Local and global limits on visual processing in schizophrenia.

Schizophrenia has been linked to impaired performance on a range of visual processing tasks (e.g. detection of coherent motion and contour detection). It has been proposed that this is due to a general inability to integrate visual information at a global level. To test this theory, we assessed the performance of people with schizophrenia on a battery of tasks designed to probe voluntary averaging in different visual domains. Twenty-three outpatients with schizophrenia (mean age: 40±8 years; 3 female) and 20 age-matched control participants (mean age 39±9 years; 3 female) performed a motion coherence task and three equivalent noise (averaging) tasks, the latter allowing independent quantification of local and global limits on visual processing of motion, orientation and size. All performance measures were indistinguishable between the two groups (ps>0.05, one-way ANCOVAs), with one exception: participants with schizophrenia pooled fewer estimates of local orientation than controls when estimating average orientation (p = 0.01, one-way ANCOVA). These data do not support the notion of a generalised visual integration deficit in schizophrenia. Instead, they suggest that distinct visual dimensions are differentially affected in schizophrenia, with a specific impairment in the integration of visual orientation information

Nutritional status of alcoholics in Peri-urban areas of the greater Accra region of Ghana

Alcoholism is a common problem in developing countries. Epidemiological studies on the relationship among excessive alcohol consumption,  malnutrition and anaemia are inconclusive. The present study examined the association between alcohol intake and nutritional status of alcoholics in the Greater Accra Region of Ghana. The study was cross-sectional involving 107 participants (men and women) aged between 20 and 76 years. Participants were identified as alcoholics after screening with a combined, but modified CAGE and AUDIT questionnaires. Anthropometric data including weight, biceps skinfold thickness, triceps skinfold thickness, hip circumference and waist circumference were collected. Body mass index (BMI) and Waist-to-hip ratio were computed using appropriate measures. Haemoglobin levels of participants were also assessed. Dietary intakes of respondents were estimated by 24-hour recall which was further converted into nutrients and energy using ESHA food processor. A pretested  questionnaire was also used to obtain data on socio-demographic and lifestyle characteristics of participants. Differences between participants based on level of alcohol intake and correlations among variables were tested for statistical significance using ANOVA and correlation analyses, respectively. Logistic regression was performed to examine the relationship between levels of total ethanol intake and overweight and obesity factors while controlling for age, smoking status, physical activity and total energy intake. There was an inverse correlation between triceps skinfold and level of alcohol consumption irrespective of predominant type of alcoholic  beverage consumed (r= -0.213, P= 0.028). Further, there was a positive correlation between alcohol consumption and hip circumference among predominant beer consumers (r= 0.585, P= 0.046). A strong positive correlation was observed between alcohol intake and haemoglobin concentration for women (r= 0.729, P= 0.040) but not among men (r= -0.053, P= 0.722). Predominant beer consumers tend to have higher weight and BMI. Moderate level of total ethanol intake was associated with greater odds of being overweight/obese, whereas high levels of intake was associated with lower odds of being overweight/obesity although these were not statistically significant. The mechanisms for the observation of higher weight, BMI and hip circumference among predominant beer consumers in this population need further exploration.Key words: Alcoholics, alcoholic beverages, nutritional statu

Awake chronic mouse model of targeted pial vessel occlusion via photothrombosis

Animal models of stroke are used extensively to study the mechanisms involved in the acute and chronic phases of recovery following stroke. A translatable animal model that closely mimics the mechanisms of a human stroke is essential in understanding recovery processes as well as developing therapies that improve functional outcomes. We describe a photothrombosis stroke model that is capable of targeting a single distal pial branch of the middle cerebral artery with minimal damage to the surrounding parenchyma in awake head-fixed mice. Mice are implanted with chronic cranial windows above one hemisphere of the brain that allow optical access to study recovery mechanisms for over a month following occlusion. Additionally, we study the effect of laser spot size used for occlusion and demonstrate that a spot size with small axial and lateral resolution has the advantage of minimizing unwanted photodamage while still monitoring macroscopic changes to cerebral blood flow during photothrombosis. We show that temporally guiding illumination using real-time feedback of blood flow dynamics also minimized unwanted photodamage to the vascular network. Finally, through quantifiable behavior deficits and chronic imaging we show that this model can be used to study recovery mechanisms or the effects of therapeutics longitudinally.R01 EB021018 - NIBIB NIH HHS; R01 MH111359 - NIMH NIH HHS; R01 NS108472 - NINDS NIH HHSPublished versio

d+idd+id Holographic Superconductors

A holographic model of $d+id$ superconductors based on the action proposed by Benini, Herzog, and Yarom [arXiv:1006.0731] is studied. This model has a charged spin two field in an AdS black hole spacetime. Working in the probe limit, the normalizable solution of the spin two field in the bulk gives rise to a $d+id$ superconducting order parameter at the boundary of the AdS. We calculate the fermion spectral function in this\ superconducting background and confirm the existence of fermi arcs for non-vanishing Majorana couplings. By changing the relative strength $\gamma$ of the $d$ and $id$ condensations, the position and the size of the fermi arcs are changed. When $\gamma =1$, the spectrum becomes isotropic and the spectral function is s-wave like. By changing the fermion mass, the fermi momentum is changed. We also calculate the conductivity for these holographic $d+id$ superconductors where time reversal symmetry has been broken spontaneously. A non-vanishing Hall conductivity is obtained even without an external magnetic field.Comment: 24 pages,17 figures, Add more discussions on hall conductivity, two new figures, Matched with published versio

