Objective:Auditory verbal hallucinations (AVHs) constitute severe, incapacitating symptoms of schizophrenia. Despite increasing interest in the functional exploration of AVHs, the available findings remain difficult to integrate because of their considerable variability. The authors' aim was to perform a robust quantitative review of existing functional data in order to elucidate consistent patterns observed during the emergence of AVHs and to orient new pathophysiological models of hallucinations. Method:Ten positron emission tomography or functional magnetic resonance imaging studies were selected for the meta-analysis after systematic review. A total of 68 patients with schizophrenia spectrum disorders experiencing AVHs during scanning were included. According to a random-effects activation likelihood estimation algorithm, stereotaxic coordinates of 129 foci, reported as significant in the source studies, were extracted and computed to estimate the brain locations most consistently associated with AVHs...

https://ajp.psychiatryonline.org/doi/pdf/10.1176/appi.ajp.2010.09101522

Cortical Activations During Auditory Verbal Hallucinations in Schizophrenia: A Coordinate-Based Meta-Analysis

Urbanization has many benefits, but it also is associated with increased levels of mental illness, including depression. It has been suggested that decreased nature experience may help to explain the link between urbanization and mental illness. This suggestion is supported by a growing body of correlational and experimental evidence, which raises a further question: what mechanism(s) link decreased nature experience to the development of mental illness? One such mechanism might be the impact of nature exposure on rumination, a maladaptive pattern of self-referential thought that is associated with heightened risk for depression and other mental illnesses. We show in healthy participants that a brief nature experience, a 90-min walk in a natural setting, decreases both self-reported rumination and neural activity in the subgenual prefrontal cortex (sgPFC), whereas a 90-min walk in an urban setting has no such effects on self-reported rumination or neural activity. In other studies, the sgPFC has been associated with a self-focused behavioral withdrawal linked to rumination in both depressed and healthy individuals. This study reveals a pathway by which nature experience may improve mental well-being and suggests that accessible natural areas within urban contexts may be a critical resource for mental health in our rapidly urbanizing world.

/pdf/nature-experience-reduces-rumination-and-subgenual-4c07zw7cbi.pdf

Nature experience reduces rumination and subgenual prefrontal cortex activation

Prediction as a Humanitarian and Pragmatic Contribution from Human Cognitive Neuroscience

How can the brain's resting state activity generate hallucinations? A ‘resting state hypothesis’ of auditory verbal hallucinations

The neural mechanisms of hallucinations: A quantitative meta-analysis of neuroimaging studies.

Previous small-sample studies have shown altered frontotemporal activity in schizophrenia patients with auditory hallucinations and impaired monitoring of self-generated speech. We examined a large cohort of patients with schizophrenia (n = 63) and a representative group of healthy controls (n = 20) to disentangle performance, illness, and symptom-related effects in functional magnetic resonance imaging-detected brain abnormalities during monitoring of self- and externally generated speech in schizophrenia. Our results revealed activation of the thalamus (medial geniculate nucleus, MGN) and frontotemporal regions with accurate monitoring across all participants. Less activation of the thalamus (MGN, pulvinar) and superior-middle temporal and inferior frontal gyri occurred in poorly performing patients (1 standard deviation below controls' mean; n = 36), relative to the combined group of controls and well-performing patients. In patients, (1) greater deactivation of the ventral striatum and hypothalamus to own voice, combined with nonsignificant activation of the same regions to others' voice, associated positively with negative symptoms (blunted affect, emotional withdrawal, poor rapport, passive social avoidance) regardless of performance and (2) exaggerated activation of the right superior-middle temporal gyrus during undistorted, relative to distorted, feedback associated with both positive symptoms (hallucinations, persecution) and poor performance. A further thalamic abnormality characterized schizophrenia patients regardless of performance and symptoms. We conclude that hypoactivation of a neural network comprised of the thalamus and frontotemporal regions underlies impaired speech monitoring in schizophrenia. Positive symptoms and poor monitoring share a common activation abnormality in the right superior temporal gyrus during processing of degraded speech. Altered striatal and hypothalamic modulation to own and others' voice characterizes emotionally withdrawn and socially avoidant patients.

