Neural correlates of audiovisual sensory integration.

OBJECTIVE: The present study aimed to investigate the neural basis of information matching during sensory integration using a spatial-temporal matching task in healthy individuals. METHOD: A total of 37 healthy participants were recruited to match spatial dots with an auditory tone sequence in a 3T GE Discovery MR750 scanner. In addition, they were examined with the sensory integration subscale of the Cambridge Neurological Inventory. RESULTS: We found that the bilateral occipital-parietal conjunction cortex and the precentral frontal gyrus were activated during the matching condition rather than in the nonmatching condition. Activation of the occipital-parietal conjunction cortex was associated with integration of information across visual and auditory modalities, whereas activation of the precentral frontal gyrus was associated with decision making of movements. In addition, activation of the left superior frontal gyrus was associated with scores on the sensory integration subscale of the Cambridge Neurological Inventory. CONCLUSIONS: These findings suggest that the bilateral occipital-parietal conjunction cortex is responsible for matching information input from multiple modalities during audiovisual sensory integration. (PsycINFO Database Record

Effects of aripiprazole and haloperidol on neural activation during a simple motor task in healthy individuals: A functional MRI study.

The dopaminergic system plays a key role in motor function and motor abnormalities have been shown to be a specific feature of psychosis. Due to their dopaminergic action, antipsychotic drugs may be expected to modulate motor function, but the precise effects of these drugs on motor function remain unclear. We carried out a within-subject, double-blind, randomized study of the effects of aripiprazole, haloperidol and placebo on motor function in 20 healthy men. For each condition, motor performance on an auditory-paced task was investigated. We entered maps of neural activation into a random effects general linear regression model to investigate motor function main effects. Whole-brain imaging revealed a significant treatment effect in a distributed network encompassing posterior orbitofrontal/anterior insula cortices, and the inferior temporal and postcentral gyri. Post-hoc comparison of treatments showed neural activation after aripiprazole did not differ significantly from placebo in either voxel-wise or region of interest analyses, with the results above driven primarily by haloperidol. We also observed a simple main effect of haloperidol compared with placebo, with increased task-related recruitment of posterior cingulate and precentral gyri. Furthermore, region of interest analyses revealed greater activation following haloperidol compared with placebo in the precentral and post-central gyri, and the putamen. These diverse modifications in cortical motor activation may relate to the different pharmacological profiles of haloperidol and aripiprazole, although the specific mechanisms underlying these differences remain unclear. Evaluating healthy individuals can allow investigation of the effects of different antipsychotics on cortical activation, independently of either disease-related pathology or previous treatment. Hum Brain Mapp 38:1833-1845, 2017. © 2017 Wiley Periodicals, Inc.

Effects of antipsychotics on cortisol, interleukin-6 and hippocampal perfusion in healthy volunteers.

This randomized within-subject, double blind study aimed to compare the effects of a single dose of two different antipsychotics (haloperidol and aripiprazole) on cortisol, interleukin (IL)-6 and hippocampal regional Cerebral Blood Flow (rCBF) in the same 17 healthy male individuals. Subjects received a single dose of haloperidol (3mg), aripiprazole (10mg) and placebo, in a randomized order on three study appointments. We measured salivary cortisol levels at multiple time points, IL-6 levels from plasma samples, and resting cerebral blood flow (rCBF), using a pulsed continuous arterial spin labeling (pCASL) sequence (1.5T). We found significantly lower cortisol levels in the haloperidol condition (F(2,32)=5.78, p=0.007), than in either placebo (p=0.013; CI=0.45, 0.406) or aripiprazole (p=0.037; CI=-0.520, -0.014). Interleukin-6 levels were also lower following haloperidol (F(2,22)=4.19, p=0.048) in comparison with placebo (p=0.02; CI=0.14, 1.8), but not with aripiprazole. Finally, we found a greater rCBF in the right (peak voxel: T=6.47, p<0.0001) and left (peak voxel T=5.17, p<0.01) hippocampus following haloperidol compared with placebo, and at trend level also in the left hippocampus following aripiprazole compared with placebo (T=4.07, p=0.057). These differences in hippocampal rCBF after both antipsychotics were no longer evident (haloperidol) or present at trend level (aripiprazole), after controlling for cortisol and IL-6 levels. Our findings suggest that haloperidol can directly regulate the hypothalamic-pituitary-adrenal (HPA) axis and immune system through a pharmacological action via D2 receptor antagonism. Finally, our data suggest that the increased hippocampal rCBF is a manifestation of the reduction in IL-6 and cortisol which follows the administration of haloperidol.

