FC07-02 - Increased parahippocampal and lingual gyrification in first-episode schizophrenia

Introduction

Surface based MRI methods are a promising approach for the identification of cerebral shape alterations in schizophrenia [1]. In particular, investigating gyrification might offer important evidence for disturbed neurodevelopmental mechanisms in schizophrenia.

Objective

The present study is the first to compare on a vertex - wise basis mean curvature as a sensitive parameter for the identification of local gyrification changes in first episode schizophrenia.

Methods

54 patients with first-episode schizophrenia and 54 healthy control subjects underwent high-resolution T1-weighted MRI scans. Surface extraction and mean curvature calculation was performed using the Freesurfer Software package. Statistical cortical maps were created to estimate gyrification differences between groups.

Results

A significantly increased gyrification was detected in patients relative to controls in a large right parahippocampal-lingual cortex area. A further analysis of cortical thickness of this cluster revealed concurrent significant reduced cortical thickness in patients.

Conclusions

This is the first study to reveal an aberrant gyrification of the medial surface in first episode schizophrenia on basis of a vertex - wise analysis of local gyrification changes of the entire cortex. Both affected areas, the parahippocampal and the lingual cortex, are of high pathophysiological relevance for schizophrenia. Thus, our data provided new in vivo evidence for an early maturational deficit of these cortical areas in schizophrenia [2].

Centrality dependence of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at sqrt[s(NN)] = 2.76 TeV

The centrality dependence of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV is presented. The charged-particle density normalized per participating nucleon pair increases by about a factor of 2 from peripheral (70%-80%) to central (0%-5%) collisions. The centrality dependence is found to be similar to that observed at lower collision energies. The data are compared with models based on different mechanisms for particle production in nuclear collisions.

Elliptic flow of charged particles in Pb-Pb collisions at sqrt[S(NN)] = 2.76 TeV

We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at sqrt[S(NN)] =2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|η|<0.8) and transverse momentum range 0.2<p t<5.0 GeV/c. The elliptic flow signal v₂, measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 ± 0.002(stat) ± 0.003(syst) in the 40%-50% centrality class. The differential elliptic flow v₂ p t reaches a maximum of 0.2 near p t =3 GeV/c. Compared to RHIC Au-Au collisions at sqrt[S(NN)] 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.

Charged-particle multiplicity density at midrapidity in central Pb-Pb collisions at sqrt[S(NN)] = 2.76 TeV

The first measurement of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at a center-of-mass energy per nucleon pair √ S NN = 2.76 TeV is presented. For an event sample corresponding to the most central 5% of the hadronic cross section, the pseudorapidity density of primary charged particles at midrapidity is 1584 ± 4(stat) ± 76(syst), which corresponds to 8.3 ± 0.4(syst) per participating nucleon pair. This represents an increase of about a factor 1.9 relative to pp collisions at similar collision energies, and about a factor 2.2 to central Au-Au collisions at √ S NN = 2.76 TeV. This measurement provides the first experimental constraint for models of nucleus-nucleus collisions at LHC energies.

Gastric mucosal nerve density: a biomarker for diabetic autonomic neuropathy?

BACKGROUND

Autonomic neuropathy is a frequent diagnosis for the gastrointestinal symptoms or postural hypotension experienced by patients with longstanding diabetes. However, neuropathologic evidence to substantiate the diagnosis is limited. We hypothesized that quantification of nerves in gastric mucosa would confirm the presence of autonomic neuropathy.

METHODS

Mucosal biopsies from the stomach antrum and fundus were obtained during endoscopy from 15 healthy controls and 13 type 1 diabetic candidates for pancreas transplantation who had secondary diabetic complications affecting the eyes, kidneys, and nerves, including a diagnosis of gastroparesis. Neurologic status was evaluated by neurologic examination, nerve conduction studies, and skin biopsy. Biopsies were processed to quantify gastric mucosal nerves and epidermal nerves.

RESULTS

Gastric mucosal nerves from diabetic subjects had reduced density and abnormal morphology compared to control subjects (p < 0.05). The horizontal and vertical meshwork pattern of nerve fibers that normally extends from the base of gastric glands to the basal lamina underlying the epithelial surface was deficient in diabetic subjects. Eleven of the 13 diabetic patients had residual food in the stomach after overnight fasting. Neurologic abnormalities on clinical examination were found in 12 of 13 diabetic subjects and nerve conduction studies were abnormal in all patients. The epidermal nerve fiber density was deficient in skin biopsies from diabetic subjects.

CONCLUSIONS

In this observational study, gastric mucosal nerves were abnormal in patients with type 1 diabetes with secondary complications and clinical evidence of gastroparesis. Gastric mucosal biopsy is a safe, practical method for histologic diagnosis of gastric autonomic neuropathy.

