Inhibitory corticotropin-releasing factor neurons in the dorsomedial prefrontal cortex promote stress-resilient behavior in male rodents

Corticotropin-releasing factor signaling and its potential role in the prefrontal cortex-dependent regulation of anxiety

A large body of literature has highlighted the significance of the corticotropin-releasing factor (CRF) system in the regulation of neuropsychiatric diseases. Anxiety disorders are among the most common neuropsychiatric disorders. An increasing number of studies have demonstrated that the CRF family mediates and regulates the development and maintenance of anxiety. Thus, the CRF family is considered to be a potential target for the treatment of anxiety disorders. The prefrontal cortex (PFC) plays a role in the occurrence and development of anxiety, and both CRF and CRF-R1 are widely expressed in the PFC. This paper begins by reviewing CRF-related signaling pathways and their different roles in anxiety and related processes. Then, the role of the CRF system in other neuropsychiatric diseases is reviewed and the potential role of PFC CRF signaling in the regulation of anxiety disorders is discussed. Although other signaling pathways are potentially involved in the process of anxiety, CRF in the PFC primarily modulates anxiety disorders through the activation of corticotropin-releasing factor type1 receptors (CRF-R1) and the excitation of the cAMP/PKA signaling pathway. Moreover, the main signaling pathways of CRF involved in sex differentiation in the PFC appear to be different. In summary, this review suggests that the CRF system in the PFC plays a critical role in the occurrence of anxiety. Thus, CRF signaling is of great significance as a potential target for the treatment of stress-related disorders in the future.

Disentangling cognitive inflexibility in major depressive disorder: A transcranial direct current stimulation study

BACKGROUND

Cognitive dysfunction is a persistent residual symptom in major depressive disorders (MDDs) that hinders social and occupational recovery. Cognitive inflexibility is a typical cognitive dysfunction in MDD and refers to difficulty in switching tasks, which requires two subcomponents: forgetting an old task and adapting to a new one. Here, we aimed to disentangle the subcomponents of cognitive inflexibility in MDD and investigate whether they can be improved by transcranial direct current stimulation (tDCS) on the prefrontal cortex.

METHODS

The current study included 20 patients with MDD (seven females) and 22 age-matched healthy controls (HCs) (seven females). The participants received anodal tDCS on either the dorsomedial prefrontal cortex (DMPFC) or dorsolateral prefrontal cortex (DLPFC) in a crossover design. Before and after the application of tDCS, the participants performed a modified Wisconsin Card Sorting Test, in which the task-switching rules were explicitly described and proactive interference from a previous task rule was occasionally released.

RESULTS

We found that the behavioral cost of a task switch was increased in patients with MDD, but that of proactive interference was comparable between patients with MDD and HCs. The response time for anodal DMPFC tDCS was decreased compared with that for anodal tDCS on the DLPFC in MDD.

CONCLUSIONS

These findings suggest that cognitive inflexibility in MDD is primarily explained by the difficulty to adapt to a new task and environment, and that tDCS on the DMPFC improves behavioral performance during cognitively demanding tasks that require conflict resolution.

Voiding and storage symptoms in depression/anxiety

We here described the frequency and nature of voiding and storage bladder symptoms in depression/anxiety, for which we propose the name "bladder somatic symptom disorder (SSD)" because such symptoms most probably have brain mechanisms. SSD was formerly called as various terms including "somatoform disorder", "medically unexplained physical symptoms", "functional somatic syndrome" and "hysterical neurosis/hysteria". Bladder SSD has the following specific features that are distinguishable from "true" neurologic/organic bladder dysfunction: 1) situation-dependence (close association with life event in some), 2) urodynamically increased bladder sensation/hypersensitivity and 3) absence of neurologic/organic diseases, in addition to 4) other stress symptoms (insomnia, etc.), are key clues to the possibility of bladder SSD. Urodynamics in these patients showed, to a lesser extent, underactive bladder without post-void residual. These findings might reflect the biological changes of the depressive brain; e.g., decreases in serotonin and GABA, and possible increases in CRH. Treatment of bladder SSD can follow that of general depression/anxiety, with the potential addition of anticholinergic or selective beta3 bladder drugs.