An experimental approach to training mood for resilience.

According to influential theories about mood, exposure to environments characterized by specific patterns of punishments and rewards could shape mood response to future stimuli. This raises the intriguing possibility that mood could be trained by exposure to controlled environments. The aim of the present study is to investigate experimental settings that increase resilience of mood to negative stimuli.

Review: The use of functional magnetic resonance imaging (fMRI) in clinical trials and experimental research studies for depression.

Functional magnetic resonance imaging (fMRI) is a non-invasive technique that can be used to examine neural responses with and without the use of a functional task. Indeed, fMRI has been used in clinical trials and pharmacological research studies. In mental health, it has been used to identify brain areas linked to specific symptoms but also has the potential to help identify possible treatment targets.

Exploring randomness in autism.

Introduction: The fast, intuitive and autonomous system 1 along with the slow, analytical and more logical system 2 constitute the dual system processing model of decision making. Whether acting independently or influencing each other both systems would, to an extent, rely on randomness in order to reach a decision. The role of randomness, however, would be more pronounced when arbitrary choices need to be made, typically engaging system 1.

Functional MRI markers for treatment-resistant depression: Insights and challenges.

Imaging studies of treatment-resistant depression (TRD) have examined brain activity, structure, and metabolite concentrations to identify critical areas of investigation in TRD as well as potential targets for treatment interventions. This chapter provides an overview of the main findings of studies using three imaging modalities: structural magnetic resonance imaging (MRI), functional MRI (fMRI), and magnetic resonance spectroscopy (MRS). Decreased connectivity and metabolite concentrations in frontal brain areas appear to characterize TRD, although results are not consistent across studies.

Reduced cortical cerebral blood flow in antipsychotic-free first-episode psychosis and relationship to treatment response.

Background: Altered cerebral blood flow (CBF) has been found in people at risk for psychosis, with first-episode psychosis (FEP) and with chronic schizophrenia (SCZ). Studies using arterial spin labelling (ASL) have shown reduction of cortical CBF and increased subcortical CBF in SCZ. Previous studies have investigated CBF using ASL in FEP, reporting increased CBF in striatum and reduced CBF in frontal cortex.

Strategic decision making and prediction differences in autism.

Background: Several theories in autism posit that common aspects of the autism phenotype may be manifestations of an underlying differentiation in predictive abilities. The present study investigates this hypothesis in the context of strategic decision making in autistic participants compared to a control group.

Method: Autistic individuals (43 adults, 35 male) and a comparison group (42 adults, 35 male) of age and gender matched individuals, played a modified version of the prisoner's dilemma (PD) task where they were asked, if capable, to predict their opponents' move.

Factors of influence in prisoner's dilemma task: a review of medical literature.

The Prisoner's Dilemma (PD) is one of the most popular concepts amongst the scientific literature. The task is used in order to study different types of social interactions by giving participants the choice to defect or cooperate in a specific social setting/dilemma. This review focuses on the technical characteristics of the PD task as it is used in medical literature and describes how the different PD settings could influence the players' behaviour.

Resting-state connectivity studies as a marker of the acute and delayed effects of subanaesthetic ketamine administration in healthy and depressed individuals: A systematic review.

Acute ketamine administration has been widely used in neuroimaging research to mimic psychosis-like symptoms. Within the last two decades, ketamine has also emerged as a potent, fast-acting antidepressant. The delayed effects of the drug, observed 2-48 h after a single infusion, are associated with marked improvements in depressive symptoms.

Ketamine Modulates the Neural Correlates of Reward Processing in Unmedicated Patients in Remission From Depression.

Background: Ketamine as an antidepressant improves anhedonia as early as 2 hours after infusion. These drug effects are thought to be exerted via actions on reward-related brain areas-yet these actions remain largely unknown. Our study investigates ketamine's effects during the anticipation and receipt of an expected reward, after the psychotomimetic effects of ketamine have passed, when early antidepressant effects are reported.

The relationship between grey matter volume and striatal dopamine function in psychosis: a multimodal F-DOPA PET and voxel-based morphometry study.

A leading hypothesis for schizophrenia and related psychotic disorders proposes that cortical brain disruption leads to subcortical dopaminergic dysfunction, which underlies psychosis in the majority of patients who respond to treatment. Although supported by preclinical findings that prefrontal cortical lesions lead to striatal dopamine dysregulation, the relationship between prefrontal structural volume and striatal dopamine function has not been tested in people with psychosis. We therefore investigated the in vivo relationship between striatal dopamine synthesis capacity and prefrontal grey matter volume in treatment-responsive patients with psychosis, and compared them to treatment non-responsive patients, where dopaminergic mechanisms are not thought to be central.

Group II metabotropic glutamate receptor agonist prodrugs LY2979165 and LY2140023 attenuate the functional imaging response to ketamine in healthy subjects.

Background: Aberrant glutamate neurotransmission, and in particular dysfunction of the N-methyl-D-aspartate receptor (NMDAR), has been implicated in psychiatric disorders and represents a novel therapeutic target. Low-dose administration of the NMDA antagonist ketamine in healthy volunteers elicits a strong blood oxygenation level dependent (BOLD) imaging signal that can be attenuated by pretreatment with single, therapeutically effective doses of marketed medicines interacting with the glutamate system.

Objective: To test the attenuation of the ketamine-induced BOLD signal by pretreatment with either a metabotropic glutamate receptor (mGluR) 2/3 or a mGluR2 agonist in healthy volunteers METHODS: We used a ketamine challenge pharmacological magnetic resonance imaging (phMRI) paradigm to assess the modulatory effects of single acute doses of LY2140023 (pomaglumetad methionil), the methionine prodrug of the mGluR2/3 agonist LY404039 (10, 40, and 160 mg; N = 16 subjects) and of LY2979165, and the alanine prodrug of the selective orthosteric mGluR2 agonist 2812223 (20 and 60 mg; N = 16 subjects).

Drk-mediated signaling to Rho kinase is required for anesthesia-resistant memory in .

Anesthesia-resistant memory (ARM) was described decades ago, but the mechanisms that underlie this protein synthesis-independent form of consolidated memory in remain poorly understood. Whether the several signaling molecules, receptors, and synaptic proteins currently implicated in ARM operate in one or more pathways and how they function in the process remain unclear. We present evidence that Drk, the ortholog of the adaptor protein Grb2, is essential for ARM within adult mushroom body neurons.

Perceptual distortions and delusional thinking following ketamine administration are related to increased pharmacological MRI signal changes in the parietal lobe.

Ketamine produces effects in healthy humans that resemble the positive, negative and cognitive symptoms of schizophrenia. We investigated the effect of ketamine administration on brain activity as indexed by blood-oxygen-level-dependent (BOLD) signal change response, and its relationship to ketamine-induced subjective changes, including perceptual distortion. Thirteen healthy participants volunteered for the study.