Neural dynamics of causal inference in the macaque frontoparietal circuit.

Natural perception relies inherently on inferring causal structure in the environment. However, the neural mechanisms and functional circuits essential for representing and updating the hidden causal structure and corresponding sensory representations during multisensory processing are unknown. To address this, monkeys were trained to infer the probability of a potential common source from visual and proprioceptive signals based on their spatial disparity in a virtual reality system. The proprioceptive drift reported by monkeys demonstrated that they combined previous experience and current multisensory signals to estimate the hidden common source and subsequently updated the causal structure and sensory representation. Single-unit recordings in premotor and parietal cortices revealed that neural activity in the premotor cortex represents the core computation of causal inference, characterizing the estimation and update of the likelihood of integrating multiple sensory inputs at a trial-by-trial level. In response to signals from the premotor cortex, neural activity in the parietal cortex also represents the causal structure and further dynamically updates the sensory representation to maintain consistency with the causal inference structure. Thus, our results indicate how the premotor cortex integrates previous experience and sensory inputs to infer hidden variables and selectively updates sensory representations in the parietal cortex to support behavior. This dynamic loop of frontal-parietal interactions in the causal inference framework may provide the neural mechanism to answer long-standing questions regarding how neural circuits represent hidden structures for body awareness and agency.

Statistical inference of body representation in the macaque brain.

The sense of one's own body is a pillar of self-consciousness and could be investigated by inducing human illusions of artificial objects as part of the self. Here, we present a nonhuman primate version of a rubber-hand illusion that allowed us to determine its computational and neuronal mechanisms. We implemented a video-based system in a reaching task in monkeys and combined a casual inference model to establish an objective and quantitative signature for the monkey's body representation. Similar to humans, monkeys were more likely to perceive an external object as part of the self when the dynamics (spatial disparity) and the features (shape and structure) of visual (V) input was closer to proprioceptive (P) signals. Neural signals in the monkey's premotor cortex reflected the strength of illusion and the likelihood of misattributing the illusory hand to oneself, thus, revealing a cortical representation of body ownership.

Effects of wine-cap Stropharia cultivation on soil nutrients and bacterial communities in forestlands of northern China.

BACKGROUND: Cultivating the wine-cap mushroom (Stropharia rugosoannulata) on forestland has become popular in China. However, the effects of wine-cap Stropharia cultivation on soil nutrients and bacterial communities are poorly understood. METHODS: We employed chemical analyses and high-throughput sequencing to determine the impact of cultivating the wine-cap Stropharia on soil nutrients and bacterial communities of forestland. RESULTS: Cultivation regimes of Stropharia on forestland resulted in consistent increases of soil organic matter (OM) and available phosphorus (AP) content. Among the cultivation regimes, the greatest soil nutrient contents were found in the one-year interval cultivation regime, and the lowest total N and alkaline hydrolysable N contents were observed in the current-year cultivation regime. No significant differences were observed in alpha diversity among all cultivation regimes. Specific soil bacterial groups, such as Acidobacteria, increased in abundance after cultivation of Stropharia rugosoannulata. DISCUSSION: Given the numerous positive effects exerted by OM on soil physical and chemical properties, and the consistent increase in OM content for all cultivation regimes, we suggest that mushroom cultivation is beneficial to forest soil nutrient conditions through increasing OM content. Based on the fact that the one-year interval cultivation regime had the highest soil nutrient content as compared with other cultivation regimes, we recommend this regime for application in farming practice. The spent mushroom compost appeared to be more influential than the hyphae of S. rugosoannulata on the soil nutrients and bacterial communities; however, this requires further study. This research provides insight into understanding the effects of mushroom cultivation on the forest soil ecosystem and suggests a relevant cultivation strategy that reduces its negative impacts.

Level of proinsulin in association with cardiovascular risk factors and sleep snoring.

