Investigating relationships between cortical thickness and cognitive performance in patients with schizophrenia and healthy adults

Individual differences in frontal cortical thickness correlate with the d-amphetamine-induced striatal dopamine response in humans

The meso-striatal dopamine system influences responses to rewards and the motivation to seek them out. Marked individual differences in these responses are seen in laboratory animals, related in part to input from the prefrontal cortex. Here we measured the relation between cortical morphology and drug-induced striatal dopamine release in healthy young people. Participants were 24 (17 male, 7 female; age 23.0 ± 6.2 years) stimulant drug-naive subjects who underwent PET [(11)C]raclopride scans with 0.3 mg/kg d-amphetamine orally and placebo, and an anatomical MRI scan for measuring cortical thickness. As expected, d-amphetamine produced significant reductions in [(11)C]raclopride binding potential in the striatum as a percentage of the value in the placebo condition. There was substantial individual variability in this response, which was correlated with cortical thickness in the frontal lobe as a whole. The association was strongest in the anterior part of the right lateral prefrontal cortex and bilateral supplementary motor area. A thicker cortex was correlated with a smaller dopamine response. Together, this work demonstrates in humans an association between cortical thickness and the striatal dopamine response to drugs of abuse. Although prefrontal regulation of striatal function has been well studied, it was unclear whether the thickness of the prefrontal cortex was an acceptable proxy to the function of that region. These results suggest it is.

The myth of schizophrenia as a progressive brain disease

Schizophrenia has historically been considered to be a deteriorating disease, a view reinforced by recent MRI findings of progressive brain tissue loss over the early years of illness. On the other hand, the notion that recovery from schizophrenia is possible is increasingly embraced by consumer and family groups. This review critically examines the evidence from longitudinal studies of (1) clinical outcomes, (2) MRI brain volumes, and (3) cognitive functioning. First, the evidence shows that although approximately 25% of people with schizophrenia have a poor long-term outcome, few of these show the incremental loss of function that is characteristic of neurodegenerative illnesses. Second, MRI studies demonstrate subtle developmental abnormalities at first onset of psychosis and then further decreases in brain tissue volumes; however, these latter decreases are explicable by the effects of antipsychotic medication, substance abuse, and other secondary factors. Third, while patients do show cognitive deficits compared with controls, cognitive functioning does not appear to deteriorate over time. The majority of people with schizophrenia have the potential to achieve long-term remission and functional recovery. The fact that some experience deterioration in functioning over time may reflect poor access, or adherence, to treatment, the effects of concurrent conditions, and social and financial impoverishment. Mental health professionals need to join with patients and their families in understanding that schizophrenia is not a malignant disease that inevitably deteriorates over time but rather one from which most people can achieve a substantial degree of recovery.

A combined DTI and structural MRI study in medicated-naïve chronic schizophrenia

Disconnection in white matter (WM) pathway and alterations in gray matter (GM) structure have been hypothesized as pathogenesis in schizophrenia. However, the relationship between the abnormal WM integrity and the alteration of GM in anatomically connected areas remains uncertain. Moreover, the potential influence of antipsychotic medication on WM anisotropy and cortical morphology was not excluded in previous studies. In this study, a total number of 34 subjects were enrolled, including 17 medicated-naïve chronic schizophrenia patients and 17 healthy controls. Tract-based spatial statistics (TBSS) were applied to investigate the level of WM integrity. The FreeSurfer surface-based analysis was used to determine GM volume, cortical thickness and the surface area of GM regions which corresponded to abnormal WM fiber tracts. We observed that patients possessed lower fractional anisotropy (FA) values in the left inferior fronto-occipital fasciculus (IFOF) and left inferior longitudinal fasciculus (ILF), along with smaller GM volume and cortical thinning in temporal lobe than the healthy controls, which reflected the underlying WM and GM disruption that contributed to the disease. In the patient population, the lower connectivity of ILF and IFOF was positively associated with cortical thickness in left lateral orbitofrontal cortex, superior temporal gyrus and lingual gyrus in males, and positively correlated with GM volume in left lateral orbitofrontal cortex in females. On the other hand, it was negatively correlated with cortical area of middle temporal gyrus in males and temporal pole in females respectively, but not when genders were combined. These findings suggested that abnormal WM integrity and anatomical correspondence of GM alterations in schizophrenia were interdependent on gender-separated analysis in patients with schizophrenia. Moreover, combining TBSS and FreeSurfer might be a useful method to provide significant insight into interacting processes related to WM fiber tracts and GM changes in schizophrenia.

