A mixed methods study of schema modes amongst people living with eating disorders.

BACKGROUND: Schema therapy is promising for people with eating disorders, especially those unresponsive to cognitive behavioural therapy. Complex underlying psychological constructs include dysfunctional schemas and maladaptive modes. This study aimed to explore people living with eating disorders' schema modes and their identification with and understanding of their high scoring modes. METHODS: Sixteen women with enduring eating disorders without prior exposure to schema therapy completed the schema mode inventory for eating disorders short form (SMI-ED-SF), then participated in semi-structured interviews discussing their high scoring modes. Interviews were analysed by thematic analysis. RESULTS: All participants scored above clinical concern on at least one maladaptive mode and many scored high on multiple modes, most commonly Demanding Mode, Vulnerable Child and Detached Self-Soother. Qualitatively, four themes emerged: 1) Adverse family environments related to (a) trauma and the vulnerable and angry child and (b) unrealistically high standards; 2) Mode effects on (a) everyday life and (b) disordered eating; 3) Modes are psychologically protective in (a) avoiding emotion by detachment and soothing, (b) people pleasing by compliance and surrender; 4) Help seeking including (a) barriers to recovery from an eating disorder, (b) dissatisfaction with interventions experienced to date, (c) schema therapy as a promising alternative. DISCUSSION: Participants recognised and identified with their high scoring schema modes. After negative experiences with previous interventions, they considered schema therapy to be a promising alternative that could understand and work on their deeper psychological issues. This suggests that schema modes are a promising way of understanding and working with enduring eating disorders.

Maladaptive modes are important in Schema Therapy for eating disorders. They are momentary patterns of thought, feeling and behaviour, triggered by experiences to which people with eating disorders can be oversensitive. In a child mode the person may be inexplicably childish. A coping mode may involve detachment, surrender to others, or perfectionist overcompensation. A parent mode may involve unrealistic standards and demands. There are also two healthy modes of Healthy Adult and Happy Child, which are often lacking in people with eating disorders. In this study women with enduring eating disorders completed the schema mode inventory and then discussed their high scoring modes. Common maladaptive modes were vulnerable child, demanding parent mode and perfectionistic over-compensator. Participants identified with their high scoring modes and thought them useful for self-understanding, so schema therapy is a promising way of understanding the psychopathology underlying enduring eating disorders.

Language Can Obscure as Well as Facilitate Apparent-Theory of Mind Performance: Part 2-The Case of Dyslexia in Adulthood.

Many studies imply causal links between linguistic competencies and Theory of Mind (ToM). But despite Dyslexia being a prime example of linguistic deficits, studies on whether it is related to ToM have been relatively unforthcoming. In the first of 2 studies (N = 89), independently-diagnosed dyslexic adults and non-dyslexic adults were presented with false-belief vignettes via computer, answering 4 types of question (Factual, Inference, 1st-order ToM & 2nd-order ToM). Dyslexia related to lower false-belief scores. Study 2 (N = 93) replicated this result with a non-computer-based variant on the false-belief task. We considered the possibility that the apparent-issue with ToM is caused by processing demands more associated to domains of cognition such as language, than to ToM itself. Addressing this possibility, study 2 additionally utilised the ToM30Q questionnaire, designed largely to circumvent issues related to language and memory. Principal-Components analysis extracted 4 factors, 2 capturing perceptual/representational ToM, and the other 2 capturing affective components related to ToM. The ToM30Q was validated via its associations to a published measure of empathy, replication of the female gender advantage over males, and for one factor from the ToM30Q there was a correlation with an existing published index of ToM. However, when we considered the performance of dyslexic and non-dyslexic participants using the ToM30Q, we found absolutely no difference between them. The contrasting findings from our 2 studies here, arguably offer the first experimental evidence with adults, that there is in fact no ToM deficit in dyslexia. Additionally, this finding raises the possibility that some other groups considered in some sense atypical, failed ToM tasks, not because they actually have a ToM deficit at all, but rather because they are asked to reveal their ToM competence through cognitive domains, such as language and memory.

Corrigendum: Visual surround suppression in schizophrenia.

[This corrects the article DOI: 10.3389/fpsyg.2013.00088.].

Adenovirus 5 recovery using nanofiber ion-exchange adsorbents.