Midrapidity antiproton-to-proton ratio in pp collisons at sqrt[s]=0.9 and 7 TeV measured by the ALICE experiment

The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at sqrt[s]=0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45<p_{t}<1.05  GeV/c and rapidity |y|<0.5. The ratio is measured to be R_{|y|<0.5}=0.957±0.006(stat)±0.014(syst) at 0.9 TeV and R_{|y|<0.5}=0.991±0.005(stat)±0.014(syst) at 7 TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on any additional contributions to baryon-number transfer over very large rapidity intervals in pp collisions.

Structure-function relationships in the context of reinforcement-related learning: a combined diffusion tensor imaging-functional magnetic resonance imaging study

In the context of probabilistic learning, previous functional magnetic resonance imaging studies have shown decreasing uncertainty accompanying decreasing neuronal activation in task-relevant networks. Moreover, initial evidence points to a relationship between white matter structure and cognitive performance. Little is known, however, about the structural correlates underlying individual differences in activation and performance in the context of probabilistic learning. This combined functional magnetic resonance imaging-diffusion tensor imaging study aimed at investigating the individual ability to reduce processing resources with decreasing uncertainty in direct relation to individual characteristics in white matter brain structure. Results showed that more successful learners, as compared with less successful learners, exhibited stronger activation decreases with decreasing uncertainty. An increased mean and axial diffusivity in, among others, the inferior and superior longitudinal fasciculus, the posterior part of the cingulum bundle, and the corpus callosum were detectable in less successful learners compared with more successful learners. Most importantly, there was a negative correlation between uncertainty-related activation and diffusivity in a fronto-parieto-striatal network in less successful learners only, indicating a direct relation between diffusivity and the ability to reduce processing resources with decreasing uncertainty. These findings indicate that interindividual variations in white matter characteristics within the normal population might be linked to neuronal activation and critically influence individual learning performance.

Intensive practice of a cognitive task is associated with enhanced functional integration in schizophrenia

BACKGROUND

There is increasing evidence that the frequently reported working memory impairments in schizophrenia might be partly due to an alteration in the functional connectivity between task-relevant areas. However, little is known about the functional connectivity patterns in schizophrenia patients during learning processes. In a previous study, Koch et al. [Neuroscience (2007) 146, 1474-1483] have demonstrated stronger exponential activation decreases in schizophrenia patients during overlearning of short-term memory material. The question arises whether these differential temporal patterns of activation in schizophrenia patients and controls are going along with changes in task-related functional connectivity.

METHOD

Therefore, in the current study, 13 patients with schizophrenia and 13 controls were studied while performing a short-term memory task associated with increasing overlearning of verbal stimulus material. Functional connectivity was investigated by analyses of psychophysiological interactions (PPI).

RESULTS

Results revealed significant task-related modulation of functional connectivity between the left dorsolateral prefrontal cortex (DLPFC) and a network including the right DLPFC, left ventrolateral prefrontal cortex, premotor cortex, right inferior parietal cortex, left and right cerebellum as well as the left occipital lobe in patients during the course of overlearning and practice. No significant PPI results were detectable in controls.

CONCLUSIONS

Activation changes with practice were associated with high functional connectivity between task-relevant areas in schizophrenia patients. This could be interpreted as a compensatory resource allocation and network integration in the context of cortical inefficiency and may be a specific neurophysiological signature underlying the pathophysiology of schizophrenia.

Study on the microbial status of unseasoned ground turkey meat from an EU producer-a new product with risk potential?

1. The aim of this study was to point out potential risks associated with a product new to the market in the European Union: unseasoned minced turkey meat. 2. On 6 d of sampling, minced turkey meat from a large-scale EU producer was analysed at 4 processing stages. 3. The packaged minced meat was examined during 10 d of storage, once using the legally recommended conditions (<+2 degrees C), and then under simulated consumer handling; one batch was stored for 3 d at +2 degrees C then kept for 45 min at 25 degrees C and then stored at +7 degrees C. Microbiological and physical variables were tested on 5 d. 4. Results showed that the mean total aerobic plate count (APC) of the unprocessed material was 3.8 log CfU/g and did not rise significantly, although the temperature rose briefly after the material left the meat chopper. Listeria monocytogenes was the pathogen detected most often, in 7 (14.6%) of 48 samples, followed by Salmonella in one (2.1%). No Campylobacter were found. 5. Initial contamination (APC) of about 4.5 log CfU/g was common in stored minced meat, conforming to European Union Regulations EC 2073/2005 and 1441/2007. Brochothrix thermosphacta and Pseudomonas spp. were the bacteria found most frequently. Under strict maintenance at a storage temperature of +2 degrees C, the maximum microbiological stability of the material was 7 d. Under simulated consumer handling, the microbial counts increased significantly, immediately after transport. 6. Our findings indicate that unseasoned minced turkey meat is a risky, perishable product, especially if the raw material does not have a low APC, is not pathogen-free and is kept under typical consumer handling and storage conditions.

