Schizophrenia is a serious mental illness that affects 1% of the population. It is beset with pro... more Schizophrenia is a serious mental illness that affects 1% of the population. It is beset with problems of diagnosis and difficulties in assessing treatment. Neuroimaging has long contributed to our understanding of schizophrenia but recent developments suggest it may ultimately play a practical role in its early detection and management.
Proceedings of the National Academy of Sciences, 1999
Antipsychotic drug treatment of schizophrenia may be complicated by side effects of widespread do... more Antipsychotic drug treatment of schizophrenia may be complicated by side effects of widespread dopaminergic antagonism, including exacerbation of negative and cognitive symptoms due to frontal cortical hypodopaminergia. Atypical antipsychotics have been shown to enhance frontal dopaminergic activity in animal models. We predicted that substitution of risperidone for typical antipsychotic drugs in the treatment of schizophrenia would be associated with enhanced functional activation of frontal cortex. We measured cerebral blood oxygenation changes during periodic performance of a verbal working memory task, using functional MRI, on two occasions (baseline and 6 weeks later) in two cohorts of schizophrenic patients. One cohort ( n = 10) was treated with typical antipsychotic drugs throughout the study. Risperidone was substituted for typical antipsychotics after baseline assessment in the second cohort ( n = 10). A matched group of healthy volunteers ( n = 10) was also studied on a si...
BackgroundThird rather than lateral ventriculomegaly may be a more specific finding in psychosis.... more BackgroundThird rather than lateral ventriculomegaly may be a more specific finding in psychosis. The relevance of ventricular abnormality remains unclear.AimsTo investigate the developmental correlates of ventricular enlargement.MethodInformation on childhood development and magnetic resonance images in 1.5-mm contiguous sections were collected on 21 patients experiencing a first episode of psychosis.ResultsPatients (n=21) had significantly less whole brain volume and enlarged third and lateral ventricles compared to controls (n=25). Third ventricle (r=0.48, P < 0.03) and lateral ventricle (r=0.65, P < 0.01) volumes correlated with developmental score. Patients with developmental delay had significantly larger third and lateral ventricles than those without.ConclusionsEnlargement of both third and lateral ventricles is found in first-episode psychosis and is related to developmental delay in childhood. Insult to periventricular areas is relevant to the neurobiology of the dis...
BackgroundPET studies of verbal fluency in schizophrenia report a failure of ‘deactivation’ of le... more BackgroundPET studies of verbal fluency in schizophrenia report a failure of ‘deactivation’ of left superior temporal gyrus (STG) in the presence of activation of left dorsolateral prefrontal cortex (DLPFC), which deficit has been attributed to underlying ‘functional disconnectivity’.AimTo test whether these findings provide trait-markers for schizophrenia.MethodWe used H215O PET to examine verbal fluency in 10 obligate carriers of the predisposition to schizophrenia, 10 stable patients and 10 normal controls.ResultsWe found no evidence of a failure of left STG deactivation in carriers or patients. Instead, patients failed to deactivate the precuneus relative to other groups. We found no differences in functional connectivity between left DLPFC and left STG but patients exhibited significant disconnectivity between left DLPFC and anterior cingulate cortex.ConclusionsFailure of left STG ‘deactivation’ and left fronto-temporal disconnectivity are not consistent findings in schizophren...
Schizophrenia is a serious mental illness that affects 1% of the population. It is beset with pro... more Schizophrenia is a serious mental illness that affects 1% of the population. It is beset with problems of diagnosis and difficulties in assessing treatment. Neuroimaging has long contributed to our understanding of schizophrenia but recent developments suggest it may ultimately play a practical role in its early detection and management.
Proceedings of the National Academy of Sciences, 1999
Antipsychotic drug treatment of schizophrenia may be complicated by side effects of widespread do... more Antipsychotic drug treatment of schizophrenia may be complicated by side effects of widespread dopaminergic antagonism, including exacerbation of negative and cognitive symptoms due to frontal cortical hypodopaminergia. Atypical antipsychotics have been shown to enhance frontal dopaminergic activity in animal models. We predicted that substitution of risperidone for typical antipsychotic drugs in the treatment of schizophrenia would be associated with enhanced functional activation of frontal cortex. We measured cerebral blood oxygenation changes during periodic performance of a verbal working memory task, using functional MRI, on two occasions (baseline and 6 weeks later) in two cohorts of schizophrenic patients. One cohort ( n = 10) was treated with typical antipsychotic drugs throughout the study. Risperidone was substituted for typical antipsychotics after baseline assessment in the second cohort ( n = 10). A matched group of healthy volunteers ( n = 10) was also studied on a si...
BackgroundThird rather than lateral ventriculomegaly may be a more specific finding in psychosis.... more BackgroundThird rather than lateral ventriculomegaly may be a more specific finding in psychosis. The relevance of ventricular abnormality remains unclear.AimsTo investigate the developmental correlates of ventricular enlargement.MethodInformation on childhood development and magnetic resonance images in 1.5-mm contiguous sections were collected on 21 patients experiencing a first episode of psychosis.ResultsPatients (n=21) had significantly less whole brain volume and enlarged third and lateral ventricles compared to controls (n=25). Third ventricle (r=0.48, P < 0.03) and lateral ventricle (r=0.65, P < 0.01) volumes correlated with developmental score. Patients with developmental delay had significantly larger third and lateral ventricles than those without.ConclusionsEnlargement of both third and lateral ventricles is found in first-episode psychosis and is related to developmental delay in childhood. Insult to periventricular areas is relevant to the neurobiology of the dis...
BackgroundPET studies of verbal fluency in schizophrenia report a failure of ‘deactivation’ of le... more BackgroundPET studies of verbal fluency in schizophrenia report a failure of ‘deactivation’ of left superior temporal gyrus (STG) in the presence of activation of left dorsolateral prefrontal cortex (DLPFC), which deficit has been attributed to underlying ‘functional disconnectivity’.AimTo test whether these findings provide trait-markers for schizophrenia.MethodWe used H215O PET to examine verbal fluency in 10 obligate carriers of the predisposition to schizophrenia, 10 stable patients and 10 normal controls.ResultsWe found no evidence of a failure of left STG deactivation in carriers or patients. Instead, patients failed to deactivate the precuneus relative to other groups. We found no differences in functional connectivity between left DLPFC and left STG but patients exhibited significant disconnectivity between left DLPFC and anterior cingulate cortex.ConclusionsFailure of left STG ‘deactivation’ and left fronto-temporal disconnectivity are not consistent findings in schizophren...
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