Gyrification abnormalities in childhood- and adolescent-onset schizophrenia

BACKGROUND

Gyrification is an important index of brain development. We used magnetic resonance scanning technology to compare brain surface morphology and measures of gyrification in children and adolescents with a schizophrenia spectrum disorder and in age-equivalent healthy controls.

METHODS

Magnetic resonance scans were obtained from 42 patients and 24 healthy controls, mean age 17.7 years for both groups. We employed novel quantitative measures of brain morphology, including cortical thickness and a variety of indices of sulcal and gyral curvature. We examined these measures in the whole brain and in the frontal, temporal, parietal, and occipital lobes.

RESULTS

There were significant decreases in cortical thickness in the patients. This was most pronounced in the cortical tissue that underlies the sulci. The patient group had significantly more flattened curvature in the sulci and more steeped or peaked curvature in the gyri.

CONCLUSIONS

This study quantitatively examines cortical thickness and surface morphology in children and adolescents with schizophrenia. Patients with schizophrenia demonstrated patterns of brain morphology that were distinctly different from healthy controls. In light of current theories of the formation of gyri and sulci, these changes may reflect aberrations in cerebral and subcortical connectivity.

Marijuana alters the human cerebellar clock

The effects of marijuana on brain perfusion and internal timing were assessed using [15O] water PET in occasional and chronic users. Twelve volunteers who smoked marijuana recreationally about once weekly, and 12 volunteers who smoked daily for a number of years performed a self-paced counting task during PET imaging, before and after smoking marijuana and placebo cigarettes. Smoking marijuana increased rCBF in the ventral forebrain and cerebellar cortex in both groups, but resulted in significantly less frontal lobe activation in chronic users. Counting rate increased after smoking marijuana in both groups, as did a behavioral measure of self-paced tapping, and both increases correlated with rCBF in the cerebellum. Smoking marijuana appears to accelerate a cerebellar clock altering self-paced behaviors.

Progressive structural brain abnormalities and their relationship to clinical outcome: a longitudinal magnetic resonance imaging study early in schizophrenia

BACKGROUND

Many studies have shown that structural brain abnormalities in schizophrenia are already present by the time of index evaluation of first-episode patients. However, whether these abnormalities progressively worsen during the subsequent course of the disorder remains unresolved.

METHODS

To study the longitudinal progression of structural brain abnormalities, high-resolution multispectral magnetic resonance images obtained on 73 recent-onset schizophrenic patients and 23 controls were analyzed using state-of-the-art, well-validated, and highly reliable neuroimaging tools. The mean duration between initial and follow-up MRIs was 3 years. Repeated-measures analysis of covariance was carried out to determine (1) whether brain volume changes differed between patients and controls and (2) the significance of regional brain changes on functional outcome in schizophrenia.

RESULTS

We found accelerated enlargement in cortical sulcal cerebrospinal fluid spaces early in the course of schizophrenia. Instead of the usual trajectory of volume enlargement, patients showed progressive reduction in frontal lobe white matter volume. A reciprocal increase in frontal lobe cerebrospinal fluid volume also occurred at a more rapid rate in patients than in controls. In keeping with most of our a priori hypotheses, patients with poor outcome had greater lateral ventricular enlargement over time than patients with good outcome. Progressive decrement in frontal lobe white matter volume and enlargement in frontal lobe cerebrospinal fluid volume were associated with greater negative symptom severity. Reductions in frontal lobe gray and white matter volumes correlated with poorer executive functioning.

CONCLUSIONS

There are ongoing changes in the brains of schizophrenic patients during the initial years after diagnosis despite ongoing antipsychotic drug treatment. These progressive changes seem to be most evident in the frontal lobes and to correlate with functional impairment. Disruptions in neurodevelopment or neural plasticity may act alone or in combination to bring about these progressive brain deficits in schizophrenia.

Subcortical, cerebellar, and magnetic resonance based consistent brain image registration

A new landmark-initialized segmentation and intensity-based (LI-SI) inverse-consistent linear elastic image registration algorithm is presented. This method uses manually identified landmarks, segmented volumetric (anatomical) structures, and normalized image signal intensity information to coregister datasets. The features used for image registration and evaluation include 35 cortical, cerebellar, and commissure landmarks manually identified by experts, subcortical and cerebellar regions defined semi-automatically by an artificial neural network and manually trimmed for validity by experts, and tissue classified images that were generated using a discriminant analysis of three magnetic resonance image sets representing T1, T2, and PD modalities. Four groups of results were computed for coregistering 16 datasets with the following registration techniques: rigid registration, extended Talairach registration, intensity-only inverse-consistent linear elastic registration, and the new LI-SI registration. Results are presented showing that relative overlap measurements increased as the dimensionality of the registration algorithm and amount of anatomical information increased. The average relative overlap improved from 0.53 for the rigid registration to 0.55 for the Talairach registration to 0.74 for the intensity-only and to 0.85 for the LI-SI algorithm. We showed a statistically significant improvement for all but one structure using the intensity-only algorithm compared to the Talairach registration. Furthermore, statistically significant improvements for all structures were achieved using the LI-SI algorithm compared to the intensity-only algorithm.

Morphology of the lateral superior temporal gyrus in neuroleptic nai;ve patients with schizophrenia: relationship to symptoms

OBJECTIVE

The superior temporal gyrus (STG) is a large structure in the temporal lobe with multiple sub-regions that are structurally and functionally distinct. This study evaluates the structural morphology of a specific sub-region of the STG, the anterior and posterior portions of the lateral aspect of the STG. Furthermore, relationships between the morphology of these regions and symptoms of the illness were explored.

METHOD

Regions of cortex were consecutively traced on a set of serial coronal slices in 25 male neuroleptic nai;ve patients with first episode schizophrenia and 25 age-matched healthy volunteers. Regional gray matter volumes were calculated and compared, and their correlations with three symptom dimensions were explored.

