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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The current study examined the neurochemical mechanisms and neuroanatomical changes underlying coexisting behavioral effects associated with chronic-stress-induced alterations in serotonin (5HT) neurons. Chronic unpredictable stress (CUS) to adult male rats produced depression-like changes with cognitive dysfunction and selective cell death in the interfascicular nucleus of the dorsal raphe (DRif), resulting in decreased 5HTergic innervation of medial prefrontal cortex (mPFC). Twenty-one days of CUS decreased basal plasma levels of corticosterone and produced a shorter latency to immobility and longer durations of immobility in the force-swim test that persisted for 1 month after CUS. Deficits in acquisition, recall, perseveration, and reversal learning were evident 1 month after CUS. MK801 treatment during CUS blocked the changes in the forced-swim test and deficits in memory recall. These behavioral changes were associated with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive soma and the eventual loss of 5HT neurons in the DRif and its projections to the mPFC as evidenced by fewer labeled cells in the DRif after retrograde tracer injections into the mPFC of stressed rats. Similar to the effects of MK801 on behavior, MK801 pretreatment during stress blocked the CUS-induced decreases in 5HT soma within the DRif and its projections to the mPFC. Finally, the depression-like behaviors were blocked by acute injection of the 5HT2A/C agonist (-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride into the mPFC before forced-swim testing. These results identify a cause and mechanism of 5HTergic dysfunction of the mPFC and associated mood and cognitive behaviors.SIGNIFICANCE STATEMENT Chronic stress causes persistent mood and cognitive changes typically associated with dysregulated serotonin (5HT) transmission in the medial prefrontal cortex (mPFC), but the cause of this dysregulation is unknown. Prior studies have focused on 5HTergic terminals in this region, but this study shows that chronic stress causes NMDA-receptor-dependent and subregion-specific cell death of 5HT neurons in the dorsal raphe. The consequent decreased 5HT innervation of the mPFC was associated with mood and cognitive changes that persisted long after the termination of stress. These findings identify a mechanism of subregion-selective death of 5HT neurons in the dorsal raphe, a defined neuroanatomical pathway, and a behavioral phenotype that mirror stress-associated diseases such as major depressive disorder.
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PMID:Chronic-Stress-Induced Behavioral Changes Associated with Subregion-Selective Serotonin Cell Death in the Dorsal Raphe. 2854 14

Repetitive cognition, including rumination such as that seen in depression, has been shown to correlate with depression symptoms in both typically developing individuals and individuals with autism spectrum disorder. Repetitive cognition is more common in autism spectrum disorder than in typically developing peers, as is depression; thus, this study evaluated the role of repetitive cognition in relation between autism spectrum symptomatology and depressive symptomatology. In all, 200 typically developing adults completed self-report questionnaires measuring autism spectrum symptomatology, different forms of repetitive cognition (general perseveration and depressive rumination), depression, and rejection sensitivity. Perseveration was found to mediate the relation between autism spectrum symptoms and depression, and to partially mediate the relation between autism spectrum symptoms and rejection sensitivity. We conclude that it is of vital importance to consider cognition when considering depression in autism spectrum disorder.
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PMID:Hooked on a feeling: Repetitive cognition and internalizing symptomatology in relation to autism spectrum symptomatology. 2874 70

Adult neurogenesis involves the generation of new neurons, particularly in the dentate gyrus of the hippocampus. Decreased hippocampal neurogenesis has been implicated in both animal models of depression and in patients with major depressive disorder (MDD), despite some inconsistency in the literature. Here, we build upon current models to generate a new testable hypothesis, linking impaired neurogenesis to downstream psychological outcomes commonly observed in MDD. We contend that disruption in adult neurogenesis impairs pattern separation, a hippocampus-dependent function requiring the careful discrimination and storage of highly similar, but not identical, sensory inputs. This, in turn, can affect downstream processing and response selection, of relevance to emotional wellbeing. Specifically, disrupted pattern separation leads to misperceived stimuli (i.e., stimulus confusion), triggering the selection and deployment of established responses inappropriate for the actual stimuli. We speculate that this may be akin to activation of automatic thoughts, described in the Cognitive Behavior Theory of MDD. Similarly, this impaired ability to discriminate information at a fundamental sensory processing level (e.g., impaired pattern separation) could underlie impaired psychological flexibility, a core component of Acceptance and Commitment Therapy of MDD. We propose that research is needed to test this model by examining the relationship between cognitive functioning (e.g., pattern separation ability), psychological processes (e.g., perseveration and psychological inflexibility), and neurogenesis, taking advantage of emerging magnetic resonance spectroscopy-based imaging that measures neurogenesis in-vivo.
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PMID:Pattern Separation: A Potential Marker of Impaired Hippocampal Adult Neurogenesis in Major Depressive Disorder. 2912 64

