Connectivity reveals relationship of brain areas for reward-guided learning and decision making in human and monkey frontal cortex

Reward-guided decision-making depends on a network of brain regions. Among these are the orbitofrontal and the anterior cingulate cortex. However, it is difficult to ascertain if these areas constitute anatomical and functional unities, and how these areas correspond between monkeys and humans. To address these questions we looked at connectivity profiles of these areas using resting-state functional MRI in 38 humans and 25 macaque monkeys. We sought brain regions in the macaque that resembled 10 human areas identified with decision making and brain regions in the human that resembled six macaque areas identified with decision making. We also used diffusion-weighted MRI to delineate key human orbital and medial frontal brain regions. We identified 21 different regions, many of which could be linked to particular aspects of reward-guided learning, valuation, and decision making, and in many cases we identified areas in the macaque with similar coupling profiles. Significance Because of the interest in reward-guided learning and decision making, these neural mechanisms have been studied in both humans and monkeys. But whether and how key brain areas correspond between the two species has been uncertain. Areas in the two species can be compared as a function of the brain circuits in which they participate, which can be estimated from patterns of correlation in brain activity measured with functional MRI. Taking such measurements in 38 humans and 25 macaques, we identified fundamental similarities between the species and one human frontal area with no monkey counterpart. Altogether these findings suggest that everyday human decision-making capitalizes on a neural apparatus similar to the one that supports monkeys when foraging in the wild.