Registration and machine learning-based automated segmentation of subcortical and cerebellar brain structures

The large amount of imaging data collected in several ongoing multi-center studies requires automated methods to delineate brain structures of interest. We have previously reported on using artificial neural networks (ANN) to define subcortical brain structures. Here we present several automated segmentation methods using multidimensional registration. A direct comparison between template, probability, artificial neural network (ANN) and support vector machine (SVM)-based automated segmentation methods is presented. Three metrics for each segmentation method are reported in the delineation of subcortical and cerebellar brain regions. Results show that the machine learning methods outperform the template and probability-based methods. Utilization of these automated segmentation methods may be as reliable as manual raters and require no rater intervention.

A method to classify schizophrenia using inter-task spatial correlations of functional brain images

The clinical heterogeneity of schizophrenia (scz) and the overlap of self reported and observed symptoms with other mental disorders makes its diagnosis a difficult task. At present no laboratory-based or image-based diagnostic tool for scz exists and such tools are desired to support existing methods for more precise diagnosis. Functional magnetic resonance imaging (fMRI) is currently employed to identify and correlate cognitive processes related to scz and its symptoms. Fusion of multiple fMRI tasks that probe different cognitive processes may help to better understand hidden networks of this complex disorder. In this paper we utilize three different fMRI tasks and introduce an approach to classify subjects based on inter-task spatial correlations of brain activation. The technique was applied to groups of patients and controls and its validity was checked with the leave-one-out method. We show that the classification rate increases when information from multiple tasks are combined.

Association between brain-derived neurotrophic factor Val66Met gene polymorphism and progressive brain volume changes in schizophrenia

OBJECTIVE

Factors underlying progressive brain volume changes in schizophrenia remain poorly understood. The authors investigated whether a gene polymorphism influencing neuroplasticity may contribute to longitudinal brain volume alterations.

METHOD

High-resolution magnetic resonance (MR) images of the whole brain were obtained for 119 patients with recent-onset schizophrenia spectrum disorders. Changes in brain volumes over an average of 3 years were compared between brain-derived neurotrophic factor (BDNF) val66met genotype groupings. Exploratory analyses were conducted to examine relationships between antipsychotic treatment and brain volume changes as well as the effects of BDNF genotype on changes in cognition and symptoms.

RESULTS

Significant genotype effects were observed on within-subject changes in volumes of frontal lobe gray matter, lateral ventricles, and sulcal CSF. Met allele carriers had significantly greater reductions in frontal gray matter volume, with reciprocal volume increases in the lateral ventricles and sulcal (especially frontal and temporal) CSF than Val homozygous patients. Independent of BDNF genotype, more antipsychotic exposure between MRI scans correlated with greater volume reductions in frontal gray matter, particularly among patients who were initially treatment naive. There were no statistically significant genotype effects on within-subject changes in cognition or symptoms.

CONCLUSIONS

BDNF(Met) variant may be one of several factors affecting progressive brain volume changes in schizophrenia.

The neural correlates of implicit sequence learning in schizophrenia

Twenty-seven schizophrenia spectrum patients and 25 healthy controls performed a probabilistic version of the serial reaction time task (SRT) that included sequence trials embedded within random trials. Patients showed diminished, yet measurable, sequence learning. Postexperimental analyses revealed that a group of patients performed above chance when generating short spans of the sequence. This high-generation group showed SRT learning that was similar in magnitude to that of controls. Their learning was evident from the very 1st block; however, unlike controls, learning did not develop further with continued testing. A subset of 12 patients and 11 controls performed the SRT in conjunction with positron emission tomography. High-generation performance, which corresponded to SRT learning in patients, correlated to activity in the premotor cortex and parahippocampus. These areas have been associated with stimulus-driven visuospatial processing. Taken together, these results suggest that a subset of patients who showed moderate success on the SRT used an explicit stimulus-driven strategy to process the sequential stimuli. This adaptive strategy facilitated sequence learning but may have interfered with conventional implicit learning of the overall stimulus pattern.

