A delay-specific neural indicator corresponds to delay-discounting behavior for both gain and loss.

OBJECTIVES: Delay-discounting, wherein the subjective value for delayed gain or loss decreases, has been attracting much attention from the social sciences as well as neuroscience and has been suggested asbeing related to reward processing in the brain. As reported, the feedback-related negativity (FRN), an electrophysiological measure of reward processing, increased by delayed-monetary gain and ΔFRN, which is the difference in FRNs for loss and gain at a certain time point, had no significant correlation with delay-discounting for gain. Thus, although a delay for gain could affect FRN, it is unclear whether FRN capturing such a delay effect has a direct relationship with delay-discounting in both gain and loss domains. METHODS: In this study, we introduced a delay-specific indicator, ΔFRNdelay, that is, the difference between FRN with and without delays, and investigated its direct relationship during the doors task with the discounting rate measured by the delay-discounting task in both the gain and loss domains. RESULTS: We found that, for loss, the delay enhanced FRN, whereas no such effect was observed for gains, and that this indicator was significantly correlated with delay-discounting in both domains. CONCLUSIONS: To our knowledge, this study is the first to suggest that FRN is sensitive to the effects of delay in losses on reward processing and that the new indicator directly corresponds to changes in subjective value as measured by delay-discounting.

Revisiting the relationship between illusory hand ownership induced by visuotactile synchrony and cardiac interoceptive accuracy.

Multisensory integration plays an important role in the experience of the bodily self. Recently, the relationship between exteroception and interoception has been actively debated. The first evidence was a report that the susceptibility of the sense of ownership over a fake hand (i.e., illusory hand ownership: IHO) in the typical rubber hand illusion is negatively modulated by the accuracy of the heartbeat perception (i.e., cardiac interoceptive accuracy: CIA). If reliable, this would suggest an antagonism between the exteroceptive and interoceptive cues underlying the bodily self. However, some inconsistent data have been reported, raising questions about the robustness of the initial evidence. To investigate this robustness, we estimated the extent of the modulatory effect of CIA on IHO susceptibility by applying Bayesian hierarchical modeling to two independent datasets. Overall, our results did not support that IHO susceptibility is modulated by CIA. The present estimates with high uncertainty cannot exclude the hypothesis that the relationship between IHO susceptibility and CIA is so weak as to be negligible. Further studies with larger sample sizes are needed to reach a conclusion about the extent of the modulatory effect. These findings highlight the lack of robustness of key evidence supporting the "antagonism hypothesis".

Supramodal Representation of the Sense of Body Ownership in the Human Parieto-Premotor and Extrastriate Cortices.

The sense of body ownership, defined as the sensation that one's body belongs to oneself, is a fundamental component of bodily self-consciousness. Several studies have shown the importance of multisensory integration for the emergence of the sense of body ownership, together with the involvement of the parieto-premotor and extrastriate cortices in bodily awareness. However, whether the sense of body ownership elicited by different sources of signal, especially visuotactile and visuomotor inputs, is represented by common neural patterns remains to be elucidated. We used functional magnetic resonance imaging (fMRI) to investigate the existence of neural correlates of the sense of body ownership independent of the sensory modalities. Participants received tactile stimulation or executed finger movements while given synchronous and asynchronous visual feedback of their hand. We used multivoxel patterns analysis (MVPA) to decode the synchronous and asynchronous conditions with cross-classification between two modalities: the classifier was first trained in the visuotactile sessions and then tested in the visuomotor sessions, and vice versa. Regions of interest (ROIs)-based and searchlight analyses revealed significant above-chance cross-classification accuracies in the bilateral intraparietal sulcus (IPS), the bilateral ventral premotor cortex (PMv), and the left extrastriate body area (EBA). Moreover, we observed a significant positive correlation between the cross-classification accuracy in the left PMv and the difference in subjective ratings of the sense of body ownership between the synchronous and asynchronous conditions. Our findings revealed the neural representations of the sense of body ownership in the IPS, PMv, and EBA that is invariant to the sensory modalities.