Structural and Functional Brain Abnormalities in Attention-Deficit/Hyperactivity Disorder and Obsessive-Compulsive Disorder: A Comparative Meta-analysis

IMPORTANCE

Patients with attention-deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD) share impaired inhibitory control. However, it is unknown whether impairments are mediated by shared or disorder-specific neurostructural and neurofunctional abnormalities.

OBJECTIVE

To establish shared and disorder-specific structural, functional, and overlapping multimodal abnormalities in these 2 disorders through a voxel-based meta-analytic comparison of whole-brain gray matter volume (GMV) and functional magnetic resonance imaging (fMRI) studies of inhibition in patients with ADHD and OCD.

DATA SOURCES

Literature search using PubMed, ScienceDirect, Web of Knowledge, and Scopus up to September 30, 2015.

STUDY SELECTION

Whole-brain voxel-based morphometry (VBM) or fMRI studies during inhibitory control comparing children and adults with ADHD or OCD with controls.

DATA EXTRACTION AND SYNTHESIS

Voxel-wise meta-analyses of GMV or fMRI differences were performed using Seed-based d-Mapping. Regional structure and function abnormalities were assessed within each patient group and then a quantitative comparison was performed of abnormalities (relative to controls) between ADHD and OCD.

MAIN OUTCOMES AND MEASURES

Meta-analytic disorder-specific and shared abnormalities in GMV, in inhibitory fMRI, and in multimodal functional and structural measures.

RESULTS

The search revealed 27 ADHD VBM data sets (including 931 patients with ADHD and 822 controls), 30 OCD VBM data sets (928 patients with OCD and 942 controls), 33 ADHD fMRI data sets (489 patients with ADHD and 591 controls), and 18 OCD fMRI data sets (287 patients with OCD and 284 controls). Patients with ADHD showed disorder-contrasting multimodal structural (left z = 1.904, P < .001; right z = 1.738, P < .001) and functional (left z = 1.447, P < .001; right z = 1.229, P < .001) abnormalities in bilateral basal ganglia/insula, which were decreased in GMV and function in patients with ADHD relative to those with OCD (and controls). In OCD patients, they were enhanced relative to controls. Patients with OCD showed disorder-specific reduced function and structure in rostral and dorsal anterior cingulate/medial prefrontal cortex (fMRI z = 2.113, P < .001; VBM z = 1.622, P < .001), whereas patients with ADHD showed disorder-specific underactivation predominantly in the right ventrolateral prefrontal cortex (z = 1.229, P < .001). Ventromedial prefrontal GMV reduction was shared in both disorders relative to controls.

CONCLUSIONS AND RELEVANCE

Shared impairments in inhibitory control, rather than representing a transdiagnostic endophenotype in ADHD and OCD, were associated with disorder-differential functional and structural abnormalities. Patients with ADHD showed smaller and underfunctioning ventrolateral prefrontal/insular-striatal regions whereas patients with OCD showed larger and hyperfunctioning insular-striatal regions that may be poorly controlled by smaller and underfunctioning rostro/dorsal medial prefrontal regions.

Abnormalities of cortical structures in adolescent-onset conduct disorder

BACKGROUND

Converging evidence has revealed both functional and structural abnormalities in adolescents with early-onset conduct disorder (EO-CD). The neurological abnormalities underlying EO-CD may be different from that of adolescent-onset conduct disorder (AO-CD) patients. However, the cortical structure in AO-CD patients remains largely unknown. The aim of the present study was to investigate the cortical alterations in AO-CD patients.

METHOD

We investigated T1-weighted brain images from AO-CD patients and age-, gender- and intelligence quotient-matched controls. Cortical structures including thickness, folding and surface area were measured using the surface-based morphometric method. Furthermore, we assessed impulsivity and antisocial symptoms using the Barratt Impulsiveness Scale (BIS) and the Antisocial Process Screening Device (APSD).

RESULTS

Compared with the controls, we found significant cortical thinning in the paralimbic system in AO-CD patients. For the first time, we observed cortical thinning in the precuneus/posterior cingulate cortex (PCC) in AO-CD patients which has not been reported in EO-CD patients. Prominent folding abnormalities were found in the paralimbic structures and frontal cortex while diminished surface areas were shown in the precentral and inferior temporal cortex. Furthermore, cortical thickness of the paralimbic structures was found to be negatively correlated with impulsivity and antisocial behaviors measured by the BIS and APSD, respectively.

