Ventromedial and dorsolateral prefrontal interactions underlie will to fight and die for a cause

Willingness to fight and die (WFD) has been developed as a measure to capture willingness to incur costly sacrifices for the sake of a greater cause in the context of entrenched conflict. WFD measures have been repeatedly used in field studies, including studies on the battlefield, although their neurofunctional correlates remain unexplored. Our aim was to identify the neural underpinnings of WFD, focusing on neural activity and interconnectivity of brain areas previously associated with value-based decision-making, such as the ventromedial prefrontal cortex (vmPFC) and the dorsolateral prefrontal cortex (dlPFC). A sample of Pakistani participants supporting the Kashmiri cause was selected and invited to participate in an functional magnetic resonance (fMRI) paradigm where they were asked to convey their WFD for a series of values related to Islam and current politics. As predicted, higher compared to lower WFD was associated with increased ventromedial prefrontal activity and decreased dorsolateral activity, as well as lower connectivity between the vmPFC and the dlPFC. Our findings suggest that WFD more prominently relies on brain areas typically associated with subjective value (vmPFC) rather than integration of material costs (dlPFC) during decision-making, supporting the notion that decisions on costly sacrifices may not be mediated by cost-benefit computation.