Quantum Back Reaction to asymptotically AdS Black Holes

We analyze the effects of the back reaction due to a conformal field theory (CFT) on a black hole spacetime with negative cosmological constant. We study the geometry numerically obtained by taking into account the energy momentum tensor of CFT approximated by a radiation fluid. We find a sequence of configurations without a horizon in thermal equilibrium (CFT stars), followed by a sequence of configurations with a horizon. We discuss the thermodynamic properties of the system and how back reaction effects alter the space-time structure. We also provide an interpretation of the above sequence of solutions in terms of the AdS/CFT correspondence. The dual five-dimensional description is given by the Karch-Randall model, in which a sequence of five-dimensional floating black holes followed by a sequence of brane localized black holes correspond to the above solutions.Comment: 13 pages, 10 figure

Energy Dependence of the Delta Resonance: Chiral Dynamics in Action

There is an important connection between the low energy theorems of QCD and the energy dependence of the Delta resonance in pi-N scattering, as well as the closely related gamma^{*} N -> pi N reaction. The resonance shape is due not only to the strong pi-N interaction in the p wave but the small interaction in the s wave; the latter is due to spontaneous chiral symmetry breaking in QCD (i.e. the Nambu-Goldstone nature of the pion). A brief overview of experimental tests of chiral perturbation theory and chiral based models is presentedComment: 11 pages, 6 figures, Festschrift for S.N. yan

Visual population receptive fields in people with schizophrenia have reduced inhibitory surrounds

People with schizophrenia (SZ) experience abnormal visual perception on a range of visual tasks, which have been linked to abnormal synaptic transmission and an imbalance between cortical excitation and inhibition. However differences in the underlying architecture of visual cortex neurons, which might explain these visual anomalies, have yet to be reported in vivo. Here, we probe the neural basis of these deficits by using functional MRI (fMRI) and population receptive field (pRF) mapping to infer properties of visually responsive neurons in people with SZ. We employed a Difference-of-Gaussian (DoG) model to capture the centre-surround configuration of the pRF, providing critical information about the spatial scale of the pRFs inhibitory surround. Our analysis reveals that SZ is associated with reduced pRF size in early retinotopic visual cortex as well as a reduction in size and depth of the inhibitory surround in V1, V2 and V4. We consider how reduced inhibition might explain the diverse range of visual deficits reported in SZ. SIGNIFICANCE STATEMENT: People with schizophrenia (SZ) experience abnormal perception on a range of visual tasks, which has been linked to abnormal synaptic transmission and an imbalance between cortical excitation/inhibition. However associated differences in the underlying architecture of visual cortex neurons have yet to be reported in vivo. We used fMRI and population receptive field (pRF) mapping to demonstrate that the fine-grained functional architecture of visual cortex in people with SZ differs from unaffected controls. SZ is associated with reduced pRF size in early retinotopic visual cortex, largely due to reduced inhibitory surrounds. An imbalance between cortical excitation and inhibition could drive such a change in the centre-surround pRF configuration, and ultimately explain the range of visual deficits experienced in SZ

Development and Validation of an Information Booklet Aimed at Promoting Mental Health for Pregnant Women with a History of Abuse.

BACKGROUND:Mental health needs of victims of domestic and family violence are often overlooked. A booklet was designed to help women update their knowledge and skills in effective coping with domestic and family violence and support them in developing effective stress reduction and problem management techniques. In addition, this booklet is believed to serve as a reference for further use. This paper describes the development process and validation of the information booklet. This booklet was used during an intervention trial conducted in Nepal to educate abused pregnant women. METHODS:This methodological study involved three stages: bibliographical survey, development of the booklet, and validation by specialists in the relevant fields and representatives of the target audiences. A total of eight experts, currently working in the field of domestic violence and/or midwifery, and 15 representatives of the target participants were involved in the validation process. A minimum Content Validity Index of 0.78 was considered for content validation, and minimum agreement of 75% for face validation. RESULTS:The booklet presented a global Content Validity Index of 0.92. The overall level of agreement within the target participants was 86.3%, which was higher than the minimum recommended level. Both subject experts and participants positively evaluated the adequacy, coverage and readability of contents of the booklet. CONCLUSIONS:The booklet was validated using content and face validity. This validated booklet is expected to be an effective tool for communication that would help pregnant women cope better with domestic and family violence and adopt strategies to remain emotionally healthy

Semi-local quantum liquids

Gauge/gravity duality applied to strongly interacting systems at finite density predicts a universal intermediate energy phase to which we refer as a semi-local quantum liquid. Such a phase is characterized by a finite spatial correlation length, but an infinite correlation time and associated nontrivial scaling behavior in the time direction, as well as a nonzero entropy density. For a holographic system at a nonzero chemical potential, this unstable phase sets in at an energy scale of order of the chemical potential, and orders at lower energies into other phases; examples include superconductors and antiferromagnetic-type states. In this paper we give examples in which it also orders into Fermi liquids of "heavy" fermions. While the precise nature of the lower energy state depends on the specific dynamics of the individual system, we argue that the semi-local quantum liquid emerges universally at intermediate energies through deconfinement (or equivalently fractionalization). We also discuss the possible relevance of such a semi-local quantum liquid to heavy electron systems and the strange metal phase of high temperature cuprate superconductors.Comment: 31 pages, 7 figure

Semi-Holographic Fermi Liquids

We show that the universal physics of recent holographic non-Fermi liquid models is captured by a semi-holographic description, in which a dynamical boundary field is coupled to a strongly coupled conformal sector having a gravity dual. This allows various generalizations, such as a dynamical exponent and lattice and impurity effects. We examine possible relevant deformations, including multi-trace terms and spin-orbit effects. We discuss the matching onto the UV theory of the earlier work, and an alternate description in which the boundary field is integrated out.Comment: 26 pages, 4 figures; v2: typos corrected and report number adde