Viral vectors such as adenovirus have successful applications in vaccines and gene therapy but the manufacture of the high-quality virus remains a challenge. It is desirable to use the adsorption-based chromatographic separations that so effectively underpin the therapeutic protein manufacture. However fundamental differences in the size and stability of this class of product mean it is necessary to revisit the design of sorbent's morphology and surface chemistry. In this study, the behaviour of a cellulose nanofiber ion-exchange sorbent derivatised with quaternary amine ligands at defined densities is characterised to address this. This material was selected as it has a large accessible surface area for viral particles and rapid process times. Initially, the impact of surface chemistry on infective product recovery using low (440 µmol/g), medium (750 µmol/g), and high (1029 µmol/g) ligand densities is studied. At higher densities product stability is reduced, this effect increased with prolonged adsorption durations of 24 min with just ~10% loss at low ligand density versus ~50% at high. This could be mitigated by using a high flow rate to reduce the cycle time to ~1 min. Next, the impact of ligand density on the separation's resolution was evaluated. Key to understanding virus quality is the virus particle: infectious virus particle ratio. It was found this parameter could be manipulated using ligand density and elution strategy. Together this provides a basis for viral vector separations that allows for their typically low titres and labile nature by using high liquid velocity to minimise both load and on-column times while separating key product and process-related impurities.

Ultra scale-down approaches to study the centrifugal harvest for viral vaccine production.

Large scale continuous cell-line cultures promise greater reproducibility and efficacy for the production of influenza vaccines, and adenovirus for gene therapy. This paper seeks to use an existing validated ultra scale-down tool, which is designed to mimic the commercial scale process environment using only milliliters of material, to provide some initial insight into the performance of the harvest step for these processes. The performance of industrial scale centrifugation and subsequent downstream process units is significantly affected by shear. The properties of these cells, in particular their shear sensitivity, may be changed considerably by production of a viral product, but literature on this is limited to date. In addition, the scale-down tool used here has not previously been applied to the clarification of virus production processes. The results indicate that virus infected cells do not actually show any increase in sensitivity to shear, and may indeed become less shear sensitive, in a similar manner to that previously observed in old or dead cell cultures. Clarification may be most significantly dependent on the virus release mechanism, with the budding influenza virus producing a much greater decrease in clarification than the lytic, non-enveloped adenovirus. A good match was also demonstrated to the industrial scale performance in terms of clarification, protein release, and impurity profile.

The mindful eye: Smooth pursuit and saccadic eye movements in meditators and non-meditators.

BACKGROUND: This study examined the effects of cultivated (i.e. developed through training) and dispositional (trait) mindfulness on smooth pursuit (SPEM) and antisaccade (AS) tasks known to engage the fronto-parietal network implicated in attentional and motion detection processes, and the fronto-striatal network implicated in cognitive control, respectively. METHODS: Sixty healthy men (19-59years), of whom 30 were experienced mindfulness practitioners and 30 meditation-naïve, underwent infrared oculographic assessment of SPEM and AS performance. Trait mindfulness was assessed using the self-report Five Facet Mindfulness Questionnaire (FFMQ). RESULTS: Meditators, relative to meditation-naïve individuals, made significantly fewer catch-up and anticipatory saccades during the SPEM task, and had significantly lower intra-individual variability in gain and spatial error during the AS task. No SPEM or AS measure correlated significantly with FFMQ scores in meditation-naïve individuals. CONCLUSIONS: Cultivated, but not dispositional, mindfulness is associated with improved attention and sensorimotor control as indexed by SPEM and AS tasks.

Moderators of noise-induced cognitive change in healthy adults.

Environmental noise causes cognitive impairment, particularly in executive function and episodic memory domains, in healthy populations. However, the possible moderating influences on this relationship are less clear. This study assessed 54 healthy participants (24 men) on a cognitive battery (measuring psychomotor speed, attention, executive function, working memory, and verbal learning and memory) under three (quiet, urban, and social) noise conditions. IQ, subjective noise sensitivity, sleep, personality, paranoia, depression, anxiety, stress, and schizotypy were assessed on a single occasion. We found significantly slower psychomotor speed (urban), reduced working memory and episodic memory (urban and social), and more cautious decision-making (executive function, urban) under noise conditions. There was no effect of sex. Variance in urban noise-induced changes in psychomotor speed, attention, Trail Making B-A (executive function), and immediate recall and social noise-induced changes in verbal fluency (executive function) and immediate recall were explained by a combination of baseline cognition and paranoia, noise sensitivity, sleep, or cognitive disorganization. Higher baseline cognition (but not IQ) predicted greater impairment under urban and social noise for most cognitive variables. Paranoia predicted psychomotor speed, attention, and executive function impairment. Subjective noise sensitivity predicted executive function and memory impairment. Poor sleep quality predicted less memory impairment. Finally, lower levels of cognitive disorganization predicted slower psychomotor speed and greater memory impairment. The identified moderators should be considered in studies aiming to reduce the detrimental effects of occupational and residential noise. These results highlight the importance of studying noise effects in clinical populations characterized by high levels of the paranoia, sleep disturbances, noise sensitivity, and cognitive disorganization.