Effects of aripiprazole and haloperidol on neural activation during the n-back in healthy individuals: A functional MRI study.

OBJECTIVE: Antipsychotic drugs target neurotransmitter systems that play key roles in working memory. Therefore, they may be expected to modulate this cognitive function via their actions at receptors for these neurotransmitters. However, the precise effects of antipsychotic drugs on working memory function remain unclear. Most studies have been carried out in clinical populations, making it difficult to disentangle pharmacological effects from pathology-related brain activation. In this study, we aim to investigate the effects of two antipsychotic compounds on brain activation during working memory in healthy individuals. This would allow elucidation of the effects of current antipsychotic treatments on brain function, independently of either previous antipsychotic use or disease-related pathology. METHODS: We carried out a fully counterbalanced, randomised within-subject, double-blinded and placebo-controlled, cross-over study of the effects of two antipsychotic drugs on working memory function in 17 healthy individuals, using the n-back task. Participants completed the functional MRI task on three separate occasions (in randomised order): following placebo, haloperidol, and aripiprazole. For each condition, working memory ability was investigated, and maps of neural activation were entered into a random effects general linear regression model to investigate main working memory function and linear load. Voxel-wise and region of interest analyses were conducted to attain regions of altered brain activation for each intervention. RESULTS: Aripiprazole did not lead to any changes in neural activation compared with placebo. However, reaction time to a correct response was significantly increased following aripiprazole compared to both placebo (p=0.046) and haloperidol (p=0.02). In contrast, compared to placebo, haloperidol dampened activation in parietal (BA 7/40; left: FWE-corr. p=0.005; FWE-corr. right: p=0.007) and frontal (including prefrontal; BA 9/44/46; left: FWE-corr. p=0.009; right: FWE-corr. p=0.014) cortices and the left putamen (FWE-corr. p=0.004). Compared with aripiprazole, haloperidol dampened activation in parietal cortex (BA7/40; left: FWE-corr. p=0.034; right: FWE-corr. p=0.045) and the left putamen (FWE-corr.p=0.015). Haloperidol had no effect on working memory performance compared with placebo. CONCLUSION: Cognitive functions are known to be impaired in schizophrenia and as such are an important target of treatments. Elucidating the mechanisms by which antipsychotic medications alter brain activation underlying cognition is essential to advance pharmacological treatment of this disorder. Studies in healthy individuals can help elucidate some of these mechanisms, whilst limiting the confounding effect of the underlying disease-related pathology. Our study provides evidence for immediate and differential effects of single-dose haloperidol and aripiprazole on brain activation during working memory in healthy individuals. We propose that these differences likely reflect their different receptor affinity profiles, although the precise mechanisms underlying these differences remain unclear.

A systematic review and meta-analysis of the effects of antipsychotic medications on regional cerebral blood flow (rCBF) in schizophrenia: association with response to treatment.

Evaluating the short- and long-term effects of antipsychotics on brain physiology is a key factor in advancing our understanding of neurophysiological changes in psychosis and improving prediction of treatment response. Understanding the nature of such changes is crucial to the interpretation of neuroimaging findings in patients with schizophrenia and psychoses in general. This review has systematically appraised existing evidence on resting cerebral blood flow (rCBF) in schizophrenia, before and after antipsychotic treatment, relating the findings to symptom severity. The review shows that antipsychotics exert regional effects on rCBF, particularly in frontal and basal ganglia regions, and that different antipsychotic generations have differential effects on rCBF. These findings are supported by an exploratory meta-analysis of a subset of studies. The review also highlights the relative lack of studies that use a priori definitions of treatment response, which is an important step in identifying testable hypotheses and ensuring clinical relevance of remission criteria. Finally, the review highlights important considerations for future psychopharmacological studies investigating the potential for rCBF to predict symptomatic improvement, which could inform the management of treatment in schizophrenia.