The global cognitive impairment in schizophrenia: consistent over decades and around the world

OBJECTIVE

Schizophrenia results in cognitive impairments as well as positive, negative, and disorganized symptomatology. The present study examines the extent to which these cognitive deficits are generalized across domains, potential moderator variables, and whether the pattern of cognitive findings reported in schizophrenia has remained consistent over time and across cultural and geographic variation.

METHOD

Relevant publications from 2006 to 2011 were identified through keyword searches in PubMed and an examination of reference lists. Studies were included if they (1) compared the cognitive performance of adult schizophrenia patients and healthy controls, (2) based schizophrenia diagnoses on contemporary diagnostic criteria, (3) reported information sufficient to permit effect size calculation, (4) were reported in English, and (5) reported data for neuropsychological tests falling into at least 3 distinct cognitive domains. A set of 100 non-overlapping studies was identified, and effect sizes (Hedge's g) were calculated for each cognitive variable.

RESULTS

Consistent with earlier analyses, patients with schizophrenia scored significantly lower than controls across all cognitive tests and domains (grand mean effect size, g=-1.03). Patients showed somewhat larger impairments in the domains of processing speed (g=-1.25) and episodic memory (g=-1.23). Our results also showed few inconsistencies when grouped by geographic region.

CONCLUSIONS

The present study extends findings from 1980 to 2006 of a substantial, generalized cognitive impairment in schizophrenia, demonstrating that this finding has remained robust over time despite changes in assessment instruments and alterations in diagnostic criteria, and that it manifests similarly in different regions of the world despite linguistic and cultural differences.

Cortical thickness of superior frontal cortex predicts impulsiveness and perceptual reasoning in adolescence

Impulsiveness is a pivotal personality trait representing a core domain in all major personality inventories. Recently, impulsiveness has been identified as an important modulator of cognitive processing, particularly in tasks that require the processing of large amounts of information. Although brain imaging studies have implicated the prefrontal cortex to be a common underlying representation of impulsiveness and related cognitive functioning, to date a fine-grain and detailed morphometric analysis has not been carried out. On the basis of ahigh-resolution magnetic resonance scans acquired in 1620 healthy adolescents (IMAGEN), the individual cortical thickness (CT) was estimated. Correlations between Cloninger's impulsiveness and CT were studied in an entire cortex analysis. The cluster identified was tested for associations with performance in perceptual reasoning tasks of the Wechsler Intelligence Scale for Children (WISC IV). We observed a significant inverse correlation between trait impulsiveness and CT of the left superior frontal cortex (SFC; Monte Carlo Simulation P<0.01). CT within this cluster correlated with perceptual reasoning scores (Bonferroni corrected) of the WISC IV. On the basis of a large sample of adolescents, we identified an extended area in the SFC as a correlate of impulsiveness, which appears to be in line with the trait character of this prominent personality facet. The association of SFC thickness with perceptual reasoning argues for a common neurobiological basis of personality and specific cognitive domains comprising attention, spatial reasoning and response selection. The results may facilitate the understanding of the role of impulsiveness in several psychiatric disorders associated with prefrontal dysfunctions and cognitive deficits.