RESULTS

The left anterior STG had a significant inverse correlation with psychotic symptoms, whereas the right posterior STG had a significant positive correlation with negative symptoms. These findings were confirmed by a follow-up analysis using extreme groups. There was no significant correlation between any region and disorganized symptoms.

CONCLUSIONS

These findings suggest that abnormalities in the lateral side of the STG may be associated with both psychotic and negative symptoms through different pathophysiological mechanisms.

NOTCH4 and the frontal lobe in schizophrenia

NOTCH4 is a developmentally expressed gene recently reported to be in linkage disequilibrium (LD) with schizophrenia. We investigated this finding in our sample of subjects, focusing on an exonic (CTG)(n) polymorphism, examining not only the association of this polymorphism with the disease phenotype, but also its effect on frontal lobe brain morphology and cognitive function in both affected individuals and a psychiatrically normal comparison group. While we did not find any association or LD with schizophrenia, we identified striking effects of NOTCH4 variability on the trait measures. Within the respective schizophrenia and comparison groups, NOTCH4 allelic variability was correlated with differences in measures of frontal lobe cognitive performance and frontal lobe brain tissue volumes that were intuitively congruent. These within-group effects, however, were in opposite directions across groups. These findings may reflect the interaction of NOTCH4 with the underlying genetic and phenotypic complexity that characterizes both schizophrenia and normal cognition and brain development.

Brain tissue volume segmentation in patients with anorexia nervosa before and after weight normalization

OBJECTIVE

To examine whether gray and white matter volumes are preferentially reduced and cerebral spinal fluid (CSF) increased with starvation in patients with anorexia nervosa compared with healthy controls and to determine what changes occur with weight normalization.

METHOD

Whole intracranial volumes of patients and controls were segmented into gray matter, white matter, and CSF volumes and results compared. A subgroup of patients were rescanned after weight normalization.

RESULTS

Total white matter and several regional white matter volumes were significantly reduced and total and regional CSF volumes were significantly increased in patients versus controls whereas gray matter was not significantly reduced. Total and regional CSF volumes were significantly decreased in patients upon weight normalization whereas white and gray matter volumes increased.

DISCUSSION

These changes in brain tissue may be related to a variety of pathophysiologic mechanisms. We hypothesize that insulin-like growth factor-1 may be involved.

Untreated initial psychosis: relation to cognitive deficits and brain morphology in first-episode schizophrenia

OBJECTIVE

Studies of patients experiencing their first episode of psychosis have demonstrated that they typically remain undiagnosed and untreated for 1-2 years. It has been postulated that prolonged untreated psychosis may have serious effects: poor response to neuroleptic medications, poor clinical outcomes, and direct neurotoxicity. This study investigated the relationships between duration of untreated initial psychosis and neurocognitive functioning and high-resolution imaging brain measurements.

METHOD

A total of 156 subjects with DSM-IV schizophrenia, schizophreniform disorder, or schizoaffective disorder were evaluated during their first episode of psychosis. Measurements included nine domains of neurocognitive functioning, volumetric measures of total brain tissue, gray and white matter, and CSF, and measures of brain surface anatomy.

RESULTS

The mean duration of untreated initial psychosis was 74.3 weeks. Correlations between neurocognitive functioning, brain volumetric measurements, and surface anatomy measurements with duration of untreated initial psychosis were weak; none reached statistical significance. When the group was divided on the basis of median duration of untreated initial psychosis, there were again no significant differences between the groups with long and short duration of untreated initial psychosis except on two measures (verbal memory and cortical sulcal depth).

CONCLUSIONS

The absence of strong correlations suggests that untreated initial psychosis has no direct toxic neural effects. These results suggest that large-scale initiatives designed to prevent neural injury through early intervention in the prepsychotic or early psychosis phase may be based on incorrect assumptions that neurotoxicity or cognitive deterioration may be avoided. Nevertheless, early treatment is justified because it reduces suffering.

Cognitive dysfunction in adult males with non-syndromic clefts of the lip and/or palate

Cognitive deficits have been well-documented in children with non-syndromic clefts of the lip and/or palate. However, no study to date has formally assessed cognition in adults with oral clefts. This study was designed to evaluate neuropsychological functioning in adult males with non-syndromic clefts of the lip and/or palate (n=50) compared to age and sex-matched controls. Subjects with oral clefts were found to have significantly lower full scale IQ, performance IQ and verbal IQ scores compared to their matched controls. After controlling for IQ, patients showed specific deficits in verbal fluency. Adult males with oral clefts manifest a specific pattern of cognitive deficits. As the development of the face is highly interdependent with the development of the brain, it is theorized that the etiology of these cognitive deficits is a primary problem with abnormal brain development.

The effects of neuroleptic medications on basal ganglia blood flow in schizophreniform disorders: a comparison between the neuroleptic-naïve and medicated states

BACKGROUND

Previous studies indicate that basal ganglia volumes of first-episode neuroleptic-naïve patients with schizophrenia are smaller than those of normal control subjects. Subsequent exposure to neuroleptic medication appears to induce volumetric change. Possible reasons for this include differences in blood flow and metabolism between the neuroleptic-naïve and medicated states.

METHODS

We used positron emission tomography (PET) to measure blood flow to the caudate and putamen, in a sample of 29 neuroleptic-naïve patients with schizophreniform disorders and 29 matched control subjects. We also studied a subset of the patient sample (n = 13), comparing their "before" versus "on" medication PET scans.

RESULTS

We did not find a significant difference in blood flow to the caudate and putamen between neuroleptic-naïve patients and control subjects even after controlling for whole brain blood flow; however, in the subset of 13 patients compared in the "on" versus "off" medication states, there was a statistically significant increase in blood flow to both the caudate and putamen.

CONCLUSIONS

Before treatment, there appears to be no difference in striatal blood flow between first-episode neuroleptic-naïve patients and healthy volunteers, but there appears to be a significant increase in blood flow to the striatum after the treatment is initiated.