Biomaterials for hollow organ tissue engineering.

Tissue engineering is a rapidly advancing field that is likely to transform how medicine is practised in the near future. For hollow organs such as those found in the cardiovascular and respiratory systems or gastrointestinal tract, tissue engineering can provide replacement of the entire organ or provide restoration of function to specific regions. Larger tissue-engineered constructs often require biomaterial-based scaffold structures to provide support and structure for new tissue growth. Consideration must be given to the choice of material and manufacturing process to ensure the de novo tissue closely matches the mechanical and physiological properties of the native tissue. This review will discuss some of the approaches taken to date for fabricating hollow organ scaffolds and the selection of appropriate biomaterials.

Effects of environmental noise on cognitive (dys)functions in schizophrenia: A pilot within-subjects experimental study.

Cognitive impairment, particularly in attention, memory and executive function domains, is commonly present and associated with poor functional outcomes in schizophrenia. In healthy adults, environmental noise adversely affects many cognitive domains, including those known to be compromised in schizophrenia. This pilot study examined whether environmental noise causes further cognitive deterioration in a small sample of people with schizophrenia. Eighteen outpatients with schizophrenia on stable doses of antipsychotics and 18 age and sex-matched healthy participants were assessed on a comprehensive cognitive battery including measures of psychomotor speed, attention, executive functioning, working memory, and verbal learning and memory under three different conditions [quiet: ~30dB(A); urban noise: building site noise, 68-78dB(A); and social noise: background babble and footsteps from a crowded hall without any discernible words, 68-78dB(A)], 7-14days apart, with counter-balanced presentation of noise conditions across participants of both groups. The results showed widespread cognitive impairment in patients under all conditions, and noise-induced impairments of equal magnitude on specific cognitive functions in both groups. Both patient and healthy participant groups showed significant disruption of delayed verbal recall and recognition by urban and social noise, and of working memory by social noise, relative to the quiet condition. Performance under urban and social noise did not differ significantly from each other for any cognitive measure in either group. We conclude that noise has adverse effects on the verbal and working memory domains in schizophrenia patients and healthy participants. This may be particularly problematic for patients as it worsens their pre-existing cognitive deficits.

Women's views on autologous cell-based therapy for post-obstetric incontinence.

AIM: Fecal and urinary incontinence are devastating consequences of obstetric-related perineal injury. The aim of the present study is to determine acceptability to parous women of autologous cell-based therapy for fecal and urinary incontinence that arises due to pelvic diaphragm tearing during vaginal childbirth. MATERIALS & METHODS: A multiple choice questionnaire survey was offered to 76 parous women at the Maternity Unit, University College Hospital, London, UK. Seventy completed questionnaires - response rate: 92%. RESULTS: In total, 84% of women indicated a willingness to accept autologous cell-based therapy for obstetric injury-induced incontinence rather than surgery. CONCLUSION: These observational data provide an indication of likely acceptance of autologous cell-based therapies for birth injury incontinence and will help with designing new therapeutic approaches.

Schizotypy and mindfulness: Magical thinking without suspiciousness characterizes mindfulness meditators.

