Brain and neuroscience advances最新文献

Performance on an emotional stop-signal task designed to assess emotional response inhibition has been associated with Negative Urgency and psychopathology, particularly self-injurious behaviors. Indeed, difficulty inhibiting prepotent negative responses to aversive stimuli on the emotional stop-signal task (i.e. poor negative emotional response inhibition) partially explains the association between Negative Urgency and non-suicidal self-injury. Here, we combine existing data sets from clinical (hospitalised psychiatric inpatients) and non-clinical (community/student participants) samples aged 18-65 years (N = 450) to examine the psychometric properties of this behavioural task and evaluate hypotheses that emotional stop-signal task metrics relate to distinct impulsive traits among participants who also completed the UPPS-P (n = 223). We specifically predicted associations between worse negative emotional response inhibition (i.e. commission errors during stop-signal trials representing negative reactions to unpleasant images) and Negative Urgency, whereas commission errors to positive stimuli - reflecting worse positive emotional response inhibition - would relate to Positive Urgency. Results support the emotional stop-signal task's convergent and discriminant validity: as hypothesised, poor negative emotional response inhibition was specifically associated with Negative Urgency and no other impulsive traits on the UPPS-P. However, we did not find the hypothesised association between positive emotional response inhibition and Positive Urgency. Correlations between emotional stop-signal task performance and self-report measures were the modest, similar to other behavioural tasks. Participants who completed the emotional stop-signal task twice (n = 61) additionally provide preliminary evidence for test-retest reliability. Together, findings suggest adequate reliability and validity of the emotional stop-signal task to derive candidate behavioural markers of neurocognitive functioning associated with Negative Urgency and psychopathology.

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. At the systems' level, several studies have investigated the acute ketamine effects on brain activity and connectivity; however, several questions remain unanswered around the brain changes that accompany the drug's antidepressant effects and how these changes relate to the brain areas that appear with altered function and connectivity in depression. This review aims to address some of these questions by focusing on resting-state brain connectivity. We summarise the studies that have examined connectivity changes in treatment-naïve, depressed individuals and those studies that have looked at the acute and delayed effects of ketamine in healthy and depressed volunteers. We conclude that brain areas that are important for emotional regulation and reward processing appear with altered connectivity in depression whereas the default mode network presents with increased connectivity in depressed individuals compared to healthy controls. This finding, however, is not as prominent as the literature often assumes. Acute ketamine administration causes an increase in brain connectivity in healthy volunteers. The delayed effects of ketamine on brain connectivity vary in direction and appear to be consistent with the drug normalising the changes observed in depression. The limited number of studies however, as well as the different approaches for resting-state connectivity analysis make it very difficult to draw firm conclusions and highlight the importance of data sharing and larger future studies.

The study assessed a mobile electroencephalography system with water-based electrodes for its applicability in cognitive and behavioural neuroscience. It was compared to a standard gel-based wired system. Electroencephalography was recorded on two occasions (first with gel-based, then water-based system) as participants completed the flanker task. Technical and practical considerations for the application of the water-based system are reported based on participant and experimenter experiences. Empirical comparisons focused on electroencephalography data noise levels, frequency power across four bands (theta, alpha, low beta and high beta) and event-related components (P300 and ERN). The water-based system registered more noise compared to the gel-based system which resulted in increased loss of data during artefact rejection. Signal-to-noise ratio was significantly lower for the water-based system in the parietal channels which affected the observed parietal beta power. It also led to a shift in topography of the maximal P300 activity from parietal to frontal regions. The water-based system may be prone to slow drift noise which may affect the reliability and consistency of low-frequency band analyses. Practical considerations for the use of water-based electrode electroencephalography systems are provided.

There is currently no brain atlas available to specifically determine stereotaxic coordinates for neurosurgery in Lister hooded rats despite the popularity of this strain for behavioural neuroscience studies in the United Kingdom and elsewhere. We have created a dataset, which we refer to as 'Ratlas-LH' (for Lister hooded). Ratlas-LH combines in vivo magnetic resonance images of the brain of young adult male Lister hooded rats with ex vivo micro-computed tomography images of the ex vivo skull, as well as a set of delineations of brain regions, adapted from the Waxholm Space Atlas of the Sprague Dawley Rat Brain. Ratlas-LH was produced with an isotropic resolution of 0.15 mm. It has been labelled in such a way as to provide a stereotaxic coordinate system for the determination of distances relative to the skull landmark of bregma. We have demonstrated that the atlas can be used to determine stereotaxic coordinates to accurately target brain regions in the Lister hooded rat brain. Ratlas-LH is freely available to facilitate neurosurgical procedures in the Lister hooded rat.

Apathy is widely reported in patients with neurological disorders or post viral infection but is also seen in otherwise-healthy aged individuals. This study investigated whether aged male mice express behavioural and physiological changes relevant to an apathy phenotype. Using measures of motivation to work for reward, we found deficits in the progressive ratio task related to rate of responding. In an effort-related decision-making task, aged mice were less willing to exert effort for high value reward. Aged mice exhibited reduced reward sensitivity but also lower measures of anxiety in the novelty supressed feeding test and an attenuated response to restraint stress with lower corticosterone and reduced paraventricular nucleus c-fos activation. This profile of affective changes did not align with those observed in models of depression but suggested emotional blunting. In a test of cognition (novel object recognition), aged mice showed no impairments, but activity was lower in a measure of exploration in a novel environment. Together, these data suggest aged mice show changes across the domains of motivated behaviour, reward sensitivity and emotional reactivity and may be a suitable model for the pre-clinical study of the psychiatric symptom of apathy.