Morphology of the cerebral cortex in preclinical Huntington's disease

OBJECTIVE

Cortical morphology was evaluated in subjects with known gene expansion for Huntington's disease and no manifest disease.

METHOD

Magnetic resonance imaging scans were obtained for 24 subjects with preclinical Huntington's disease and were compared to those for 24 matched healthy subjects by means of novel imaging methods to quantify aspects of cortical structure.

RESULTS

In relation to the comparison subjects, those with preclinical Huntington's disease showed altered cortex morphology with enlargement of gyral crowns and abnormally thin sulci. These changes were manifested in global alterations of gyral and sulcal shape.

CONCLUSION

These findings lend support to the notion that, in addition to the degenerative process, abnormal neural development may also be an important process in the pathoetiology of Huntington's disease.

Abnormal brain structure in adults with Van der Woude syndrome

Van der Woude syndrome (VWS) is an autosomal dominant disorder manifested in cleft lip and/or palate and lip pits. Isolated clefts of the lip and/or palate (ICLP) have both genotype and phenotype overlap with VWS. Subjects with ICLP have abnormalities in brain structure and function. Given the similarities between VWS and ICLP, the current study was designed to evaluate the pattern of brain structure of adults with VWS. Fourteen adults with VWS were compared to age- and gender-matched healthy controls. Brain structure was evaluated using magnetic resonance imaging. All subjects with VWS had enlarged volumes of the anterior regions of the cerebrum. Men with VWS had reduced volumes of the posterior cerebrum. Anterior cerebrum volume was negatively correlated with intelligent quotient in the subjects with VWS indicating that the enlargement of this brain region was 'pathologic.' The pattern of brain structure in VWS is nearly identical to those seen in ICLP. In addition, men are affected more severely. Pathologic enlargement of the tissue and a gender effect with men affected more severely are common features of neurodevelopmental disorders supporting the notion that the brain structure of VWS and ICLP may be because of abnormal brain development.

Morphology of the Ventral Frontal Cortex: Relationship to Femininity and Social Cognition

Females have been shown in a number of studies to be more adept in social perception compared with males. In addition, studies have reported that brain regions important in interpretation of nonverbal social cues, such as the ventral frontal cortex (VFC), are morphologically different between genders. To investigate the relationship between the structure of the VFC and social cognition, gray matter volume and surface area of the VFC were measured on magnetic resonance imaging (MRI) scans from 30 men and 30 women matched for age and IQ. The VFC was subdivided into the orbitofrontal cortex (OFC) and the straight gyrus (SG). The SG, but not the OFC, was proportionately larger in women. A subset of subjects was administered the Interpersonal Perception Task (IPT), a test of social perceptiveness, and the Personal Attributes Questionnaire (PAQ), a scale of femininity and masculinity. Identification with more feminine traits on the PAQ correlated with greater SG gray matter volume and surface area. In addition, higher degrees of femininity correlated with better performance on the IPT. Taken together, these data suggest a complex relationship between femininity, social cognition, and the structure of the SG.

Reduced thalamic volume in first-episode non-affective psychosis: correlations with clinical variables, symptomatology and cognitive functioning

Structural studies have inconsistently shown the presence of thalamic volume differences in patients with schizophrenia. However, only a few studies have examined the relation between thalamic structure and clinical and cognitive variables in early phases of the illness. Thalamic volumes in right-handed minimally treated first episode patients with non-affective psychosis (N=61) relative to those of right-handed healthy comparison subjects (N=40) were measured. Thalamic volumes in the right and left hemispheres and total thalamic volume were automatically segmented and analyzed using BRAINS2. Analysis of covariance was used to control for intracranial volume. Clinical symptoms were assessed by total scores of BPRS, SAPS and SANS. The relationship between three cognitive dimensions (verbal learning and memory, speed processing/executive functioning and sustained attention/vigilance), and thalamic volume was evaluated. The impact of the duration of untreated illness, untreated psychosis and prodrome period in thalamic morphometry was also explored. Right, left, and total thalamic volumes of the patients with non-affective psychosis were significantly smaller than those of the healthy subjects. Larger thalamic volumes were associated with an earlier age of onset, a poorer cognitive functioning and a more severe negative symptomatology. Thalamic volumetric differences between patients with non-affective psychosis and healthy controls are already present at early phases of the illness. However, further investigations are warranted to fully clarify the relationship between those structural anomalies and clinical and cognitive outcomes.

