Risky decision-making in older adults without cognitive deficits: an fMRI study of VMPFC using the Iowa Gambling Task

Some older adults without neurological disease exhibit impaired decision-making in risky, nontransparent situations, like the Iowa Gambling Task (IGT). The prefrontal cortices are particularly vulnerable to age-related decline, and numerous studies implicate the ventromedial prefrontal cortex (VMPFC) in successful IGT performance. However, the relationship between IGT performance and VMPFC function in older adults has not yet been tested by fMRI. In the present study, older adults with seemingly no cognitive impairments performed the IGT and a non-gambling control task during fMRI. Group analyses indicate that in these older adults, regardless of IGT performance level, a right VMPFC subregion is activated during the IGT, while successful IGT performance is correlated with left VMPFC activation, suggesting that bilateral VMPFC during risky, nontransparent situations may contribute to successful decision-making in older adults. Individual subject analyses reveal substantial variation regarding the extent and location of VMPFC activation during the IGT, a finding not captured in the group analysis: There is no correlation between IGT performance and extent of activation in the right VMPFC, although there is such a correlation between left VMPFC activation and IGT performance.