A neural circuit for male sexual behavior and reward.

Male sexual behavior is innate and rewarding. Despite its centrality to reproduction, a molecularly specified neural circuit governing innate male sexual behavior and reward remains to be characterized. We have discovered a developmentally wired neural circuit necessary and sufficient for male mating. This circuit connects chemosensory input to BNSTprTac1 neurons, which innervate POATacr1 neurons that project to centers regulating motor output and reward. Epistasis studies demonstrate that BNSTprTac1 neurons are upstream of POATacr1 neurons, and BNSTprTac1-released substance P following mate recognition potentiates activation of POATacr1 neurons through Tacr1 to initiate mating. Experimental activation of POATacr1 neurons triggers mating, even in sexually satiated males, and it is rewarding, eliciting dopamine release and self-stimulation of these cells. Together, we have uncovered a neural circuit that governs the key aspects of innate male sexual behavior: motor displays, drive, and reward.

Hypothalamic neurons that mirror aggression.

Social interactions require awareness and understanding of the behavior of others. Mirror neurons, cells representing an action by self and others, have been proposed to be integral to the cognitive substrates that enable such awareness and understanding. Mirror neurons of the primate neocortex represent skilled motor tasks, but it is unclear if they are critical for the actions they embody, enable social behaviors, or exist in non-cortical regions. We demonstrate that the activity of individual VMHvlPR neurons in the mouse hypothalamus represents aggression performed by self and others. We used a genetically encoded mirror-TRAP strategy to functionally interrogate these aggression-mirroring neurons. We find that their activity is essential for fighting and that forced activation of these cells triggers aggressive displays by mice, even toward their mirror image. Together, we have discovered a mirroring center in an evolutionarily ancient region that provides a subcortical cognitive substrate essential for a social behavior.

Oxytocin receptor is not required for social attachment in prairie voles.

Prairie voles are among a small group of mammals that display long-term social attachment between mating partners. Many pharmacological studies show that signaling via the oxytocin receptor (Oxtr) is critical for the display of social monogamy in these animals. We used CRISPR mutagenesis to generate three different Oxtr-null mutant prairie vole lines. Oxtr mutants displayed social attachment such that males and females showed a behavioral preference for their mating partners over a stranger of the opposite sex, even when assayed using different experimental setups. Mothers lacking Oxtr delivered viable pups, and parents displayed care for their young and raised them to the weanling stage. Together, our studies unexpectedly reveal that social attachment, parturition, and parental behavior can occur in the absence of Oxtr signaling in prairie voles.

The pharmacodynamic effect of terlipressin versus high-dose octreotide in reducing hepatic venous pressure gradient: a randomized controlled trial.

BACKGROUND: Vasoactive drugs can reduce portal venous pressure and control variceal bleeding. However, few studies have explored the hemodynamic effects of terlipressin and high-dose octreotide in such patients. Our purpose was to evaluate the hemodynamic changes and safety of using terlipressin and high-dose octreotide in patients with decompensated liver cirrhosis. METHODS: A multi-center randomized controlled trial was conducted. Cirrhotic patients with a history of variceal bleeding were included. Terlipressin or high-dose octreotide was administered during the procedure of measuring hepatic venous pressure gradient (HVPG). Hemodynamic parameters and symptoms were recorded. RESULTS: A total of 88 patients were included. HVPG was significantly reduced at 10, 20, and 30 min after drug administration in the terlipressin group (16.3±6.4 vs. 14.7±5.9, 14.0±6.1, and 13.8±6.1, respectively, P<0.001) and the high-dose octreotide group (17.4±6.6 vs. 15.1±5.8, 15.3±6.2, and 16.1±6.0, respectively P<0.01). Decreased heart rate and increased mean arterial pressure were more often observed in the terlipressin group. The overall response rates were not significantly different between the groups (52.8% vs. 44.8%, P=0.524). The terlipressin group had significantly higher response rates at 30 min compared to the high-dose octreotide group in those with alcoholic liver cirrhosis [6/6 (100%) vs. 0/4 (0%), P=0.005]. The incidence of adverse drug events was rare and similar in the two groups. CONCLUSIONS: Both terlipressin and high-dose octreotide were effective and safe for reducing HVPG. The pharmacodynamic effect of terlipressin persisted longer. The terlipressin group had higher response rates in those with alcoholic cirrhosis (trial number: NCT02119884).

The Parabrachial Nucleus Directly Channels Spinal Nociceptive Signals to the Intralaminar Thalamic Nuclei, but Not the Amygdala.