Maintenance of adequate tissue perfusion through a dense network of cerebral microvessels is critical for the perseveration of normal brain function. Regulation of the cerebral blood flow has to ensure adequate delivery of nutrients and oxygen with moment-to-moment adjustments to avoid both hypo- and hyper-perfusion of the brain tissue. Even mild impairments of cerebral blood flow regulation can have significant implications on brain function. Evidence suggests that chronic stress and depression elicits multifaceted functional impairments to the cerebral microcirculation, which plays a critical role in brain health and the pathogenesis of stress-related cognitive impairment and cerebrovascular events. Identifying the functional and structural changes to the brain that are induced by stress is crucial for achieving a realistic understanding of how related illnesses, which are highly disabling and with a large economic cost, can be managed or reversed. This overview discusses the stress-induced alterations in neurovascular coupling with specific attention to cerebrovascular regulation (endothelial dependent and independent vasomotor function, microvessel density). The pathophysiological consequences of cerebral microvascular dysfunction with stress and depression are explored.
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PMID:Cerebrovascular dysfunction with stress and depression. 3027 36

Research has indicated that craving is one of the strongest predictors of treatment outcome and relapse in Alcohol Use Disorders (AUD) but there is little consensus on the factors that may influence its activation and escalation. Research has also shown that desire thinking is an important cognitive process which may exacerbate craving in problem drinkers. The aim of present study was to explore, for the first time, the role of desire thinking in prospectively predicting relapse, craving and binge drinking in patients receiving treatment for AUD. One hundred and thirty-five patients admitted to two rehabilitation centres and two outpatient services for addiction and mental health problems were administered baseline, treatment completion and three months follow-up measures of anxiety and depression, AUD severity, binge drinking frequency, craving and desire thinking. Results indicated that the verbal perseveration component of desire thinking at treatment completion was the only significant predictor of relapse at follow-up over and above baseline AUD severity and binge drinking frequency. Furthermore, the imaginal prefiguration component of desire thinking and craving levels at treatment completion were found to predict craving levels at follow-up independently of AUD severity and binge drinking frequency at baseline. Finally, both the imaginal prefiguration and verbal perseveration components of desire thinking at treatment completion were found to be the only predictors of binge drinking frequency at follow-up independently of AUD severity and binge drinking frequency at baseline. Treatments for AUD should aim to reduce desire thinking in people to enhance clinical outcomes and reduce relapse risk.
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PMID:Desire thinking as a predictor of drinking status following treatment for alcohol use disorder: A prospective study. 3085 46

Seasonal variations in environmental light influence switches between moods in seasonal affective disorder (SAD) and bipolar disorder (BD), with depression arising during short active (SA) winter periods. Light-induced changes in behavior are also seen in healthy animals and are intensified in mice with reduced dopamine transporter expression. Specifically, decreasing the nocturnal active period (SA) of mice increases punishment perseveration and forced swim test (FST) immobility. Elevating acetylcholine with the acetylcholinesterase inhibitor physostigmine induces depression symptoms in people and increases FST immobility in mice. We used SA photoperiods and physostigmine to elevate acetylcholine prior to testing in a probabilistic learning task and the FST, including reversing subsequent deficits with nicotinic and scopolamine antagonists and targeted hippocampal adeno-associated viral administration. We confirmed that physostigmine also increases punishment sensitivity in a probabilistic learning paradigm. In addition, muscarinic and nicotinic receptor blockade attenuated both physostigmine-induced and SA-induced phenotypes. Finally, viral-mediated hippocampal expression of human AChE used to lower ACh levels blocked SA-induced elevation of FST immobility. These results indicate that increased hippocampal acetylcholine neurotransmission is necessary for the expression of SA exposure-induced behaviors. Furthermore, these studies support the potential for cholinergic treatments in depression. Taken together, these results provide evidence for hippocampal cholinergic mechanisms in contributing to seasonally depressed affective states induced by short day lengths.
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PMID:Converging evidence that short-active photoperiod increases acetylcholine signaling in the hippocampus. 3279 1


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