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

Abstract

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.

Keywords:

• Decision-making
• Ventromedial prefrontal cortex
• fMRI
• Aging

Acknowledgments

We would like to thank Malaak Moussa (subject recruitment and data collection), Prof. Jonas Kaplan (data analysis), Prof. Mara Mather (comments), and Prof. Antoine Bechara (support and comments) for their help in the performance of the study and for their helpful comments. This research was supported by the National Institute on Aging, grant 5-P50-AG00512-24.

Notes

¹Our results for the “ABCD” IGT variant and the similar “KLMN” IGT coincide with Denburg et al.'s “ABCD” IGT variant data (no other variant was used by Denburg et al.). To our knowledge, no study has tested older adults on the loss-oriented IGT variants that yielded chance performance in the current study, and thus these IGF variants were excluded from further analyses.

²For the purposes of this discussion, we have briefly summarized and perhaps simplified the relationship between VMPFC and somatic responses during the IGT. The important elements for the current discussion with implications regarding somatic responses and aging have been highlighted. See Damasio (1996) and Bechara et al. (2000) for a more complete discussion.