CONCLUSIONS

The present study indicates that AO-CD is characterized by cortical structural abnormalities in the paralimbic system, and, in particular, we highlight the potential role of deficient structures including the precuneus and PCC in the etiology of AO-CD.

Possible involvement of rumination in gray matter abnormalities in persistent symptoms of major depression: an exploratory magnetic resonance imaging voxel-based morphometry study

BACKGROUND

A recent meta-analysis of many magnetic resonance imaging (MRI) studies has identified brain regions with gray matter (GM) abnormalities in patients with major depressive disorder (MDD). A few studies addressing GM abnormalities in patients with treatment-resistant depression (TRD) have yielded inconsistent results. Moreover, although TRD patients tend to exhibit ruminative thoughts, it remains unclear whether rumination is related to GM abnormalities in such patients or not.

METHODS

We conducted structural MRI scans and voxel-based morphometry (VBM) to identify GM differences among 29 TRD patients and 29 healthy age-matched and sex-matched controls. A response style questionnaire was used to assess the respective degrees of rumination in TRD patients. Structural correlates of rumination were examined.

RESULTS

TRD patients showed several regions with smaller GM volume than in healthy subjects: the left dorsal anterior cingulate cortex (ACC), right ventral ACC, right superior frontal gyrus, right cerebellum (Crus I), and cerebellar vermis. GM volumes in these regions did not correlate to rumination. However, whole-brain analysis revealed that rumination was positively correlated with the GM volume in the right superior temporal gyrus in TRD patients.

LIMITATIONS

Structural correlates of rumination were examined only in TRD patients.

CONCLUSIONS

Our data provide additional evidence supporting the hypothesis that TRD patients show GM abnormalities compared with healthy subjects. Furthermore, this report is the first to describe a study identifying brain regions for which the GM volume is correlated with rumination in TRD patients. These results improve our understanding of the anatomical characteristics of TRD.

Volumetric abnormalities in connectivity-based subregions of the thalamus in patients with chronic schizophrenia

OBJECTIVE

The thalamus, which consists of multiple subnuclei, has been of particular interest in the study of schizophrenia. This study aimed to identify abnormalities in the connectivity-based subregions of the thalamus in patients with schizophrenia.

METHODS

Thalamic volume was measured by a manual tracing on superimposed images of T1-weighted and diffusion tensor images in 30 patients with schizophrenia and 22 normal volunteers. Cortical regional volumes automatically measured by a surface-based approach and thalamic subregional volumes measured by a connectivity-based technique were compared between the two groups and their correlations between the connected regions were calculated in each group.

RESULTS

Volume reduction was observed in the bilateral orbitofrontal cortices and the left cingulate gyrus on the cortical side, whereas in subregions connected to the right orbitofrontal cortex and bilateral parietal cortices on the thalamic side. Significant volumetric correlations were identified between the right dorsal prefrontal cortex and its related thalamic subregion and between the left parietal cortex and its related thalamic subregion only in the normal group.

CONCLUSIONS

Our results suggest that patients with schizophrenia have a structural deficit in the corticothalamic systems, especially in the orbitofrontal-thalamic system. Our findings may present evidence of corticothalamic connection problems in schizophrenia.

Infraoptic course of anterior cerebral arteries associated with abnormal gyral segmentation

✓ The authors report the case of a 34-year-old woman who presented with increasing headaches. Neuroimaging revealed bilateral anomalous vessels arising at the level of each ophthalmic artery, coursing rostromedially to join the anterior communicating artery (ACA), which harbored an aneurysm. Intraoperatively, the authors identified an abnormal gyral segmentation of the frontoorbital region, with a median gyrus separated from the olfactory tracts on each side by the gyrus rectus. No interhemispheric fissure was observed in the exposed area. This is the first report in the literature of an abnormal gyral segmentation in association with an infraoptic course of an ACA. Recognition of this possible gyral abnormality in association with this vascular anomaly is relevant for surgical exposure and treatment of aneurysms by clip placement.

Abnormalities of cingulate gyrus neuroanatomy in schizophrenia

OBJECTIVE AND METHODS

Abnormalities of the neuroanatomy of the gray matter of the cingulate gyrus, especially its anterior segment, have been suggested to be an important characteristic of schizophrenia. In this study, T1-weighted magnetic resonance scans were collected in 53 individuals with schizophrenia and 68 comparison subjects matched for age, gender, race and parental socioeconomic status. We applied Labeled Cortical Mantle Distance Mapping to assess the volume, surface area and thickness of the cortical mantle within the anterior (AC) and posterior (PC) segments of the cingulate gyrus, excluding the paracingulate gyrus, and related these anatomical measures to measures of psychopathology and illness duration.

