One fundamental question concerning brain reward mechanisms is to determine how reward-related activity is influenced by the nature of rewards. Here, we review the neuroimaging literature and explicitly assess to what extent the representations of primary and secondary rewards overlap in the human brain. To achieve this goal, we performed an activation likelihood estimation (ALE) meta-analysis of 87 studies (1452 subjects) comparing the brain responses to monetary, erotic and food reward outcomes. Those three rewards robustly engaged a common brain network including the ventromedial prefrontal cortex, ventral striatum, amygdala, anterior insula and mediodorsal thalamus, although with some variations in the intensity and location of peak activity. Money-specific responses were further observed in the most anterior portion of the orbitofrontal cortex, supporting the idea that abstract secondary rewards are represented in evolutionary more recent brain regions. In contrast, food and erotic (i.e. primary) rewards were more strongly represented in the anterior insula, while erotic stimuli elicited particularly robust responses in the amygdala. Together, these results indicate that the computation of experienced reward value does not only recruit a core "reward system" but also reward type-dependent brain structures.

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Prematurity is associated with cerebral abnormalities that might account for poorer cognitive performance. The aim of our study was to investigate the correlations between corpus callosum reductions and neuropsychologic performance in adolescents who were born preterm. Twenty-five subjects born before 33 weeks' gestation were compared with 25 subjects born at term and of similar age, gender, and sociocultural status. All subjects underwent magnetic resonance imaging and neuropsychologic examinations. Premature subjects performed worse than controls in global cognitive functioning, verbal memory, and verbal fluency. Corpus callosum measurements showed a global reduction owing mainly to thinning in the splenium, posterior midbody, and genu. Corpus callosum size significantly correlated with gestational age, Wechsler Performance IQ, and memory performance. These results suggest that cerebral growth during infancy does not compensate for corpus callosum reduction and that this reduction reflects neuropsychologic deficit. The cognitive impairment can arise from the paucity of the complex interneuronal connections owing to fiber damage, particularly myelinated fibers.