Cerebral blood flow changes associated with Schneiderian first-rank symptoms in schizophrenia

The authors examined the severity of Schneiderian first-rank symptoms in relation to regional cerebral blood flow (rCBF) with the use of PET. Eighty-seven schizophrenic patients were imaged during an eyes-closed condition during which they were instructed to relax and not perform any specific task (random episodic silent thought, or REST). Schneiderian symptoms were rated by using structured assessment instruments. The Schneiderian score of the patients was positively correlated with rCBF in right superior parietal cortex and negatively correlated with rCBF in left posterior cingulate gyrus and in left lingual gyrus. The results of this study demonstrate a cerebral pattern of activation related to Schneiderian symptoms and reinforce the hypothesis of an involvement of cortical areas that mediate space and body representation in such phenomena.

Manual and automated measurement of the whole thalamus and mediodorsal nucleus using magnetic resonance imaging

The thalamus is an important relay structure in the brain that may be relevant to a variety of brain diseases. It is divided into multiple subnuclei with different cortical connections. The medial dorsal (MD) nucleus is particularly important because it forms key connections with the prefrontal cortex. The current study reports precise and efficient methods for measuring the whole thalamus and the MD with MRI that have a high degree of interrater reliability. A multispectral image acquisition and novel image processing technique were used to improve structure visibility. The tricolor image assigns a color to each of the T1, T2, and PD weighted images, represented by red, green, and blue, respectively. The manually defined regions were then used to train an artificial neural network (ANN) to automatically define both the whole thalamus and the MD. The ANN provides an efficient automated method, making studies using larger sample sizes more feasible.

Insomnia as a predictor for symptom worsening following antipsychotic withdrawal in schizophrenia

Sleep disturbances have been associated with schizophrenia, and are an especially prominent feature during the prodrome preceding psychotic relapse. In this study, we examined the changes in sleep quality following withdrawal of antipsychotic treatment, as well as the predictive value of sleep disturbances on symptom exacerbation. One hundred twenty-two patients with schizophrenia, schizophreniform disorder, or schizoaffective disorder underwent a 3-week medication wash-out prior to neuroimaging studies. Sleep quality was rated using items on the Hamilton Rating Scale for Depression (HAM-D), while symptom severity was measured using the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS). Sleep quality deteriorated progressively following antipsychotic discontinuation. Total insomnia score prior to antipsychotic withdrawal had a significant effect on the severity of psychotic symptoms at the last weekly assessment, while baseline terminal insomnia had a significant effect on disorganized symptoms at the end of the medication-free period. These findings were independent of baseline symptom severity. Our findings suggest that schizophrenia patients with sleep disturbances are at a greater risk for worsening of positive symptoms after antipsychotic discontinuation. The implications of these findings in research and clinical settings are discussed.

Manual and semiautomated measurement of cerebellar subregions on MR images

Previous structural and functional imaging studies suggest that the corticocerebellar-thalamic-cortical circuit is dysfunctional in schizophrenia. Accurate identification and volumetric measurement of cerebellar subregions are essential to the assessment of the cerebellum's role in healthy and disease states. Manual parcellation of the cerebellum on MR images was performed with the use of guide traces. Guide traces identified relevant fissures and borders in several planes, and their intersections with the primary tracing plane were used to maintain consistency and accuracy during the parcellation. The cerebellum was parcellated into right and left anterior lobes, superior posterior lobes, inferior posterior lobes, and corpus medullare. A systematic review of the final traces ensured their accuracy. An artificial neural network was trained using a novel landmark-warped method to help account for wide variability in structure size and location. Overlaps of the manually traced lobes (intersection/union) ranged from 0.78 to 0.85 and intraclass correlations (r2) ranged from 0.82 to 0.94. In a comparison of the semiautomated method with the manual method overlaps ranged from 0.83 to 0.88 and intraclass correlations ranged from 0.92 to 0.97. For two raters using the semiautomated method overlaps ranged from 0.83 to 0.88 and intraclass correlations ranged from 0.97 to 0.99. The semiautomated method was built on the groundwork of the manual method to produce more reliable results in a fraction of the time, making valid measurements possible on a large number of subjects.

Possible association of a cholecystokinin promoter variant to schizophrenia

Several lines of research indicate a cholecystokinin (CCK) deficit in schizophrenia patients. A C to T substitution was found in the promoter region of the CCK gene. We investigated this promoter variant in patients with schizophrenia and geographically-matchedcontrols. The T allele was detected in 24% of the 85 schizophrenics and 16% of the 247 controls. No significant difference in the T allele frequency was found between patients and controls (chi(2) = 2.77, P > 0.1). The schizophrenia sample was analyzed further along the dimensions of positive and negative symptoms. The patients with prominent negative symptoms presented a statistically significant association to the T allele (chi(2) = 4.13, P < 0.04). However, the significance disappeared after the Bonferroni correction (P > 0.15). Since the case-control analysis may present incorrect ethnic match between cases and controls, we applied the family-based tests to verify the above findings. Both transmission disequilibrium test (TDT; chi(2) = 5.33, P < 0.025 in 12 trios) and haplotype relative risk (HRR; chi(2) = 3.844, P < 0.05 in 60 trios) indicated a significantly high transmission of T allele to schizophrenia offspring probands from their parents. While our family-based tests seem to support the CCK involvement in schizophrenia, no definite conclusion can be drawn based on such a small sample size. This preliminary finding is subjected to future investigations.

Morphology of the ventral frontal cortex in schizophrenia: relationship with social dysfunction

BACKGROUND

Studies have reported premorbid as well as postonset social dysfunction in schizophrenia. This impairment has also been observed to emerge after lesions in the ventral aspect of the frontal cortex (i.e., straight gyrus and orbitofrontal cortex).

METHODS

Magnetic resonance imaging scans were obtained from 45 male patients with schizophrenia and 45 matched control subjects. Cortical gray matter volume and surface area were determined for the ventral frontal cortex (VFC), subdivided into the orbitofrontal cortex (OFC) and the straight gyrus (SG).