Neurocognitive function in long-term treated schizophrenia: a five-year follow-up study

Neurocognitive deficits are a core feature of schizophrenia. Deficits covering a wide range of functions have been well documented. However there is still a lack of longitudinal studies regarding the development of neurocognitive impairment. The current study examined the effect of time in long-term treated patients with schizophrenia and healthy controls on cognitive functions. A neurocognitive test-battery was administered to 36 patients and 46 controls on two occasions with approximately 4.5 years interval. Patients performed significantly worse on all measures on both occasions. The only significant decline over time was the ability to shift mental set between different rules or categories (measured by Trail Making Test B). This decline was present in both patients and controls. Improvement on attention (tested by Continuous Performance Test) was found in patients only and improvement on verbal learning (tested by Rey Auditory Verbal Learning Test) was found only in controls. Education was significantly related to outcome in patients and age was related to outcome in controls. We conclude that neurocognitive function is relatively stable over 4.5 years in patients with long-term treated schizophrenia, in line with previous scientific research. The authors discuss the impact of age and education and limitations of the study.

Heritability of multivariate gray matter measures in schizophrenia

Structural brain measures are employed as endophenotypes in the search for schizophrenia susceptibility genes. We analyzed two independent structural imaging datasets with voxel-based morphometry and with source-based morphometry, a multivariate, independent components analysis, to determine the stability and heritability of regional gray matter concentration abnormalities in schizophrenia. The samples comprised 209 and 102 patients with schizophrenia and 208 and 96 healthy volunteers, respectively. The second sample additionally included non-ill siblings of participants with and without schizophrenia. A standard voxel-based analysis showed reproducible regional gray matter deficits in the affected participants compared with unrelated, unaffected controls in both datasets: patients showed significant gray matter concentration deficits in cortical frontal, temporal, and insular lobes. Source-based morphometry (SBM) was applied to the gray matter images of the entire sample to determine the effects of diagnosis on networks of covarying structures. The SBM analysis extracted 24 significant sets of covarying regions (components). Four of these components showed significantly lower gray matter concentrations in patients (p < .05). We determined the familiality of the observed SBM components based on 66 sibling pairs (25 discordant for schizophrenia). Two components, one including the medial frontal, insular, inferior frontal, and temporal lobes, and the other including the posterior occipital lobe, showed significant familiality (p < .05). We conclude that structural brain deficits in schizophrenia are replicable, and that SBM can extract unique familial and likely heritable components. SBM provides a useful data reduction technique that can provide measures that may serve as endophenotypes for schizophrenia.

Associations of cortical thickness and cognition in patients with schizophrenia and healthy controls

Previous studies have found varying relationships between cognitive functioning and brain volumes in patients with schizophrenia. However, cortical thickness may more closely reflect cytoarchitectural characteristics than gray matter density or volume estimates. Here, we aimed to compare associations between regional variation in cortical thickness and executive functions, memory, as well as verbal and spatial processing in patients with schizophrenia and healthy controls (HCs). We obtained magnetic resonance imaging and neuropsychological data for 131 patients and 138 matched controls. Automated cortical pattern matching methods allowed testing for associations with cortical thickness estimated as the shortest distance between the gray/white matter border and the pial surface at thousands of points across the entire cortical surface. Two independent measures of working memory showed robust associations with cortical thickness in lateral prefrontal cortex in HCs, whereas patients exhibited associations between working memory and cortical thickness in the right middle and superior temporal lobe. This study provides additional evidence for a disrupted structure-function relationship in schizophrenia. In line with the prefrontal inefficiency hypothesis, schizophrenia patients may engage a larger compensatory network of brain regions other than frontal cortex to recall and manipulate verbal material in working memory.

