Antipsychotic drug effects on motor activation measured by functional magnetic resonance imaging in schizophrenic patients

Neuroimaging studies of the early stages of psychosis: A critical review

Psychiatric imaging, in particular functional imaging techniques such as functional magnetic resonance imaging (fMRI) are potentially powerful tools to explore the neurophysiological basis of the early stages of psychosis. Despite this impressive growth, neuroimaging has yet to become an established as diagnostic instrument this area, partly as a result of significant heterogeneity across the findings from research studies. The present review aims to: (i) assess the determinants of inconsistencies in the results from neuroimaging studies of the early stages of psychosis; and (ii) suggest approaches for future imaging research in this field that may reduce methodological differences between studies.

Functional brain networks in never-treated and treated long-term Ill schizophrenia patients

This study compared the topological organization of brain function in never-treated and treated long-term schizophrenia patients. In a cross-sectional study, 21 never-treated schizophrenia patients with illness duration over 5 years, 26 illness duration-matched antipsychotic-treated patients and 24 demographically-matched healthy controls underwent a resting-state functional magnetic resonance imaging (MRI) scan. The topological properties of brain functional networks were compared across groups, and then we tested for differential age-related effects in regions with significant group differences. Both never-treated and antipsychotic-treated schizophrenia patient groups showed altered nodal centralities in left pre-/postcentral gyri relative to controls. Never-treated patients demonstrated reduced global efficacy, decreased nodal centralities in right amygdala/hippocampus and bilateral putamen/caudate relative to antipsychotic-treated patients and controls. No significant relationships of age and altered functional metrics were seen in either patient group, and no alterations were greater in the treated group. These findings provide insight into brain function deficits over the longer-term course of schizophrenia independent from potential effects of antipsychotic medication. The presence of greater alterations in never-treated than treated patients suggests that long-term antipsychotic treatment may partially protect or enhance brain global and nodal topological function over the course of schizophrenia, notably involving the amygdala, hippocampus, and striatum that have long been associated with the disorder.

Effects of aripiprazole and haloperidol on neural activation during a simple motor task in healthy individuals: A functional MRI study

The dopaminergic system plays a key role in motor function and motor abnormalities have been shown to be a specific feature of psychosis. Due to their dopaminergic action, antipsychotic drugs may be expected to modulate motor function, but the precise effects of these drugs on motor function remain unclear. We carried out a within-subject, double-blind, randomized study of the effects of aripiprazole, haloperidol and placebo on motor function in 20 healthy men. For each condition, motor performance on an auditory-paced task was investigated. We entered maps of neural activation into a random effects general linear regression model to investigate motor function main effects. Whole-brain imaging revealed a significant treatment effect in a distributed network encompassing posterior orbitofrontal/anterior insula cortices, and the inferior temporal and postcentral gyri. Post-hoc comparison of treatments showed neural activation after aripiprazole did not differ significantly from placebo in either voxel-wise or region of interest analyses, with the results above driven primarily by haloperidol. We also observed a simple main effect of haloperidol compared with placebo, with increased task-related recruitment of posterior cingulate and precentral gyri. Furthermore, region of interest analyses revealed greater activation following haloperidol compared with placebo in the precentral and post-central gyri, and the putamen. These diverse modifications in cortical motor activation may relate to the different pharmacological profiles of haloperidol and aripiprazole, although the specific mechanisms underlying these differences remain unclear. Evaluating healthy individuals can allow investigation of the effects of different antipsychotics on cortical activation, independently of either disease-related pathology or previous treatment. Hum Brain Mapp 38:1833-1845, 2017. © 2017 Wiley Periodicals, Inc.

The MCIC collection: a shared repository of multi-modal, multi-site brain image data from a clinical investigation of schizophrenia

Expertly collected, well-curated data sets consisting of comprehensive clinical characterization and raw structural, functional and diffusion-weighted DICOM images in schizophrenia patients and sex and age-matched controls are now accessible to the scientific community through an on-line data repository (coins.mrn.org). The Mental Illness and Neuroscience Discovery Institute, now the Mind Research Network (MRN, http://www.mrn.org/ ), comprised of investigators at the University of New Mexico, the University of Minnesota, Massachusetts General Hospital, and the University of Iowa, conducted a cross-sectional study to identify quantitative neuroimaging biomarkers of schizophrenia. Data acquisition across multiple sites permitted the integration and cross-validation of clinical, cognitive, morphometric, and functional neuroimaging results gathered from unique samples of schizophrenia patients and controls using a common protocol across sites. Particular effort was made to recruit patients early in the course of their illness, at the onset of their symptoms. There is a relatively even sampling of illness duration in chronic patients. This data repository will be useful to 1) scientists who can study schizophrenia by further analysis of this cohort and/or by pooling with other data; 2) computer scientists and software algorithm developers for testing and validating novel registration, segmentation, and other analysis software; and 3) educators in the fields of neuroimaging, medical image analysis and medical imaging informatics who need exemplar data sets for courses and workshops. Sharing provides the opportunity for independent replication of already published results from this data set and novel exploration. This manuscript describes the inclusion/exclusion criteria, imaging parameters and other information that will assist those wishing to use this data repository.

Functional imaging of cerebral perfusion

The functional imaging of perfusion enables the study of its properties such as the vasoreactivity to circulating gases, the autoregulation and the neurovascular coupling. Downstream from arterial stenosis, this imaging can estimate the vascular reserve and the risk of ischemia in order to adapt the therapeutic strategy. This method reveals the hemodynamic disorders in patients suffering from Alzheimer's disease or with arteriovenous malformations revealed by epilepsy. Functional MRI of the vasoreactivity also helps to better interpret the functional MRI activation in practice and in clinical research.

Neuropsychopharmacology of auditory hallucinations: insights from pharmacological functional MRI and perspectives for future research

Experiencing auditory verbal hallucinations is a prominent symptom in schizophrenia that also occurs in subjects at enhanced risk for psychosis and in the general population. Drug treatment of auditory hallucinations is challenging, because the current understanding is limited with respect to the neural mechanisms involved, as well as how CNS drugs, such as antipsychotics, influence the subjective experience and neurophysiology of hallucinations. In this article, the authors review studies of the effect of antipsychotic medication on brain activation as measured with functional MRI in patients with auditory verbal hallucinations. First, the authors examine the neural correlates of ongoing auditory hallucinations. Then, the authors critically discuss studies addressing the antipsychotic effect on the neural correlates of complex cognitive tasks. Current evidence suggests that blood oxygen level-dependant effects of antipsychotic drugs reflect specific, regional effects but studies on the neuropharmacology of auditory hallucinations are scarce. Future directions for pharmacological neuroimaging of auditory hallucinations are discussed.