Correlation between extraversion and regional cerebral blood flow in response to olfactory stimuli

OBJECTIVE

Extraversion, a trait associated with individual differences in approach motivation and the experience of positive emotional states, is negatively correlated with certain psychiatric disorders, including depression and social phobia. The authors examined the correlation between extraversion and regional cerebral blood flow (rCBF) while participants were exposed to olfactory stimuli in order to further characterize individual differences in hedonic processing associated with this trait.

METHOD

Twelve healthy participants were exposed to pleasant and unpleasant odors while rCBF was measured using [(15)O] water PET. The NEO Five-Factor Inventory was used to assess extraversion. Associations between extraversion scores and rCBF in each olfactory stimulus condition were assessed by correlational analysis.

RESULTS

During the pleasant smell condition, extraversion was correlated with rCBF in the amygdala and occipital cortex. During the unpleasant smell condition, extraversion was correlated with rCBF in the occipital cortex and inferior temporal gyrus.

CONCLUSIONS

These results provide important evidence for the biological basis of extraversion and indicate that there are systematic individual differences in patterns of brain activation in response to affective stimuli.

DSM and the death of phenomenology in america: an example of unintended consequences

During the 19th century and early 20th century, American psychiatry shared many intellectual traditions and values with Great Britain and Europe. These include principles derived from the Enlightenment concerning the dignity of the individual and the value of careful observation. During the 20th century, however, American psychiatry began to diverge, initially due to a much stronger emphasis on psychoanalytic principles, particularly in comparison with Great Britain. By the 1960s and 1970s, studies such as the US-UK study and the International Pilot Study of Schizophrenia demonstrated that the psychodynamic emphasis had gone too far, leading to diagnostic imprecision and inadequate evaluation of traditional evaluations of signs and symptoms of psychopathology. Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III) was developed in this context, under the leadership of representatives from institutions that had retained the more traditional British-European approaches (eg, Washington University, Iowa). The goal of DSM-III was to create a comprehensive system for diagnosing and evaluating psychiatric patients that would be more reliable, more valid, and more consistent with international approaches. This goal was realized in many respects, but unfortunately it also had many unintended consequences. Although the original creators realized that DSM represented a "best effort" rather than a definitive "ground truth," DSM began to be given total authority in training programs and health care delivery systems. Since the publication of DSM-III in 1980, there has been a steady decline in the teaching of careful clinical evaluation that is targeted to the individual person's problems and social context and that is enriched by a good general knowledge of psychopathology. Students are taught to memorize DSM rather than to learn complexities from the great psychopathologists of the past. By 2005, the decline has become so severe that it could be referred to as "the death of phenomenology in the United States."

Structure and function of the superior temporal plane in adult males with cleft lip and palate: pathologic enlargement with no relationship to childhood hearing deficits

BACKGROUND

In a previous study from our lab, adult males with non-syndromic cleft lip and/or palate (NSCLP) were shown to have significantly lower temporal lobe gray matter volume than matched controls. The current study was designed to begin a regional analysis of specific subregions of the temporal lobe. The superior temporal plane (STP) is a brain region involved in the governance of auditory processing and aspects of language. The cognitive deficit of subjects with NSCLP is characterized by specific deficits in language; therefore this region of the temporal lobe is particularly important to investigate in this population. The STP has been found to be structurally abnormal in subjects with dyslexia, another developmental disorder involving language deficit. The hypothesis for the current study was that the STP in subjects with NSCLP would be structurally abnormal and that the abnormality would be related to cognitive deficit, but not to developmental hearing deficit.

METHODS

Manual tracing of the STP in NSCLP males and matched controls was performed on magnetic resonance imaging (MRI) scans. Ratios of STP to total temporal lobe gray matter volume were calculated and compared across groups. In addition, the morphology of the STP was correlated to cognitive function as well as measures of hearing deficit during infancy and childhood.