Functional significance of atypical cortical organization in spina bifida myelomeningocele: relations of cortical thickness and gyrification with IQ and fine motor dexterity

The cortex in spina bifida myelomeningocele (SBM) is atypically organized, but it is not known how specific features of atypical cortical organization promote or disrupt cognitive and motor function. Relations of deviant cortical thickness and gyrification with IQ and fine motor dexterity were investigated in 64 individuals with SBM and 26 typically developing (TD) individuals, aged 8-28 years. Cortical thickness and 3D local gyrification index (LGI) were quantified from 33 cortical regions per hemisphere using FreeSurfer. Results replicated previous findings, showing regions of higher and lower cortical thickness and LGI in SBM relative to the TD comparison individuals. Cortical thickness and LGI were negatively associated in most cortical regions, though less consistently in the TD group. Whereas cortical thickness and LGI tended to be negatively associated with IQ and fine motor outcomes in regions that were thicker or more gyrified in SBM, associations tended to be positive in regions that were thinner or less gyrified in SBM. The more deviant the levels of cortical thickness and LGI-whether higher or lower relative to the TD group-the more impaired the IQ and fine motor outcomes, suggesting that these cortical atypicalities in SBM are functionally maladaptive, rather than adaptive.

Thinner cortex in the frontal lobes in mentally disordered offenders

Antisocial and violent behaviour have been associated with both structural and functional brain abnormalities in the frontal and the temporal lobes. The aim of the present study was to assess cortical thickness in offenders undergoing forensic psychiatric assessments, one group with psychopathy (PSY, n=7) and one group with autism spectrum disorder (ASD, n=7) compared to each other as well as to a reference group consisting of healthy non-criminal subjects (RG, n=12). A second aim was to assess correlation between scores on a psychopathy checklist (PCL-SV) and cortical thickness. Magnetic resonance imaging (MRI) and surface-based cortical segmentation were used to calculate cortical thickness. Analyses used both regions of interest and statistical maps. When the two groups of offenders were compared, there were no differences in cortical thickness, but the PSY group had thinner cortex in the temporal lobes and in the whole right hemisphere compared to RG. There were no differences in cortical thickness between the ASD group and RG. Across subjects there was a negative correlation between PCL-SV scores and cortical thickness in the temporal lobes and the whole right hemisphere. The findings indicate that thinner cortex in the temporal lobes is present in psychopathic offenders and that these regions are important for the expression of psychopathy. However, whether thinner temporal cortex is a cause or a consequence of the antisocial behaviour is still unknown.

Regional cortical thinning in patients with major depressive disorder: a surface-based morphometry study

This study uses surfaced-based morphometry to investigate cortical thinning and its functional correlates in patients with major depressive disorder (MDD). Subjects with MDD (N=36) and healthy control subjects (N=36) were enrolled in the study. Each subject received T1 structural magnetic resonance imaging (MRI), clinical evaluations, and neuropsychological examinations of executive functions with the Color Trail Test (CTT) and the Wisconsin Card Sorting Test (WCST). This study used an automated surface-based method (FreeSurfer) to measure cortical thickness and to generate the thickness maps for each subject. Statistical comparisons were performed using a general linear model. Compared with healthy controls, subjects with MDD showed the largest area of cortical thinning in the prefrontal cortex. This study also noted smaller areas of cortical thinning in the bilateral inferior parietal cortex, left middle temporal gyrus, left entorhinal cortex, left lingual cortex, and right postcentral gyrus. Regression analysis demonstrated cortical thinning in several frontoparietal regions, predicting worse executive performance measured by CTT 2, though the patterns of cortical thickness/executive performance correlation differed in healthy controls and MDD subjects. In conclusion, the results provide further evidence for the significant role of a prefrontal structural deficit and an aberrant structural/functional relationship in patients with MDD.

Reduced anterior cingulate cognitive activation is associated with prefrontal-temporal cortical thinning in schizophrenia

BACKGROUND

The anterior cingulate cortex plays a central role in altered processes of cognitive control in schizophrenia. However, the cortical foundations of disturbed anterior cingulate cognitive activation are poorly understood. Therefore, this study investigated the association of anterior cingulate cognitive activation and cortical thickness in schizophrenia combining functional magnetic resonance imaging (fMRI) and surface-based morphometry.