Distinct structural alterations independently contributing to working memory deficits and symptomatology in paranoid schizophrenia

Schizophrenia is considered a brain disease with a quite heterogeneous clinical presentation. Studies in schizophrenia have yielded a wide array of correlations between structural and functional brain changes and clinical and cognitive symptoms. Reductions of grey matter volume (GMV) in the prefrontal and temporal cortex have been described which are crucial for the development of positive and negative symptoms and impaired working memory (WM). Associations between GMV reduction and positive and negative symptoms as well as WM impairment were assessed in schizophrenia patients (symptomatology in 34, WM in 26) and compared to healthy controls (36 total, WM in 26). GMV was determined by voxel-based morphometry and its relation to positive and negative symptoms as well as WM performance was assessed. In schizophrenia patients, reductions of GMV were evident in anterior cingulate cortex, ventrolateral prefrontal cortex (VLPFC), superior temporal cortex, and insula. GMV reductions in the superior temporal gyrus (STG) were associated with positive symptom severity as well as WM impairment. Furthermore, the absolute GMV of VLPFC was strongly related to negative symptoms. These predicted WM performance as well as processing speed. The present results support the assumption of two distinct pathomechanisms responsible for impaired WM in schizophrenia: (1) GMV reductions in the VLPFC predict the severity of negative symptoms. Increased negative symptoms in turn are associated with a slowing down of processing speed and predict an impaired WM. (2) GMV reductions in the temporal and mediofrontal cortex are involved in the development of positive symptoms and impair WM performance, too.

The biology of schizophrenia

Schizophrenia is an illness where the clinical signs and symptoms, course, and cognitive characteristics are well described. Successful pharmacological treatments do exist, even though they are likely palliative. However, this broad knowledge base has not yet led to the identification of its pathophysiology or etiology The risk factors for schizophrenia are most prominently genetic and scientists anticipate that contributions from the new genetic information in the human genome will help progress towards discovering a disease mechanism. Brain-imaging techniques have opened up the schizophrenic brain for direct inquiries, in terms of structure, neurochemisiry, and function. New proposals for diagnosis include grouping schizophrenia together with schizophrenia-related personality disorders into the same disease entity, and calling this schizophrenia spectrum disorder. New hypotheses of pathophysiology do not overlook dopamine as playing a major role, but do emphasize the participation of integrative neural systems in the expression of the illness and of the limbic system in generating symptoms. Critical observations for future discovery are likely to arise from molecular genetics, combined with hypothesis-generating experiments using brain imaging and human postmortem tissue.

Association between white matter fiber integrity and subclinical psychotic symptoms in schizophrenia patients and unaffected relatives

In this study, we investigate whether aberrant integrity of white matter (WM) fiber tracts represents a genetically determined biological marker of schizophrenia (SZ), and its relation with clinical symptoms. We collected brain DTI data from 28 SZ patients, 18 first-degree relatives and 22 matched controls and used voxel-based analysis with tract-based spatial statistics (TBSS) in order to compare fractional anisotropy (FA) between groups. Mean voxel-based FA values from the entire skeleton of each group were compared. We did a multiple regression analysis, followed by single post-hoc contrasts between groups. FA values were extracted from the statistically significant areas. The results showed significantly smaller FA values for SZ patients in comparison with controls in cortico-spinal tracts, in commissural fibers, in thalamic projections, in association fibers and in cingulum bundles. A significant increase of FA in SZ patients in comparison with healthy controls was only found in the arcuate fasciculus. Relatives had intermediate values between patients and controls which were deemed significant in the comparison to patients and controls in association fibers, arcuate fasciculus and cingulum bundles. Lower FA values in association fibers were significantly associated with predisposition toward hallucinations (in SZ patients and relatives), with higher PANSS scores of positive symptoms and with duration of illness (SZ patients). Our results suggest that clinical and subclinical presentations of psychotic symptoms are associated with aberrant integrity of multiple WM tracts. This association may represent an endophenotype of schizophrenia, since it is present in unaffected relatives as well. Such endophenotypes may serve as quantitative traits for future genetic studies and as candidate markers for early and preclinical identification of subjects at risk.

Abnormal functional motor lateralization in healthy siblings of patients with schizophrenia

Earlier neuroimaging studies of motor function in schizophrenia have demonstrated reduced functional lateralization in the motor network during motor tasks. Here, we used event-related functional magnetic resonance imaging during a visually guided motor task in 18 clinically unaffected siblings of patients with schizophrenia and 24 matched controls to investigate if abnormal functional lateralization is related to genetic risk for this brain disorder. Whereas activity associated with motor task performance was mainly contralateral with only a marginal ipsilateral component in healthy participants, unaffected siblings had strong bilateral activity with significantly greater response in ipsilateral and contralateral premotor areas as well as in contralateral subcortical motor regions relative to controls. Reduced lateralization in siblings was also identified with a measure of laterality quotient. These findings suggest that abnormal functional lateralization of motor circuitry is related to genetic risk of schizophrenia.

Movement-related potentials point towards an impaired tuning of reafferent sensory feedback by preceding motor activation in schizophrenia

The link between focal motor system activation and reafferent sensory feedback is thought to be crucial for the perception that a movement is actively performed. In this article, we examine how schizophrenia affects the relationship between motor and somatosensory system activation. Movement-related potential source analysis allowed us to separate and compare motor activation deficits and reafferent feedback processing. We analyzed lateralized movement-related potentials during choice reaction movements in 16 subjects with schizophrenia/schizoaffective disorder. These subjects had partial remissions with predominantly negative symptoms and were compared to an age-matched healthy control group. In the schizophrenia/schizoaffective group, dipole source analysis indicated a significantly reduced lateralized sensorimotor activation immediately preceding movement execution. In contrast, activation by reafferent feedback was relatively unimpaired. Subjects with schizophrenia/schizoaffective disorder lacked a focal motor and reafferent sensory processing correlation, which can be identified through a significantly different regression slope from healthy controls. Reduced action-related motor system activation in subjects with schizophrenia/schizoaffective disorder was associated with preserved activation by reafferent sensory feedback. Most importantly, motor-sensory tuning, i.e. a specific enhancement of sensory information necessary to monitor movements, could not be found in subjects with schizophrenia/schizoaffective disorder. Our data provide further evidence for disturbed motor-sensory interactions in schizophrenia.

Lateralized movement-related potential amplitudes differentiate between schizophrenia/schizoaffective disorder and major depression

OBJECTIVE

To examine whether deficits in focal lateralized motor system activation would differentiate between subjects with schizophrenia/schizoaffective disorder and subjects with a major depressive episode. Reductions of Bereitschaftspotential amplitude have been described for both diagnostic groups.

METHODS

We analyzed multi-channel lateralized movement-related potentials (LMRP) during choice reaction movements in 16 schizophrenic/schizoaffective patients in partial remission with predominant negative symptoms, 18 patients with a non-psychotic major depression and two healthy control groups age-matched to the respective patient groups (20/23 subjects).

RESULTS

A significant reduction of lateralized potentials over the (pre-)motor areas immediately preceding and around movement execution was found only in subjects with schizophrenia/schizoaffective disorder but not with a major depressive episode. Reduced LMRP amplitudes correlated with negative symptoms (SANS score). Other movement stages (preceding response-locked 'contingent negative variation' during response selection and post-movement evaluation during motor postimperative negative variation) were not affected in the same way.