RESULTS

Despite overall deficit in temporal lobe gray matter, the STP is disproportionately large in subjects with NSCLP compared to controls. Further, gray matter volume of the STP was inversely correlated with IQ and language test scores in CLP subjects. Hearing loss throughout childhood and adulthood was not significantly correlated with brain morphology.

CONCLUSIONS

The structure of the superior temporal plane in adult males with NSCLP was disproportionately large. This abnormally increased volume was directly related to IQ, with greater STP volume being associated with lower cognitive functioning, thus characterizing the finding as 'pathologic enlargement'. Moreover, there was no relationship between the structure of the STP and measures of childhood hearing impairment, supporting the notion that the language deficits of this population are more likely due to abnormal brain development than to the effects of hearing deficit during childhood.

Increased expression of activity-dependent genes in cerebellar glutamatergic neurons of patients with schizophrenia

OBJECTIVE

The purpose of this study was to evaluate the functional state of glutamatergic neurons in the cerebellar cortex of patients with schizophrenia.

METHOD

The authors measured messenger ribonucleic acid (mRNA) levels of three activity-dependent genes expressed by glutamatergic neurons in the cerebellar cortex (GAP-43, BDNF, and GABA OLE_LINK2>(A)-delta subunit) in the tissues of 14 patients with schizophrenia and 14 matched nonpsychiatric comparison subjects. Since its level of expression does not change in response to neuronal activity, gamma-aminobutyric acid(A)-alpha6 subunit mRNA was used as a control.

RESULTS

The levels of GAP-43 and BDNF mRNAs were significantly elevated in patients with schizophrenia, and a similar finding was observed for GABA(A)-delta mRNA. In contrast, the levels of the GABA(A)-alpha6 subunit mRNA, which is expressed in cerebellar granule cells in an activity-independent manner, did not differ from comparison subjects.

CONCLUSIONS

These results suggest that glutamatergic neurons may be hyperactive in the cerebellar cortices of patients with schizophrenia.

Neuropsychological performance in first-episode adolescents with schizophrenia: a comparison with first-episode adults and adolescent control subjects

BACKGROUND

The goal of this study was to compare the extent of cognitive deficits between adolescents and adults early in the course of schizophrenia.

METHODS

A comprehensive neuropsychological battery was performed on 49 adolescents with childhood- or adolescent-onset schizophrenia, 139 adults with adult-onset schizophrenia, 32 healthy adolescent volunteers, and 240 healthy adult volunteers. Both patient groups were assessed early in the course of their illness and were matched to their respective control groups on age and parental education.

RESULTS

The adolescent patients performed significantly worse than the adult patients on tasks of working memory, language, and motor function. The healthy adolescents also performed significantly worse than the healthy adults in working memory and language tasks but were significantly better than the adults in motor function. When accounting for developmental differences in the control group, only motor performance was worse in the adolescent patients compared with the adult patients.

CONCLUSIONS

These findings, when coupled with published retrospective studies reporting greater cognitive deficits in earlier onset schizophrenia, implicate a cessation in development in specific cognitive domains following the onset of schizophrenia in adolescent patients.

Anterior cingulate cortex: An MRI-based parcellation method

OBJECTIVE

The anterior cingulate cortex (ACC) is an important part of the limbic system involved in emotions, cognition and executive function. The ACC has structurally distinct subregions, both microscopically and functionally, that have been implicated in several major psychiatric disorders. However, a structural analysis of these subregions with magnetic resonance imaging (MRI) has not been done. Our main purpose was to develop an MRI-based parcellation method of the ACC that permits us to explore plausible abnormalities in 4 functionally relevant subregions: dorsal, rostral, subcallosal and subgenual.

METHODS

The reliability study for gray matter volume and surface area of each subregion was performed on 14 randomly selected MR scans by 3 different raters. Our method posits to conserve the topographic uniqueness of individual brains and is based on our ability to visualize both the 3-dimensional rendered brain and the 3 orthogonal planes simultaneously with BRAINS2 software. We developed rules to hand-trace regions of interest (ROI) to surround contiguous areas of gray matter for dorsal, rostral, subcallosal and subgenual regions. The ACC was then parcellated into these 4 distinct subregions (8 when both right and left hemispheres were measured).

