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A high level of expressed emotion (EE) in the form of criticism and hostility by family members towards schizophrenia patients increases the risk of relapse to a psychotic episode. Studying the neural response to relatives’ criticisms would help to understand how patients interpret and cope with EE in terms of the salience patients attach to criticisms and how this information is encoded and stored. Formerly depressed patients fail to activate the dorso-lateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) on hearing maternal criticisms. We tested the hypothesis, for the first time, that individuals with high schizotypy would have an altered DLPFC and ACC response to relatives’ criticisms. Twenty-four healthy individuals, 12 with low schizotypy (LS) and 12 with high schizotypy (HS), listened to a close relative's criticisms, compliments and neutral comments about them while undergoing functional MRI. The relative's EE level was assessed using the Camberwell Family Interview. HS relatives were more likely to show high EE than LS relatives. Activation maps in LS and HS groups during each comment type were compared using SPM5. During criticisms relative to neutral comments, HS activated and LS deactivated the DLPFC and ACC. During compliments relative to neutral comments, LS activated and HS deactivated the insula, lingual gyrus, cerebellum, thalamus, postcentral gyrus and medial frontal gyrus. Our finding of DLPFC-ACC activation in HS, but deactivation in LS individuals when listening to relatives’ criticisms suggests that HS individuals may have difficulty suppressing emotional interference during cognitive control.
Understanding the biogeochemical behaviour of arsenic in the weathering and shallow subsurface environment depends critically upon determining the nature and distribution of the chemical species present in natural waters. To this end, coupled ion chromatography-inductively coupled plasma mass spectrometry (IC-ICP-MS) is widely used, though species fractionation during ultrasonic nebulization, and matrix-dependent ionization in the plasma are analytical issues that need to be addressed. Hexapole collision cell technology is shown to be effective in suppressing chloride-based polyatomic interferences. Irrespective of the analytical technique used, As(III)/As(V) ratios of natural waters may change substantially during storage due to (1) differential adsorption of arsenic species on hydrated ferric oxides (HFOs); and (2) microbial activity. A wide range of apparently contradictory speciation changes observed by various workers can be rationalized in terms of the differences of microbial consortia present in different water samples. Arsenic speciation in certain water types can be stabilized for days or even weeks by combined filtration, acidification and refrigeration whilst the addition of EDTA and the use of 0.1 mm filters is indicated for iron-rich waters and waters with high activities of redox-active bacteria, respectively. Although the use of hydrochloric acid has been reported elsewhere as resulting in the apparent oxidation of As(III), we show that for certain water types it acts as an extremely effective preservative of arsenic speciation.
Our recent discovery of hazardous concentrations of arsenic in shallow sedimentary aquifers in Cambodia raises the spectre of future deleterious health impacts on a population that, particularly in non-urban areas, extensively use untreated groundwater as a source of drinking water and, in some instances, as irrigation water. We present here small-scale hazard maps for arsenic in shallow Cambodian groundwaters based on >1000 groundwater samples analysed in the Manchester Analytical Geochemistry Unit and elsewhere. Key indicators for hazardous concentrations of arsenic in Cambodian groundwaters include: (1) well depths greater than 16 m; (2) Holocene host sediments; and (3) proximity to major modern channels of the Mekong (and its distributary the Bassac). However, high-arsenic well waters are also commonly found in wells not exhibiting these key characteristics, notably in some shallower Holocene wells, and in wells drilled into older Quaternary and Neogene sediments.
It is emphasized that the maps and tables presented are most useful for identifying current regional trends in groundwater arsenic hazard and that their use for predicting arsenic concentrations in individual wells, for example for the purposes of well switching, is not recommended, particularly because of the lack of sufficient data (especially at depths >80 m) and because, as in Bangladesh and West Bengal, there is considerable heterogeneity of groundwater arsenic concentrations on a scale of metres to hundreds of metres. We have insufficient data at this time to determine unequivocally whether or not arsenic concentrations are increasing in shallow Cambodian groundwaters as a result of groundwater-abstraction activities.
Grey matter and other structural brain abnormalities are consistently
reported in first-onset schizophrenia, but less is known about the extent
of neuroanatomical changes in first-onset affective psychosis
To determine which brain abnormalities are specific to (a) schizophrenia
and (b) affective psychosis
We obtained dual-echo (proton density/T2-weighted) magnetic resonance
images and carried out voxel-based analysis on the images of 73 patients
with first-episode psychosis (schizophrenia n=44,
affective psychosis n=29) and 58 healthy controls
Both patients with schizophrenia and patients with affective psychosis
had enlarged lateral and third ventricle volumes. Regional cortical grey
matter reductions (including bilateral anterior cingulate gyrus, left
insula and left fusiform gyrus) were evident in affective psychosis but
not in schizophrenia, although patients with schizophrenia displayed
decreased hippocampal grey matter and increased striatal grey matter at a
more liberal statistical threshold
Both schizophrenia and affective psychosis are associated with volumetric
abnormalities at the onset of frank psychosis, with some of these evident
in common brain areas
Background. Patients with obsessive–compulsive disorder (OCD) have symptoms that pre-dominantly concern washing (washers) or checking (checkers), or both. Functional neuroimaging has been used to identify the neural correlates of the urge to ritualize but has not distinguished between washing and checking symptoms in OCD. We used functional magnetic resonance imaging to compare the neural response to emotive pictures in washers and checkers.
Methods. In one of two 5-minute experiments, washers (N = 7), checkers (N = 7) and age-matched normal controls (N = 14) were scanned while viewing alternating blocks of normally disgusting (rated as disgusting by all subjects) and neutral pictures. In the other experiment, all patients and a normal subgroup (N = 8) viewed alternating blocks of washer-relevant (rated as more disgusting by washers than normal controls or checkers) and neutral pictures.
Results. In all subjects, normally disgusting pictures activated visual regions implicated in perception of aversive stimuli and the insula, important in disgust perception. Only in washers were similar regions activated by washer-relevant pictures. In checkers, these pictures activated fronto-striatal regions associated with the urge to ritualize in OCD. Normal controls were more similar in neural response to checkers than washers to these pictures. Both normal controls and checkers had frontal regions activated significantly more by washer-relevant than normally disgusting pictures, and had these regions activated significantly more than washers by washer-relevant pictures.
Conclusions. We demonstrate a differential neural response to washer-relevant disgust in washers and checkers: only washers demonstrate a neural response to washer-relevant disgust associated with emotion perception rather than attention to non-emotive visual detail.
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