CONCLUSIONS

Deficits in focal motor cortex activation during movement execution may reflect rather schizophrenia-specific deficits in fronto-striatal circuits. A general lack of drive and depressed mood did not alter the degree of lateralization of motor activation during movement execution.

SIGNIFICANCE

Lateralization of movement-related potentials could differentiate psychotic from non-psychotic disorders on the group level.

Resting state cerebral blood flow and objective motor activity reveal basal ganglia dysfunction in schizophrenia

Reduced motor activity has been reported in schizophrenia and was associated with subtype, psychopathology and medication. Still, little is known about the neurobiology of motor retardation. To identify neural correlates of motor activity, resting state cerebral blood flow (CBF) was correlated with objective motor activity of the same day. Participants comprised 11 schizophrenia patients and 14 controls who underwent magnetic resonance imaging with arterial spin labeling and wrist actigraphy. Patients had reduced activity levels and reduced perfusion of the left parahippocampal gyrus, left middle temporal gyrus, right thalamus, and right prefrontal cortex. In controls, but not in schizophrenia, CBF was correlated with activity in the right thalamic ventral anterior (VA) nucleus, a key module within basal ganglia-cortical motor circuits. In contrast, only in schizophrenia patients positive correlations of CBF and motor activity were found in bilateral prefrontal areas and in the right rostral cingulate motor area (rCMA). Grey matter volume correlated with motor activity only in the left posterior cingulate cortex of the patients. The findings suggest that basal ganglia motor control is impaired in schizophrenia. In addition, CBF of cortical areas critical for motor control was associated with volitional motor behavior, which may be a compensatory mechanism for basal ganglia dysfunction.

Antipsychotic dose and diminished neural modulation: a multi-site fMRI study

BACKGROUND

The effect of antipsychotics on the blood oxygen level dependent signal in schizophrenia is poorly understood. The purpose of the present investigation is to examine the effect of antipsychotic medication on independent neural networks during a motor task in a large, multi-site functional magnetic resonance imaging investigation.

METHODS

Seventy-nine medicated patients with schizophrenia and 114 comparison subjects from the Mind Clinical Imaging Consortium database completed a paced, auditory motor task during functional magnetic resonance imaging (fMRI). Independent component analysis identified temporally cohesive but spatially distributed neural networks. The independent component analysis time course was regressed with a model time course of the experimental design. The resulting beta weights were evaluated for group comparisons and correlations with chlorpromazine equivalents.

RESULTS

Group differences between patients and comparison subjects were evident in the cortical and subcortical motor networks, default mode networks, and attentional networks. The chlorpromazine equivalents correlated with the unimotor/bitemporal (rho=-0.32, P=0.0039), motor/caudate (rho=-0.22, P=0.046), posterior default mode (rho=0.26, P=0.020), and anterior default mode networks (rho=0.24, P=0.03). Patients on typical antipsychotics also had less positive modulation of the motor/caudate network relative to patients on atypical antipsychotics (t(77)=2.01, P=0.048).

CONCLUSION

The results suggest that antipsychotic dose diminishes neural activation in motor (cortical and subcortical) and default mode networks in patients with schizophrenia. The higher potency, typical antipsychotics also diminish positive modulation in subcortical motor networks. Antipsychotics may be a potential confound limiting interpretation of fMRI studies on the disease process in medicated patients with schizophrenia.

Functional magnetic resonance imaging of a parametric working memory task in schizophrenia: relationship with performance and effects of antipsychotic treatment

RATIONALE

Working memory dysfunction is frequently observed in schizophrenia. The neural mechanisms underlying this dysfunction remain unclear, with functional neuroimaging studies reporting increased, decreased or unchanged activation compared to controls.

OBJECTIVES

We investigated the neural correlates of spatial working memory in schizophrenia with particular consideration of effects of antipsychotic treatment and relation to performance levels in the patient group.

METHOD

We used functional magnetic resonance imaging and studied the blood-oxygen-level-dependent (BOLD) response of 45 schizophrenia outpatients and 19 healthy controls during a parametric spatial n-back task.

RESULTS

Performance in both groups deteriorated with increasing memory load (0-back, 1-back, 2-back), but the two groups did not significantly differ in performance overall or as a function of load. Patients produced stronger BOLD signal in occipital and lateral prefrontal cortex during task performance than controls. This difference increased with increasing working memory load in the prefrontal areas. We also found that in patients with good task performance, the BOLD response in left prefrontal cortex showed a stronger parametric increase with working memory load than in patients with poor performance. Second-generation antipsychotics were independently associated with left prefrontal BOLD increase in response to working memory load, whereas first-generation antipsychotics were associated with BOLD decrease with increasing load in this area.

CONCLUSIONS

Together, these findings suggest that in schizophrenia patients, normal working memory task performance may be achieved through compensatory neural activity, especially in well-performing patients and in those treated with second-generation antipsychotics.

Qualifying brain functional MRI parameters as endophenotypes in schizophrenia

Although the genetic contribution to schizophrenia pathogenesis has been well established, with an approximate heritability of 81%, the endeavor to elucidate the complex genetic architecture of schizophrenia has met limited success. ‘Endophenotypes’, or ‘intermediate phenotypes’, are more restricted constructs of genetic risk than the clinical manifestations hitherto employed by molecular geneticists. They are, putatively, intermediate in the pathophysiological pathway between genetic variation and clinical phenomenology and can possibly be used to assist in the elucidation of genetic diathesis for schizophrenia. In this article, we present the current evidence that supports functional MRI parameters as promising candidate endophenotypes in schizophrenia.

[Functional magnetic resonance tomography in patients with schizophrenia: neural correlates of symptoms, cognition and emotion]

In patients with schizophrenia, numerous mental processes are impaired, which can be related to brain systems using functional imaging methods (e.g. functional magnetic resonance imaging; fMRI). In this review the methodological and conceptual background of fMRI will first be discussed. Secondly, the cerebral networks involved in important symptoms of schizophrenia such as hallucinations, delusions and formal thought disorders will be outlined. Furthermore, the pathways of the central nervous system involved in cognitive dysfunction in patients with schizophrenia will be described also in the dependence on genotype and medicinal status. Functional imaging methods provide psychiatry and psychotherapy with the unique opportunity to correlate mental processes and dysfunctions with neural networks.