RESULTS AND DISCUSSION

The intraclass R coefficients for gray matter volume of each subregion ranged between 0.85 and 0.93. The current study describes a new highly reliable and reproducible topography-based parcellation method of the ACC into its dorsal, rostral, subcallosal and subgenual regions.

CONCLUSIONS

This new parcellation method provides a new means of exploring the role of the functionally and structurally distinct subregions of the ACC in schizophrenia, depression and various other brain illnesses.

From Austria, Through Aplysia , Toward the Mind

In Search of Memory . The Emergence of a New Science of Mind. By Eric R. Kandel . Norton, New York, 2006. 526 pp. $29.95, C$42, £19.99. ISBN 0-393-05863-8.

The Nobel Prize-winning author weaves together his memories and an accessible sketch of our current understanding of the biological basis of thought, learning, and memory.

Cognitive and magnetic resonance imaging brain morphometric correlates of brain-derived neurotrophic factor Val66Met gene polymorphism in patients with schizophrenia and healthy volunteers

CONTEXT

Relatively little is known about genetic determinants of cognitive dysfunction in schizophrenia. Recent studies suggest that a brain-derived neurotrophic factor (BDNF) prodomain single nucleotide polymorphism resulting in a valine (Val)-to-methionine (Met) substitution is associated with impaired declarative memory in healthy volunteers and patients with schizophrenia. These studies indicate that the BDNF(Met) variant may mediate hippocampal cognitive functions by modulating intracellular trafficking and activity-dependent BDNF release. To our knowledge, the way in which this functional single nucleotide polymorphism affects other neurocognitive measures has not been examined. Its role in determining cognitive deficits in schizophrenia has also not been systematically studied.

OBJECTIVES

To characterize the neurocognitive and brain morphometric phenotypic correlates of the BDNF Val66Met polymorphism and to test the specificity of the BDNF(Met) variant on cognitive dysfunction in schizophrenia.

DESIGN, SETTING, AND PARTICIPANTS

A comprehensive battery of standardized neuropsychological tests was administered to 144 healthy volunteers and 293 patients with schizophrenia spectrum disorder at a tertiary care university hospital. Approximately two thirds of the sample also underwent high-resolution magnetic resonance imaging brain scans.

MAIN OUTCOME MEASURES

Genotype effects (in Met allele carriers vs Val homozygotes) on 5 cognitive domain z scores and magnetic resonance imaging gray matter brain volume measures (Talairach atlas-based cerebral lobes and optimized voxel-based morphometry) were examined using general linear models.

RESULTS

On verbal memory, there was a significant genotype effect but no genotype x diagnosis effects. In both patients with schizophrenia and healthy volunteers, Met allele carriers had poorer verbal memory performance than their Val-homozygous counterparts. On visuospatial abilities, there were significant genotype and genotype x diagnosis effects. Met allele-associated visuospatial impairment was specific to patients with schizophrenia but not healthy volunteers. There were significant genotype effects on gray matter volumes within brain regions known to subserve these 2 cognitive domains, with Met allele carriers having smaller temporal and occipital lobar gray matter volumes. Optimized voxel-based morphometry further suggests that parietal heteromodal cortical gray matter deficits may underlie visuospatial impairment in patients with schizophrenia carrying the Met allele.

CONCLUSIONS

We replicated the association between the BDNF(Met) variant and poor medial temporal lobe-related memory performance. The consonance of our cognitive and brain morphology findings further suggests that the BDNF(Met) variant may have a specific role in conferring visuospatial dysfunction in schizophrenia.