Despite growing evidence for demonstrated efficacy of mindfulness in various disorders, there is a continuous concern about the relationship between mindfulness practice and psychosis. As schizotypy is part of the psychosis spectrum, we examined the relationship between long-term mindfulness practice and schizotypy in two independent studies. Study 1 included 24 experienced mindfulness practitioners (19 males) from the Buddhist tradition (meditators) and 24 meditation-naïve individuals (all males). Study 2 consisted of 28 meditators and 28 meditation-naïve individuals (all males). All participants completed the Schizotypal Personality Questionnaire (Raine, 1991), a self-report scale containing 9 subscales (ideas of reference, excessive social anxiety, magical thinking, unusual perceptual experiences, odd/eccentric behavior, no close friends, odd speech, constricted affect, suspiciousness). Participants of study 2 also completed the Five-Facet Mindfulness Questionnaire which assesses observing (Observe), describing (Describe), acting with awareness (Awareness), non-judging of (Non-judgment) and non-reactivity to inner experience (Non-reactivity) facets of trait mindfulness. In both studies, meditators scored significantly lower on suspiciousness and higher on magical thinking compared to meditation-naïve individuals and showed a trend towards lower scores on excessive social anxiety. Excessive social anxiety correlated negatively with Awareness and Non-judgment; and suspiciousness with Awareness, Non-judgment and Non-reactivity facets across both groups. The two groups did not differ in their total schizotypy score. We conclude that mindfulness practice is not associated with an overall increase in schizotypal traits. Instead, the pattern suggests that mindfulness meditation, particularly with an emphasis on the Awareness, Non-judgment and Non-reactivity aspects, may help to reduce suspiciousness and excessive social anxiety.

GRID and docking analyses reveal a molecular basis for flavonoid inhibition of Src family kinase activity.

Flavonoids reduce cardiovascular disease risk through anti-inflammatory, anti-coagulant and anti-platelet actions. One key flavonoid inhibitory mechanism is blocking kinase activity that drives these processes. Flavonoids attenuate activities of kinases including phosphoinositide-3-kinase, Fyn, Lyn, Src, Syk, PKC, PIM1/2, ERK, JNK and PKA. X-ray crystallographic analyses of kinase-flavonoid complexes show that flavonoid ring systems and their hydroxyl substitutions are important structural features for their binding to kinases. A clearer understanding of structural interactions of flavonoids with kinases is necessary to allow construction of more potent and selective counterparts. We examined flavonoid (quercetin, apigenin and catechin) interactions with Src family kinases (Lyn, Fyn and Hck) applying the Sybyl docking algorithm and GRID. A homology model (Lyn) was used in our analyses to demonstrate that high-quality predicted kinase structures are suitable for flavonoid computational studies. Our docking results revealed potential hydrogen bond contacts between flavonoid hydroxyls and kinase catalytic site residues. Identification of plausible contacts indicated that quercetin formed the most energetically stable interactions, apigenin lacked hydroxyl groups necessary for important contacts and the non-planar structure of catechin could not support predicted hydrogen bonding patterns. GRID analysis using a hydroxyl functional group supported docking results. Based on these findings, we predicted that quercetin would inhibit activities of Src family kinases with greater potency than apigenin and catechin. We validated this prediction using in vitro kinase assays. We conclude that our study can be used as a basis to construct virtual flavonoid interaction libraries to guide drug discovery using these compounds as molecular templates.

A simple and robust method for pre-wetting poly (lactic-co-glycolic) acid microspheres.

Poly (lactic-co-glycolic) acid microspheres are amenable to a number of biomedical procedures that support delivery of cells, drugs, peptides or genes. Hydrophilisation or wetting of poly (lactic-co-glycolic) acid are an important pre-requisites for attachment of cells and can be achieved via exposure to plasma oxygen or nitrogen, surface hydrolysis with NaOH or chloric acid, immersion in ethanol and water, or prolonged incubation in phosphate buffered saline or cell culture medium. The aim of this study is to develop a simple method for wetting poly (lactic-co-glycolic) acid microspheres for cell delivery applications. A one-step ethanol immersion process that involved addition of serum-supplemented medium and ethanol to PLGA microspheres over 30 min-24 h is described in the present study. This protocol presents a more efficient methodology than conventional two-step wetting procedures. Attachment of human skeletal myoblasts to poly (lactic-co-glycolic) acid microspheres was dependent on extent of wetting, changes in surface topography mediated by ethanol pre-wetting and serum protein adsorption. Ethanol, at 70% (v/v) and 100%, facilitated similar levels of wetting. Wetting with 35% (v/v) ethanol was only achieved after 24 h. Pre-wetting (over 3 h) with 70% (v/v) ethanol allowed significantly greater (p ≤ 0.01) serum protein adsorption to microspheres than wetting with 35% (v/v) ethanol. On serum protein-loaded microspheres, greater numbers of myoblasts attached to constructs wetted with 70% ethanol than those partially wetted with 35% (v/v) ethanol. Microspheres treated with 70% (v/v) ethanol presented a more rugose surface than those treated with 35% (v/v) ethanol, indicating that more efficient myoblast adhesion to the former may be at least partially attributed to differences in surface structure. We conclude that our novel protocol for pre-wetting poly (lactic-co-glycolic) acid microspheres that incorporates biochemical and structural features into this biomaterial can facilitate myoblast delivery for use in clinical settings.