White matter integrity as a predictor of response to treatment in first episode psychosis.

The integrity of brain white matter connections is central to a patient's ability to respond to pharmacological interventions. This study tested this hypothesis using a specific measure of white matter integrity, and examining its relationship to treatment response using a prospective design in patients within their first episode of psychosis. Diffusion tensor imaging data were acquired in 63 patients with first episode psychosis and 52 healthy control subjects (baseline). Response was assessed after 12 weeks and patients were classified as responders or non-responders according to treatment outcome. At this second time-point, they also underwent a second diffusion tensor imaging scan. Tract-based spatial statistics were used to assess fractional anisotropy as a marker of white matter integrity. At baseline, non-responders showed lower fractional anisotropy than both responders and healthy control subjects (P < 0.05; family-wise error-corrected), mainly in the uncinate, cingulum and corpus callosum, whereas responders were indistinguishable from healthy control subjects. After 12 weeks, there was an increase in fractional anisotropy in both responders and non-responders, positively correlated with antipsychotic exposure. This represents one of the largest, controlled investigations of white matter integrity and response to antipsychotic treatment early in psychosis. These data, together with earlier findings on cortical grey matter, suggest that grey and white matter integrity at the start of treatment is an important moderator of response to antipsychotics. These findings can inform patient stratification to anticipate care needs, and raise the possibility that antipsychotics may restore white matter integrity as part of the therapeutic response.

Cortical folding defects as markers of poor treatment response in first-episode psychosis.

IMPORTANCE: At present, no reliable predictors exist to distinguish future responders from nonresponders to treatment during the first episode of psychosis. Among potential neuroimaging predictors of treatment response, gyrification represents an important marker of the integrity of normal cortical development that may characterize, already at illness onset, a subgroup of patients with particularly poor outcome. OBJECTIVE: To determine whether patients with first-episode psychosis who do not respond to 12 weeks of antipsychotic treatment already have significant gyrification defects at illness onset. DESIGN: Case-control study with 12 weeks' longitudinal follow-up to determine treatment response. SETTING: Secondary psychiatric services in an inner-city area (South London, England). PARTICIPANTS: A total of 126 subjects, including 80 patients presenting with first-episode psychosis and 46 healthy controls. Patients were scanned at the outset and received various antipsychotic medications in a naturalistic clinical setting. They were followed up for 12 weeks and classified as responders or nonresponders if they reached criteria for symptom remission, evaluated with the Psychiatric and Personal History Schedule. OBSERVATION: Patients were exposed to naturalistic antipsychotic treatment for 12 weeks following a magnetic resonance imaging scan. MAIN OUTCOMES AND MEASURES: Cortical gyrification was assessed using local gyrification index in a vertexwise fashion across the entire cortical surface with correction for multiple testing using permutation analysis. Differences in local gyrification index were assessed between responders, nonresponders, and healthy controls. The effect of diagnosis (affective vs nonaffective psychosis) on the local gyrification index was also investigated in responders and nonresponders. RESULTS: Patients with first-episode psychosis showed a significant reduction in gyrification (hypogyria) across multiple brain regions compared with healthy controls. Interestingly, nonresponders showed prominent hypogyria at bilateral insular, left frontal, and right temporal regions when compared with responders (all clusters significant at P < .05). These effects were present for both affective and nonaffective psychoses. CONCLUSIONS AND RELEVANCE: Gyrification appears to be a useful predictor of antipsychotic treatment response. Early neurodevelopmental aberrations may predict unfavorable prognosis in psychosis, irrespective of the existing diagnostic boundaries.

Acute effects of single-dose aripiprazole and haloperidol on resting cerebral blood flow (rCBF) in the human brain.