RESULTS

After covarying for total cerebral volume, individuals with schizophrenia showed smaller AC gray matter volume (p=0.024), thickness (trend, p=0.081), but not surface area (p=0.16), than comparison subjects. Similar group differences were found for PC gray matter volume (p=0.0005) and thickness (trend, p=0.055), but not surface area (p=0.15). Across both groups, there was a significant L>R asymmetry in thickness of the AC, and a significant L>R asymmetry in the surface area of the PC. However, there were no significant group-by-hemisphere interactions. In the individuals with schizophrenia, thinning of the AC, but not the PC, was correlated with a longer duration of illness and a greater severity of psychotic symptoms.

CONCLUSIONS

Individuals with schizophrenia showed smaller gray matter volumes across the entire cingulate gyrus, mostly due to a reduction in cortical mantle thickness. However, structural measures of the AC were more closely related to clinical features of the illness.

Volume reduction of the left planum temporale gray matter associated with long duration of untreated psychosis in schizophrenia: a preliminary report

A longer duration of untreated psychosis (DUP) in schizophrenia is reported to lead to a poorer clinical outcome, possibly reflecting a neurodegenerative process after the onset of overt psychosis. However, the effect of DUP on brain morphology in schizophrenia is still poorly understood. In this study, we used magnetic resonance imaging to investigate the relation between DUP and volumetric measurements for the superior temporal sub-regions (Heschl's gyrus, planum temporale, and caudal superior temporal gyrus), the medial temporal lobe structures (hippocampus and amygdala), and the frontal lobe regions (prefrontal area and anterior cingulate gyrus) in a sample of 38 schizophrenia patients (20 males and 18 females) whose illness duration was less than five years. We found a significant negative correlation between DUP and the volume of gray matter in the left planum temporale even after controlling for age, age at illness onset, and duration and dosage of neuroleptic medication. There was no such correlation for the other brain regions including each sub-region of the prefrontal cortex (the superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus, ventral medial prefrontal cortex, orbitofrontal cortex, and straight gyrus). When subjects were divided into two groups around the median DUP, the long-DUP group had a significantly smaller planum temporale gray matter than the short-DUP group. These findings may reflect a progressive pathological process in the gray matter of the left planum temporale during the initial untreated phase of schizophrenia, whereas abnormalities in the medial temporal regions might be, as has been suggested from previous longitudinal findings, relatively static at least during the early course of the illness.

Dorsolateral prefrontal and anterior cingulate cortex volumetric abnormalities in adults with attention-deficit/hyperactivity disorder identified by magnetic resonance imaging

OBJECTIVES

Gray and white matter volume deficits have been reported in a number of studies of children with attention-deficit/hyperactivity disorder (ADHD); however, there is a paucity of structural magnetic resonance imaging (MRI) studies of adults with ADHD. This structural MRI study used an a priori region of interest approach.

METHODS

Twenty-four adults with DSM-IV ADHD and 18 healthy controls comparable on age, socioeconomic status, sex, handedness, education, IQ, and achievement test performance had an MRI on a 1.5T Siemens scanner. Cortical and sub-cortical gray and white matter were segmented. Image parcellation divided the neocortex into 48 gyral-based units per hemisphere. Based on a priori hypotheses we focused on prefrontal, anterior cingulate cortex (ACC) and overall gray matter volumes. General linear analyses of the volumes of brain regions, adjusting for age, sex, and total cerebral volumes, were used to compare groups.

RESULTS

Relative to controls, ADHD adults had significantly smaller overall cortical gray matter, prefrontal and ACC volumes.

CONCLUSIONS

Adults with ADHD have volume differences in brain regions in areas involved in attention and executive control. These data, largely consistent with studies of children, support the idea that adults with ADHD have a valid disorder with persistent biological features.