RESULTS

The global measures of gray matter volume and surface area in the VFC was not significantly different between patients and control subjects; however, there was a regional difference, with the right SG volume and surface area being smaller in patients compared with control subjects. Volume of the VFC had an inverse correlation with measurements of both premorbid and postdiagnosis social function. The smaller the gray matter in these regions, the greater the social dysfunction. There was no relationship between morphology of this brain region and any other clinical variable.

CONCLUSIONS

Morphology of the VFC is directly related to abnormal social function in schizophrenia, including measures of social dysfunction that predate the onset of illness.

Structural MR image processing using the BRAINS2 toolbox

Medical imaging has opened a new door into biomedical research. In order to study various diseases of the brain and detect their impact on brain structure, robust and user friendly image processing packages are required. These packages must be multi-faceted to distinguish variations in size, shape, volume, and the ability to detect longitudinal changes over the course of an illness. This paper describes the BRAINS2 image processing package, which contains both manual and automated tools for structural identification, methods for tissue classification and cortical surface generation. These features are described in detail, as well as the reliability of these procedures.

Capacity to provide informed consent for participation in schizophrenia and HIV research

OBJECTIVE

The degree to which people with psychiatric symptoms and cognitive dysfunction can provide informed consent to participate in research is a controversial issue. This study was designed to examine the capacity of subjects with schizophrenia and subjects with HIV to provide informed consent for research participation and to determine the relationships among cognitive dysfunction, psychiatric symptoms, and decisional capacity.

METHOD

Twenty-five men and women with a DSM-IV diagnosis of schizophrenia and 25 men and women with HIV were recruited. The groups were compared in terms of neuropsychological functioning, psychiatric symptoms, and ability to provide informed consent to a hypothetical drug trial.

RESULTS

Eighty percent of the subjects with schizophrenia and 96% of the HIV-positive subjects demonstrated adequate capacity to consent to the hypothetical drug trial, but subjects in the schizophrenia group had significantly lower scores on two of the four aspects of decisional capacity. For the subjects with schizophrenia, neuropsychological functioning and psychiatric symptoms (e.g., apathy and avolition), but not psychotic symptoms (e.g., hallucinations and delusions), were significantly associated with decisional capacity.

CONCLUSIONS

The majority of subjects who are recruited and willing to participate in schizophrenia or HIV research will have adequate capacity to provide consent. Cognitive dysfunction and the symptoms shown to be associated with impaired decisional capacity are not unique to schizophrenia and may occur with many other forms of illness. These findings underscore the importance of considering how decisional capacity will be assessed in all types of research, regardless of the specific condition being studied.

Longitudinal assessment of premorbid cognitive functioning in patients with schizophrenia through examination of standardized scholastic test performance

OBJECTIVE

Studies suggest the presence of premorbid cognitive impairment in patients with schizophrenia, yet the onset and course of these deficits remain unclear. The purpose of this study was to investigate the longitudinal course of premorbid cognitive functioning in individuals with schizophrenia by using prospective data obtained from scholastic test results.

METHOD

Scores from grades 4, 8, and 11 on the Iowa Tests of Basic Skills and the Iowa Tests of Educational Development were obtained for 70 subjects who later developed schizophrenia. The mean percentile rank of the subjects' scores in the areas of vocabulary, reading comprehension, language, mathematics, sources of information, and an overall composite category were compared with state norms.

RESULTS

The subjects scored below the 50th percentile for each category in all three grades, but only language, reading, sources of information, and composite scores from grade 11 were significantly below state norms. With regard to longitudinal course, there was a significant linear decrease in language scores over time. Scores from grade 11 were positively correlated with WAIS-R IQ, verbal fluency, and Rey Auditory Verbal Learning scores at first illness episode. Scores from grade 11 were not significantly correlated with age at illness onset or ratings of disorganized, psychotic, or negative symptoms.

CONCLUSIONS

Scholastic test scores at grades 4 and 8 were nonsignificantly below average in this group of children who later developed schizophrenia. However, test scores dropped significantly between grades 8 and 11. This corresponds to ages 13-16 years, or the onset of puberty. Poor or declining scholastic performance may be a precursor to the cognitive impairment seen during the first episode of illness.

Effects of smoking marijuana on brain perfusion and cognition

The effects of smoking marijuana on regional cerebral blood flow (rCBF) and cognitive performance were assessed in 12 recreational users in a double-blinded, placebo-controlled study. PET with [(15)Oxygen]-labeled water ([(15)O]H(2)O) was used to measure rCBF before and after smoking of marijuana and placebo cigarettes, as subjects repeatedly performed an auditory attention task. Smoking marijuana resulted in intoxication, as assessed by a behavioral rating scale, but did not significantly alter mean behavioral performance on the attention task. Heart rate and blood pressure increased dramatically following smoking of marijuana but not placebo cigarettes. However, mean global CBF did not change significantly. Increased rCBF was observed in orbital and mesial frontal lobes, insula, temporal poles, anterior cingulate, as well as in the cerebellum. The increases in rCBF in anterior brain regions were predominantly in "paralimbic" regions and may be related to marijuana's mood-related effects. Reduced rCBF was observed in temporal lobe auditory regions, in visual cortex, and in brain regions that may be part of an attentional network (parietal lobe, frontal lobe and thalamus). These rCBF decreases may be the neural basis of perceptual and cognitive alterations that occur with acute marijuana intoxication. There was no significant rCBF change in the nucleus accumbens or other reward-related brain regions, nor in basal ganglia or hippocampus, which have a high density of cannabinoid receptors.

The relationship of akathisia with suicidality and depersonalization among patients with schizophrenia

An association of suicidality and depersonalization with akathisia has been reported, but it is not clear whether these phenomena are specific to akathisia or are nonspecific manifestations of distress. The authors used the Barnes Akathisia Rating Scale, Brief Psychiatric Rating Scale, and Hamilton Rating Scale for Depression (Ham-D) to examine the relationships between suicidality, depersonalization, dysphoria, and akathisia in 68 patients with schizophrenia or schizophreniform disorder. Akathisia was associated with higher scores on the Ham-D ratings of suicidality, depersonalization, and agitation. In a logistic regression model, depressive mood and subjective awareness of akathisia appeared to be the only predictors of suicidality and depersonalization, respectively. These findings support the association between akathisia and both suicidality and depersonalization. However, these symptoms appear to be nonspecific responses to accompanying depressive mood and the subjective awareness of the akathisia syndrome, respectively.