Altered brain response without behavioral attention deficits in healthy siblings of schizophrenic patients: an event-related fMRI study

Attention deficits are common in schizophrenics and sometimes reported in their healthy relatives. The aim of this study was to analyse the behavioural performance and the brain activation of healthy siblings of schizophrenic patients during a sustained-attention task. Eleven healthy siblings of schizophrenic patients and eleven matched controls performed a Continuous Performance Test (CPT), during 1.5 T fMRI. The stimuli were presented at three difficulty-levels, using different degrees of degradation (0, 25 and 40%). There were no significant differences in CPT performance (mean reaction time and percentage of errors) between the two groups. Performance worsened with increasing degradation in both groups. Differences were found when comparing the BOLD signal change in the medial frontal gyrus/dorsal anterior cingulate, right precentral gyrus, bilateral posterior cingulate and bilateral insula. The most evident between group differences were observed in the left insula/inferior frontal gyrus: siblings showed a larger activation during wrong responses and a reduced activation during correct responses in the degraded runs. In conclusion, healthy siblings of schizophrenic patients showed differences in brain function in several brain regions previously reported in schizophrenic subjects, in the absence of behavioral attention deficits. The differences were greater in the two more difficult levels of attention demand and might be expressions of altered and/or compensatory mechanisms in subjects at increased risk for schizophrenia.

Increased hippocampal, thalamic, and prefrontal hemodynamic response to an urban noise stimulus in schizophrenia

OBJECTIVE

People with schizophrenia often have difficulty ignoring unimportant noises in the environment. While experimental measures of sensory gating have yielded insight into neurobiological mechanisms related to this deficit, the degree to which these measures reflect the real-world experience of people with schizophrenia is unknown. The goal of this study was to develop a clinically relevant sensory gating paradigm and to assess differences in brain hemodynamic responses during the task in schizophrenia.

METHOD

Thirty-five participants, including 18 outpatients with schizophrenia and 17 healthy comparison subjects, underwent scanning on a 3-T MR system while passively listening to an "urban white noise" stimulus, a mixture of common sounds simulating a busy urban setting, including multiple conversations and events recorded from a neighborhood gathering, music, and talk radio. P50 evoked responses from a typical paired-click sensory gating task also were measured.

RESULTS

Listening to the urban white noise stimulus produced robust activation of the auditory pathway in all participants. Activation was observed in the bilateral primary and secondary auditory cortices, medial geniculate nuclei, and inferior colliculus. Greater activation was observed in the schizophrenia patients relative to the comparison subjects in the hippocampus, thalamus, and prefrontal cortex. Higher P50 test/conditioning ratios also were observed in the schizophrenia patients. These evoked responses correlated with hemodynamic responses in the hippocampus and the prefrontal cortex.

CONCLUSIONS

The finding of greater activation of the hippocampus, thalamus, and prefrontal cortex during a sensory gating task with high face validity further supports the involvement of these brain regions in gating deficits in schizophrenia. This link is strengthened by the observed correlation between evoked responses in the paired-click paradigm and hemodynamic responses in a functional MRI sensory gating paradigm.

Cerebral network deficits in post-acute catatonic schizophrenic patients measured by fMRI

Twelve patients with catatonic schizophrenia and 12 matched healthy controls were examined with functional MRI while performing a motor task. The aim of our study was to identify the intracerebral pathophysiological correlates of motor symptoms in catatonic patients. The motor task included three conditions: a self-initiated (SI), an externally triggered (ET) and a rest condition. Statistical analysis was performed with SPM5. During the self-initiated movements patients showed significantly less activation than healthy controls in the supplementary motor area (SMA), the prefrontal and parietal cortex. Our results suggest a dysfunction of the "medial motor system" in catatonic patients. Self-initiated and externally triggered movements are mediated by different motor loops. The "medial loop" includes the SMA, thalamus and basal ganglia, and is necessary for self-initiated movements. The "lateral loop" includes parts of the cerebellum, lateral premotor cortex, thalamus and parietal association areas. It is involved in the execution of externally triggered movements. Our findings are in agreement with earlier behavioral data, which show deficits in self-initiated movements in catatonic patients but no impairment of externally triggered movements.

Sequential neural changes during motor learning in schizophrenia

Positron emission tomography (PET) was used to investigate differences in neural plasticity associated with learning a unique motor task in patients with schizophrenia and healthy volunteers. Working with a robotic manipulandum, subjects learned reaching movements in a force field. Visual cues were provided to guide the reaching movements. PET rCBF measures were acquired while participants learned the motor skill over successive runs. The groups did not differ in behavioral performance but did differ in their rCBF activity patterns. Healthy volunteers displayed blood flow increases in primary motor cortex and supplementary motor area with motor learning. The patients with schizophrenia displayed an increase in the primary visual cortex with motor learning. Changes in these regions were positively correlated with changes in each group's motor accuracy, respectively. This is the first study to employ a unique arm-reaching motor learning test to assess neural plasticity during multiple phases of motor learning in patients with schizophrenia. The patients may have an inability to rapidly tune motor cortical neural populations to a preferred direction. The visual system, however, appears to be highly compensated in schizophrenia and the inability to rapidly modulate the motor cortex may be substantially corrected by the schizophrenic group's visuomotor adaptations.

Effects of acute antipsychotic treatment on brain activation in first episode psychosis: an fMRI study

This study aimed to assess the neurophysiological effects of acute atypical antipsychotic treatment on cognitive functioning in subjects presenting with a first episode of psychosis. We used functional MRI to examine the modulatory effects of acute psychopharmacological intervention on brain activation during four different cognitive tasks: overt verbal fluency, random movement generation, n-back and a spatial object memory task. Treatment with atypical antipsychotics was associated with alterations in regional activation during each task and also when task demands were manipulated within paradigms. The initial treatment of psychosis with atypical antipsychotics thus appears to be associated with modifications of the neurofunctional correlates of executive and mnemonic functions. These effects need to be considered when interpreting group differences in activation between medicated patients and controls.

Neurofunctional correlates of vulnerability to psychosis: a systematic review and meta-analysis

An understanding of the neurobiological correlates of vulnerability to psychosis is fundamental to research on schizophrenia. We systematically reviewed data from studies published from 1992 to 2006 on the neurocognitive correlates (as measured by fMRI) of increased vulnerability to psychosis. We also conducted a meta-analysis of abnormalities of activation in the prefrontal cortex (PFC) in high-risk and first episode subjects, and reviewed neuroimaging studies of high-risk subjects that used PET, SPECT and MRS. Twenty-four original fMRI papers were identified, most of which involved tasks that engaged the PFC. In fMRI studies, vulnerability to psychosis was associated with medium to large effect sizes when prefrontal activation was contrasted with that in controls. Relatives of patients affected with psychosis, the co-twins of patients and subjects with an At Risk Mental State (ARMS) appear to share similar neurocognitive abnormalities. Furthermore, these are qualitatively similar but less severe than those observed in the first episode of illness. These abnormalities have mainly been described in the prefrontal and anterior cingulated cortex, the basal ganglia, hippocampus and cerebellum.

