Background: Prepulse inhibition (PPI) of the startle response refers to the ability of a weak prestimulus to transiently inhibit the response to a closely following strong sensory stimulus. PPI provides an operational index of sensorimotor gating and is reduced, on average, in people with schizophrenia, relative to healthy people. Given the variable response to Cognitive Behaviour Therapy for psychosis (CBTp) and positive associations between pre-therapy brain and cognitive functions and CBT outcome across disorders, we examined whether pre-therapy level of PPI is associated with clinical outcome following CBTp.
View Article and Find Full Text PDFCognitive insight in schizophrenia encompasses the evaluation and reinterpretation of distorted beliefs and appraisals. We investigated the neuropsychological basis of cognitive insight in psychosis. It was predicted that, like clinical insight, cognitive insight would be associated with a wide range of neuropsychological functions, but would be most strongly associated with measures of executive function.
View Article and Find Full Text PDFWe examined whether startle abnormalities are present in bipolar disorder (BD) patients and their unaffected siblings. Twenty-one remitted patients with BD, 19 unaffected siblings, and 42 controls were presented with 18 pleasant, 18 unpleasant, and 18 neutral pictures. Acoustic probes (104 dB) were presented during 12 of 18 pictures in each affective category at 300, 3000, and 4500 ms after picture onset, so that there were 4 pictures per valence per probe onset type.
View Article and Find Full Text PDFPrepulse inhibition (PPI) of the startle response is sensitive to sex, with healthy young women showing less PPI compared with age-matched men, and varies according to the menstrual cycle phase in women. Relatively less is known regarding sex and hormonal influences in prepulse facilitation (PPF). Menstrual phase-related variability in PPI is suggested to be mediated by fluctuating estrogen level, based on the observations of more PPI in women during the follicular, relative to the luteal, phase.
View Article and Find Full Text PDFBackground: Schizophrenia has been associated with limited abilities to interact effectively in social situations. Face perception and ability to recognise familiar faces are critical for social interaction. Patients with chronic schizophrenia are known to show impaired face recognition.
View Article and Find Full Text PDFBackground: Prepulse inhibition (PPI) of the startle response refers to the ability of a weak prestimulus to transiently inhibit the response to a closely following strong sensory stimulus. This effect is reduced in a number of disorders known to be associated with impaired gating of sensory, cognitive or motor information. The aim of this study was to investigate PPI deficit in relation to the dimensions of auditory hallucinations in patients with schizophrenia or schizoaffective disorder.
View Article and Find Full Text PDFNeuropsychopharmacology
October 2008
Prepulse inhibition (PPI) of the startle response is sensitive to sex with women showing less PPI compared with age-matched men and varies according to the menstrual cycle in women. Relatively less is known about sex differences in prepulse facilitation (PPF). To examine further the roles of sex and circulating sex hormones, pre- (n=20) and postmenopausal women (n=20) were compared with men of similar ages (n=17, 18-40 years; n=18, 55-69 years).
View Article and Find Full Text PDFBackground: While it is known that patients with schizophrenia recognize facial emotions, specifically negative emotions, less accurately, little is known about how they misattribute these emotions to other emotions and whether such misattribution biases are associated with symptoms, course of the disorder, or certain cognitive functions.
Method: Outpatients with schizophrenia or schizoaffective disorder (n=73) and healthy controls (n=30) performed a computerised Facial Emotion Attribution Test and Wisconsin Card Sorting Test (WCST). Patients were also rated on the Positive and Negative Syndrome Scale (PANSS).
Background: The stigma and negative societal views attached to schizophrenia can make the diagnosis distressing. There is evidence that poor insight into symptoms of the disorder and need for treatment may reflect the use of denial as a coping style. However, the relationships between insight and other coping styles have seldom been investigated.
View Article and Find Full Text PDFPrevious studies have suggested a relationship between frontal lobe-based neuropsychological functions and insight in schizophrenia. There is some evidence linking both smaller whole brain volume and frontal cortical atrophy to poor insight in this population. We investigated the relationship between total as well as specific prefrontal regional volumes and insight in schizophrenia.
View Article and Find Full Text PDFCognitive impairment has the greatest impact on illness outcome in schizophrenia. The most significant challenge in schizophrenia therapeutics, thus, is to develop an efficacious treatment for cognitive impairments. Acetylcholinesterase inhibitors, such as Physostigmine and Rivastigmine, are considered effective treatments for cognitive decline in Alzheimer's Disease, where the loss of cholinergic neurons is thought to be responsible for various cognitive deficits.
View Article and Find Full Text PDFContemporary theories and evidence implicate frontal lobe dysfunction in violent behaviour as well as in schizophrenia. We applied functional magnetic resonance imaging (fMRI) to investigate and compare brain activation during an 'n-back' working memory task in groups of men with (i) schizophrenia and a history of serious physical violence (VS; n=13), (ii) schizophrenia without a history of violence (NVS: n=12), (iii) antisocial personality disorder (APD) and a history of serious physical violence (n=10), and (iv) no history of violence or a mental disorder (n=13). We observed comparable performance in all four groups during the control (0-back) condition.
View Article and Find Full Text PDFFacilitation 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.
View Article and Find Full Text PDFJ Clin Psychopharmacol
August 2005
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.
View Article and Find Full Text PDFNeural 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.
View Article and Find Full Text PDFPrepulse 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).
View Article and Find Full Text PDFRecent 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).
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