sleep improves cognitive-emotional decision-making: evidence for a 'deck B sleep effect' in the Iowa Gambling Task.

The Iowa Gambling Task (IGT) is widely used to assess real life decision-making impairment in a wide variety of clinical populations. Our study evaluated how IGT learning occurs across two sessions, and whether a period of intervening sleep between sessions can enhance learning. Furthermore, we investigate whether pre-sleep learning is necessary for this improvement. A 200-trial version of the IGT was administered at two sessions separated by wake, sleep or sleep and wake (time-of-day control). Participants were categorized as learners and non-learners based on initial performance in session one. In session one, participants initially preferred the high-frequency reward decks B and D, however, a subset of learners decreased choice from negative expected value 'bad' deck B and increased choices towards with a positive expected value 'good' decks (decks C and D). The learners who had a period of sleep (sleep and sleep/wake control conditions) between sessions showed significantly larger reduction in choices from deck B and increase in choices from good decks compared to learners that had intervening wake. Our results are the first to show that post-learning sleep can improve performance on a complex decision-making task such as the IGT. These results provide new insights into IGT learning and have important implications for understanding the neural mechanisms of "sleeping on" a decision.