Antipsychotic drugs act on the dopaminergic system (first-generation antipsychotics, FGA), but some also directly affect serotonergic function (second-generation antipsychotics, SGA) in the brain. Short and long-term effects of these drugs on brain physiology remain poorly understood. Moreover, it remains unclear whether any physiological effect in the brain may be different for FGAs and SGAs. Immediate (+3.30 h) and different effects of single-dose FGA (haloperidol, 3 mg) and a SGA (aripiprazole, 10 mg) on resting cerebral blood flow (rCBF) were explored in the same 20 healthy volunteers using a pulsed continuous arterial spin labeling (pCASL) sequence (1.5T) in a placebo-controlled, repeated measures design. Both antipsychotics increased striatal rCBF but the effect was greater after haloperidol. Both decreased frontal rCBF, and opposite effects of the drugs were observed in the temporal cortex (haloperidol decreased, aripiprazole increased rCBF) and in the posterior cingulate (haloperidol increased, aripiprazole decreased rCBF). Further increases were evident in the insula, hippocampus, and anterior cingulate after both antipsychotics, in the motor cortex following haloperidol and in the occipital lobe the claustrum and the cerebellum after aripiprazole. Further decreases were observed in the parietal and occipital cortices after aripiprazole. This study suggests that early and different rCBF changes are evident following a single-dose of FGA and SGA. The effects occur in healthy volunteers, thus may be independent from any underlying pathology, and in the same regions identified as structurally and functionally altered in schizophrenia, suggesting a possible relationship between antipsychotic-induced rCBF changes and brain alterations in schizophrenia.

Social disadvantage: cause or consequence of impending psychosis?

BACKGROUND: An association between social disadvantage and established psychosis is well documented in the literature, but there remains a lack of data on the social circumstances of patients before they became ill. We investigated whether social disadvantage at, and prior to, first contact with psychiatric services, is associated with psychosis. METHOD: We collected information on social disadvantage in childhood and adulthood from 278 cases presenting with their first episode of psychosis to the South London and Maudsley National Health Service Foundation Trust and from 226 controls recruited from the local population. Three markers of childhood social disadvantage and 3 markers of disadvantage in adulthood were analyzed. RESULTS: Long term separation from, and death of, a parent before the age of 17 years were both strongly associated with a 2- to 3-fold-increased odds of psychosis. Cases were also significantly more likely to report 2 or more markers of adult social disadvantage than healthy controls (OR = 9.03) at the time of the first presentation with psychosis, independent of a number of confounders. When we repeated these analyses for long-standing adult social disadvantage, we found that the strength of the association decreased but still remained significant for 1 year (OR = 5.67) and 5 years (OR = 2.57) prior to the first contact. CONCLUSIONS: Social disadvantage indexes exposure to factors operating prior to onset that increase the risk of psychosis, both during childhood and adulthood.

Confirmation that the AKT1 (rs2494732) genotype influences the risk of psychosis in cannabis users.

BACKGROUND: Cannabis use is associated with an increased risk of psychosis. One study has suggested that genetic variation in the AKT1 gene might influence this effect. METHODS: In a case-control study of 489 first-episode psychosis patients and 278 control subjects, we investigated the interaction between variation at the AKT1 rs2494732 single nucleotide polymorphism and cannabis use in increasing the risk of psychosis. RESULTS: The rs2494732 locus was not associated with an increased risk of a psychotic disorder, with lifetime cannabis use, or with frequency of use. We did, however, find that the effect of lifetime cannabis use on risk of psychosis was significantly influenced by the rs2494732 locus (likelihood ratio statistic for the interaction = 8.54; p = .014). Carriers of the C/C genotype with a history of cannabis use showed a greater than twofold increased likelihood of a psychotic disorder (odds ratio = 2.18 [95% confidence interval: 1.12, 4.31]) when compared with users who were T/T carriers. Moreover, the interaction between the rs2494732 genotype and frequency of use was also significant at the 5% level (likelihood ratio = 13.39; p = .010). Among daily users, C/C carriers demonstrated a sevenfold increase in the odds of psychosis compared with T/T carriers (odds ratio = 7.23 [95% confidence interval: 1.37, 38.12]). CONCLUSIONS: Our findings provide strong support for the initial report that genetic variation at rs2494732 of AKT1 influences the risk of developing a psychotic disorder in cannabis users.