The face does predict the brain--midline facial and forebrain defects uncovered during the investigation of nasal obstruction and rhinorrhea. Case report and a review of holoprosencephaly and its classifications

When the embryonic forebrain (the prosencephalon) fails to sufficiently divide into the two cerebral hemispheres, holoprosencephaly (HPE) results. This disorder can result in various skull and facial defects with brain abnormalities of varying severity. These brain defects ultimately dictate the prognosis. This varies from death in utero, to normal or near normal brain development. In these less severe cases, otherwise normally developing babies are born with rarely seen midfacial cleft deformities, giving away a structural brain deformity. We report a case of an otherwise developmentally normal seven-year-old boy who was being assessed for nasal obstruction and rhinorrhea. Investigation directed by a high index of suspicion uncovered an occult case of holoprosencephaly.

Global and regional gray matter reductions in ADHD: A voxel-based morphometric study

Attention deficit hyperactivity disorder (ADHD) is a developmental disorder characterized by inattentiveness, motor hyperactivity and impulsivity. According to neuroimaging data, the neural substrate underlying ADHD seems to involve fronto-striatal circuits and the cerebellum. However, there are important discrepancies between various studies, probably due to the use of different techniques. The aim of this study is to examine cerebral gray (GM) and white (WM) matter abnormalities in a group of ADHD children using a voxel-based morphometry protocol. The sample consisted of 25 children/adolescents with DSM-IV TR diagnosis of ADHD (medicated, aged 6-16 years) who were compared with 25 healthy volunteer children/adolescents. ADHD brains on an average showed a global volume decrease of 5.4% as compared to controls. Additionally, there were regionally specific effects in the left fronto-parietal areas (left motor, premotor and somatosensory cortex), left cingulate cortex (anterior/middle/posterior cingulate), parietal lobe (precuneus bilaterally), temporal cortices (right middle temporal gyrus, left parahippocampal gyrus), and the cerebellum (bilateral posterior). There were no differences in WM volume between ADHD children and control subjects. The results are consistent with previous studies that used different techniques, and may represent a possible neural basis for some of the motor and attentional deficits commonly found in ADHD.

Hippocampal and anterior cingulate morphology in subjects at ultra-high-risk for psychosis: the role of family history of psychotic illness

BACKGROUND

While structural brain imaging abnormalities have been identified in schizophrenia and related disorders, it is unclear when they arise. Some appear to predate the illness and may be genetic in origin, while others are associated with the onset of the disorder.

METHODS

We examined the hippocampal volumes and anterior cingulate morphology from the MRI scans of 79 male subjects at ultra-high-risk (UHR) for developing psychosis, 35 of whom had a family history of schizophrenia, and compared them with 49 healthy male volunteers.

RESULTS

Analysis of covariance demonstrated that left hippocampal volumes were significantly smaller in the UHR group without a family history of schizophrenia, when compared to the UHR group with such history. A similar pattern was found for the left anterior cingulate region, both in terms of reduced paracingulate folding and cingulate sulcus interruptions, although this did not reach significance.

CONCLUSIONS

We found that a family history of schizophrenia was not associated with a greater degree of structural brain abnormalities in an ultra-high-risk group, and in fact it was those UHR patients without such history who displayed greater abnormalities, although this only reached significance for the left hippocampus. Thus, it appears that the mechanisms that result in gross morphological anomalies in the hippocampus and anterior cingulate in psychosis are driven more by environmental than genetic factors.

Abnormal development of the anterior cingulate in childhood-onset schizophrenia: a preliminary quantitative MRI study

The anterior cingulate is a key component of neural networks subserving attention and emotion regulation, functions often impaired in patients with psychosis. The study aimed to examine anterior cingulate volumes and sulcal morphology in a group of patients with childhood-onset schizophrenia (COS) compared with controls. Brain magnetic resonance imaging (MRI) scans were obtained in 13 COS and 18 matched control children, ages 6-17 years. Volume measures for the anterior cingulate gyrus (ACG) were obtained through manual labeling. A determination of cingulate sulcal pattern (single or double) was made for each hemisphere. The COS group had a reduced leftward skew of the double cingulate sulcal pattern, and absence of the normal left>right ACG volume asymmetry. The right ACG was larger in the COS than in controls. The schizophrenic children showed decreases in all ACG volumes with age, while the controls showed increases or no change. The data suggest that significant cingulate abnormalities may result from deviations in progressive neurodevelopmental processes, beginning before birth and continuing through childhood and adolescence, in persons who develop schizophrenia. These structural differences may relate to the well-described cognitive deficits these children display, and to the cardinal symptoms of schizophrenia.

