RT Journal Article
SR Electronic
T1 Tuning the Brake While Raising the Stake: Network Dynamics during Sequential Decision-Making
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 5417
OP 5426
DO 10.1523/JNEUROSCI.3191-15.2016
VO 36
IS 19
A1 David Meder
A1 Brian Numelin Haagensen
A1 Oliver Hulme
A1 Tobias Morville
A1 Sofie Gelskov
A1 Damian Marc Herz
A1 Beata Diomsina
A1 Mark Schram Christensen
A1 Kristoffer Hougaard Madsen
A1 Hartwig Roman Siebner
YR 2016
UL http://www.jneurosci.org/content/36/19/5417.abstract
AB When gathering valued goods, risk and reward are often coupled and escalate over time, for instance, during foraging, trading, or gambling. This escalating frame requires agents to continuously balance expectations of reward against those of risk. To address how the human brain dynamically computes these tradeoffs, we performed whole-brain fMRI while healthy young individuals engaged in a sequential gambling task. Participants were repeatedly confronted with the option to continue with throwing a die to accumulate monetary reward under escalating risk, or the alternative option to stop to bank the current balance. Within each gambling round, the accumulation of gains gradually increased reaction times for “continue” choices, indicating growing uncertainty in the decision to continue. Neural activity evoked by “continue” choices was associated with growing activity and connectivity of a cortico-subcortical “braking” network that positively scaled with the accumulated gains, including pre-supplementary motor area (pre-SMA), inferior frontal gyrus, caudate, and subthalamic nucleus (STN). The influence of the STN on continue-evoked activity in the pre-SMA was predicted by interindividual differences in risk-aversion attitudes expressed during the gambling task. Furthermore, activity in dorsal anterior cingulate cortex (ACC) reflected individual choice tendencies by showing increased activation when subjects made nondefault “continue” choices despite an increasing tendency to stop, but ACC activity did not change in proportion with subjective choice uncertainty. Together, the results implicate a key role of dorsal ACC, pre-SMA, inferior frontal gyrus, and STN in computing the trade-off between escalating reward and risk in sequential decision-making.SIGNIFICANCE STATEMENT Using a paradigm where subjects experienced increasing potential rewards coupled with increasing risk, this study addressed two unresolved questions in the field of decision-making: First, we investigated an “inhibitory” network of regions that has so far been investigated with externally cued action inhibition. In this study, we show that the dynamics in this network under increasingly risky decisions are predictive of subjects' risk attitudes. Second, we contribute to a currently ongoing debate about the anterior cingulate cortex's role in sequential foraging decisions by showing that its activity is related to making nondefault choices rather than to choice uncertainty.