Cell-Type-Specific Role of ΔFosB in Nucleus Accumbens In Modulating Intermale Aggression.

A growing number of studies implicate the brain's reward circuitry in aggressive behavior. However, the cellular and molecular mechanisms within brain reward regions that modulate the intensity of aggression as well as motivation for it have been underexplored. Here, we investigate the cell-type-specific influence of ΔFosB, a transcription factor known to regulate a range of reward and motivated behaviors, acting in the nucleus accumbens (NAc), a key reward region, in male aggression in mice. We show that ΔFosB is specifically increased in dopamine D1 receptor (Drd1)-expressing medium spiny neurons (D1-MSNs) in NAc after repeated aggressive encounters. Viral-mediated induction of ΔFosB selectively in D1-MSNs of NAc intensifies aggressive behavior without affecting the preference for the aggression-paired context in a conditioned place preference (CPP) assay. In contrast, ΔFosB induction selectively in D2-MSNs reduces the time spent exploring the aggression-paired context during CPP without affecting the intensity of aggression per se. These data strongly support a dissociable cell-type-specific role for ΔFosB in the NAc in modulating aggression and aggression reward.SIGNIFICANCE STATEMENT Aggressive behavior is associated with several neuropsychiatric disorders and can be disruptive for affected individuals as well as their victims. Studies have shown a positive reinforcement mechanism underlying aggressive behavior that shares many common features with drug addiction. Here, we explore the cell-type-specific role of the addiction-associated transcription factor ΔFosB in the nucleus accumbens in aggression. We found that ΔFosB expression promotes aggressive behavior, effects that are dissociable from its effects on aggression reward. This finding is a significant first step in identifying therapeutic targets for the reduction of aggressive behavior across a range of neuropsychiatric illnesses.

Continuous nonfluoroscopic localization of the esophagus during radiofrequency catheter ablation of atrial fibrillation.

INTRODUCTION: Atrial-esophageal fistula formation is a dreaded complication of radiofrequency catheter ablation for atrial fibrillation. Esophageal localization is of potential value in avoiding lesion placement where the left atrium is juxtaposed to the esophagus. METHODS AND RESULTS: Twenty-seven patients underwent 33 pulmonary vein encirclement procedures. All the patients received general anesthesia with inhalational agents and either a fenestrated laryngeal mask airway or an endotracheal tube. A diagnostic electrophysiologic catheter was inserted into the esophagus, and a virtual esophageal tube was created using an electroanatomic mapping system. In all cases, the catheter was placed without difficulty and satisfactory virtual esophageal images were created. The catheter remained in the esophagus until the end of each ablation procedure. Esophageal catheter location during and after the ablation was compared with the initial location. Areas of close proximity between the left atrium and esophagus were easily identified. Change in esophageal location was not observed. Identification of esophageal proximity to the pulmonary veins allowed for identification of high-risk cases. In such cases, the planned procedure was modified to avoid esophageal injury (12 of 27 patients). CONCLUSIONS: (1) Real-time localization of esophageal position using a nonfluoroscopic mapping system during atrial fibrillation ablation is safe, practical, and straightforward. (2) Among patients who receive general anesthesia, esophageal position appears to be static, suggesting that one initial virtual image is sufficient for the duration of an ablation procedure.

Use of the retained guidewire technique facilitates left ventricular epicardial capture during biventricular defibrillator implantation.

We report a case of biventricular implantable cardioverter-defibrillator (ICD) insertion in which standard lead placement techniques could not achieve left ventricular capture. Protrusion of the guidewire beyond a venous stenosis provided adequate left ventricular capture.