Within the postpartum period, both mothers and infants are susceptible; but because PPD typically occurs for short durations and has moderate symptoms, there exists challenges in exploring and addressing the underlying cause of the depression. This fact highlights the need for relevant animal models. In the present study, postpartum adult female cynomolgus monkeys(Macaca fascicularis) living in breeding groups were observed for typical depressive behavior. The huddle posture behavior was utilized as an indicator of behavioral depression postpartum(BDP) as it has been established as the core depressive-like behavior in primates. Monkeys were divided into two groups: A BDP group(n=6), which were found to spend more time huddling over the first two weeks postpartum than other individuals that formed a non-depression control group(n=4). The two groups were then further analyzed for locomotive activity, stressful events, hair cortisol levels and for maternal interactive behaviors. No differences were found between the BDP and control groups in locomotive activity, in the frequencies of stressful events experienced and in hair cortisol levels. These findings suggested that the postpartum depression witnessed in the monkeys was not related to external factors other than puerperium period. Interestingly, the BDP monkeys displayed an abnormal maternal relationship consisting of increased infant grooming. Taken together, these findings suggest that the adult female cynomolgus monkeys provide a natural model of behavioral postpartum depression that holds a number of advantages over commonly used rodent systems in PPD modeling. The cynomolgus monkeys have a highly-organized social hierarchy and reproductive characteristics without seasonal restriction—similar to humans—as well as much greater homology to humans than rodents. As such, this model may provide a greater translational efficiency and research platform for systematically investigating the etiology, treatment, prevention of PPD.
Xun-Xun CHUJoshua Dominic RizakShang-Chuan YANGJian-Hong WANGYuan-Ye MAXin-Tian HU
Recently, resting-state functional magnetic resonance imaging has been used to parcellate the brain into functionally distinct regions based on the information available in functional connectivity maps. However, brain voxels are not independent units and adjacent voxels are always highly correlated, so functional connectivity maps contain redundant information, which not only impairs the computational efficiency during clustering, but also reduces the accuracy of clustering results. The aim of this study was to propose feature-reduction approaches to reduce the redundancy and to develop semisimulated data with defined ground truth to evaluate these approaches. We proposed a feature-reduction approach based on the Affinity Propagation Algorithm (APA) and compared it with the classic featurereduction approach based on Principal Component Analysis (PCA). We tested the two approaches to the parcellation of both semisimulated and real seed regions using the K-means algorithm and designed two experiments to evaluate their noiseresistance. We found that all functional connectivity maps (with/without feature reduction) provided correct information for the parcellation of the semisimulated seed region and the computational efficiency was greatly improved by both featurereduction approaches. Meanwhile, the APA-based feature-reduction approach outperformed the PCAbased approach in noise-resistance. The results suggested that functional connectivity maps can provide correct information for cortical parcellation, and feature-reduction does not significantly change the information. Considering the improvement in computational efficiency and the noise-resistance, feature-reduction of functional connectivity maps before cortical parcellation is both feasible and necessary.
Xiaoguang TianCirong LiuTianzi JiangJoshua RizakYuanye MaXintian Hu
Opiates and dopamine (DA) play key roles in learning and memory in humans and animals. Although interactions between these neurotransmitters have been found, their functional roles remain to be fully elucidated, and their dysfunction may contribute to human diseases and addiction. Here we investigated the interactions of morphine and dopaminergic neurotransmitter systems with respect to learning and memory in rhesus monkeys by using the Wisconsin General Test Apparatus (WGTA) delayed-response task. Morphine and DA agonists (SKF-38393, apomorphine and bromocriptine) or DA antagonists (SKF-83566, haloperidol and sulpiride) were co-administered to the monkeys 30 min prior to the task. We found that dose-patterned co-administration of morphine with D1 or D2 antagonists or agonists reversed the impaired spatial working memory induced by morphine or the compounds alone. For example, morphine at 0.01 mg/kg impaired spatial working memory, while morphine (0.01 mg/kg) and apomorphine (0.01 or 0.06 mg/kg) co-treatment ameliorated this effect. Our findings suggest that the interactions between morphine and dopaminergic compounds influence spatial working memory in rhesus monkeys. A better understanding of these interactive relationships may provide insights into human addiction.
Jian-Hong WangJoshua Dominie RizakYan-Mei ChenLiang LiXin-Tian HuYuan-Ye Ma
Studies estimating eye movements have demonstrated that non-human primates have fixation patterns similar to humans at the first sight of a picture.In the current study,three sets of pictures containing monkeys,humans or both were presented to rhesus monkeys and humans.The eye movements on these pictures by the two species were recorded using a Tobii eye-tracking system.We found that monkeys paid more attention to the head and body in pictures containing monkeys,whereas both monkeys and humans paid more attention to the head in pictures containing humans.The humans always concentrated on the eyes and head in all the pictures,indicating the social role of facial cues in society.Although humans paid more attention to the hands than monkeys,both monkeys and humans were interested in the hands and what was being done with them in the pictures.This may suggest the importance and necessity of hands for survival.Finally,monkeys scored lower in eye-tracking when fixating on the pictures,as if they were less interested in looking at the screen than humans.The locations of fixation in monkeys may provide insight into the role of eye movements in an evolutionary context.
Ying-Zhou HuHui-Hui JiangCi-Rong LiuJian-Hong WangCheng-Yang YuSynnve CarlsonShang-Chuan YangVeli-Matti SaarinenJoshua D RizakXiao-Guang TianHen TanZhu-Yue ChenYuan-Ye MaXin-Tian Hu
