No abstract

The effects of oxytocin (OT) on the social brain can be tracked upon assessing the neural activity in resting and task states, and developing a system-level framework for characterizing the state-based functional relationships of its distinct effect. Here, we contribute to this framework by examining how OT modulates social brain network correlations during resting and task states, using fMRI. First, we investigated network activation, followed by an analysis of the relationships between networks and individual differences. Subsequently, we evaluated the functional connectivity in both states. Finally, the relationship between networks across states was represented by the predictive power of networks in the resting state for task-evoked activities. The differences in the predicted accuracy between the subjects displayed individual variations in this relationship. Our results showed that the activity of the dorsal default mode network in the resting state had the largest predictive power for task-evoked activation of the precuneus network (PN) only in the OT group. The results also demonstrated that OT reduced the individual variation in PN in the prediction process. These findings suggest a distributed but modulatory effect of OT on the association between resting and task-dependent brain networks.

Oxytocin (OT) is a neuropeptide that modulates social behaviors and the social brain. The effects of OT on the social brain can be tracked by assessing the neural activity in the resting and task states, providing a system-level framework for characterizing state-based functional relationships of its distinct effect. Here, we contribute to this framework by examining how OT modulates social brain network correlations during the resting and task states using fMRI. Firstly, we investigated network activation, followed by analyzing the relationship between networks and individual differences measured by the Positive and Negative Affect Schedule and the Big-Five scales. Subsequently, we evaluated functional connectivity in both states. Finally, the relationship between networks across the states was represented by the predictive power of networks in the resting state for task-evoked activity. The difference in predicted accuracy between subjects displayed individual variations in this relationship. Our results showed decreased dorsal default mode network (DDMN) for OT group in the resting state. Additionally, only in the OT group, the activity of the DDMN in the resting state had the largest predictive power for task-evoked activation of the precuneus network (PN). The results also demonstrated OT reduced individual variation of PN, specifically, the difference of accuracy between predicting a subject's own and others' PN task activation. These findings suggest a distributed but modulatory effect of OT on the association between resting brain networks and task-dependent brain networks, showing increased DDMN to PN connectivity after OT administration, which may support OT-induced distributed processing during task performance.

In order to explore the effects of grazing frequency on functional traits and to test whether Stipa gandis has compensatory photosynthesis during the frequent grazing period, we investigated morphological traits, biomass allocation, photosynthetic traits, and chlorophyll fluorescence parameters of the species in Inner Mongolia, China. The grazing frequency treatments included fencing (T 0), grazing in May and July (T 1 , i.e., two months per year) and grazing from May to September (T 2 , i.e., continuous five months per year). Results indicate that T 1 and T 2 treatments did not affect individual biomass, but T 2 treatment negatively affected individual size, i.e., plant height, stem length, and leaf length. Physiological traits of S. grandis were significantly affected by grazing, year, and their interaction. In July 2014 (i.e., dry environment and low relative humidity), the photosynthetic rate, transpiration rate and water use efficiency were highest under T 2 treatment, which was caused by the increase in stomatal conductance. However, in July 2015 (i.e., wet environment and high relative humidity), the photosynthetic rate and water use efficiency were higher under T 1 and T 2 treatments, which were caused by the increase in actual quantum efficiency and stomatal conductance. Our results implied that under frequent grazing treatment, S. grandis had small height and efficient compensatory photosynthesis, which promoted its resistance to severe grazing.