Abstract
Auditory-verbal hallucinations (AVH) are often associated with high levels of distress and disability in individuals with schizophrenia-spectrum disorders. In around 30% of individuals with ...distressing AVH and diagnosed with schizophrenia, traditional antipsychotic drugs have little or no effect. Thus, it is important to develop mechanistic models of AVH to inform new treatments. Recently a small number of studies have begun to explore the use of real-time functional magnetic resonance imaging neurofeedback (rtfMRI-NF) for the treatment of AVH in individuals with schizophrenia. rtfMRI-NF protocols have been developed to provide feedback about brain activation in real time to enable participants to progressively achieve voluntary control over their brain activity. We offer a conceptual review of the background and general features of neurofeedback procedures before summarizing and evaluating existing mechanistic models of AVH to identify feasible neural targets for the application of rtfMRI-NF as a potential treatment. We consider methodological issues, including the choice of localizers and practicalities in logistics when setting up neurofeedback procedures in a clinical setting. We discuss clinical considerations relating to the use of rtfMRI-NF for AVH in individuals distressed by their experiences and put forward a number of questions and recommendations about best practice. Lastly, we conclude by offering suggestions for new avenues for neurofeedback methodology and mechanistic targets in relation to the research and treatment of AVH.
Achievement motivation is a core component of human decision making. However, neural mechanisms that link achievement motivation and intertemporal choice have not yet been elucidated. Here, we ...examined neural pathways underlying the relationship between achievement motivation and intertemporal choice using a delay discounting task and resting-state functional magnetic resonance imaging on 86 healthy subjects. Behaviorally, delay discounting rate was positively correlated with achievement motivation. Functional coupling of the dorsolateral prefrontal cortex (dlPFC) with the medial prefrontal cortex (mPFC), medial orbitofrontal cortex and ventral striatum was positively correlated with achievement motivation. Notably, the mediation analysis showed that the impact of achievement motivation on delay discounting was mediated by intrinsic connectivity between the dlPFC and mPFC. Our findings suggest that intrinsic organization within the prefrontal cortex plays a key role in linking achievement motivation and intertemporal choice.
Low levels of insulin-like growth factor-1 (IGF-1), an essential neurotrophic factor, have been associated with worse cognitive function in older adults. However, few studies have assessed the ...prospective association of serum IGF-1 with cognitive function. We aimed to determine the association between serum IGF-1 on concurrent and prospective cognitive function in a population sample of men aged 40-80 years. Blood samples were assessed for IGF-1 levels at baseline and neuropsychological assessments were performed at baseline (n = 400) and at follow-up after a mean duration of 8.3 years (n = 286). Linear regression analyses were carried out to determine the associations between quintiles of IGF-1 and cognitive function at the baseline and follow-up visits. Results showed that those in the top quintile of IGF-1 had lower processing capacity and global cognition scores at follow-up after controlling for cognitive function at baseline and other confounding factors. Additional analyses exploring associations with IGF-1 separately in middle-aged and older participants, and with quartiles of IGF-1 produced similar results. In those older than 60 years, high IGF-1 levels were also associated with lower baseline processing capacity. These results suggest that high IGF-1 levels are associated with worse long-term cognition in men. Together with past studies, we suggest that both, high and low levels of IGF-1 may be associated with poor cognitive function and that optimum levels of IGF-1 (quintile 2 and 3 in current study) may be associated with better cognitive function.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Taking the perspective of somebody else (Theory of Mind; ToM) is an essential human ability depending on a large cerebral network comprising prefrontal and temporo-parietal regions. Recently, ToM was ...suggested to consist of two processes: (1) self-perspective inhibition and (2) belief reasoning. Moreover, it has been hypothesized that self-perspective inhibition may build upon basic motor response inhibition. This study tested both hypotheses for the first time using functional Magnetic Resonance Imaging (fMRI), through administering both a ToM and a stop-signal paradigm in the same subjects. Both self-perspective and motor response inhibition yielded bilateral inferior frontal gyrus (IFG) activation, suggesting a common inhibitory mechanism, while belief reasoning was mediated by the superior temporal gyrus (STG) and temporo-parietal junction (TPJ). Thus, we provide neurobiological evidence for a subdivision of ToM into self-perspective inhibition and belief reasoning. Furthermore, evidence for partially shared neural mechanisms for inhibition in complex social situations and basic motor response inhibition was found.