AIM: To explore the relationship between the level of proinsulin with cardiovascular risk factors and sleep snoring. METHODS: Based on the random stratified sampling principle, 1 193 Chinese residents in Pizhou City, Jiangsu Province (530 males and 663 females, aged 35-59 years with an average age of 46.69 years) were recruited. Their sleep snoring habits were investigated. Biotin-avidin based double mAbs ELISA was used to detect specific insulin and proinsulin, and a risk factor score was established to evaluate the individuals according to the number of their risk factors. RESULTS: The results of Spearman correlation analysis and covariate ANOVA analysis after age and sex were controlled, indicated that not only the level of proinsulin (r = 0.156, P = 0.000, F = 5.980 P = 0.000), but also cardiovascular risk factors score (r = 0.194, P = 0.000, F = 11.135, P = 0.000) significantly associated with the frequency of sleep snoring, and the significant relationship between true insulin and frequency of sleep snoring was only shown in the covariate ANOVA analysis (F = 2.868, P = 0.022). The result of multivariate stepwise logistic regression after age, sex, body mass index, waist circumference and true insulin were controlled showed that proinsulin (division by interval of quartile) was an independent risk factor for sleep snoring (OR = 1.220, 95%CI: 1.085-1.373, P = 0.001). CONCLUSION: The interaction of cardiovascular risk factors clustering, high proinsulin level and sleep breathing disorder may be a syndrome, which has not been recognized in human beings so far.

Significant association of insulin and proinsulin with clustering of cardiovascular risk factors.

AIM: To investigate the association between true insulin and proinsulin and clustering of cardiovascular risk factors. METHODS: Based on the random stratified sampling principles, 1196 Chinese people (533 males and 663 females, aged 35-59 years with an average age of 46.69 years) were recruited. Biotin-avidin based double monoclonal antibody ELISA method was used to detect the true insulin and proinsulin, and a risk factor score was set to evaluate individuals according to the number of risk factors. RESULTS: The median (quartile range) of true insulin and proinsulin was 4.91 mIu/L (3.01-7.09 mIu/L) and 3.49 pmol/L (2.14-5.68 pmol/L) respectively, and the true insulin level of female subjects was significantly higher than that of male subjects (P = 0.000), but the level of proinsulin displayed no significant difference between males and females (P = 0.566). The results of covariate ANOVA after age and sex were controlled showed that subjects with any of the risk factors had a significantly higher true insulin level (P = 0.002 for hypercholesterolemia, P = 0.021 for high low-density lipoprotein cholesterol, P = 0.003 for low high-density lipoprotein cholesterol, and P = 0.000 for other risk factors) and proinsulin level (P = 0.001 for low high-density lipoprotein cholesterol, and P = 0.000 for other risk factors) than those with no risk factors. Furthermore, subjects with higher risk factor scores had a higher true insulin and proinsulin level than those with lower risk factor scores (P = 0.000). The multiple linear regression models showed that true insulin and proinsulin were significantly related to cardiovascular risk factor scores respectively (P = 0.000). CONCLUSION: True insulin and proinsulin are significantly associated with the clustering of cardiovascular risk factors.

[Relationship between insulin resistance and cardiovascular risk factors clustering: an epidemiological study].

OBJECTIVE: To study the relationship between insulin resistance and cardiovascular risk factor clustering. METHODS: The height, body weight, waist circumference, and hip circumference were measured, and fasting venous blood was drawn among 1 196 rural residents, 533 males (44.57%) and 663 females (55.43%), aged 35 approximately 59 with the average age of 46.69, in Pizhou City, Jiangsu Province, selected by random sampling. Fasting serum true insulin (TI) was determined by ELISA. Blood lipids were measured by completely automatic biochemical analyzer. Homeostasis model assessment (HOMA) index was calculated and used as the indicator to evaluate insulin resistance. The statistic methods, such as Spearman correlation, partial correlation and multivariate Logistic regression were used to study the relationship between insulin resistance and hypertension, overweight, visceral obesity, dyslipidemia and cardiovascular risk factors clustering. RESULTS: The median (Q(R)) of TI and HOMA index were 4.89 (3.02 approximately 7.09) mIU/L and 0.98 (0.57 approximately 1.44) respectively, and TI and HOMA index of the female subjects were significantly higher than those of the male subjects (P < 0.01). The correlation coefficient between HOMA index and cardiovascular risk factors number was 0.290 (P < 0.01) by Spearman correlation analysis and 0.177 6 (P < 0.01) by partial correlation analysis after adjustment by age, sex, body mass index and waist circumference respectively. The results of non-conditional multivariate stepwise Logistic regression indicated that insulin resistance associated with cardiovascular risk factors aggregation and was independent of age, sex, body mass index and waist circumference, and the odds ratio (95% CI) was 1.250 (1.089 approximately 1.434). CONCLUSION: Insulin resistance may be a common pathogenetic mechanism of cardiovascular risk factor dustering.