The ability of the mind to conceptualize what is not present is essential. It allows
us to reason counterfactually about what might have happened had events
unfolded differently or had another course of action been taken. It allows us to
think about what might happen – to perform 'Gedankenexperimente' (thought
experiments) – before we act. However, the cognitive and neural mechanisms
mediating this ability are poorly understood. We suggest that the frontopolar
cortex (FPC) keeps track of and evaluates alternative choices (what we might
have done), whereas the anterior lateral prefrontal cortex (alPFC) compares
simulations of possible future scenarios (what we might do) and evaluates their
reward values. Together, these brain regions support the construction of suppositional
scenarios
