Delay discounting without decision-making: medial prefrontal cortex and amygdala activations reflect immediacy processing and correlate with impulsivity and anxious-depressive traits.

Humans value rewards less when these are delivered in the future as opposed to immediately, a phenomenon referred to as delay discounting. While delay discounting has been studied during the anticipation of rewards and in the context of intertemporal decision-making, little is known about its neural correlates in the outcome phase (during reward delivery) and their relation to personality. Personality traits that have been associated with increased delay discounting include impulsivity and, potentially, anxious-depressive traits. Here we performed functional magnetic resonance imaging (fMRI) in 72 healthy participants while they carried out a monetary incentive delay (MID) task with a delay manipulation. In sixty percent of the experimental trials, participants won rewards that differed in magnitude (0.05€, 0.50€ or 1€) and delay until delivery (immediately, 10 days, or 100 days). A factor analysis on questionnaires yielded two factors reflecting Impulsivity and Anxiety/Depression, which we used to examine potential relationships between personality and delay discounting. When winning a reward, medial prefrontal cortex (mPFC) activation was higher for immediate compared to delayed rewards. Moreover, amygdala activation correlated with reward magnitude for immediate but not for delayed rewards. Amygdala activation to winning immediate rewards was higher in more impulsive participants, while mPFC activation to winning immediate rewards was higher in more anxious-depressed participants. Our results uncover neural correlates of delay discounting during reward delivery, and suggest that impulsivity and subclinical anxious-depressive traits are related to stronger neural responses for winning immediate relative to delayed rewards.

Attachment representation modulates oxytocin effects on the processing of own-child faces in fathers.

Oxytocin (OT) plays a crucial role in parental-infant bonding and attachment. Recent functional imaging studies reveal specific attachment and reward related brain regions in individuals or within the parent-child dyad. However, the time course and functional stage of modulatory effects of OT on attachment-related processing, especially in fathers, are poorly understood. To elucidate the functional and neural mechanisms underlying the role of OT in paternal-child attachment, we performed an event-related potential study in 24 healthy fathers who received intranasal OT in a double-blind, placebo-controlled, within-subject experimental design. Participants passively viewed pictures of their own child (oC), a familiar (fC) and an unfamiliar child (ufC) while event-related potentials were recorded. Familiarity of the child's face modulated a broad negativity at occipital and temporo-parietal electrodes within a time window of 300-400ms, presumably reflecting a modulation of the N250 and N300 ERP components. The oC condition elicited a more negative potential compared to the other familiarity conditions suggesting different activation of perceptual memory representations and assignment of emotional valence. Most importantly, this familiarity effect was only observed under placebo (PL) and was abolished under OT, in particular at left temporo-parietal electrodes. This OT induced attenuation of ERP responses was related to habitual attachment representations in fathers. In summary, our results demonstrate an OT-specific effect at later stages of attachment-related face processing presumably reflecting both activation of perceptual memory representations and assignment of emotional value.

Oxytocin modulates neural reactivity to children's faces as a function of social salience.

Oxytocin (OT) enhances social behaviors such as attachment and parental caretaking. Neural correlates of maternal attachment are found in reward-related brain regions, for example, in the globus pallidus (GP). The present work investigates the effects of OT on the neural correlates of parental attachment. Fathers viewed pictures of their own child (oC), a familiar child (fC), and an unfamiliar child (uC) after intranasal application of OT vs placebo. OT reduced activation and functional connectivity of the left GP with reward- and attachment-related regions responsive to pictures of the oC and the uC. The present results emphasize the key role of OT in human parental attachment and suggest that OT reduces neural reactivity to social cues as a function of social salience. Our results together with previous findings speak to a selective reduction of neural reactivity to social stimuli, irrespective of their valence. We argue that one major pathway by which OT exerts its positive effects on affiliative and social behaviors is the attenuation of automatic neural responses, which in turn leads to increased approach behaviors and decreased social avoidance.