The parabrachial nucleus (PBN) is one of the major targets of spinal projection neurons and plays important roles in pain. However, the architecture of the spinoparabrachial pathway underlying its functional role in nociceptive information processing remains elusive. Here, we report that the PBN directly relays nociceptive signals from the spinal cord to the intralaminar thalamic nuclei (ILN). We demonstrate that the spinal cord connects with the PBN in a bilateral manner and that the ipsilateral spinoparabrachial pathway is critical for nocifensive behavior. We identify Tacr1-expressing neurons as the major neuronal subtype in the PBN that receives direct spinal input and show that these neurons are critical for processing nociceptive information. Furthermore, PBN neurons receiving spinal input form functional monosynaptic excitatory connections with neurons in the ILN, but not the amygdala. Together, our results delineate the neural circuit underlying nocifensive behavior, providing crucial insight into the circuit mechanism underlying nociceptive information processing.

The role of a multidisciplinary team in the management of portal hypertension.

BACKGROUND: Gastroesophageal variceal hemorrhage is the most severe complication of portal hypertension, with a high mortality rate. The current recommendations for gastroesophageal varices include pharmacological treatment, endoscopic treatment, transjugular intrahepatic portosystemic shunt (TIPS) placement, and splenectomy with devascularization surgery. Multidisciplinary team (MDT) comprises of a group of medical experts and specialists across a range of disciplines, providing personalized and targeted patient care tailored to each individual's condition, circumstances, and expectations. METHODS: Patients referred to the MDT clinic since its establishment in September 2014 were prospectively enrolled and followed-up for at least 12 months. Patient baseline characteristics, treatment methods, outcome and survival were compared to non-MDT patients retrieved from a prospectively maintained database with propensity score matching. RESULTS: Propensity-score matching (PSM) was carried out to balance available covariates, resulting in 58 MDT patients vs. 111 non-MDT patients. Overall survival and variceal rebleed was compared between the two groups. The rate of variceal rebleed was significantly higher in the non-MDT group, while no difference in overall survival was observed. CONCLUSIONS: This study is the first to investigate the role of a multidisciplinary team in the management of gastroesophageal varices secondary to portal hypertension. Patients treated based on MDT clinic recommendations had a significantly lower risk for variceal rebleed.

Periodic Remodeling in a Neural Circuit Governs Timing of Female Sexual Behavior.

Behaviors are inextricably linked to internal state. We have identified a neural mechanism that links female sexual behavior with the estrus, the ovulatory phase of the estrous cycle. We find that progesterone-receptor (PR)-expressing neurons in the ventromedial hypothalamus (VMH) are active and required during this behavior. Activating these neurons, however, does not elicit sexual behavior in non-estrus females. We show that projections of PR+ VMH neurons to the anteroventral periventricular (AVPV) nucleus change across the 5-day mouse estrous cycle, with ∼3-fold more termini and functional connections during estrus. This cyclic increase in connectivity is found in adult females, but not males, and regulated by estrogen signaling in PR+ VMH neurons. We further show that these connections are essential for sexual behavior in receptive females. Thus, estrogen-regulated structural plasticity of behaviorally salient connections in the adult female brain links sexual behavior to the estrus phase of the estrous cycle.

Medial Preoptic Area Modulates Courtship Ultrasonic Vocalization in Adult Male Mice.

Adult male mice emit highly complex ultrasonic vocalizations (USVs) in response to female conspecifics. Such USVs, thought to facilitate courtship behaviors, are routinely measured as a behavioral index in mouse models of neurodevelopmental and psychiatric disorders such as autism. While the regulation of USVs by genetic factors has been extensively characterized, the neural mechanisms that control USV production remain largely unknown. Here, we report that optogenetic activation of the medial preoptic area (mPOA) elicited the production of USVs that were acoustically similar to courtship USVs in adult mice. Moreover, mPOA vesicular GABA transporter-positive (Vgat +) neurons were more effective at driving USV production than vesicular glutamate transporter 2-positive neurons. Furthermore, ablation of mPOA Vgat+ neurons resulted in altered spectral features and syllable usage of USVs in targeted males. Together, these results demonstrate that the mPOA plays a crucial role in modulating courtship USVs and this may serve as an entry point for future dissection of the neural circuitry underlying USV production.

AGRP Neurons Project to the Medial Preoptic Area and Modulate Maternal Nest-Building.