Dopaminergic modulation of brain systems subserving decision making under uncertainty: a study with fMRI and methylphenidate challenge

There is evidence that the dopaminergic system is involved in probabilistic reinforcement learning and reward-related decision-making. However, little is known about the effects of external dopaminergic challenges on processing of uncertainty in decision-making tasks. Therefore, the present study examined changes in fMRI activation patterns in a natural sampling paradigm. Decision making under uncertainty was examined before and after administration of a single dose of 40 mg methylphenidate as an acute dopaminergic pharmacological challenge. We found that the level of uncertainty was positively correlated with activations in the prefrontal cortex. Conversely, negative correlations with uncertainty were found in the left hippocampus, right amygdale, and right middle temporal gyrus. The drug intervention with methylphenidate revealed a differential picture. Uncertain information processing was associated with higher activation in the parietal association cortex and posterior cingulate cortex after placebo relative to methylphenidate. The methylphenidate challenge relative to placebo was associated with higher left and right parahippocampal as well as cerebellar activation under uncertainty. Apparently, the pro-dopaminergic pharmacological influence induces a relative shift towards recruitment of hippocampal areas under uncertainty, whereas under placebo conditions, higher levels of parietal cortex activations are involved in the task. The findings suggest a role of dopamine in uncertainty processing and shed light on the pharmacological mechanisms of methylphenidate.

Fronto-cingulate effective connectivity in major depression: a study with fMRI and dynamic causal modeling

Functional imaging studies are indicating disrupted error monitoring and executive control in a fronto-cingulate network in major depression. However, univariate statistical analyses allow only for a limited assessment of directed neuronal interactions. Therefore, the present study used dynamic causal modeling (DCM) of a fronto-cingulate network to re-analyze the data from a preceding fMRI study in 16 drug-free patients with major depression and 16 healthy controls using the Stroop Color-Word Test (Wagner et al., 2006). In both groups, a significant reciprocal interregional connectivity was found in a cognitive control network including prefrontal cortex (PFC) and dorsal anterior cingulate cortex (ACC). With regard to intrinsic connections we detected a significant difference for dorsal to rostral ACC connectivity between depressive patients and controls in terms of higher connectivity in patients. Additionally, a task by group interaction was observed for the bilinear interaction signaling enhanced task-related input from the dorsal to rostral ACC in subjects with depression. This could be related to the inability of patients to down-regulate rostral ACC activation as observed in the previous univariate analysis. The correlation between interference scores and intrinsic connections from dorsal ACC to dorsolateral PFC (DLPFC) was significant for both groups together, but no significant group differences in correlations could be detected. Thus, the observed relationship between control functions of the dorsal ACC exerted over DLPFC and interference scores appears to be valid in both patients with depression and controls. The findings are consistent with current models of a differential involvement of the fronto-cingulate system in the pathophysiology of major depression.

Association of variants in the fat mass and obesity associated (FTO) gene with polycystic ovary syndrome

AIMS/HYPOTHESIS

Variants in the fat-mass and obesity-associated gene (FTO) influence susceptibility to type 2 diabetes via an effect on adiposity/obesity. Given the important role of obesity in the aetiology of both polycystic ovary syndrome (PCOS) and type 2 diabetes mellitus, our aim was to establish whether FTO variants are also implicated in PCOS susceptibility.

METHODS

We performed a genetic association study of FTO variant rs9939609 using case-control analyses, conducted in 463 PCOS patients (geometric mean BMI 27.5 kg/m(2)) and 1,336 female controls (geometric mean BMI 25.3 kg/m(2)) of UK British/Irish origin. We also sought evidence for associations between FTO variation and circulating testosterone levels in 324 UK PCOS patients and 1,000 women from the Northern Finland Birth Cohort of 1966. Outcome measures included FTO rs9939609 genotype frequencies by participant group and androgen measures (testosterone, free androgen index) by genotype.

RESULTS

There was a significant association between FTO genotype and PCOS status in the UK case-control analysis, which was attenuated by adjustment for BMI (Cochran-Armitage test, odds ratio [per minor allele copy] 1.30 [95% CI 1.12, 1.51], p = 7.2 x 10(-4) [unadjusted], p = 2.9 x 10(-3) [adjusted]). This association was most evident in obese PCOS patients (PCOS patients below median BMI vs UK controls, p = 0.11; above median BMI vs controls, p = 2.9 x 10(-4)). No relationship between FTO genotype and androgen levels was seen.

CONCLUSIONS/INTERPRETATION

We provide the first evidence that variants that predispose to common obesity also result in altered susceptibility to PCOS, confirming the mechanistic link between these conditions. The predominant effect of FTO variants on PCOS susceptibility is probably mediated through adiposity.