Use of magnetic resonance imaging in tracking the course and treatment of schizophrenia

Confirming the early conceptualization of Bleuler (1911) and Kraepelin (1919), magnetic resonance imaging (MRI) studies have demonstrated structural and functional brain abnormalities, predominantly involving the frontal and temporal lobes, in schizophrenia. Most of the abnormalities are already present at illness onset. However, there is, growing evidence for treatment-related neural changes in schizophrenia, such as enlargement of the caudate nucleus (neurotoxic effect) with the use of typical antipsychotics and increases in cortical volumes and improved functional responses (neurotrophic effect) with the use of atypical antipsychotics. More recently, brain changes during the prodrome and transition-to-illness stages of schizophrenia have begun to be characterized. Another area of importance is the use of MRI, as a biological marker, to monitor and define partial or full resistance to medication. Understanding the trait- and state-related influences of brain abnormalities during the course of the illness is critical for developing effective treatment and possibly prevention strategies in schizophrenia.

Quantitative analysis of motor disturbances in schizophrenic patients

The presence of neurological signs and disturbed psychomotor performance have been consistently confirmed by clinical studies in schizophrenic patients. These parameters are mainly assessed by using clinical rating scales. In recent years, new approaches such as ultrasonic movement analysis systems have been introduced in order to objectively evaluate motor disturbances in schizophrenic patients. Ultrasonic movement analysis systems calculate the three-dimensional positions of tiny markers, which are attached to moving body parts, with high spatial and temporal resolution. Thus, key parameters of gait and hand movements can be determined precisely. This article summarizes and discusses several studies using these new methods. Results indicate that schizophrenia causes a specific motor deficit pattern, with a predominant disturbance of spatial parameters. Conventional antipsychotic treatment usually worsens these deficits, whereas the effects of atypical antipsychotic treatments are less pronounced. Disturbed motor performance can be normalized by external sensory stimuli, but only when no major attentional processes are required, and it can be enhanced by an attentional strategy, but not to the extent that motor parameters are normalized.

Language processing and human voice perception in schizophrenia: a functional magnetic resonance imaging study

BACKGROUND

Neuroimaging studies have demonstrated either reduced left-lateralized activation or reversed language dominance in schizophrenia. These findings of left hemispheric dysfunction could be attributed to language processing tasks, which activate mainly left hemispheric function. Recent functional magnetic resonance imaging studies reported right-lateralized temporal activation by human voice perception, but few studies have investigated activation by human voice in schizophrenia. We aimed to clarify the cerebral function of language processing in schizophrenia patients by considering cerebral activation of human voice perception.

METHODS

Fourteen right-handed schizophrenia patients and 14 right-handed controls with matched handedness, sex, and education level were scanned by functional magnetic resonance imaging while listening to sentences (SEN), reverse sentences (rSEN), and identifiable non-vocal sounds (SND).

RESULTS

Under the SEN-SND and SEN-rSEN contrasts including language processing, patients showed less activation of the left hemisphere than controls in the language-related fronto-tempo-parietal region, hippocampus, thalamus and cingulate gyrus. Under the rSEN-SND contrast including human voice perception, patients showed less activation than controls in the right-lateralized temporal cortices and bilateral posterior cingulate.

CONCLUSIONS

Our results indicate that schizophrenia patients have impairment of broader bilateral cortical-subcortical regions related to both the semantic network in the left hemisphere and the voice-specific network in the right hemisphere.

Effects of nicotine on hippocampal and cingulate activity during smooth pursuit eye movement in schizophrenia

BACKGROUND

Abnormal smooth pursuit eye movement (SPEM) in schizophrenic patients is a well known phenomenon, but the neurophysiological mechanisms underlying the deficit are unknown. Nicotine temporarily improves SPEM and has been associated with reduced hippocampal hemodynamic activity in schizophrenics. Nicotine's effect on brain activity in control subjects performing SPEM has not been studied. The purpose of this work was to determine if nicotine differentially affects brain activity in schizophrenic and control subjects during pursuit eye tracking.

METHODS

16 subjects with schizophrenia and 16 control subjects underwent functional MR imaging during SPEM after receiving placebo or nicotine gum. Four brain regions were analyzed for main effects of group, drug, and interactions: hippocampus, cingulate gyrus, frontal eye fields, and area MT.

RESULTS

Nicotine reduced hippocampal activity in both groups, but the effect was greater in control subjects. A group by drug interaction was observed in the anterior cingulate gyrus, where nicotine decreased activity in control subjects and increased activity in schizophrenic subjects. There were no significant effects of group, drug, or interactions in frontal eye fields or area MT.

CONCLUSIONS

Nicotine may improve SPEM performance in people with schizophrenia through cholinergic stimulation of the hippocampus and cingulate gyrus. Potential mechanisms include improved inhibitory function and attention.

Methodological and Conceptual Issues in Functional Magnetic Resonance Imaging: Applications to Schizophrenia Research

Functional magnetic resonance imaging (MRI) is a noninvasive, highly repeatable, and increasingly available method to study disordered brain activity among patients with psychological or neurological disorders. In this chapter the biophysical principles underlying functional MRI are presented, and methodological limitations of the method are discussed. Artifacts related to the biophysical basis of the functional MRI signal or associated with image acquisition methods are presented, as are artifacts related to baseline effects-especially those associated with medication, caffeine, and nicotine use. The difficulties associated with the comparison of groups of subjects differing in performance receive special attention. The limitations of cognitive subtraction designs for functional MRI are also discussed. Functional MRI studies of schizophrenia patients are used to illustrate these points.

[One decade of functional imaging in schizophrenia research. From visualisation of basic information processing steps to molecular-genetic oriented imaging]

Modern neuroimaging techniques such as magnetic resonance imaging (MRI) and positron emission tomography (PET) have contributed tremendously to our current understanding of psychiatric disorders in the context of functional, biochemical and microstructural alterations of the brain. Since the mid-nineties, functional MRI has provided major insights into the neurobiological correlates of signs and symptoms in schizophrenia. The current paper reviews important fMRI studies of the past decade in the domains of motor, visual, auditory, attentional and working memory function. Special emphasis is given to new methodological approaches, such as the visualisation of medication effects and the functional characterisation of risk genes.

Gait disturbances in patients with schizophrenia and adaptation to treadmill walking

This study evaluated the gait patterns of schizophrenic patients at free gait and at three fixed velocities on a treadmill. The effects of illness and antipsychotic treatment on gait parameters and on adaptation to treadmill walking were compared. Gait parameters of 14 drug-naive schizophrenic patients, 14 patients treated with conventional antipsychotics, 14 patients treated with olanzapine, as well as 14 matched controls were assessed on a walkway and on a treadmill at three different velocities (very slow, intermediately slow, and comfortable) using an ultrasonic movement analysis system. At free gait, all patients showed a significantly decreased gait velocity, predominantly due to a shorter stride length, when compared to the controls, with the most striking difference observed between the patients treated with conventional neuroleptics and the controls (ANOVA, P < or = 0.001). Cadence (steps per second) did not differ between the investigated groups. When gait was evaluated on the treadmill, differences in stride length and cadence were significant only at the very slow treadmill velocity (ANOVA, P < or = 0.05). In all patient groups, mean stride length was decreased and cadence compensationally increased. Significant differences between the patient groups were no longer detectable. With increasing treadmill velocities, gait parameters of all patient groups normalized. The results show that, like in patients with Parkinson's Disease, impaired gait parameters can also be normalized in schizophrenic patients by external stimulation via treadmill walking.

