Cognitive impairment but preservation of sexual dimorphism in cognitive abilities in chronic schizophrenia.

Neurocognitive impairment in schizophrenia is well established, though sex differences on cognitive tasks have produced equivocal findings. The present study was designed to examine performance of schizophrenia patients on a sexually dimorphic cognitive battery. The cognitive battery comprising tests of spatial (mental rotation, computerized version of the Benton Judgment of Line Orientation) and verbal abilities (phonological and semantic fluency) was administered to men (n = 22) and women (n = 21) with schizophrenia and healthy controls (n = 21 men and 21 women).

The sterol-binding antibiotic nystatin inhibits entry of non-opsonized Leishmania donovani into macrophages.

Leishmania donovani is an obligate intracellular parasite that infects macrophages of the vertebrate host resulting in visceral leishmaniasis in humans, a major public health problem worldwide. The molecular mechanisms involved in internalization of Leishmania are still poorly characterized. We report here that cholesterol sequestration by the sterol-binding antifungal polyene antibiotic nystatin markedly inhibits binding and entry of non-opsonized L.

Comparable fMRI activity with differential behavioural performance on mental rotation and overt verbal fluency tasks in healthy men and women.

To explicate the neural correlates of sex differences in visuospatial and verbal fluency tasks, we examined behavioural performance and blood-oxygenation-level-dependent (BOLD) regional brain activity, using functional magnetic resonance imaging, during a three-dimensional (3D) mental rotation task and a compressed sequence overt verbal fluency task in a group of healthy men (n=9) and women (n=10; tested during the low-oestrogen phase of the menstrual cycle). Men outperformed women on the mental rotation task, and women outperformed men on the verbal fluency task. For the mental rotation task, men and women activated areas in the right superior parietal lobe and the bilateral middle occipital gyrus in association with the rotation condition.

Neural correlates of adjunctive rivastigmine treatment to antipsychotics in schizophrenia: a randomized, placebo-controlled, double-blind fMRI study.

Facilitation of central cholinergic activity may form a potential treatment strategy for cognitive impairment in schizophrenia. In a randomized, placebo-controlled, double-blind, parallel-group design, we investigated the neural correlates of cognitive effects of rivastigmine, an acetylcholinesterase inhibitor, given as an add-on therapy to antipsychotic-treated schizophrenia patients. Thirty-six chronic schizophrenia patients with mild cognitive impairment took part.

Reduced prepulse inhibition in unaffected siblings of schizophrenia patients.

We investigated whether prepulse inhibition of the startle response is reduced in siblings of schizophrenia patients compared to age- and sex-matched healthy controls. Nineteen unaffected biological siblings and 19 controls were assessed on prepulse inhibition by monaural and binaural acoustic prepulse stimuli, with the startle stimuli always presented binaurally. There was significantly less prepulse inhibition in siblings, compared to controls, with binaural prepulse stimuli, as also seen previously in schizophrenia patients.

Evidence for deficit in tasks of ventral, but not dorsal, prefrontal executive function as an endophenotypic marker for bipolar disorder.

Background: Trait functional abnormalities in BD patients have only been reported in the ventral prefrontal cortex (VPFC). We examined whether deficits in VPFC-related inhibitory processes, but not dorsal prefrontal (DPFC) based executive functions, represent an endophenotypic marker for bipolar disorder I (BDI).

Methods: We used the Wisconsin Card Sorting Test (WCST), commonly associated with DPFC function, and the Hayling Sentence Completion Task (HSCT) which engages the VPFC.

The relationship of structural alterations to cognitive deficits in schizophrenia: a voxel-based morphometry study.

Background: Region of interest studies have identified a number of structure-cognition associations in schizophrenia and revealed alterations in structure-cognition relationship in this population.

Methods: We examined the relationship of structural brain alterations, identified using voxel-based morphometry, to cognitive deficits in 45 schizophrenia patients relative to 43 healthy control subjects and tested the hypothesis that structure-cognition relationship is altered in schizophrenia.