Evaluation of the GTRACT diffusion tensor tractography algorithm: A validation and reliability study

Fiber tracking, based on diffusion tensor imaging (DTI), is the only approach available to non-invasively study the three-dimensional structure of white matter tracts. Two major obstacles to this technique are partial volume artifacts and tracking errors caused by image noise. In this paper, a novel fiber tracking algorithm called Guided Tensor Restore Anatomical Connectivity Tractography (GTRACT) is presented. This algorithm utilizes a multi-pass approach to fiber tracking. In the first pass, a 3D graph search algorithm is utilized. The second pass incorporates anatomical connectivity information generated in the first pass to guide the tracking in this stage. This approach improves the ability to reconstruct complex fiber paths as well as the tracking accuracy. Validation and reliability studies using this algorithm were performed on both synthetic phantom data and clinical human brain data. A method is also proposed for the evaluating reliability of fiber tract generation based both on the position of the fiber tracts, as well the anisotropy values along the path. The results demonstrate that the GTRACT algorithm is less sensitive to image noise and more capable of handling areas of complex fiber crossing, compared to conventional streamline methods.

Perception of socially relevant stimuli in schizophrenia

To examine whether patients with schizophrenia have deficits in the appraisal of socially relevant stimuli, we tested 20 patients and 14 healthy volunteers equated for parental socioeconomic status on recognition of gender stimuli, emotional people stimuli, and emotional scenes. Patients with schizophrenia showed deficits in discrimination of subtle gender differences and in the identification of emotion from human shapes and body motion. Patients showed no impairment on measures of hedonic appraisal of emotional scenes and recognition of emotional expression in human face stimuli. Across tasks, subjects with schizophrenia showed poorer identification of happiness, anger, and fear. The findings point towards circumscribed domains of impaired social cognition in schizophrenia and suggest specific further hypotheses about the neural dysfunction that may underlie them.

Prism adaptation in schizophrenia

The prism adaptation test examines procedural learning (PL) in which performance facilitation occurs with practice on tasks without the need for conscious awareness. Dynamic interactions between frontostriatal cortices, basal ganglia, and the cerebellum have been shown to play key roles in PL. Disruptions within these neural networks have also been implicated in schizophrenia, and such disruptions may manifest as impairment in prism adaptation test performance in schizophrenia patients. This study examined prism adaptation in a sample of patients diagnosed with schizophrenia (N=91) and healthy normal controls (N=58). Quantitative indices of performance during prism adaptation conditions with and without visual feedback were studied. Schizophrenia patients were significantly more impaired in adapting to prism distortion and demonstrated poorer quality of PL. Patients did not differ from healthy controls on aftereffects when the prisms were removed, but they had significantly greater difficulties in reorientation. Deficits in prism adaptation among schizophrenia patients may be due to abnormalities in motor programming arising from the disruptions within the neural networks that subserve PL.

Using a brief intervention to improve decisional capacity in schizophrenia research

Studies have shown that individuals with psychiatric or general medical illness can benefit from interventions designed to enhance decisional capacity for research informed consent. In some cases, interventions have been rather lengthy or complex. The current study was designed to determine whether a brief intervention could improve decisional capacity in people with schizophrenia. Thirty individuals with schizophrenia and 30 healthy comparison participants were presented with a hypothetical research scenario. Decisional capacity was assessed with the MacArthur Competence Assessment Tool-Clinical Research version. Those with schizophrenia received a brief intervention aimed at improving understanding of the research protocol, after which decisional capacity was reassessed. A neuropsychological battery and symptom rating scales were also administered. At baseline, the schizophrenia group earned significantly lower scores than the comparison group on 2 aspects of decisional capacity (understanding, appreciation). At follow-up, the schizophrenia group had improved significantly on understanding and was no longer significantly different from the comparison group on any of the 4 dimensions of decisional capacity. Follow-up analyses also showed a significant effect of the intervention on a subset of the schizophrenia group who had performed most poorly at baseline. Participants with schizophrenia earned significantly lower scores than those in the comparison group across multiple neuropsychological domains. These findings add to the existing literature indicating that brief interventions can improve decisional capacity in individuals with schizophrenia, despite the fact that the illness typically causes significant cognitive dysfunction. The use of such interventions will enable a larger number of people with schizophrenia to make informed decisions regarding research participation.