Sustained activation of the hippocampus in response to fearful faces in schizophrenia

BACKGROUND

In healthy individuals, the activity of the medial temporal lobe habituates rapidly with the repeated presentation of a stimulus. Using functional magnetic resonance imaging (fMRI), we tested the hypothesis that habituation of the medial temporal lobe is reduced in schizophrenia.

METHODS

During fMRI scanning, fearful and happy faces were presented repeatedly to healthy control subjects (n =16) and patients with schizophrenia (n =18). Habituation of medial temporal lobe structures was measured by comparing the hemodynamic response occurring during the early and late portions of the presentation of each face.

RESULTS

Control subjects demonstrated significant medial temporal lobe habituation to fearful but not to happy faces. In contrast, patients with schizophrenia did not demonstrate medial temporal lobe habituation in response to fearful or happy faces. In a direct, between-group comparison, right hippocampal habituation to fearful faces was significantly greater in control subjects than in the schizophrenia patients. Also, there were no significant differences between the patients and control subjects in the early medial temporal lobe response to fearful faces, suggesting that attenuated hippocampal habituation in schizophrenia is not associated with a reduction in initial activation.

CONCLUSIONS

These findings suggest that there is abnormal modulation of hippocampal responses to fearful faces in schizophrenia.

Funktionelle Magnetresonanztomographie und Antipsychotika

Recently, there has been growing interest in using functional magnetic resonance imaging (fMRI) for the evaluation of psychopharmacological drugs. fMRI studies in healthy human volunteers and psychiatric patients focus on cerebral activity following acute drug administration (single challenge) and on adaptive effects on neural networks due to long-term medication. In our own fMRI studies, the effects of olanzapine or amisulpride in never treated or medication-free schizophrenic patients using robust motor, visual, and acoustic tasks was longitudinally examined. In agreement with previous reports in the literature it could be shown that, in contrast to traditional neuroleptics, atypical drugs do not decrease the activation of the sensorimotor cortex but rather normalize the reduced frontoparietal activation as well as the neuropsychological test results. This encourages the assumption that atypical antipsychotics seem to support the recovery or normalization of frontoparietal brain dysfunction in schizophrenia. However, with these new opportunities additional methodological considerations and limitations emerge.

An fMRI study of differential neural response to affective pictures in schizophrenia

Although emotional dysfunction is considered a fundamental symptom of schizophrenia, studies investigating the neural basis of emotional dysfunction in schizophrenia are few. Using functional magnetic resonance imaging (fMRI) and a task viewing affective pictures, we aimed to examine automatic emotional response and to elucidate the neural basis of impaired emotional processing in schizophrenia. Fifteen healthy volunteers and 15 schizophrenics were studied. During the scans, the subjects were instructed to indicate how each of the presented pictures made them feel. Whole brain activities in response to the affective pictures were measured by fMRI. Controls recruited the neural circuit including amygdaloid-hippocampal region, prefrontal cortex, thalamus, basal ganglia, cerebellum, midbrain, and visual cortex while viewing unpleasant pictures. Despite an equal behavioral result to controls, the patients showed less activation in the components of the circuit (right amygdala, bilateral hippocampal region, medial prefrontal cortex (MPFC), basal ganglia, thalamus, cerebellum, midbrain, and visual cortex). This study demonstrated functional abnormalities in the neural circuit of emotional processing in schizophrenia. In particular, decreased activation in the right amygdala and MPFC appears to be an important finding related to dysfunctional emotional behavior in schizophrenia.

Functional lateralization of the sensorimotor cortex in patients with schizophrenia: effects of treatment with olanzapine

BACKGROUND

Earlier cross-sectional studies with functional magnetic resonance imaging (fMRI) in treated patients with schizophrenia have reported abnormalities of cortical motor processing, including reduced lateralization of primary sensory motor cortex. The objective of the present longitudinal study was to evaluate whether such cortical abnormalities represent state or trait phenomena of the disorder.

METHODS

Seventeen acutely ill, previously untreated patients were studied after 4 weeks and after 8 weeks of olanzapine therapy. Seventeen matched healthy subjects served as control subjects. All subjects underwent two fMRI scans 4 weeks apart during a visually paced motor task using a simple periodic block design. Functional magnetic resonance imaging data were analyzed in Statistical Parametric Mapping (SPM99). Region of interest analyses were used to determine a laterality quotient (an index of lateralization) of motor cortical regions.

RESULTS

The fMRI data indicated that patients had reduced activation of the primary sensory motor cortex at 4 weeks but not at 8 weeks; however, the laterality quotient in the primary sensory motor cortex was reduced in patients at both time points.

CONCLUSIONS

These results suggest that some cortical abnormalities during motor processing represent state phenomena, whereas reduced functional lateralization of the primary sensory motor cortex represents an enduring trait of schizophrenia.

Spatial and temporal parameters of gait disturbances in schizophrenic patients

This study assessed the locomotor patterns of gait in schizophrenic patients and differentiated intrinsic effects of the illness from those caused by conventional and atypical neuroleptic treatment. Gait parameters of drug-naïve, conventionally and atypically treated patients as well as control subjects were evaluated. Differences in gait velocity and in stride length between the four investigated groups were highly significant (ANOVA: p<0.001). Mean gait velocities of all patient groups were significantly slower than those of controls, with the most striking difference observed between the control group and patients treated with conventional neuroleptics (p <0.001). Amongst the patient groups, significant differences were detected between patients treated with conventional neuroleptics and both patients treated with atypical neuroleptics and drug-naïve patients (p < 0.05), but not between untreated and atypically treated patients. In all patient groups the reduction of gait velocity was due to a smaller mean stride length, while the cadence (steps per minute) was not changed. These results indicate that schizophrenia causes a primary disturbance of stride length regulation. Conventional antipsychotic treatment intensifies this deficit, whereas atypical antipsychotic treatment does not cause any additional gait disturbances. In contrast to the spatial parameters, the temporal structure of schizophrenic gait is not affected either by antipsychotic treatment or schizophrenia itself.

A functional magnetic resonance imaging study of cortical asymmetry in bipolar disorder

OBJECTIVES

Individuals with bipolar disorder (BPD) exhibit motor, perceptual, and cognitive disturbances involving predominantly right hemisphere dysfunction. This asymmetry has been used to advance the hypothesis that the pathogenesis of bipolar disorder may be related to disturbances of the right cerebral hemisphere. We employed functional magnetic resonance imaging to examine hemispheric asymmetries in manic and depressed BPD. A secondary goal of the study was to examine effects of psychotropic medications on blood volume changes in the motor cortices.