Age and regional cerebral blood flow in schizophrenia: age effects in anterior cingulate, frontal, and parietal cortex

Positron emission tomography ([(15)O] water PET) was used to examine the relationship between age and regional cerebral blood flow (rCBF) in schizophrenia. Forty-nine unmedicated male patients, ages 20-51, underwent imaging during an eyes-closed resting condition. Negative correlations were observed between age and rCBF in the anterior cingulate, as well as in frontal (Brodmann area 8) and parietal cortex (area 40) bilaterally. The observation of reduced rCBF in the anterior cingulate with increased age is consistent with previous findings in healthy subjects. In contrast, the reduced flow observed in the frontal and parietal regions may be unique to schizophrenia.

Effects of frequent marijuana use on memory-related regional cerebral blood flow

It is uncertain whether frequent marijuana use adversely affects human brain function. Using positron emission tomography (PET), memory-related regional cerebral blood flow was compared in frequent marijuana users and nonusing control subjects after 26+ h of monitored abstention. Memory-related blood flow in marijuana users, relative to control subjects, showed decreases in prefrontal cortex, increases in memory-relevant regions of cerebellum, and altered lateralization in hippocampus. Marijuana users differed most in brain activity related to episodic memory encoding. In learning a word list to criterion over multiple trials, marijuana users, relative to control subjects, required means of 2.7 more presentations during initial learning and 3.1 more presentations during subsequent relearning. In single-trial recall, marijuana users appeared to rely more on short-term memory, recalling 23% more than control subjects from the end of a list, but 19% less from the middle. These findings indicate altered memory-related brain function in marijuana users.

Brain volumes and surface morphology in monozygotic twins

Because healthy monozygotic twins share an identical genetic complement, they provide a unique opportunity to explore the genetic and environmental determinants of brain development. The purpose of this study was to evaluate the similarities between measures of cerebral and subcortical volumes and surface morphology in monozygotic twins compared with a matched control sample. Combinations of automated and manual methods were used to evaluate total brain volume, gray matter, white matter, ventricles and volumes of the frontal, temporal, parietal and occipital lobes. An artificial neural network algorithm was used to measure the cerebellum, thalamus, caudate and putamen. Measures of surface morphology included an index of gyral and sulcal curvature, surface area and cortical depth. The cerebral volume regions, including the gray matter, white matter and lobar volumes, were highly correlated within monozygotic twin pairs, with nearly all correlation coefficients >0.90. The cerebellum was also highly correlated (r = 0.99). Reasonably high correlations were found for the cortical depth (r = 0.84), caudate (r = 0.84), thalamus (r = 0.75) and putamen (r = 0.75). The surface measures, however, demonstrated the least correlation within twin pairs and thus are more prone to environmental influences. The high to moderate correlations between MZ twins compared with the matched controls highlights the role of heredity in both prenatal and postnatal neurodevelopment.

Structural brain abnormalities in adult males with clefts of the lip and/or palate

PURPOSE

To evaluate brain morphology of adult males with nonsyndromic clefts of the lip and/or palate (NSCLP) in comparison to a matched healthy control group.

METHODS

Brain structure was measured using quantitative analysis of magnetic resonance images.

RESULTS

Subjects with NSCLP had significant abnormalities in brain morphology consisting of abnormally enlarged anterior regions of the cerebrum, and decreased volumes of the posterior cerebrum and cerebellum. Overall, the most severely affected region was the left temporal lobe. Furthermore, these structural abnormalities were directly related to cognitive dysfunction.

CONCLUSIONS

These findings highlight the important relationship and interplay between face and brain development.

Color enhancement of multispectral MR images: improving the visualization of subcortical structures

PURPOSE

The current investigation was undertaken to evaluate a new method for creating MR multispectral color images, which we call "Superimages." They were developed to improve the delineation of small brain structures composed of mixed tissue types, such as the basal ganglia.

METHOD

To qualitatively validate the method, visual comparisons were made of six unimodal and multispectral images, including the Superimage. Quantitative validation was undertaken by comparing the reliability values for parcellation of the globus pallidus (GP) using either a gray scale (T1-weighted) image or the Superimage.

RESULTS

Qualitative assessment of the Superimage revealed enhanced visualization of the GP, caudate, and putamen. Quantitative assessment resulted in good reliability for Superimage traces.

CONCLUSION

The Superimage significantly improves both the visualization and the parcellation of structures visualized by MRI.

Increased incidence of a midline brain anomaly in patients with nonsyndromic clefts of the lip and/or palate

BACKGROUND AND PURPOSE

Nonsyndromic clefts of the lip and palate (CLP) are developmental craniofacial abnormalities that are often associated with cognitive dysfunction. This study was designed to evaluate, in patients with CLP, the presence of a specific midline brain anomaly (enlarged cavum septi pellucidi [CSP]) that has been shown in other developmental syndromes to be related to poor cognitive function.

METHODS

Brain images were obtained using magnetic resonance imaging on 49 adult men with CLP and 75 healthy controls. Size of CSP was measured using consecutive coronal images.

RESULTS

The incidence of large CSP in the CLP group was 8% (4 of 49), significantly higher than that found in the control group. In 2 of these 4 subjects, the anomaly was complete nonfusion of the septal leaflets, known as a combined CSP and cavum vergae. Furthermore, there was a significant inverse relationship of IQ and CSP in CLP patients that was not present in controls. That is, in individuals with CLP, the larger the CSP, the lower the IQ.

CONCLUSIONS

Adult men with CLP have an increased prevalence of enlarged CSP. Moreover, this anomaly is directly related to cognitive deficits. This study provides further evidence that the development of the face and the development of the brain are intimately related and that defects in craniofacial development are most likely associated with defects in brain development.