A manual and automated MRI study of anterior cingulate and orbito-frontal cortices, and caudate nucleus in obsessive-compulsive disorder: comparison with healthy controls and patients with schizophrenia

Functional imaging and neuropsychological data suggest that interconnected brain structures including the orbito-frontal cortex (OFC), anterior cingulate cortex (ACC) and caudate nucleus (CN) are involved in the pathophysiology of obsessive-compulsive disorder (OCD), but structural imaging studies investigating these regions have yielded inconclusive results. This may be due to inconsistencies in the identification of anatomical boundaries and methodologies utilised (i.e. automated vs. manual tracing). This magnetic resonance imaging study used manual tracing to measure volumes of selected brain regions (OFC, ACC and CN) in OCD patients and compared them with samples of healthy (HC) and psychiatric (schizophrenia; SCZ) controls (n=18 in each group). Concurrently, automated voxel-based analysis was also used to detect subtle differences in cerebral grey and white matter. For the OCD vs. HC comparison, there were no significant volumetric differences detected using the manual or the automated method (although the latter revealed a deficit in the subcortical white matter of the right temporal region). A direct comparison of the two patient groups showed no significant differences using the manual method. However, a moderate effect size was detected for OFC grey matter (reduced in SCZ), which was supported by findings of reduced OFC volume in the automated analysis. Automated analyses also showed reduced volumes in the dorsal (white matter) and ventral ACC (grey and white matter), as well as the left posterior cingulate (grey and white matter) in SCZ. The findings suggest that in contrast to findings in SCZ, there are very few (if any) gross structural anomalies in OCD.

Volume of the cingulate and outcome in schizophrenia

BACKGROUND

Previous studies indicated that schizophrenia patients have reduced frontal volumes in comparison with normal, but among schizophrenics, reduced volumes of the posterior (temporal, parietal and occipital) cortex were associated with poor outcome. We examined whether this pattern is seen within the anteroposterior arch of the cingulate gyrus.

METHODS

MR images were acquired in 37 schizophrenia patients (Kraepelinian, n = 13; non-Kraepelinian, n = 24) and 37 controls, and CSF, gray and white matter volumes in individual Brodmann's areas (BA) of the cingulate arch (areas 25, 24, 23, 31, 30, 29) were assessed and examined in relation to outcome.

RESULTS

Schizophrenia patients had significant gray matter reductions in the absolute (mm(3)) volume of Brodmann's area 24 in anterior cingulate and, when corrected for brain size, in the whole cingulate and retrosplenial (areas 29-30) cortex. White matter volumes were increased in right posterior cingulate (area 31). Schizophrenia patients also showed abnormal lateralization of white matter volumes in retrosplenial cortex (area 30) and had lower correlations between frontal and anterior cingulate regions than controls. Poor-outcome subgroup exhibited significant bilateral gray matter deficits in posterior cingulate and retrosplenial cortices compared to good-outcome patients, while no white matter increases in these areas were seen.

CONCLUSIONS

Poor outcome was associated with gray matter deficits in posterior cingulate while compensatory white matter increases in dorsal posterior regions may be related to better outcome. Possible consequences of this may include thought disorder, disturbance of consciousness, treatment resistance, and cognitive decline indicative of a dementing process as a superimposed or inherent part of this schizophrenia subtype.

Cingulate gyrus volume and metabolism in the schizophrenia spectrum

BACKGROUND

The cingulate gyrus, which is involved in affect, attention, memory and higher executive functions, has been implicated as a dysfunctional region in schizophrenia. Postmortem studies report cytoarchitectural changes in the anterior cingulate gyrus (ACG) and functioning imaging studies show correlations between the degree of hypometabolism of the anterior cingulate and clinical symptoms in schizophrenia.

METHODS

Unmedicated patients with schizophrenia (n=27) and schizotypal personality disorder (SPD) (n=13), as well as sex- and age-matched control subjects (n=32), were studied with (18)F-fluorodeoxyglucose positron emission tomography (PET) scans and magnetic resonance imaging (MRI). As a control over mental activity, all subjects performed a verbal working memory task during the PET protocol. The cingulate gyrus was first outlined on the MRI scans and, after coregistration, the coordinates were applied to the PET scans to yield a three-dimensional metabolic map of the cingulate gyrus for each subject. A statistical resampling method was used to analyze the metabolic differences between groups.