METHODS

We studied 18 right-handed BPD and 13 right-handed normal healthy comparison subjects. Blood oxygen level dependent (BOLD) responses in the primary motor area (M1) and supplementary motor area (SMA) of both hemispheres were elicited during reaction time (RT) tasks.

RESULTS

Healthy subjects activated the SMA in a reciprocal fashion with significantly greater activity in the left SMA for right hand trials and the right SMA for left hand trials. Depressed BPD subjects failed to show this normal reciprocity indicating a failure to suppress unwanted activity in the ipsilateral right SMA, whereas manic BPD subjects failed to suppress unwanted ipsilateral SMA activity in both hemispheres. Manic and depressed BPD subjects exhibited greater activity in the left primary motor area suggesting increased cortical excitability. BPD subjects treated with antipsychotics or mood-stabilizing medications exhibited longer RTs, lower BOLD responses in M1 and SMA, and a loss of normal hemispheric asymmetry in the SMA than untreated subjects.

CONCLUSIONS

The presence of a right hemisphere disturbance in BPD is consistent with the hypothesis that the right hemisphere may be dominant in mood regulation. The presence of both left and right hemisphere disturbances in mania may explain the coexisting psychotic and affective symptoms observed in this condition.

Neural correlates of action attribution in schizophrenia

Patients with first-rank symptoms (FRS) of schizophrenia do not experience all of their actions and personal states as their own. FRS may be associated with an impaired ability to correctly attribute an action to its origin. In the present study, we examined regional cerebral blood flow (rCBF) with positron emission tomography during an action-attribution task in a group of patients with FRS. We used a device previously used with healthy subjects that allows the experimenter to modulate the subject's degree of movement control (and thus action attribution) of a virtual hand presented on a screen. In healthy subjects, the activity of the right angular gyrus and the insula cortex appeared to be modulated by the subject's degree of movement control of the virtual hand. In the present study, the schizophrenic patients did not show this pattern. We found an aberrant relationship between the subject's degree of control of the movements and rCBF in the right angular gyrus and no modulation in the insular cortex. The implications of these results for understanding pathological conditions such as schizophrenia are discussed.

Functional magnetic resonance imaging in schizophrenia: cortical response to motor stimulation

Previous functional magnetic resonance imaging (fMRI) studies suggest that motor system abnormalities are present in schizophrenia. However, these studies have often produced conflicting or ambiguous findings. The purpose of this study was to ascertain whether activation differences could be identified in stable schizophrenic patients on the basis of BOLD measures in two motor regions, the primary motor cortex, Brodmann area 4 (BA4) and the premotor and supplementary motor area, Brodmann area 6 (BA6). Twenty-one schizophrenic patients and 21 healthy control subjects were studied with BOLD fMRI methods during a sequential finger tapping task. Statistical parametric maps were generated for each subject, and anatomic regions were automatically defined using an anatomic atlas. Compared with controls, the schizophrenic patients showed a significant reduction in contralateral activation for both BA4 and BA6 (P<0.001), and in ipsilateral activation in BA4 (P=0.007) and BA6 (P=0.002). In healthy controls, the coactivation in the ipsilateral cortex is reduced in comparison with the contralateral cortex for right and left handed tasks. In BA4, this reduction is significant for right (P=0.007) and left (P=0.003) finger tapping. Similar results were obtained for BA6. Further analyses are necessary to evaluate the activation in other motor system regions.

Hemodynamic responses in visual, motor, and somatosensory cortices in schizophrenia

Recent advances in functional neuroimaging allow comparisons between individuals with schizophrenia and control groups. Previous studies of schizophrenia have used blocked task paradigms and, more recently, "rapid event-related" designs in which stimuli of different types are presented close together in an intermixed fashion. The validity of between-group comparisons in both of these types of paradigms depends on excluding the possibility that observed functional response differences are attributable to altered hemodynamic responses in individuals with schizophrenia. The goal of the current study was to begin a systematic examination of the hemodynamic response in schizophrenia. We administered a flashing checkerboard paradigm with a motor response to 17 individuals with schizophrenia and 24 healthy controls. Both groups showed robust activation of visual, motor, somatosensory, and supplementary motor regions. For the most part, the individuals with schizophrenia demonstrated intact peak amplitude, variance, latency, and linear summation properties in regions activated by this task. We did find some evidence for increased variability in the amplitude and latency of the hemodynamic responses in the visual and somatosensory cortices, although the magnitudes of these group differences were relatively small. These results begin to validate the interpretation of functional neuroimaging studies of schizophrenia in terms of neuronal as opposed to vascular mechanisms.

Cortical motor activation in akinetic schizophrenic patients: A pilot functional MRI study

Akinesia is associated with supplementary motor area (SMA) dysfunction in Parkinson's disease. We looked for a similar association in patients with schizophrenia. Using functional magnetic resonance imaging (fMRI), we compared motor activation in 6 akinetic neuroleptic-treated schizophrenic patients and 6 normal subjects. Schizophrenic patients had a defective activation in the SMA, left primary sensorimotor cortex, bilateral lateral premotor and inferior parietal cortices, whereas the right primary sensorimotor cortex and a mesial frontal area were hyperactive. SMA was hypoactive in akinetic schizophrenic patients, emphasizing the role of this area in motor slowness. Other abnormal signals likely reflect schizophrenia-related abnormal intracortical connections.

Management of the negative symptoms of schizophrenia: new treatment options

This article presents a systematic review of pharmacological treatment for negative symptoms of schizophrenia, based on MEDLINE searches from 1995 to September 2002 to identify pertinent clinical trials. The pharmacotherapy of negative symptoms in schizophrenia includes novel/atypical antipsychotics and classical antipsychotics, as well as antidepressants, glutamatergic compounds, antiepileptic drugs and estrogens. In the assessment of therapy for negative symptoms of schizophrenia, it is imperative that better studies of sound methodology are performed. In such studies, some important aspects to be considered include an accurate definition and assessment of negative symptoms (including well designed, valid and reliable rating scales), the differentiation between primary and secondary negative symptoms, an appropriate selection of standard comparators, adequate dosages of comparators (e.g. haloperidol dosages) and an overall optimal study design. Most of the available studies on treating negative symptoms in schizophrenia have focused on the atypical antipsychotics, while other potential candidates, mostly in the context of add-on therapy, have not been so intensively investigated. Atypical antipsychotics have been proven in placebo-controlled trials to be effective in treating negative symptoms of acute schizophrenic episodes. In many of the comparator studies, they showed efficacy in treating negative symptoms that was superior to that of typical antipsychotics. Data on stable, predominant negative symptoms in subchronic or chronic cases of schizophrenia, although limited, have demonstrated the efficacy of atypical antipsychotics. If the beneficial tolerability profile with respect to extrapyramidal symptoms is also taken into account during clinical decision making, the atypical antipsychotics should be preferred for the treatment of negative symptoms. It is also worth noting that the traditional antipsychotics have the risk of inducing negative symptoms in the context of akinesia. The benefits of add-on therapy with SSRIs or a glutamatergic compound are well documented. Estrogen add-on therapy seems promising. Other traditionally suggested approaches, such as comedication with an antiepileptic drug, lithium or beta-adrenoceptor antagonist, cannot generally be recommended on the basis of the available data.