Are there specific neuropsychological deficits underlying poor insight in first episode psychosis?

Insight in psychosis is a multi-dimensional phenomenon, and has been hypothesised to have some sort of neuropsychological basis. It is unclear to what extent specific neuropsychological abilities are able to predict insight beyond the effect of generalised cognitive ability. We aimed to test this association, alongside the relationship of insight with illness duration and diagnosis, in a sample of first episode psychosis patients. 110 first episode psychosis patients were recruited and a comprehensive assessment was administered, including insight, symptoms, diagnosis and neuropsychological function. Low insight was related to worse performance in a variety of neuropsychological tasks. Regression analysis tested whether any specific tasks were related to insight (or dimensions of insight) beyond the effect of IQ. Verbal memory had an effect on total insight and all dimensions of insight (except compliance) beyond the effect of IQ. Insight appeared to vary with diagnosis, with those diagnosed with depressive affective psychoses having better insight than those with manic affective psychoses. There was no relationship between insight and DUP, but there was a relationship between time spent in treatment before assessment and insight, even after controlling for severity of symptoms. These results suggest a model of insight in early psychosis with a significant neuropsychological component, particularly with verbal memory but also with generalised cognitive ability. There is likely to be a social component to insight affected by initial time spent in contact with treatment, helping patients to understand and come to terms with their illness.

Stress and inflammation reduce brain-derived neurotrophic factor expression in first-episode psychosis: a pathway to smaller hippocampal volume.

BACKGROUND: Reduced brain-derived neurotrophic factor (BDNF) levels have been reported in the serum and plasma of patients with psychosis. The aim of this cross-sectional case-control study was to investigate potential causes and consequences of reduced BDNF expression in these patients by examining the association between BDNF levels and measures of stress, inflammation, and hippocampal volume in first-episode psychosis. METHOD: Brain-derived neurotrophic factor, interleukin (IL)-6, and tumor necrosis factor (TNF)-α messenger RNA levels were measured in the leukocytes of 49 first-episode psychosis patients (DSM-IV criteria) and 30 healthy controls, all aged 18 to 65 years, recruited between January 2006 and December 2008. Patients were recruited from inpatient and outpatient units of the South London and Maudsley National Health Service Foundation Trust in London, United Kingdom, and the healthy controls were recruited from the same catchment area via advertisement and volunteer databases. In these same subjects, we measured salivary cortisol levels and collected information about psychosocial stressors (number of childhood traumas, number of recent stressors, and perceived stress). Finally, hippocampal volume was measured using brain magnetic resonance imaging in a subsample of 19 patients. RESULTS: Patients had reduced BDNF (effect size, d = 1.3; P < .001) and increased IL-6 (effect size, d = 1.1; P < .001) and TNF-α (effect size, d = 1.7; P < .001) gene expression levels when compared with controls, as well as higher levels of psychosocial stressors. A linear regression analysis in patients showed that a history of childhood trauma and high levels of recent stressors predicted lower BDNF expression through an inflammation-mediated pathway (adjusted R(2) = 0.23, P = .009). In turn, lower BDNF expression, increased IL-6 expression, and increased cortisol levels all significantly and independently predicted a smaller left hippocampal volume (adjusted R(2) = 0.71, P < .001). CONCLUSIONS: Biological changes activated by stress represent a significant factor influencing brain structure and function in first-episode psychosis through an effect on BDNF.

Higher cortisol levels are associated with smaller left hippocampal volume in first-episode psychosis.

