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Profound neuroplastic changes have been demonstrated in various limbic structures after chronic stress exposure and antidepressant treatment in animal models of mood disorders. Here, we examined in rats the effect of chronic social stress and concomitant antidepressant treatment on cell proliferation in the medial prefrontal cortex (mPFC). We also examined(More)
Stress, especially chronic stress, is one of the most important factors responsible for precipitation of affective disorders in humans. The animal models commonly used in the investigation of stress effects are based mainly on powerful physical stressors. In the majority of cases, these models are not relevant to situations that human beings encounter in(More)
Chronic social stress is one of the most important factors responsible for precipitation of depressive disorder in humans. In recent years, the impact of social stress on the development of psychopathologies has been thoroughly investigated in preclinical animal studies. We have shown recently that behavioural effects of chronic social stress in rats can be(More)
Recently, we described an advanced model of chronic social stress in male rats based on the resident intruder paradigm. In this model, rats subjected to daily social stress for 5 weeks showed behavioral changes resembling anhedonia and motivational deficits in humans. In the present study, male Wistar rats were subjected to 5 weeks of daily social defeat by(More)
Depressive disorder is often associated with cognitive biases. In this study, we took a unique opportunity to investigate whether trait pessimism could predict vulnerability to stress-induced anhedonia in an animal model of depression. In a series of ambiguous-cue interpretation (ACI) tests, we identified animals displaying 'pessimistic' and 'optimistic'(More)
Using a model of depression in which chronic social stress induces depressive-like symptoms, we investigated effects of the selective serotonin-reuptake inhibitor (SSRI) citalopram on gene expression in the dorsal raphe nucleus of male rats. Expression of tryptophan hydroxylase (TPH) protein was found to be upregulated by the stress and normalized by(More)
The neuropeptide Y (NPY) system has been largely studied in relation to affective disorders, in particular for its role in the mechanisms regulating the pathophysiology of anxiety and depression and in the stress-related behaviours. Although NPY has been previously investigated in a variety of animal models of mood disorders, the receptor subtype mainly(More)
Recently, we have described a new model of chronic social stress in rats, based on the resident-intruder paradigm. In this model, rats show behavioural changes that may be considered correlates of depressive symptoms, such as anhedonia and motivational deficits. The present study was designed for pharmacological validation of this model. Animals were(More)
Emotions can bias human decisions- for example depressed or anxious people tend to make pessimistic judgements while those in positive affective states are often more optimistic. Several studies have reported that affect contingent judgement biases can also be produced in animals. The animals, however, cannot self-report; therefore, the valence of their(More)
The discrimination reversal paradigm is commonly used to measure a subject's ability to adapt their behavior according to changes in stimulus-reward contingencies. Human functional neuroimaging studies have demonstrated activations in the lateral orbitofrontal cortex (OFC) and the inferior frontal gyrus (IFG) in subjects performing this task. Excitotoxic(More)