RESULTS

Compared with controls, patients with schizophrenia had lower relative glucose metabolic rates in the left anterior cingulate and the right posterior cingulate gyrus (PCG) assessed by 3-D significance probability mapping. SPD patients had higher glucose metabolic rates (GMRs) in the left posterior cingulate than did controls. Furthermore, volumetric measurement with MRI showed the left anterior cingulate and Brodmann area 24' to be smaller in schizophrenic patients than controls.

CONCLUSIONS

Compared with controls, patients with schizophrenia have metabolic and volumetric reductions in a cingulate gyrus area that is related to higher executive functions. Schizotypal patients rely more on sensory association areas to perform a cognitive task than do controls and seem to be a group that is partially distinct in its physiological and functional characteristics.

Validation of semiautomated methods for quantifying cingulate cortical metrics in schizophrenia

This paper validates semiautomated methods for reconstructing cortical surfaces of the cingulate gyrus from high-resolution magnetic resonance (MR) images. Bayesian segmentation was used to delineate the image voxels into five tissue types: cerebrospinal fluid (CSF), gray matter (GM), white matter (WM), and partial volumes of CSF/GM and GM/WM; the tissues were then recalibrated as CSF, GM, and WM via the Neyman-Pearson Likelihood Ratio Test. To generate cortical surfaces at the interface of GM and WM, the thresholds between the tissue types were first used to reassign partial volume voxels to CSF, GM, and WM with minimum error (that varied from 0.06 to 0.15 for the 10 subjects). Next, topology-correct cortical surfaces were generated and validated with almost all surface vertices lying within one voxel (0.5 mm) of hand contours. Dynamic programming was used to delineate and extract the cingulate gyrus from the cortical surfaces based on its gyral and sulcal boundaries. The intraclass correlation coefficient for surface area obtained by two raters for all 10 surfaces was 0.82. In addition, by repeating the entire procedure three times in one subject, we obtained a coefficient of variation of 0.0438 for surface area.

Anterior cingulum abnormalities in male patients with schizophrenia determined through diffusion tensor imaging

OBJECTIVE

This study used diffusion tensor imaging to examine fractional anisotropy in the anterior cingulum and posterior cingulum bundles in patients with schizophrenia.

METHOD

Twenty-one male patients and 20 healthy comparison men were studied.

RESULTS

Reduced fractional anisotropy was seen for both sides of the anterior cingulum in the schizophrenia patients, who also exhibited less left-greater-than-right asymmetry in the anterior cingulum than was seen in the comparison subjects.

CONCLUSIONS

The findings suggest structural disconnections in the anterior cingulum in patients with schizophrenia.

Anterior cingulate, gyrus rectus, and orbitofrontal abnormalities in elderly depressed patients: an MRI-based parcellation of the prefrontal cortex

OBJECTIVE

To examine structural abnormalities in subregions of the prefrontal cortex in elderly patients with depression, the authors explored differences in gray matter, white matter, and CSF volumes by applying a parcellation method based on magnetic resonance imaging (MRI).

METHOD

Twenty-four elderly patients with major depression and 19 group-matched comparison subjects were studied with high-resolution MRI. Cortical surface extraction, tissue segmentation, and cortical parcellation methods were applied to obtain volume measures of gray matter, white matter, and CSF in seven prefrontal subregions: the anterior cingulate, gyrus rectus, orbitofrontal cortex, precentral gyrus, superior frontal cortex, middle frontal cortex, and inferior frontal cortex.

RESULTS

Highly significant bilateral volume reductions in gray matter were observed in the anterior cingulate, the gyrus rectus, and the orbitofrontal cortex. Depressed patients also exhibited significant bilateral white matter volume reductions and significant CSF volume increases in the anterior cingulate and the gyrus rectus. Finally, the depressed group showed significant CSF volume reductions in the orbitofrontal cortex relative to the comparison subjects. None of the other regions examined revealed significant structural abnormalities.

CONCLUSIONS

The prominent bilateral gray matter deficits in the anterior cingulate and the gyrus rectus as well as the orbitofrontal cortex may reflect disease-specific modifications of elderly depression. The differential pattern of abnormalities detected in the white matter and CSF compartments imply that distinct etiopathological mechanisms might underlie the structural cortical changes in these regions.