Results: Patients had smaller total brain, gray matter, and white matter volumes.

Effects of rivastigmine on sustained attention in schizophrenia: an FMRI study.

This study assessed the neural correlates of the effects of rivastigmine, a CNS-selective cholinesterase inhibitor, given as an add-on therapy to antipsychotics-treated patients with schizophrenia who displayed moderate cognitive impairments, using functional magnetic resonance imaging (fMRI) during a sustained attention task. The study used a placebo-controlled, randomized, double-blind longitudinal design. Twenty patients stable on antipsychotics, 11 assigned to receive rivastigmine and 9 to receive placebo, underwent fMRI and clinical assessments at baseline and after 12 weeks.

Nicotine use in schizophrenia: the self medication hypotheses.

The behavioural and cognitive effects of nicotine in schizophrenia have received much interest in recent years. The rate of smoking in patients with schizophrenia is estimated to be two- to four-fold the rate seen in the general population. Furthermore such patients favour stronger cigarettes and may also extract more nicotine from their cigarettes than other smokers.

Structural brain correlates of prepulse inhibition of the acoustic startle response in healthy humans.

Neural regions modulating prepulse inhibition (PPI) of the startle response, an operational measure of sensorimotor gating, are well established from animal studies using surgical and pharmacological procedures. The limbic and cortico-pallido-striato-thalamic circuitry is thought to be responsible for modulation of PPI in the rat. The involvement of this circuitry in human PPI is suggested by observations of deficient PPI in a number of neuropsychiatric disorders characterized by abnormalities at some level in this circuitry and recent functional neuroimaging studies in humans.

Sex differences and individual differences in cognitive performance and their relationship to endogenous gonadal hormones and gonadotropins.

Sexually dimorphic cognitive performance in men (n=42) and women (n=42) was related to testosterone, estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, and sex hormone binding globulin, measured in 10-ml blood samples collected between 0900 and 1030 and, among women, during the follicular phase of the menstrual cycle. Significant sex differences favored men on spatial tasks (Mental Rotation and Judgment of Line Orientation) and on an inhibition task and favored women on a verbal task (category fluency). However, there were no significant relationships between any of the hormones and cognitive performance, suggesting that there are few, if any, consistent, substantial relationships between endogenous, nonfluctuating levels of gonadal hormones or gonadotropins and these cognitive abilities in men or women.

Lack of association between prepulse inhibition and antisaccadic deficits in chronic schizophrenia: implications for identification of schizophrenia endophenotypes.

Individuals with schizophrenia, compared to healthy individuals, are known to exhibit deficient prepulse inhibition (PPI) of the startle response as well as reduced performance on the antisaccade task. There is evidence for genetic transmission of both PPI and antisaccadic abnormalities in schizophrenia. It has been suggested that PPI and antisaccade measures identify separate endophenotypes, on the basis of a lack of relationship between PPI and antisaccade deficits in patients with schizotypal personality disorder.

A neuropsychological investigation into violence and mental illness.

Previous research has reported cognitive impairment in patients with schizophrenia and antisocial personality disorder (APD), the two psychiatric illnesses most implicated in violent behaviour. Previous studies have focused on either group exclusively, and have been criticized for procedural inadequacies and sample heterogeneity. The authors investigated and compared neuropsychological profiles of individuals with APD and violent and nonviolent individuals with schizophrenia in a single investigation.

Sex effects in prepulse inhibition and facilitation of the acoustic startle response: implications for pharmacological and treatment studies.

Prepulse inhibition (PPI) refers to the reduction in the response amplitude to a startling stimuli (pulse) if it is preceded (i.e. 30-500 ms) by a weak stimulus (prepulse).

Structural neural correlates of prosaccade and antisaccade eye movements in healthy humans.

We previously reported that prosaccade amplitude gain and antisaccade error rate are correlated with cerebellar and posterior frontal grey matter volume, respectively. This study sought to replicate and extend these findings in a sample of 32 right-handed, healthy volunteers (14 males, 18 females). Participants underwent structural magnetic resonance imaging (MRI) at 1.