► ToM can be subdivided into self-perspective inhibition and belief reasoning. ► Self-perspective inhibition is mediated by the bilateral IFG. ► Belief reasoning is mediated by the left STG, TPJ and MTG. ► Self-inhibition and response inhibition build upon similar neural mechanisms.
Numerous brain disorders demonstrate structural brain abnormalities, which are thought to arise from molecular perturbations or connectome miswiring. The unique and shared contributions of these ...molecular and connectomic vulnerabilities to brain disorders remain unknown, and has yet to be studied in a single multi-disorder framework. Using MRI morphometry from the ENIGMA consortium, we construct maps of cortical abnormalities for thirteen neurodevelopmental, neurological, and psychiatric disorders from N = 21,000 participants and N = 26,000 controls, collected using a harmonised processing protocol. We systematically compare cortical maps to multiple micro-architectural measures, including gene expression, neurotransmitter density, metabolism, and myelination (molecular vulnerability), as well as global connectomic measures including number of connections, centrality, and connection diversity (connectomic vulnerability). We find a relationship between molecular vulnerability and white-matter architecture that drives cortical disorder profiles. Local attributes, particularly neurotransmitter receptor profiles, constitute the best predictors of both disorder-specific cortical morphology and cross-disorder similarity. Finally, we find that cross-disorder abnormalities are consistently subtended by a small subset of network epicentres in bilateral sensory-motor, inferior temporal lobe, precuneus, and superior parietal cortex. Collectively, our results highlight how local molecular attributes and global connectivity jointly shape cross-disorder cortical abnormalities.
Efficacy of repetitive Transcranial Magnetic Stimulation (rTMS) targeting the temporo-parietal junction (TPJ) for the treatment of auditory verbal hallucinations (AVH) remains under debate. We ...assessed the influence of a 1Hz rTMS treatment on neural networks involved in a cognitive mechanism proposed to subserve AVH.
Patients with schizophrenia (N=24) experiencing medication-resistant AVH completed a 10-day 1Hz rTMS treatment. Participants were randomized to active stimulation of the left or bilateral TPJ, or sham stimulation. The effects of rTMS on neural networks were investigated with an inner speech task during fMRI. Changes within and between neural networks were analyzed using Independent Component Analysis.
rTMS of the left and bilateral TPJ areas resulted in a weaker network contribution of the left supramarginal gyrus to the bilateral fronto-temporal network. Left-sided rTMS resulted in stronger network contributions of the right superior temporal gyrus to the auditory-sensorimotor network, right inferior gyrus to the left fronto-parietal network, and left middle frontal gyrus to the default mode network. Bilateral rTMS was associated with a predominant inhibitory effect on network contribution. Sham stimulation showed different patterns of change compared to active rTMS.
rTMS of the left temporo-parietal region decreased the contribution of the left supramarginal gyrus to the bilateral fronto-temporal network, which may reduce the likelihood of speech intrusions. On the other hand, left rTMS appeared to increase the contribution of functionally connected regions involved in perception, cognitive control and self-referential processing. These findings hint to potential neural mechanisms underlying rTMS for hallucinations but need corroboration in larger samples.
•The effect of rTMS on networks associated with auditory hallucinations are studied.•Left-sided rTMS resulted in reduced involvement of the stimulation site.•Left-sided rTMS increased the contribution of functionally connected regions.•Bilateral rTMS primarily resulted in decreased involvement of brain areas.
While the majority of cognitive studies on auditory hallucinations (AHs) have been conducted in schizophrenia (SZ), an increasing number of researchers are turning their attention to different ...clinical and nonclinical populations, often using SZ findings as a model for research. Recent advances derived from SZ studies can therefore be utilized to make substantial progress on AH research in other groups. The objectives of this article were to (1) present an up-to-date review regarding the cognitive mechanisms of AHs in SZ, (2) review findings from cognitive research conducted in other clinical and nonclinical groups, and (3) integrate these recent findings into a cohesive framework. First, SZ studies show that the cognitive underpinnings of AHs include self-source-monitoring deficits and executive and inhibitory control dysfunctions as well as distortions in top-down mechanisms, perceptual and linguistic processes, and emotional factors. Second, consistent with SZ studies, findings in other population groups point to the role of top-down processing, abnormalities in executive inhibition, and negative emotions. Finally, we put forward an integrated model of AHs that incorporates the above findings. We suggest that AHs arise from an interaction between abnormal neural activation patterns that produce salient auditory signals and top-down mechanisms that include signal detection errors, executive and inhibition deficits, a tapestry of expectations and memories, and state characteristics that influence how these experiences are interpreted. Emotional factors play a particular prominent role at all levels of this hierarchy. Our model is distinctively powerful in explaining a range of phenomenological characteristics of AH across a spectrum of disorders.