Effects of olanzapine on cerebellar functional connectivity in schizophrenia measured by fMRI during a simple motor task

BACKGROUND

According to current theories, schizophrenia results from altered connectivity in brain circuits for fundamental cognitive operations. Consequently, the poorly understood mechanisms of neuroleptic treatment may be explainable by altered functional interactions within such networks. The 'cognitive dysmetria' model hypothesizes that one key structure in these circuits is the cerebellum. To investigate the effects of olanzapine on cerebellar functional connectivity (CFC), a seed-voxel correlation analysis (SVCA) was used in a functional magnetic resonance imaging (fMRI) study of a simple finger-tapping task.

METHODS

fMRI scans were obtained from six schizophrenic patients under both drug-free and olanzapine-treated conditions and from a matched control group of six healthy subjects at corresponding time points. SVCAs were performed for anatomically and functionally standardized seed voxels in the anterior cerebellum. SVCA results were then processed by three different randomization analyses.

RESULTS

The analyses revealed that olanzapine caused widespread changes of CFC, including prominent changes in prefrontal cortex and mediodorsal thalamus. Significant changes in motor structures were found after subtractions within both groups and may thus indicate repetition effects rather than drug effects. Olanzapine 'normalized' the patients' CFC patterns for the right, but not for the left cerebellum.

CONCLUSION

Even for a simple motor task, olanzapine affects functional interactions between the cerebellum and many non-motor brain regions, including elements of the 'cognitive dysmetria' circuit. Altogether, our findings suggest that olanzapine has a stronger differential effect on neural activity in prefrontal cortex and thalamus than in motor structures.

Neural mechanisms of anhedonia in schizophrenia: a PET study of response to unpleasant and pleasant odors

CONTEXT

Loss of the capacity to experience pleasure (anhedonia) is a core clinical feature of schizophrenia. Although functional imaging techniques have been successful in identifying the neural basis of cognitive impairments in schizophrenia, no attempts to date have been made to investigate neural systems underlying emotional disturbances.

OBJECTIVE

To study the neural basis of emotional processing in schizophrenia by exploring the pattern of brain responses to olfactory stimuli in patients and healthy volunteers.

DESIGN

Positron emission tomographic study of patients with schizophrenia and healthy volunteers. Positron emission tomographic data were collected between July 21, 1995, and September 11, 1997, and data analyses were conducted in 1999-2001.

SETTING

The Mental Health Clinical Research Center at the University of Iowa, Iowa City.

PARTICIPANTS

Sixteen healthy volunteers with a mean age of 29.5 years and 18 patients with schizophrenia and a mean age of 30.0 years.

MAIN OUTCOME MEASURE

Areas of relative increase or decrease in regional cerebral blood flow, measured using positron emission tomography and the [(15)O]water method while participants performed an emotion-induction olfactory task to determine response to pleasant (vanillin) and unpleasant (4-methylvaleric acid) odors, compared between patients and healthy volunteers.

RESULTS

Patients with schizophrenia subjectively experienced unpleasant odors in a manner similar to healthy volunteers but showed impairment in the experience of pleasant odors. The analysis of the regional cerebral blood flow revealed that patients failed to activate limbic/paralimbic regions (eg, insular cortex, nucleus accumbens, and parahippocampal gyrus) during the experience of unpleasant odors, recruiting a compensatory set of frontal cortical regions instead.

CONCLUSION

Abnormalities in the complex functional interactions between mesolimbic and frontal regions may underlie emotional disturbances in schizophrenia.

Effects of retroactive and proactive interference on word list recall in schizophrenia

Schizophrenia spectrum patients (N = 143) and healthy controls (N = 160) were administered the Rey Auditory Verbal Learning Test (RAVLT) and tests of executive functioning to directly investigate the effects of proactive interference (PI) and retroactive interference (RI) on word list recall. It was hypothesized that by virtue of the predicted preferential association between executive functioning and RI (relative to PI), patients would demonstrate increased susceptibility to RI in their ability to recall word lists. Results indicated that patients show increased susceptibility to RI relative to PI. Furthermore, this difference appeared to be related to the frontally-mediated central executive functions that were preferentially associated with RI but not PI susceptibility.

Comparison of the effects of risperidone and haloperidol on regional cerebral blood flow in schizophrenia

BACKGROUND

Atypical antipsychotics, such as risperidone, have been shown to be more effective for the treatment of the symptoms of schizophrenia and have a greater beneficial effect on neurocognition compared to the conventional antipsychotics. The present study used [(15)O]H(2)O positron emission tomography imaging of regional cerebral blood flow to examine and compare the effects of haloperidol and risperidone on brain function.

METHODS

Thirty-two subjects with schizophrenia participated in the study. Each subject was scanned in a medication-free state, and after being on a stable clinically assigned dose of either risperidone or haloperidol for 3 weeks. The off-medication scan was subtracted from the on-medication scan, using a within-subjects design. A randomization analysis was used to determine differences between the effects of haloperidol and risperidone on regional cerebral blood flow.

RESULTS

Haloperidol was associated with a significantly greater increase in regional cerebral blood flow in the left putamen and posterior cingulate, and a significantly greater decrease in regional cerebral blood flow in frontal regions compared to risperidone. Risperidone was associated with a significantly greater decrease in regional cerebral blood flow in the cerebellum bilaterally compared to haloperidol.

CONCLUSIONS

The results show that risperidone and haloperidol have significantly different effects on brain function, which may be related to their differences in efficacy and side effects. Further work is required to more precisely determine the mechanisms by which different antipsychotic medications exert their therapeutic effects on the clinical symptoms and cognition in schizophrenia. These findings emphasize the importance of controlling for both medication status and the individual antipsychotic in neuroimaging studies.