No hypofrontality, but absence of prefrontal lateralization comparing verbal and spatial working memory in schizophrenia

Hypofrontality and decreased lateralization have been two major, albeit controversial, results from functional neuroimaging studies of schizophrenia. We used fMRI to study cortical activation during a verbal and spatial working memory (WM) task (2-back) in 15 inpatients acutely ill with schizophrenia and 15 matched control subjects. We hypothesized (i) hypofrontality in patients in both tasks and (ii) decreased lateralization of prefrontal activation in patients under the assumption that, in controls, left prefrontal cortex (PFC) is engaged preferentially in the verbal task (verbal domain dominance) and the right prefrontal cortex is engaged preferentially in the spatial task (spatial domain dominance). Our results showed no significant differences in frontal activation between controls and patients, i.e. no hypofrontality in patients, even at a very liberal threshold (p<0.01). This may be explained by the fact that nearly all patients studied received atypical neuroleptics. Nonetheless, we found evidence for more subtle, domain-related prefrontal dysfunction. Whereas controls showed verbal WM domain dominance in left inferior frontal cortex and spatial WM domain dominance in right prefrontal cortex, these domain dominance effects were absent in the patient group, i.e. there were no lateralization effects. Finally, only patients showed an inverse correlation between performance and right prefrontal activation in verbal WM. We conclude that the finding of hypofrontality may depend on the medication of the patients and that there is prefrontal dysfunction even in the absence of hypofrontality.

Haloperidol challenge in healthy male humans: a functional magnetic resonance imaging study

Functional magnetic resonance imaging (fMRI) was used to determine the acute blood oxygen level dependent effect (BOLD) of neuroleptic drugs in healthy male subjects. Using a robust simultaneous visuo-acoustic stimulation paradigm fMRI measurements were obtained prior to as well as 1 h and 24 h after intravenous infusion of 5 mg haloperidol to six healthy young men. After the administration, subjects showed significantly reduced BOLD contrast in the middle occipital gyrus while BOLD contrast was increased in the lingual gyrus. This pattern normalised within 24 h. Our results emphasise the necessity to control for interactions through acute medication and confirm fMRI as a non-invasive method for studying cerebral psychopharmacological effects.

Functional magnetic resonance imaging: emerging clinical applications

Functional magnetic resonance imaging (fMRI) is a relatively new and noninvasive method of functional brain mapping. Functional MRI is increasingly being applied to the study of neuropsychiatric disorders, including schizophrenia, Alzheimer's disease, traumatic brain injury, and others. Particularly noteworthy are findings related to plasticity in the adult human brain. Despite the promise of fMRI for improving the conceptualization, assessment, and treatment of neuropsychiatric disorders, important technical and scientific issues remain. Future research will address integrating fMRI with other emerging neuroimaging techniques.

Differential amygdala response during facial recognition in patients with schizophrenia: an fMRI study

Human lesion or neuroimaging studies suggest that amygdala is involved in facial emotion recognition. Although impairments in recognition of facial and/or emotional expression have been reported in schizophrenia, there are few neuroimaging studies that have examined differential brain activation during facial recognition between patients with schizophrenia and normal controls. To investigate amygdala responses during facial recognition in schizophrenia, we conducted a functional magnetic resonance imaging (fMRI) study with 12 right-handed medicated patients with schizophrenia and 12 age- and sex-matched healthy controls. The experiment task was a type of emotional intensity judgment task. During the task period, subjects were asked to view happy (or angry/disgusting/sad) and neutral faces simultaneously presented every 3 s and to judge which face was more emotional (positive or negative face discrimination). Imaging data were investigated in voxel-by-voxel basis for single-group analysis and for between-group analysis according to the random effect model using Statistical Parametric Mapping (SPM). No significant difference in task accuracy was found between the schizophrenic and control groups. Positive face discrimination activated the bilateral amygdalae of both controls and schizophrenics, with more prominent activation of the right amygdala shown in the schizophrenic group. Negative face discrimination activated the bilateral amygdalae in the schizophrenic group whereas the right amygdala alone in the control group, although no significant group difference was found. Exaggerated amygdala activation during emotional intensity judgment found in the schizophrenic patients may reflect impaired gating of sensory input containing emotion.

Motor-induced brain activation in cortical, subcortical and cerebellar regions in schizophrenic inpatients. A whole brain fMRI fingertapping study

Motor symptoms including neurological soft signs have been found to be more prevalent in schizophrenic patients. In addition, catatonic symptoms and neuroleptic treatment as well may influence cortical and subcortical motor organization in schizophrenia. The results of previous neuroimaging studies exploring motor function in patients with schizophrenia are inhomogenous reporting on a decreased activity in cortical motor regions in some studies and normal activity in others. Using fMRI, we studied 40 subjects performing a unilateral self-paced fingertapping task. Analyzing a general linear model of four groups, we compared patients with schizophrenia according to DSM-IV treated with olanzapine (OL; 10) or haloperidol (HA; 10) to healthy controls (HC; 10) and untreated patients (UN; 10). Brainvoyager software was used for data analyzing. In all groups, the contralateral motor cortex was significantly activated. Significant activation of the ipsilateral cerebellum was found in the UN group, the control group and the OL group. The contralateral basal ganglia were activated in UN and in controls. Motor-induced cortical and subcortical brain activation in HC was significantly higher than in patients with schizophrenia. UN with schizophrenia showed a significant overactivation than the other groups. In conclusion, we revealed a diminished activation in the patient group treated with neuroleptic drugs. This study outlines the importance of further fMRI studies to investigate interindividual activation differences under different conditions especially focusing on basal ganglia.

Subcortical overactivation in untreated schizophrenic patients: a functional magnetic resonance image finger-tapping study

Functional magnetic resonance imaging (fMRI) is a well established, non-invasive technique for mapping the working brain. Yet imaging of subcortical regions has proven to be difficult. We studied 40 subjects performing an unilateral self-paced finger-tapping task. Patients with schizophrenia according to DSM-IV treated with olanzapine (n =10) or haloperidol (n=10) were compared to healthy controls (n =10) and untreated patients (n=10). Brainvoyager software was used for data-analyzing. All subjects showed highly significant activation in the contralateral sensorimotor area, the supplementary motor area and the ipsilateral cerebellum. In every investigated subject contralateral subcortical regions were also significantly activated (P < 0.001). Activation in ipsilateral pallidum was significantly higher in untreated patients compared with the other groups indicating an increase in subcortical coactivation. In addition, significant correlations were revealed within groups. This study emphasizes the possibility of investigating subcortical brain activation in patients with schizophrenia. The results of the present study outline the importance of further fMRI studies to investigate interindividual activation differences under different conditions especially focusing on basal ganglia.