This study investigated the relationship between cortisol secretion and hippocampal volume in first-episode psychosis and healthy controls. Hippocampal volume was measured by magnetic resonance imaging (MRI) in 24 first-episode psychosis patients and in 18 healthy controls, together with diurnal cortisol levels. Twelve patients received a second MRI scan at 3-month follow-up. Diurnal cortisol levels were inversely correlated with left hippocampal volume in patients, both at baseline and at follow-up, while no correlation was found in controls. Our findings suggest that smaller hippocampal volume in first-episode psychosis can partly be explained by stress-related processes in the brain, as measured by cortisol hyper-secretion.

Abnormal cortisol levels during the day and cortisol awakening response in first-episode psychosis: the role of stress and of antipsychotic treatment.

First-episode psychosis (FEP) patients show hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, but the mechanisms leading to this are still unclear. The aim of this study was to investigate the role of stress and antipsychotic treatment on diurnal cortisol levels, and on cortisol awakening response, in FEP. Recent stressful events, perceived stress and childhood trauma were collected in 50 FEP patients and 36 healthy controls using structured instruments. Salivary cortisol was obtained at awakening, at 15, 30, and 60min after awakening, and at 12 and 8pm. Patients experienced more recent stressful events, perceived stress and childhood trauma than controls (p<0.001). Patients had a trend for higher diurnal cortisol levels (p=0.055), with those with less than two weeks of antipsychotics showing significantly higher cortisol levels than both patients with more than two weeks of antipsychotics (p=0.005) and controls (p=0.002). Moreover, patients showed a blunted cortisol awakening response compared with controls, irrespectively of antipsychotic treatment (p=0.049). These abnormalities in patients were not driven by the excess of stressors: diurnal cortisol levels were negatively correlated with the number of recent stressful events (r=-0.36, p=0.014), and cortisol awakening response was positively correlated with a history of sexual childhood abuse (r=0.33, p=0.033). No significant correlations were found between perceived stress or severity of symptoms and cortisol levels, either diurnal or in the awakening response. Our study shows that antipsychotics normalize diurnal cortisol hyper-secretion but not the blunted cortisol awakening response in FEP; factors other than the excess of psychosocial stress explain HPA axis abnormalities in FEP.

High-potency cannabis and the risk of psychosis.

BACKGROUND: People who use cannabis have an increased risk of psychosis, an effect attributed to the active ingredient Delta 9-tetrahydrocannabinol (Delta 9-THC). There has recently been concern over an increase in the concentration of Delta 9-THC in the cannabis available in many countries. AIMS: To investigate whether people with a first episode of psychosis were particularly likely to use high-potency cannabis. METHOD: We collected information on cannabis use from 280 cases presenting with a first episode of psychosis to the South London & Maudsley National Health Service (NHS) Foundation Trust, and from 174 healthy controls recruited from the local population. RESULTS: There was no significant difference between cases and controls in whether they had ever taken cannabis, or age at first use. However, those in the cases group were more likely to be current daily users (OR = 6.4) and to have smoked cannabis for more than 5 years (OR = 2.1). Among those who used cannabis, 78% of the cases group used high-potency cannabis (sinsemilla, 'skunk') compared with 37% of the control group (OR 6.8). CONCLUSIONS: The finding that people with a first episode of psychosis had smoked higher-potency cannabis, for longer and with greater frequency, than a healthy control group is consistent with the hypothesis that Delta 9-THC is the active ingredient increasing risk of psychosis. This has important public health implications, given the increased availability and use of high-potency cannabis.

Depression, anxiety, and within-person variability in adults aged 18 to 85 years.

Mild depression and anxiety were investigated in relation to measures of within-person (WP) variability and mean reaction time from psychomotor, executive function, visual search, and word recognition tasks in a continuous age range (18-85 years, M=50.33, SD=20.37) of 300 community-dwelling adults. Structural equation modeling identified a significant Age x Depression interaction in relation to visual search for measures of WP variability but not for mean reaction time. Older more depressed adults exhibited greater variability. WP variability in executive function and other cognitive constructs covaried, and the significant Age x Depression interaction with visual search was accounted for by WP variability in executive control. The findings suggest that age- and depression-related reductions in attentional resources may contribute to increased variability in visual search and that variability in executive control may be the mechanism underlying these effects.