Understanding noise stress-induced cognitive impairment in healthy adults and its implications for schizophrenia.

Noise stress (NS) is detrimental to many aspects of human health and behavior. Understanding the effect of noise stressors on human cognitive function is a growing area of research and is crucial to helping clinical populations, such as those with schizophrenia, which are particularly sensitive to stressors. A review of electronic databases for studies assessing the effect of acute NS on cognitive functions in healthy adults revealed 31 relevant studies. The review revealed (1) NS exerts a clear negative effect on attention, working memory and episodic recall, and (2) personality characteristics, in particular neuroticism, and sleep influence the impact of noise stressors on performance in interaction with task complexity. Previous findings of consistent impairment in NS-relevant cognitive domains, heightened sensitivity to stressors, elevated neuroticism and sleep disturbances in schizophrenia, taken together with the findings of this review, highlight the need for empirical studies to elucidate whether NS, a common aspect of urban environments, exacerbates cognitive deficits and other symptoms in schizophrenia and related clinical populations.

Oxidized alginate hydrogels as niche environments for corneal epithelial cells.

Chemical and biochemical modification of hydrogels is one strategy to create physiological constructs that maintain cell function. The aim of this study was to apply oxidised alginate hydrogels as a basis for development of a biomimetic niche for limbal epithelial stem cells that may be applied to treating corneal dysfunction. The stem phenotype of bovine limbal epithelial cells (LEC) and the viability of corneal epithelial cells (CEC) were examined in oxidised alginate gels containing collagen IV over a 3-day culture period. Oxidation increased cell viability (P ≤ 0.05) and this improved further with addition of collagen IV (P ≤ 0.01). Oxidised gels presented larger internal pores (diameter: 0.2-0.8 µm) than unmodified gels (pore diameter: 0.05-0.1 µm) and were significantly less stiff (P ≤ 0.001), indicating that an increase in pore size and a decrease in stiffness contributed to improved cell viability. The diffusion of collagen IV from oxidised alginate gels was similar to that of unmodified gels suggesting that oxidation may not affect the retention of extracellular matrix proteins in alginate gels. These data demonstrate that oxidised alginate gels containing corneal extracellular matrix proteins can influence corneal epithelial cell function in a manner that may impact beneficially on corneal wound healing therapy.

Investigating flavonoids as molecular templates for the design of small-molecule inhibitors of cell signaling.

Epidemiological and clinical trials reveal compelling evidence for the ability of dietary flavonoids to lower cardiovascular disease risk. The mechanisms of action of these polyphenolic compounds are diverse, and of particular interest is their ability to function as protein and lipid kinase inhibitors. We have previously described structure-activity studies that reinforce the possibility for using flavonoid structures as templates for drug design. In the present study, we aim to begin constructing rational screening strategies for exploiting these compounds as templates for the design of clinically relevant, antiplatelet agents. We used the platelet as a model system to dissect the structural influence of flavonoids, stilbenes, anthocyanidins, and phenolic acids on inhibition of cell signaling and function. Functional groups identified as relevant for potent inhibition of platelet function included at least 2 benzene rings, a hydroxylated B ring, a planar C ring, a C ring ketone group, and a C-2 positioned B ring. Hydroxylation of the B ring with either a catechol group or a single C-4' hydroxyl may be required for efficient inhibition of collagen-stimulated tyrosine phosphorylated proteins of 125 to 130 kDa, but may not be necessary for that of phosphotyrosine proteins at approximately 29 kDa. The removal of the C ring C-3 hydroxyl together with a hydroxylated B ring (apigenin) may confer selectivity for 37 to 38 kDa phosphotyrosine proteins. We conclude that this study may form the basis for construction of maps of flavonoid inhibitory activity on kinase targets that may allow a multitargeted therapeutic approach with analogue counterparts and parent compounds.

Flavonoid inhibitory pharmacodynamics on platelet function in physiological environments.