METHODS

Fifty-three patients with schizophrenia according to DSM-IV and 53 age- and sex-matched healthy subjects were included and underwent fMRI and high-resolution T1-weighted MRI. fMRI data was analyzed using SPM5. Cortical thickness was calculated using an automated computerized algorithm (Freesurfer Software). Statistical cortical maps were created correlating anterior cingulate activation and cortical thickness on a node-by-node basis covering the entire cortex in schizophrenia and healthy control subjects.

RESULTS

Patients demonstrated a significantly reduced anterior cingulate cognitive activation. Significantly differing associations of anterior cingulate activation and cortical thickness were found in a pattern of dorsolateral prefrontal, superior frontal-anterior cingulate, and superior temporal cortical regions, where patients but not healthy control subjects demonstrated a significant association of reduced anterior cingulate activation and cortical thinning. A direct comparison of cortical thickness between the diagnostic groups revealed a significantly reduced cortical thickness of these prefrontotemporal regions in schizophrenia.

CONCLUSIONS

To our best knowledge, this is the first study indicating that prefrontotemporal cortical thinning constitutes a relevant cortical pathomechanism for altered cognitive activation in schizophrenia. Our data additionally reveal a profound disruption of structural and functional integration in the prefrontotemporal system in schizophrenia.

Alteration of the pro-oxidant xanthine oxidase (XO) in the thalamus and occipital cortex of patients with schizophrenia

OBJECTIVES

Mounting evidence shows that oxidative stress (OS) and the purine/adenosine system play a key role in the pathophysiology of schizophrenia. Lately, our group pointed out that not only antioxidants, but also the prooxidant system plays an important role in neuro-psychiatric disorders. Xanthine oxidase (XO) is an enzyme of special interest in this context, since it acts as a prooxidant, but its main product is a vastly important antioxidant, uric acid (UA). Furthermore, XO plays major part in the purine/adenosine metabolism, which has been hypothesised to play a role in schizophrenia as well.

METHODS

We examined the activity of XO in the striato-cortico-limbic system of schizophrenic patients (SP) and controls using a commercially available activity assay.

RESULTS

We found decreased activity of XO in the occipital cortex and thalamus of patients with psychosis. Furthermore, XO shows a significant positive correlation with chlorpromazine equivalents in the putamen and the temporal cortex.

CONCLUSIONS

Nevertheless, our results might suggest a downregulation of cellular defence mechanisms in schizophrenia in several brain regions, which could account for neuronal alterations which have been described before. This demonstrates that more research is needed to fully understand the role of the complex enzyme XO in the pathophysiology of schizophrenia.

Brain cortical thickness and surface area correlates of neurocognitive performance in patients with schizophrenia, bipolar disorder, and healthy adults

Relationships between cortical brain structure and neurocognitive functioning have been reported in schizophrenia, but findings are inconclusive, and only a few studies in bipolar disorder have addressed this issue. This is the first study to directly compare relationships between cortical thickness and surface area with neurocognitive functioning in patients with schizophrenia (n = 117) and bipolar disorder (n = 121) and healthy controls (n = 192). MRI scans were obtained, and regional cortical thickness and surface area measurements were analyzed for relationships with test scores from 6 neurocognitive domains. In the combined sample, cortical thickness in the right rostral anterior cingulate was inversely related to working memory, and cortical surface area in four frontal and temporal regions were positively related to neurocognitive functioning. A positive relationship between left transverse temporal thickness and processing speed was specific to schizophrenia. A negative relationship between right temporal pole thickness and working memory was specific to bipolar disorder. In conclusion, significant cortical structure/function relationships were found in a large sample of healthy controls and patients with schizophrenia or bipolar disorder. The differences that were found between schizophrenia and bipolar may indicate differential relationship patterns in the two disorders, which may be of relevance for understanding the underlying pathophysiology.

Association of genetic variants on 15q12 with cortical thickness and cognition in schizophrenia

CONTEXT

Cortical thickness is a highly heritable structural brain measurement, and reduced thickness has been associated with schizophrenia, bipolar disorder, and decreased cognitive performance among healthy control individuals. Identifying genes that contribute to variation in cortical thickness provides a means to elucidate some of the biological mechanisms underlying these diseases and general cognitive abilities.