AGRP (agouti-related neuropeptide) expressing inhibitory neurons sense caloric needs of an animal to coordinate homeostatic feeding. Recent evidence suggests that AGRP neurons also suppress competing actions and motivations to mediate adaptive behavioral selection during starvation. Here, in adult mice of both sexes we show that AGRP neurons form inhibitory synapses onto ∼30% neurons in the medial preoptic area (mPOA), a region critical for maternal care. Remarkably, optogenetically stimulating AGRP neurons decreases maternal nest-building while minimally affecting pup retrieval, partly recapitulating suppression of maternal behaviors during food restriction. In parallel, optogenetically stimulating AGRP projections to the mPOA or to the paraventricular nucleus of hypothalamus but not to the LHA (lateral hypothalamus area) similarly decreases maternal nest-building. Chemogenetic inhibition of mPOA neurons that express Vgat (vesicular GABA transporter), the population targeted by AGRP terminals, also decreases maternal nest-building. In comparison, chemogenetic inhibition of neurons in the LHA that express vesicular glutamate transporter 2, another hypothalamic neuronal population critical for feeding and innate drives, is ineffective. Importantly, nest-building during low temperature thermal challenge is not affected by optogenetic stimulation of AGRP→mPOA projections. Finally, via optogenetic activation and inhibition we show that distinctive subsets of mPOA Vgat+ neurons likely underlie pup retrieval and maternal nest-building. Together, these results show that AGRP neurons can modulate maternal nest-building, in part through direct projections to the mPOA. This study corroborates other recent discoveries and underscores the broad functions that AGRP neurons play in antagonizing rivalry motivations to modulate behavioral outputs during hunger.SIGNIFICANCE STATEMENT In order for animals to initiate ethologically appropriate behaviors, they must typically decide between behavioral repertoires driven by multiple and often conflicting internal states. How neural pathways underlying individual behaviors interact to coherently modulate behavioral outputs, in particular to achieve a proper balance between behaviors that serve immediate individual needs versus those that benefit the propagation of the species, remains poorly understood. Here, by investigating projections from a neuronal population known to drive hunger behaviors to a brain region critical for maternal care, we show that activation of AGRP→mPOA projections in females dramatically inhibits maternal nest-building while leaving mostly intact pup retrieval behavior. Our findings shed new light on neural organization of behaviors and neural mechanisms that coordinate behavioral selection.

Thromboembolic Events Secondary to Endoscopic Cyanoacrylate Injection: Can We Foresee Any Red Flags?

Background: Gastric varices (GV) are associated with high morbidity and mortality in patients with portal hypertension. Endoscopic cyanoacrylate injection is the first-line recommended therapy for GV obliteration. This study aims to explore the reason behind related adverse events and better prevent its occurrence. Methods: A retrospective case series study was conducted from January 1, 2013, to December 31, 2016, to identify patients who experienced severe adverse events secondary to endoscopic cyanoacrylate injection. A literature review of similar cases was performed on two medical databases, Medline and Embase. Results: A total of 652 patients underwent cyanoacrylate injection at our center within the study duration. Five cases of severe adverse events related to the use of tissue adhesives were identified. Detailed clinical presentation, patient treatment, and outcomes were reviewed and analyzed. Twenty-seven similar cases were identified based on the literature review providing further insight into the study. Conclusion: Although rare in incidence, systemic embolism associated with cyanoacrylate injection is often fatal or debilitating. This report may raise awareness in treatment protocol, including the necessity of preoperative angiographic studies, to avoid similar adverse events in clinical practice.

Patient Response to Endoscopic Therapy for Gastroesophageal Varices Based on Endoscopic Ultrasound Findings.

Background/Aims: Gastroesophageal variceal hemorrhage is a common complication of portal hypertension. Endoscopic therapy is currently recommended for preventing gastroesophageal variceal rebleed. However, the rate of variceal rebleed and its associated mortality remain concerning. This study is aimed at differentiating patient response to endoscopic therapy based on endoscopic ultrasound (EUS) findings. Methods: One-hundred seventy patients previously treated with repeat endoscopic therapy for secondary prophylaxis were enrolled and classified into two groups based on treatment response. Prior to consolidation therapy, all patients received an EUS examination to observe for extraluminal phenomena. All available follow-up endoscopic examination records were retrieved to validate study results. Results: Of the 170 subjects, 106 were poor responders, while 64 were good responders. The presence of para-gastric, gastric perforating, and esophageal perforating veins was associated with poor patient response (p<0.001). The odds ratio for para-gastric veins was 5.374. Follow-up endoscopic findings for poor responders with incomplete variceal obliteration was closely correlated with the presence of para-gastric veins (p=0.002). Conclusions: The presence of para-gastric veins is a characteristic of poor response to endoscopic therapy for treating gastroesophageal varices. Early identification of this subgroup necessitates a change in course of treatment to improve overall patient outcome.

Non-invasive predictive model for hepatic venous pressure gradient based on a 3-dimensional computed tomography volume rendering technology.