The complex relationship between flavonoid-based nutrition and cardiovascular disease may be dissected by understanding the activities of these compounds in biological systems. The aim of the present study was to explore a hierarchy for the importance of dietary flavonoids on cardiovascular health by examining the structural basis for inhibitory effects of common, dietary flavonoids (quercetin, apigenin, and naringenin) and the plasma metabolite, tamarixetin. Understanding flavonoid effects on platelets in vivo can be informed by investigations of the ability of these compounds to attenuate the function of these cells. Inhibition of platelet function in whole blood and plasma was structure-dependent. The order of potency was apigenin > tamarixetin > quercetin = naringenin indicating that in vivo, important functional groups are potentially a methylated B ring, and a non-hydroxylated, planar C ring. Apigenin and the methylated metabolite of quercetin, tamarixetin significantly reduced thrombus volume at concentrations (5 µM) that suggested their reported physiological levels (0.1-1 µM) may exert low levels of inhibition. Flavonoid interactions with erythrocytes, leukocytes and human serum albumin in whole blood reduce their inhibitory activities against platelet function. The diminished inhibitory activity of flavonoids that we observed in whole blood and plasma indicated that these interactions do not overcome the attenuating effects of these compounds. Furthermore, inhibition of platelet aggregation by flavonoids was enhanced with increases in exposure time, indicating the potential for measurable inhibitory effects during resident plasma times. We conclude that flavonoid structures may be a major influence of their activities in vivo with methylated metabolites and those of flavones being more potent than those of flavonols and flavanones.

The secretome of alginate-encapsulated limbal epithelial stem cells modulates corneal epithelial cell proliferation.

Limbal epithelial stem cells may ameliorate limbal stem cell deficiency through secretion of therapeutic proteins, delivered to the cornea in a controlled manner using hydrogels. In the present study the secretome of alginate-encapsulated limbal epithelial stem cells is investigated. Conditioned medium was generated from limbal epithelial stem cells encapsulated in 1.2% (w/v) calcium alginate gels. Conditioned medium proteins separated by 1-D gel electrophoresis were visualized by silver staining. Proteins of interest including secreted protein acidic and rich in cysteine, profilin-1, and galectin-1 were identified by immunoblotting. The effect of conditioned medium (from alginate-encapsulated limbal epithelial stem cells) on corneal epithelial cell proliferation was quantified and shown to significantly inhibit (P≤0.05) their growth. As secreted protein acidic and rich in cysteine was previously reported to attenuate proliferation of epithelial cells, this protein may be responsible, at least in part, for inhibition of corneal epithelial cell proliferation. We conclude that limbal epithelial stem cells encapsulated in alginate gels may regulate corneal epithelialisation through secretion of inhibitory proteins.

Limbal epithelial stem cell identification using immunoblotting analysis.

The unambiguous identification of limbal epithelial stem cells is currently a major challenge in corneal stem cell biology. Specific molecular markers which characterize these cells are lacking. At present, the best strategy for identification of limbal epithelial stem cells is to investigate a variety of putative markers for these cells in a differentiated (cytokeratin (CK) 3: CK3, integrin α6), undifferentiated (CK14), and naive state (∆Np63α, ATP-binding cassette subfamily G member 2 (ABCG2), integrin α9, Notch-1), alongside functional assays which indicate their stemness. The focus of this chapter is to highlight advances in the Western blotting technique for quantitative assessment of corneal epithelial cell markers, and the use of this technique for investigation of a range of different protein markers which identify limbal epithelial stem cells.

Visual surround suppression in schizophrenia.

Compared to unaffected observers patients with schizophrenia (SZ) show characteristic differences in visual perception, including a reduced susceptibility to the influence of context on judgments of contrast - a manifestation of weaker surround suppression (SS). To examine the generality of this phenomenon we measured the ability of 24 individuals with SZ to judge the luminance, contrast, orientation, and size of targets embedded in contextual surrounds that would typically influence the target's appearance. Individuals with SZ demonstrated weaker SS compared to matched controls for stimuli defined by contrast or size, but not for those defined by luminance or orientation. As perceived luminance is thought to be regulated at the earliest stages of visual processing our findings are consistent with a suppression deficit that is predominantly cortical in origin. In addition, we propose that preserved orientation SS in SZ may reflect the sparing of broadly tuned mechanisms of suppression. We attempt to reconcile these data with findings from previous studies.