"I could have done otherwise": The neural bases of counterfactual representations

Counterfactual thinking, the ability to mentally represent how events might have unfolded differently, plays a central role in decision-making, memory, learning, and emotional regulation, and has even been described as a foundation of human cognition itself. Yet the neural systems supporting this capacity remain debated. Here, we present a quantitative meta-analysis of 20 fMRI studies, synthesising evidence across tasks involving both counterfactual generation, where individuals voluntarily and constructively imagine alternative self-referential scenarios, and counterfactual evaluation, where the brain assess externally provided or rapidly inferred unchosen outcomes during decision-making. This analysis identified a specific set of regions encompassing the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), hippocampus, striatum, and amygdala. Within this set, the OFC emerged as a hub for representing counterfactual options and their value, while the ACC, particularly its dorsal subdivision, linked these representations to behavioural control. The hippocampus supported constructive aspects of counterfactual thought, overlapping with episodic memory processes, and the amygdala contributed to the affective responses, particularly regret. Separate analyses for counterfactual generation and counterfactual evaluation revealed partial dissociations. Counterfactual generation prominently recruited the superior frontal gyrus, involved in constructive memory processes. Counterfactual evaluation engaged, among other regions, the striatum, where fictive error signals encoded the value of unchosen outcomes and predicted subsequent behaviour. These findings indicate that counterfactual thinking relies on distinct but interacting set of regions for valuation, control, memory, and emotion, highlighting its multifaceted role in adaptive human cognition.