Search

AimSymptoms of bipolar disorder (BD) include changes in mood, activity, energy, sleep, and appetite. Since many of these processes are regulated by circadian function, circadian rhythm disturbance has been examined as a biological feature underlying BD. The International Society for Bipolar Disorders Chronobiology Task Force (CTF) was commissioned to review evidence for neurobiological and behavioral mechanisms pertinent to BD.MethodDrawing upon expertise in animal models, biomarkers, physiology, and behavior, CTF analyzed the relevant cross-disciplinary literature to precisely frame the discussion around circadian rhythm disruption in BD, highlight key findings, and for the first time integrate findings across levels of analysis to develop an internally consistent, coherent theoretical framework.ResultsEvidence from multiple sources implicates the circadian system in mood regulation, with corresponding associations with BD diagnoses and mood-related traits reported across genetic, cellular, physiological, and behavioral domains. However, circadian disruption does not appear to be specific to BD and is present across a variety of high-risk, prodromal, and syndromic psychiatric disorders. Substantial variability and ambiguity among the definitions, concepts and assumptions underlying the research have limited replication and the emergence of consensus findings.ConclusionsFuture research in circadian rhythms and its role in BD is warranted. Well-powered studies that carefully define associations between BD-related and chronobiologically-related constructs, and integrate across levels of analysis will be most illuminating.

Bacteria play many important roles in animal digestive systems, including the provision of enzymes critical to digestion. Typically, complex communities of bacteria reside in the gut lumen in direct contact with the ingested materials they help to digest. Here, we demonstrate a previously undescribed digestive strategy in the wood-eating marine bivalve Bankia setacea, wherein digestive bacteria are housed in a location remote from the gut. These bivalves, commonly known as shipworms, lack a resident microbiota in the gut compartment where wood is digested but harbor endosymbiotic bacteria within specialized cells in their gills. We show that this comparatively simple bacterial community produces wood-degrading enzymes that are selectively translocated from gill to gut. These enzymes, which include just a small subset of the predicted wood-degrading enzymes encoded in the endosymbiont genomes, accumulate in the gut to the near exclusion of other endosymbiont-made proteins. This strategy of remote enzyme production provides the shipworm with a mechanism to capture liberated sugars from wood without competition from an endogenous gut microbiota. Because only those proteins required for wood digestion are translocated to the gut, this newly described system reveals which of many possible enzymes and enzyme combinations are minimally required for wood degradation. Thus, although it has historically had negative impacts on human welfare, the shipworm digestive process now has the potential to have a positive impact on industries that convert wood and other plant biomass to renewable fuels, fine chemicals, food, feeds, textiles, and paper products.

Sleep, circadian rhythms, and mental health are reciprocally interlinked. Disruption to the quality, continuity, and timing of sleep can precipitate or exacerbate psychiatric symptoms in susceptible individuals, while treatments that target sleep--circadian disturbances can alleviate psychopathology. Conversely, psychiatric symptoms can reciprocally exacerbate poor sleep and disrupt clock-controlled processes. Despite progress in elucidating underlying mechanisms, a cohesive approach that integrates the dynamic interactions between psychiatric disorder with both sleep and circadian processes is lacking. This review synthesizes recent evidence for sleep--circadian dysfunction as a transdiagnostic contributor to a range of psychiatric disorders, with an emphasis on biological mechanisms. We highlight observations from adolescent and young adults, who are at greatest risk of developing mental disorders, and for whom early detection and intervention promise the greatest benefit. In particular, we aim to a) integrate sleep and circadian factors implicated in the pathophysiology and treatment of mood, anxiety, and psychosis spectrum disorders, with a transdiagnostic perspective; b) highlight the need to reframe existing knowledge and adopt an integrated approach which recognizes the interaction between sleep and circadian factors; and c) identify important gaps and opportunities for further research. [ABSTRACT FROM AUTHOR]

Low‐grade epilepsy‐associated tumors (LEATs) are a common cause of drug‐resistant epilepsy in children. Herein, we demonstrate the feasibility of using tumor tissue derived from stereoelectroencephalography (sEEG) electrodes upon removal to molecularly characterize tumors and aid in diagnosis. An 18‐year‐old male with focal epilepsy and MRI suggestive of a dysembryoplastic neuroepithelial tumor (DNET) in the left posterior temporal lobe underwent implantation of seven peri‐tumoral sEEG electrodes for peri‐operative language mapping and demarcation of the peri‐tumoral ictal zone prior to DNET resection. Using electrodes that passed through tumor tissue, we show successful isolation of tumor DNA and subsequent analysis using standard methods for tumor classification by DNA, including Glioseq targeted sequencing and DNA methylation array analysis. This study provides preliminary evidence for the feasibility of molecular diagnosis of LEATs or other lesions using a minimally invasive method with microscopic tissue volumes. The implications of sEEG electrodes in tumor characterization are broad but would aid in diagnosis and subsequent targeted therapeutic strategies. [ABSTRACT FROM AUTHOR]

Disrupted sleep and circadian rhythms are linked with substance abuse risk. Human studies that investigate relationships between sleep, circadian rhythm, and substance use reward generally rely on indirect means to infer dopaminergic function, such as functional magnetic resonance imaging. In this issue of the JCI, Zhang and colleagues used positron emission tomography (PET) to image striatal dopamine D1 (D1R) and D2/3 receptor (D/3R) availability in healthy adults. The authors assessed rest-activity rhythms, then conducted PET scans using radioligand antagonists selective for D1 receptors or D2/D3 receptors to measure D1R and D2/3R availability. They also measured the subjective drug effects of oral methylphenidate. Higher D1R availability in caudate and a greater methylphenidate reward sensitivity were associated with delayed rest-activity rhythms. Unexpectedly, lower overall activity was associated with higher D2/3R availability in the nucleus accumbens, which coincided with greater methylphenidate reward score. These findings may inform personalized prevention and/or treatment interventions., Linking sleep/circadian rhythm phenotypes with drug reward Disruptions in circadian rhythms and sleep have been increasingly linked to substance abuse risk (1). Along with insomnia and insufficient sleep, a circadian [...]