/pdf/functional-mri-of-verbal-self-monitoring-in-schizophrenia-4g540r2gpu.pdf

Functional MRI of Verbal Self-monitoring in Schizophrenia: Performance and Illness-Specific Effects

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Despite the favourable effects of antipsychotics on positive symptoms of schizophrenia, many patients continue to suffer from distressing symptoms. Additional benefi ts of cognitive behavior therapy for psychosis (CBTp) have been reported for approximately 50% of such patients. Given the role of left hemisphere-based language processes in responsiveness to CBT for depression, and language pathway abnormalities in psychosis, this study examined whether pre-therapy brain activity during a verbal monitoring task predicts CBTp responsiveness in schizophrenia. Fifty-two outpatients, stable on antipsychotics with at least one persistent distressing positive symptom and wishing to receive CBTp adjunctive to their treatment-as-usual, and 20 healthy participants underwent fMRI during monitoring of self- and externally-generated (normal and distorted) speech. Subsequently, 26 patients received CBTp for 6-8 months adjunctive to their treatment-as-usual (CBTp + TAU, 20 completers), and 26 continued with their treatment-as-usual (TAU-alone, 18 completers). Symptoms were assessed (blindly) at entry and follow-up. The CBTp + TAU and TAU-alone groups had comparable demographic characteristics, performance and baseline symptoms. Only the CBTp + TAU group showed improved symptoms at follow-up. CBTp responsiveness was associated with (i) greater left inferior frontal gyrus (IFG) activity during accurate monitoring, especially of own voice, (ii) less inferior parietal deactivation with own,  relative to others', voice, and (iii) less medial prefrontal deactivation and greater thalamic and precuneus activation during monitoring of distorted, relative to undistorted, voices. CBTp + TAU patients, on average, displayed left IFG and thalamic hypo-activation  (

/pdf/beyond-dopamine-functional-mri-predictors-of-responsiveness-1bog8dwygw.pdf

Beyond dopamine: functional MRI predictors of responsiveness to cognitive behaviour therapy for psychosis.

Background: An area of recent interest in schizophrenia research is to investigate specific neural and cognitive abnormalities associated with symptoms of this disorder.



Objective:  To establish clinical, cognitive and neural correlates of self-monitoring deficits in schizophrenia, which according to various theoretical models can account for the first-rank symptoms of this disorder.



Methods:  Relevant data were identified from PubMed and PsycInfo searches up to July 2006 using combinations of keywords including ‘self-monitoring’, ‘symptoms’, ‘self-agency’, ‘neuropsychological’, ‘cognitive’, ‘brain activity’, ‘PET’ and ‘fMRI’.



Conclusions:  Self-monitoring deficit is most consistently observed in patients with schizophrenia with auditory hallucinations and passivity experiences. This deficit may not be schizophrenia specific. At present, there are insufficient direct data to reach meaningful conclusions about the cognitive correlates of this deficit. Functional neuroimaging studies in patients with schizophrenia with auditory hallucinations point to defective engagement of the neural regions known to be involved in self-monitoring in healthy people. Further multimodal studies using validated cognitive and clinical measures, self-monitoring paradigms and appropriate imaging tools to analyze patients with schizophrenia with and without self-monitoring deficits are required to increase our understanding of this topic.

Vinodkumar Raveendran

Papers

Functional MRI of Verbal Self-monitoring in Schizophrenia: Performance and Illness-Specific Effects

Beyond dopamine: functional MRI predictors of responsiveness to cognitive behaviour therapy for psychosis.

Clinical, cognitive and neural correlates of self-monitoring deficits in schizophrenia: an update