Anatomic and functional variability: the effects of filter size in group fMRI data analysis

In the analysis of group fMRI scans, an optimal spatial filter should be large enough to accurately blend functionally homologous anatomic regions, yet small enough not to blur the functionally distinct regions. Hanning filters varying from 0.0 to 18.0 mm were evaluated in a group analysis of six healthy controls performing a simple finger-tapping paradigm. Test-retest reliability and Talairach-based measurements of the sensorimotor region were used to explore the optimal filter size. Two distinct regions of functional activation were noted in the sensorimotor cortex in group images (n = 6) at both time 1 and time 2. These regions merge once the filter size exceeds approximately 6.0 mm. The original hypothesis that these represented a motor and sensory activation was rejected on the basis of structural and functional variability. A discussion of the inherent difficulties in choosing an appropriate filter size is presented.

Sex differences in the absence of massa intermedia in patients with schizophrenia versus healthy controls

OBJECTIVE

To evaluate sexual dimorphism and incidence of absent massa intermedia (MI), a midline thalamic structure, in patients with schizophrenia and healthy controls.

METHODS

Thin slice magnetic resonance images of the brain were obtained. The presence of MI was determined by viewing sagittal, coronal, and axial planes.

RESULTS

In healthy controls, females had a significantly lower incidence of absent MI (13.56%) compared with males (32.08%). In patients with schizophrenia, there was a sex by diagnosis interaction. Female patients had significantly higher incidence of absent MI (32.76%) compared with their healthy controls (13.56%), whereas the male patients showed no difference in incidence of absent MI compared with their controls.

CONCLUSION

The MI, a sexually dimorphic midline structure, is more commonly absent in female patients with schizophrenia. These results support the growing literature reporting structural aberration of the thalamus, as well as other midline structures in the brains of patients with schizophrenia.

Diagnosis and classification of schizophrenia

Schizophrenia is a clinical syndrome of both extraordinary importance and extraordinary complexity. Its conceptual history contains many perspectives on the "essential" nature of the illness. For example, Kraepelin in 1919 emphasized primarily onset and course, although he also stressed the importance of some symptoms such as changes in affect and volition. Bleuler in 1911 took a more cross-sectional approach and attempted to identify fundamental characteristic symptoms, especially stressing fragmenting of thought processes. Schneider's (1959) approach was cross-sectional, stressing a group of "first-rank symptoms." DSM-III and its successors attempted to achieve a synthesis of these concepts. Nevertheless, heterogeneity in the clinical presentation of schizophrenia is certain, and heterogeneity in pathophysiology and etiology is likely. Although we can now define a particular construct of schizophrenia with reasonable agreement, the construct must be recognized as provisional and based on a need to achieve consensus about definitions rather than on an understanding of pathophysiology and etiology. The major challenge confronting the student of schizophrenia is to identify its mechanisms and causes in order to develop improved strategies for treatment and prevention. Several different approaches have been proposed to achieve this goal. Early attempts to explore and validate the construct of schizophrenia stressed descriptive and epidemiological techniques; the "validity" of a given construct of schizophrenia would be determined by evaluation of familial aggregation, course and outcome, response to treatment, and laboratory tests. This earlier approach to validation is now complemented by one that draws on techniques from neuroscience and attempts to understand schizophrenia in terms of underlying neural mechanisms. While the earlier approach conceptualized schizophrenia primarily in terms of a single disease entity, the second approach is particularly useful for the exploration of subtypes or dimensions. Research strategies for the study of schizophrenia have been developed to explore its heterogeneity. Three different competing models are discussed: (1) A single etiopathological process leading to diverse manifestations, similar to multiple sclerosis; (2) multiple disease entities leading to schizophrenia by different etiopathological processes, similar to the syndrome of mental retardation; and (3) specific symptom clusters within schizophrenia reflecting different disease processes that come together in different ways in different patients. Each of these models has strengths and weaknesses for the identification of etiology and pathophysiology.

A new method for the in vivo volumetric measurement of the human hippocampus with high neuroanatomical accuracy

Accurate and reproducible in vivo measurement of hippocampal volumes using magnetic resonance (MR) imaging is complicated by the morphological complexity of the structure. Additionally, separation of certain parts of the hippocampus from the adjacent brain structures on MR images is sometimes very difficult. These difficulties have led most investigators to either use arbitrary landmarks or to exclude certain parts of the structure from their measurements. Based on three-dimensional MR data, we have developed a reliable in vivo volumetric measurement of the human hippocampus. In contrast to most of the previously described volumetric MR-based methods, we aimed to sample the entire hippocampal formation using its true anatomical definition. This was accomplished by relying on the capacity of the BRAINS software to simultaneously visualize in multiple planes, to "telegraph" tracings or cursor position from one plane to another, and to simultaneously rely on multispectral data from three different image sets (T1, T2, and tissue classified). The methods for identifying boundaries and measuring the hippocampal volume are described. The method has excellent reliability, sensitivity, and specificity. The method may be of use in studies of structure-function relationships in neuropsychiatric disorders such as schizophrenia, temporal lobe epilepsy, and Alzheimer's disease. Future work will use these measurements as training data for a neural net-based technique to identify the anatomical boundaries automatically.

Clinical features characterizing young-onset and intermediate-onset schizophrenia

Late-onset schizophrenia has been noted to have distinct clinical characteristics. The authors compared symptom characteristics between early- and intermediate-onset patients (N = 259) to determine whether clinical features distinguished differences within younger populations. On global measures of psychotic, disorganized, and negative symptoms, early-onset patients had greater disorganized and negative symptoms but did not differ in hallucinations and delusions. The dichotomy of early vs. late onset may extend to a younger population, reflecting a more continuous influence.