Abstract
Alexithymia has been characterized as an impaired ability of emotion processing and regulation. The definition of alexithymia does not include a social component. However, there is some ...evidence that social cognition may be compromised in individuals with alexithymia. Hence, emotional impairments associated with alexithymia may extend to socially relevant information. Here, we recorded electrophysiological responses of individuals meeting the clinically relevant cutoff for alexithymia (ALEX; n = 24) and individuals without alexithymia (NonALEX; n = 23) while they viewed affective scenes that varied on the dimensions of sociality and emotional valence during a rapid serial visual presentation task. We found that ALEX exhibited lower accuracy and larger N2 than NonALEX in the perception of social negative scenes. Source reconstruction revealed that the group difference in N2 was localized at the dorsal anterior cingulate cortex. Irrespective of emotional valence, ALEX showed stronger alpha power than NonALEX in social but not non-social conditions. Our findings support the hypothesis of social processing being selectively affected by alexithymia, especially for stimuli with negative valence. Electrophysiological evidence suggests altered deployment of attentional resources in the perception of social-specific emotional information in alexithymia. This work sheds light on the neuropsychopathology of alexithymia and alexithymia-related disorders.
Alexithymia has been associated with emotion recognition deficits in both auditory and visual domains. Although emotions are inherently multimodal in daily life, little is known regarding ...abnormalities of emotional multisensory integration (eMSI) in relation to alexithymia. Here, we employed an emotional Stroop‐like audiovisual task while recording event‐related potentials (ERPs) in individuals with high alexithymia levels (HA) and low alexithymia levels (LA). During the task, participants had to indicate whether a voice was spoken in a sad or angry prosody while ignoring the simultaneously presented static face which could be either emotionally congruent or incongruent to the human voice. We found that HA performed worse and showed higher P2 amplitudes than LA independent of emotion congruency. Furthermore, difficulties in identifying and describing feelings were positively correlated with the P2 component, and P2 correlated negatively with behavioral performance. Bayesian statistics showed no group differences in eMSI and classical integration‐related ERP components (N1 and N2). Although individuals with alexithymia indeed showed deficits in auditory emotion recognition as indexed by decreased performance and higher P2 amplitudes, the present findings suggest an intact capacity to integrate emotional information from multiple channels in alexithymia. Our work provides valuable insights into the relationship between alexithymia and neuropsychological mechanisms of emotional multisensory integration.
Our behavioral and electrophysiological data provide substantial evidence for intact emotion multisensory integration in relation to alexithymia. With high ecological validity, these findings are of particular importance given that humans are constantly exposed to competing, complex audiovisual emotional information in social interaction contexts. Our work has important implications for the psychophysiology of alexithymia and emotional processing.
The personality trait neuroticism is a potent risk marker for psychopathology. Although the neurobiological basis remains unclear, studies have suggested that alterations in connectivity may underlie ...it. Therefore, the aim of the current study was to shed more light on the functional network organization in neuroticism. To this end, we applied graph theory on resting-state functional magnetic resonance imaging (fMRI) data in 120 women selected based on their neuroticism score. Binary and weighted brain-wide graphs were constructed to examine changes in the functional network structure and functional connectivity strength. Furthermore, graphs were partitioned into modules to specifically investigate connectivity within and between functional subnetworks related to emotion processing and cognitive control. Subsequently, complex network measures (ie, efficiency and modularity) were calculated on the brain-wide graphs and modules, and correlated with neuroticism scores. Compared with low neurotic individuals, high neurotic individuals exhibited a whole-brain network structure resembling more that of a random network and had overall weaker functional connections. Furthermore, in these high neurotic individuals, functional subnetworks could be delineated less clearly and the majority of these subnetworks showed lower efficiency, while the affective subnetwork showed higher efficiency. In addition, the cingulo-operculum subnetwork demonstrated more ties with other functional subnetworks in association with neuroticism. In conclusion, the 'neurotic brain' has a less than optimal functional network organization and shows signs of functional disconnectivity. Moreover, in high compared with low neurotic individuals, emotion and salience subnetworks have a more prominent role in the information exchange, while sensory(-motor) and cognitive control subnetworks have a less prominent role.
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