Disruption of learned irrelevance in acute schizophrenia in a novel continuous within-subject paradigm suitable for fMRI.

Learned irrelevance (LIrr) is closely related to latent inhibition (LI). In LI a to-be-conditioned stimulus (CS) is prexposed alone prior to the opportunity to learn an association between the CS and an unconditioned stimulus (UCS). In LIrr preexposure consists of intermixed presentations of both CS and UCS in a random relationship to each other.

Personality predicts brain responses to cognitive demands.

Eysenck (1981) proposed that the personality dimension of introversion- extraversion (E) reflects individual differences in a cortical arousal system modulated by reticulothalamic- cortical pathways: it is chronically more active in introverts relative to extraverts and influences cognitive performance in interaction with task parameters. A circuit with connections to this system, including the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate (AC) cortex, has been identified in studies applying functional magnetic resonance imaging (fMRI) to a broad range of cognitive tasks. We examined the influence of E, assessed with the Eysenck Personality Questionnaire-Revised (Eysenck and Eysenck, 1991), in fMRI activity during an "n-back" task involving four memory loads (0-, 1-, 2-, and 3-back) and a rest condition in healthy men.

Sex differences in prepulse inhibition deficits in chronic schizophrenia.

Recent years have seen a dramatic growth in the number of studies using prepulse inhibition (PPI) paradigms to index information processing deficits in schizophrenia. There are, however, robust sex differences in PPI in healthy subjects, with women exhibiting less PPI than men in the absence of any psychopathology. To investigate the role of sex in prepulse modification deficits in the long-term course of schizophrenia, we assessed PPI (response inhibition with the prepulse preceding the pulse by 30-150 ms) and prepulse facilitation (PPF; response facilitation with the prepulse preceding the pulse by 1000 ms) of the acoustic startle response in 42 chronic schizophrenia patients (27 men; all 42 on typical antipsychotics) and 35 controls (15 men).

Volumetric neural correlates of antisaccade eye movements in first-episode psychosis.

Objective: The authors investigated the structural brain correlates of antisaccade performance.

Method: Magnetic resonance imaging was used to measure the volumes of the prefrontal, premotor, sensorimotor, and occipitoparietal cortices as well as the caudate, thalamus, cerebellar vermis, and cerebrum in 20 first-episode psychosis patients and 18 healthy comparison subjects. Antisaccades were recorded by using infrared oculography.

The relationship between brain structure and neurocognition in schizophrenia: a selective review.

Both Kraepelin [1919. Dementia Praecox and Paraphrenia, Livingston, Edinburgh.] and Bleuler [1911.

Saccadic eye movements, schizotypy, and the role of neuroticism.

We investigated the relationships of anti- and prosaccades with psychometric schizotypy. One aim was to estimate the role of negative emotionality and general psychopathology (i.e.

Neurological soft signs and their relationship to cognitive and clinical efficacy of atypical antipsychotics in schizophrenia.

Neurological soft signs (NSS) are nonspecific indicators of brain dysfunction that are found to be in excess and correlated with cognitive dysfunction and psychopathology in patients with schizophrenia. The aim of the study was to examine whether the severity of NSS determines the efficacy of atypical antipsychotics in schizophrenia. Forty-three patients with schizophrenia were assessed on psychopathology and cognitive domains of executive functioning, memory, attention, and psychomotor speed at baseline and 6 months after they had been switched from typical to atypical antipsychotics.

Cognitive generation of affect in bipolar depression: an fMRI study.

Individuals with bipolar disorder manifest the full spectrum of emotions ranging from depression to mania. In attempting to understand the functional substrates of mood we attempted to identify brain regions associated with the cognitive generation of affect in bipolar depressed patients. We therefore examined ten depressed female subjects with bipolar affective disorder, and ten age-matched and sex-matched healthy comparison subjects using functional magnetic resonance imaging (fMRI) while viewing alternating blocks of captioned pictures designed to evoke negative, positive or no affective change.