Brain structure in preclinical Huntington's disease

BACKGROUND

Huntington's disease (HD) is traditionally conceptualized as a degenerative disease of the striatum. Recent scientific advances, however, have suggested neurodevelopmental contributions and extrastriatal brain abnormalities. This study was designed to assess the morphology of the brain in participants who had previously undergone elective DNA analyses for the HD mutation who did not currently have a clinical diagnosis of HD (preclinical HD subjects).

METHODS

Twenty-four preclinical participants with the gene expansion for HD underwent brain magnetic resonance imaging and were compared with a group of 24 healthy control subjects, matched by gender and age.

RESULTS

Huntington's disease preclinical participants had substantial morphologic differences from controls throughout the cerebrum. Volume of the cerebral cortex was significantly increased in preclinical HD, whereas the basal ganglia and cerebral white matter volume were substantially decreased.

CONCLUSIONS

In individuals with the HD gene mutation who are considered healthy (preclinical for manifest disease), the morphology of the brain is substantially altered compared with matched control subjects. Although decreased volumes of the striatum and cerebral white matter could represent early degenerative changes, the novel finding of enlarged cortex suggests that developmental pathology occurs in HD.

Morphology of the anterior cingulate gyrus in patients with schizophrenia: relationship to typical neuroleptic exposure

OBJECTIVE

The anterior cingulate gyrus is a pivotal component of brain networks directing affective and cognitive functions, and abnormalities of the anterior cingulate gyrus may be involved in the pathophysiology of schizophrenia. However, magnetic resonance imaging studies of the morphology of this region have been few and the results inconsistent. Many of the studies have not accounted for confounding factors such as gender, handedness, or clinical variables such as neuroleptic exposure.

METHOD

The morphology and clinical correlates of the anterior cingulate gyrus were evaluated in a group of 30 right-handed male subjects with schizophrenia and a comparison group matched for age, sex, and handedness. The patient group was specifically designed to provide measures of multiple phenomenological differences such as severity of illness, duration of illness, and exposure to typical neuroleptics.

RESULTS

The patient group had a significantly larger left anterior cingulate gyrus volume relative to comparison subjects, whereas right anterior cingulate gyrus volume did not differ between groups. Depth of the left anterior cingulate gyrus was significantly correlated with neuroleptic exposure, indicating that greater exposure to neuroleptics was associated with greater cortical depth of this region. There was no significant relationship between anterior cingulate gyrus morphology and duration of illness or severity of symptoms.

CONCLUSIONS

Anterior cingulate gyrus depth in subjects with schizophrenia is directly related to typical medication exposure (the greater the exposure, the thicker the anterior cingulate gyrus) but not to other clinical variables such as length of illness or symptom severity. Future research is needed to determine the functional consequences of these changes and relationship to atypical neuroleptic use.

Subgenual prefrontal cortex volumes in major depressive disorder and schizophrenia: diagnostic specificity and prognostic implications

OBJECTIVE

A variety of findings have implicated the portion of the anterior cingulate cortex ventral to the corpus callosum in the pathophysiology of familial depressive disorder. There are, as yet, few data to address the specificity of these abnormalities to depressive disorders or to characterize their stability over time.

METHOD

The authors studied 10 subjects who were judged to have had major depressive disorder with psychotic features, who underwent magnetic resonance imaging (MRI) protocols, and who participated in a longitudinal study of recent-onset psychosis. These were group-matched to 10 subjects with schizophrenia and to 10 well comparison subjects. Volumetric measures were made of the posterior and anterior portions of the subgenual prefrontal cortex for these 30 subjects. Follow-up scans done an average of 4 years after intake were available for seven subjects with major depressive disorder, nine subjects with schizophrenia, and five well comparison subjects.

RESULTS

Volumes of the left side of the posterior subgenual prefrontal cortex differed significantly by group and were smallest for the group with psychotic major depressive disorder. Volumes of the anterior subgenual prefrontal cortex did not differ significantly by group. Patients with major depressive disorder were more likely to show increases in posterior subgenual prefrontal cortex volume on follow-up than were comparison subjects or patients with schizophrenia.

CONCLUSIONS

These findings add to the evidence that abnormalities in the subgenual region of the anterior cingulate play a role in at least some types of mood disorder.