Portal hypertension secondary to liver cirrhosis may cause a number of life-threatening complications. The rupture of gastroesophageal varices is associated with a high mortality rate of 15-30%. Hepatic venous pressure gradient (HVPG) is an accurate reflection of disease severity, however this can only be assessed via an invasive interventional procedure. The aim of the present study was to explore a non-invasive method based on 3D computed tomography (CT) volume rendering technology to accurately predict HVPG. A total of 77 patients diagnosed with liver cirrhosis underwent HVPG examination in the present study and the appropriate clinical and radiological data were retrospectively reviewed. A 3D liver and spleen volume rendering was constructed for volume measurements. All non-invasive parameters were tested using univariate analysis and the resulting variables that were statistically significant (P<0.20) were used in the multivariate linear regression model. The HVPG predictive model was as follows: HVPG = 18.726 - 0.324 (albumin) + 1.57 (aminotransferase-to-platelet ratio index) + 0.004 (liver volume) (multivariate regression analysis, P=0.006). The corresponding area under receiver operating characteristic curve to identify clinically significant portal hypertension defined as HVPG ≥10 mmHg was 0.810 (95% confidence interval; 0.705-0.891), with an optimal cut-off value of 12.84, yielding a sensitivity of 80.36% a specificity of 76.19%. The results of the present study indicate that 3D CT volume rendering technology may have the potential to be used for non-invasive prediction of HVPG.

An optimal trapdoor zeolite for exclusive admission of CO2 at industrial carbon capture operating temperatures.

High purity molecular trapdoor chabazite with an optimal Si/Al ratio (1:9) was prepared from fly ash. Gas adsorption isotherms and binary breakthrough experiments show dramatically large selectivities for CO2 over N2 and CH4, which are the highest among physisorbents at operating temperatures suitable for postcombustion carbon capture and natural gas separations.

Medial preoptic area in mice is capable of mediating sexually dimorphic behaviors regardless of gender.

The medial preoptic area (mPOA) differs between males and females in nearly all species examined to date, including humans. Here, using fiber photometry recordings of Ca2+ transients in freely behaving mice, we show ramping activities in the mPOA that precede and correlate with sexually dimorphic display of male-typical mounting and female-typical pup retrieval. Strikingly, optogenetic stimulation of the mPOA elicits similar display of mounting and pup retrieval in both males and females. Furthermore, by means of recording, ablation, optogenetic activation, and inhibition, we show mPOA neurons expressing estrogen receptor alpha (Esr1) are essential for the sexually biased display of these behaviors. Together, these results underscore the shared layout of the brain that can mediate sex-specific behaviors in both male and female mice and provide an important functional frame to decode neural mechanisms governing sexually dimorphic behaviors in the future.

Presence of pups suppresses hunger-induced feeding in virgin adult mice of both sexes.

Despite recent progress on neural pathways underlying individual behaviors, how an animal balances and prioritizes behavioral outputs remains poorly understood. While studying the relationship between hunger-induced feeding and pup-induced maternal behaviors in virgin female mice, we made the unexpected discovery that presence of pups strongly delayed and decreased food consumption. Strikingly, presence of pups also suppressed feeding induced by optogenetic activation of Agrp neurons. Such a suppressive effect inversely correlated with the extents of maternal behaviors, but did not rely on the display of these behaviors, and was also present in virgin males. Furthermore, chemogenetic activation of Vglut2+ neurons in the medial preoptic area (mPOA), a region critical for maternal behaviors and motivation, was sufficient to suppress hunger-induced feeding. However, muscimol inhibition of the mPOA, while disrupting maternal behaviors, did not prevent pup suppression of feeding, indicating that neural pathways in other brain regions may also mediate such an effect. Together, these results provide novel insights into neural coordination of pup care and feeding in mice and organizations of animal behaviors in general.

Sex differences in brain-derived neurotrophic factor signaling: Functions and implications.

Brain-derived neurotrophic factor (BDNF) regulates diverse processes such as neuronal survival, differentiation, and plasticity. Accumulating evidence suggests that molecular events that direct sexual differentiation of the brain interact with BDNF signaling pathways. This Mini-Review first examines potential hormonal and epigenetic mechanisms through which sex influences BDNF signaling. We then examine how sex-specific regulation of BDNF signaling supports the development and function of sexually dimorphic neural circuits that underlie male-specific genital reflexes in rats and song production in birds. Finally, we discuss the implications of sex differences in BDNF signaling for gender-biased presentation of neurological and psychiatric diseases such as Alzheimer's disease. Although this Mini-Review focuses on BDNF, we try to convey the general message that sex influences brain functions in complex ways and underscore the requirement for and challenge of expanding research on sex differences in neuroscience. © 2016 Wiley Periodicals, Inc.