Neural basis of novel and well-learned recognition memory in schizophrenia: a positron emission tomography study

The level of familiarity of a given stimulus plays an important role in memory processing. Indeed, the novelty/familiarity of learned material has been proven to affect the pattern of activations during recognition memory tasks. We used visually presented words to investigate the neural basis of recognition memory for relatively novel and familiar stimuli in schizophrenia. Subjects were 34 healthy volunteers and 19 schizophrenia spectrum patients. Two experimental cognitive conditions were used: 1 week and again 1 day prior to the PET imaging subjects had to thoroughly learn a list of 18 words (well-learned memory). Subjects were also asked to learn another set of 18 words presented 1 min before the PET experiment (novel memory). During the PET session, subjects had to recognize the list of 18 words among 22 new (distractor) words. Subjects also performed a control task (reading words). A nonparametric randomization test and a statistical t-mapping method were used to determine between- and within-group differences. In patients the recognition of novel material produced relatively less flow in several frontal areas, superior temporal gyrus, insular cortex, and parahippocampal areas, and relatively higher activity in parietal areas, visual cortex, and cerebellum, compared to controls. No significant differences in flow were seen when comparing well-learned memory activations between groups. These results suggest that different neural pathways are engaged during novel recognition memory in patients with schizophrenia compared to healthy individuals. During recognition of novel material, patients failed to activate frontal/limbic regions, recruiting a set of posterior perceptual brain regions instead.

Population-based association analyses of the HOPA12bp polymorphism for schizophrenia and hypothyroidism

HOPA is an Xq13 chromosome gene that codes for a RXR nuclear receptor co-activator. In a prior study of the genetic basis of schizophrenia, we showed that exonic polymorphisms in HOPA were associated with increased risk of schizophrenia and hypothyroidism in a large cohort of probands from New York. In an attempt to replicate these findings, we examined this relationship in a cohort of 173 schizophrenic probands (128 males and 45 females providing 218 alleles) from Iowa. Consistent with the prior findings, we found an increased rate of the HOPA12bP exonic polymorphism in schizophrenic probands compared with random newborn controls (9 of 218 alleles vs. 33 of 2,049 alleles, P < 0.02). Furthermore, retrospective review of the medical records showed that two of the nine probands possessing the HOPA12bp allele in whom thyroid function was assessed were hypothyroid compared with 6 of 164 probands possessing the normal HOPAwild allele(s) (P < 0.06). We conclude that the HOPA12bp polymorphism shows a nominally significant association with schizophrenia and a nominal trend for association with hypothyroidism in our study and that further studies are required to define the features of this syndrome and the molecular mechanisms of disease pathogenesis.

An MRI study of midbrain morphology in patients with schizophrenia: relationship to psychosis, neuroleptics, and cerebellar neural circuitry

BACKGROUND

The midbrain contains the perikarya of all the dopamine neurons in the human brain. Although other neurochemicals may well be involved, dopamine dysregulation is central in the pathophysiology of psychosis. Despite this, few imaging studies have evaluated the morphology of the midbrain.

METHODS

Using high-resolution magnetic resonance imaging, morphology of three posterior fossa and brain stem structures were measured: midbrain, pons, and medulla. The patient sample consisted of 50 men with schizophrenia, matched by gender and age to 50 healthy control subjects.

RESULTS

Patients had significantly smaller midbrain measures compared with control subjects. There were no differences between groups in measures of pons or medulla. Furthermore, midbrain size was significantly and inversely correlated with positive symptoms and cumulative neuroleptic exposure, but not with negative or disorganized symptoms. After controlling for the effect of cumulative neuroleptic exposure, the relationship between midbrain morphology and positive symptoms remained significant.

CONCLUSIONS

Midbrain morphology of patients with schizophrenia is abnormal, being smaller in patients compared with control subjects. Although this appears to be specifically related to psychotic symptoms, there is also a robust medication effect, with greater exposure to neuroleptics being associated with greater morphologic abnormality. We discuss the role of dopaminergic dysregulation and possible neural circuit involvement.

Cerebral cortex: a topographic segmentation method using magnetic resonance imaging

Remarkable developments in magnetic resonance imaging (MRI) technology provide a broad range of potential applications to explore in vivo morphological characteristics of the human cerebral cortex. MR-based parcellation methods of the cerebral cortex may clarify the structural anomalies in specific brain subregions that reflect underlying neuropathological processes in brain illnesses. The present study describes detailed guidelines for the parcellation of the cerebral cortex into 41 subregions. Our method conserves the topographic uniqueness of individual brains and is based on our ability to visualize the three orthogonal planes, the triangulated gray matter isosurface and the three-dimensional (3D) rendered brain simultaneously. Based upon topographic landmarks of individual sulci, every subregion was manually segmented on a set of serial coronal or transaxial slices consecutively. The reliability study indicated that the cerebral cortex could be parcelled reliably; intraclass correlation coefficients for each subregion ranged from 0.60 to 0.99. The validity of the method is supported by the fact that gyral subdivisions are similar to regions delineated in functional imaging studies conducted in our center. Ultimately, this method will permit us to detect subtle morphometric impairments or to find abnormal patterns of functional activation in circumscribed cortical subregions. The description of a thorough map of regional structural and functional cortical abnormalities will provide further insight into the role that different subregions play in the pathophysiology of brain illnesses.

Insular cortex abnormalities in schizophrenia: a structural magnetic resonance imaging study of first-episode patients

The insular cortex is a limbic integration region that is engaged in emotional and cognitive functions. To investigate possible insular cortex abnormalities in schizophrenia, we measured insular gray matter volume and cortical surface size in drug-naive first-episode patients. Magnetic resonance images were used to explore the morphology of the insular cortex of 25 healthy male volunteers, and 25 male schizophrenic patients. Groups were matched for age, sex, height, and parental socio-economic status. Clinical dimension scores were correlated with insular gray matter volume and cortical surface area. Patients had a significant reduction in cortical surface area [patients=2020 (206); controls=2142 (204); F=5.83, df=1, 47; P=0.01] and gray matter volume [patients=8.12 (0.77); controls=8.57 (0.94); F=3.93, df=1,47; P=0.05] in the left insular cortex. Insular gray matter volume and cortical surface size correlated negatively and significantly with the psychotic symptom dimension. Schizophrenic patients show morphological abnormalities in the insular cortex at early stages of the illness. These abnormalities are related to the severity of psychotic symptoms. Further investigations are needed to evaluate the role of the insula in the pathophysiology of schizophrenia.