Abnormal anterior cingulum in patients with schizophrenia: a diffusion tensor imaging study

Diffusion tensor imaging (DTI) can non-invasively examine the molecular diffusion of water in vivo and directly reflects the anatomical integrity of neural fibers in white matter. Fractional anisotropy (FA) can be calculated from DTI data, and utilized to evaluate white matter integrity. DTI was performed on 30 patients with schizophrenia and 19 healthy controls, and their FA values were subsequently measured in multiple brain regions. Statistical analyses revealed that FA values were decreased in the anterior cingulum of schizophrenia subjects. There were no significant differences between patients and controls in any other regions. This study supports the hypothesis that schizophrenia is associated with abnormal white matter integrity of the anterior cingulum.

Neuroimaging communality between schizophrenia and obsessive compulsive disorder: a putative basis for schizo-obsessive disorder?

Four major brain regions have been repeatedly implicated in the pathophysiology of obsessive compulsive disorder (OCD) in in vivo neuroimaging studies: the caudate nucleus, the orbitofrontal cortex, the anterior cingulate gyrus and the mediodorsal thalamic nucleus. The present review describes the neuroimaging studies on schizophrenia, pertaining to these brain regions. Our working hypothesis is that such common brain regions, if dysfunctional in schizophrenic patients, would be candidates for a neural network subserving the newly emerging syndrome of schizo-obsessive disorder. Findings, though, are controversial. We conclude that further studies, aimed at specific monitoring of these brain regions, in patients suffering from the schizo-obsessive syndrome are warranted.

Interruptions of early cortical development affect limbic association areas and social behaviour in rats; possible relevance for neurodevelopmental disorders

Deficits in social behaviour are found in several neuropsychiatric disorders with a presumed developmental origin. Adequate social behaviour may rely importantly on the associative integration of new stimuli with previously stored, related information. The limbic allocortex, in particular the entorhinal region, is thought to support this kind of processing. Therefore, in the present study, gestating dams were treated with methylazoxymethanol acetate (MAM) on one of gestational days nine to twelve, to interrupt neuronal proliferation in the entorhinal region of the developing foetuses. Effects of prenatal MAM administration on social behaviour were evaluated in adult animals. As the entorhinal cortex has been implicated by some studies in spatial memory, effects on this function were also investigated. Following the behavioural studies, brain morphology was screened for effects of MAM. Our results show moderate to severe social impairment in MAM-treated animals, depending on the exact timing of prenatal exposure. By contrast, spatial reference and working memory were not importantly affected in any group. Analysis of brain morphology in the MAM-treated offspring supported maldevelopment of the entorhinal cortex and revealed mild abnormalities also in some connected limbic and limbic affiliated structures, such as the perirhinal and ectorhinal cortex, the anterior cingulate cortex and the medial septum-diagonal band region. Findings are discussed with respect to entorhinal cortex function, and with regard to their relevance for psychiatric disorders with a putatively neurodevelopmental pathogenesis, such as schizophrenia.

Cortical maturation in normal and abnormal fetuses as assessed with prenatal MR imaging

PURPOSE

To establish the appearance of normal fetal cortical development in utero and compare it with the appearance of abnormal cortical development.

MATERIALS AND METHODS

Magnetic resonance (MR) images of the brain in 53 normal and 40 abnormal fetuses at 14-38 weeks gestational age (GA) were reviewed. The GAs at the time of MR imaging visualization of the fissures or sulci were compared with the GA guidelines based on neuroanatomic studies.

RESULTS

In normal fetuses, the sulcation landmarks appeared on MR images in the order predicted by using anatomic studies, with a 0-8-week lag in the MR imaging visualization of the sulci compared with the reported time of visualization of the sulci in anatomic specimens. When landmarks were grouped by range of GAs, the expected MR imaging sulcation landmarks in the group with younger GAs than the actual GA were seen in 50 of 53 (94%) normal fetuses, in five of nine fetuses (56%, P < .05) with isolated mild ventriculomegaly, and in 24 of 31 fetuses (77%, P < .05) with other CNS anomalies.

CONCLUSION

Normal fetal cortical maturation at MR imaging follows a predictable course that is slightly delayed compared with that described in neuroanatomic specimens. This maturation is often further delayed in fetuses with CNS abnormalities.

Clinical-neuroendocrinological syndromes due to lesions of the cingulate gyrus in humans

Clinical and neuroendocrinological studies were performed in 41 patients with arteriovenous malformations (AVM) of the cingulate gyrus. Before surgery, the primary affliction in 38 patients consisted of memory disturbance, 5 of these having signs of Korsakov's syndrome. Autonomic and epileptic fits were not typical. Of 38 patients undergoing surgery, postoperative worsening of memory occurred in 23, but no qualitatively new disturbances appeared. Korsakov's syndrome appeared de novo after surgery in 3 patients. The extent of memory disturbances correlated with the extent of lesions to the cingulate gyrus and with the extent to which AVM affected the corpus callosum. Qualitative analysis of memory loss syndromes revealed alterations in trace selectivity in nearly all patients and failure to retain the meaning of stories, which was accompanied by lack of insight into the patients' abnormalities. The signs of these syndromes showed clear similarity with memory deficiencies in patients with frontal lesions. This suggests that not only the frontal lobes themselves, but also their connections, are involved in producing the clinical picture in humans.

Prenatal cocaine exposure: long-term deficits in learning and motor performance

We have developed a rabbit model of in utero exposure to intravenous injections of cocaine given twice daily to dams from gestational days 8-29. At the doses employed (4 mg/kg, injected twice daily), no differences were found in the body weight gain of dams, time to delivery, litter size, and body weight or other physical characteristics of the offspring. However, cocaine-exposed pups displayed an abnormal structural and neurochemical development of the anterior cingulate cortex which persisted into adulthood. In agreement with the known functions of the anterior cingulate cortex, we found that adult, sexually mature rabbits, exposed to cocaine prenatally, demonstrate impairments in motor function, alterations in associative learning and severe impairments in discrimination learning. Moreover, the alterations in discrimination learning were interpreted to be due to deficits in attentional processes. Specifically, cocaine progeny preferentially attend to more salient stimuli even when these are not relevant to the task. Consequently they have difficulty in attending to less salient but relevant stimuli when more salient but irrelevant stimuli occur in the same context. We concluded that the learning deficits are a reflection of the morphologic and neurochemical abnormalities of the anterior cingulate cortex. Alterations in dopamine function of the caudate nucleus may also contribute to the deficits in motor performance.

Holoprosencephaly manifesting with fusion of the gyri cinguli

In this paper we report a 7-month-old boy with lobar holoprosencephaly in whom midline interhemispheric fusion occurred between thickened gyri cinguli of both hemispheres at the middle frontal region. This anomaly appears to be a variation of a recently recognized type of holoprosencephaly associated with midline interhemispheric fusion and atypical callosal dysgenesis. In contrast to the previously reported a few cases, in our patient the corpus callosum was thinned but intact. In addition, the condition was associated with diffuse cortical dysplasia. The malformations in this patient is of interest because it contributes to our understanding of variations of holoprosencephaly.

Gelastic seizures in a child with focal cortical dysplasia of the cingulate gyrus

We present a case of gelastic seizures in a child with focal cortical dysplasia of the anterior cingulate gyrus. This is only the second published case of a confirmed lesion at this site presenting in such a way. The underlying neurological mechanism is described.

Previously apparently undescribed syndrome: shallow orbits, ptosis, coloboma, trigonocephaly, gyral malformations, and mental and growth retardation

We describe 2 children with severe ptosis, trigonocephaly, broad nasal bridge, and major brain malformation. A total of 8 children have been reported who share most of these findings. Two of the individuals have had identical pericentric inversions involving chromosome 2p12-q14. These cases appear to represent a unique malformation syndrome.

[Cerebellar agenesia associated with microencephaly and agyria: report of an autopsied case in a newborn infant and a review of the literature]

A post-mortem examined case of cerebellar agenesis associated with microcephaly, agyria and deformities of the extremities and of the external ear in a newborn is presented. Such an association has not yet been reported in the literature. This is the seventh case of cerebellar agenesis ever registered in the literature. This case is compared with other previously published cases and the possible etiological factors involved as well as the period during which the cerebral malformations appeared in the present case are commented upon.

Lissencephaly and Pachygyria: an architectonic and topographical analysis

The architectonic features of abnormal cerebral cortex in a brain with lissencephaly and pachygyria suggest that neuronal migration was interrupted by cortical and subcortical laminar necrosis in the fourth fetal month. The severest cortical abnormality lies in the distal perfusion fields of the major cerebral arteries, while the normal areas are located in the proximal perfusion fields. These architectonic and topographic features suggest that intra-uterine hypoxia or perfusion failure may be a pathogenetic mechanism leading to lissencephaly and pachygyria.