OBJECTIVES

To identify common genetic variants that affect cortical thickness in patients with schizophrenia, patients with bipolar disorder, and controls and to test these variants for association with cognitive performance.

DESIGN

A total of 597 198 single-nucleotide polymorphisms were tested for association with average cortical thickness in a genome-wide association study. Significantly associated single-nucleotide polymorphisms were tested for their effect on several measures of cognitive performance.

SETTING

Four major hospitals in Oslo, Norway.

PARTICIPANTS

A total of 1054 case individuals and controls were analyzed in the genome-wide association study and follow-up cognitive study. The genome-wide association study included controls (n = 181) and individuals with DSM-IV -diagnosed schizophrenia spectrum disorder (n = 94), bipolar spectrum disorder (n = 97), and other psychotic and affective disorders (n = 49).

MAIN OUTCOME MEASURES

Cortical thickness measured with magnetic resonance imaging and cognitive performance as assessed by several neuropsychological tests.

RESULTS

Two closely linked genetic variants (rs4906844 and rs11633924) within the Prader-Willi and Angelman syndrome region on chromosome 15q12 showed a genome-wide significant association (P = 1.1 x 10(-8) with average cortical thickness and modest association with cognitive performance (permuted P = .03) specifically among patients diagnosed as having schizophrenia.

CONCLUSION

This genome-wide association study identifies a common genetic variant that contributes to the heritable reduction of cortical thickness in schizophrenia. These results highlight the usefulness of cortical thickness as an intermediate phenotype for neuropsychiatric diseases. Future independent replication studies are required to confirm these findings.

Genetic influence on the working memory circuitry: behavior, structure, function and extensions to illness

Working memory is a highly heritable complex cognitive trait that is critical for a number of higher-level functions. However, the neural substrates of this behavioral phenotype are intricate and it is unknown through what precise biological mechanism variation in working memory is transmitted. In this review we explore different functional and structural components of the working memory circuitry, and the degree to which each of them is contributed to by genetic factors. Specifically, we consider dopaminergic function, glutamatergic function, white matter integrity and gray matter structure all of which provide potential mechanisms for the inheritance of working memory deficits. In addition to discussing the overall heritability of these measures we also address specific genes that may play a role. Each of these heritable components has the potential to uniquely contribute to the working memory deficits observed in genetic disorders, including 22q deletion syndrome, fragile X syndrome, phenylketonuria (PKU), and schizophrenia. By observing the individual contributions of disruptions in different components of the working memory circuitry to behavioral performance, we highlight the concept that there may be many routes to a working memory deficit; even though the same cognitive measure may be a valid endophenotype across different disorders, the underlying cause of, and treatment for, the deficit may differ. This has implications for our understanding of the transmission of working memory deficits in both healthy and disordered populations.

Cortical thickness is linked to executive functioning in adulthood and aging

Executive functions that are dependent upon the frontal-parietal network decline considerably during the course of normal aging. To delineate neuroanatomical correlates of age-related executive impairment, we investigated the relation between cortical thickness and executive functioning in 73 younger (20-32 years) and 56 older (60-71 years) healthy adults. Executive functioning was assessed using the Wisconsin Card Sorting Test (WCST). Cortical thickness was measured at each location of the cortical mantle using surface-based segmentation procedures on high-resolution T1-weighted magnetic resonance images. For regions involved in WCST performance, such as the lateral prefrontal and parietal cortices, we found that thicker cortex was related to higher accuracy. Follow-up ROI-based analyses revealed that these associations were stronger in older than in younger adults. Moreover, among older adults, high and low performers differed in cortical thickness within regions generally linked to WCST performance. Our results indicate that the structural cortical correlates of executive functioning largely overlap with previously identified functional patterns. We conclude that structural preservation of relevant brain regions is associated with higher levels of executive performance in old age, and underscore the need to consider the heterogeneity of brain aging in relation to cognitive functioning.

Normalization of cortical gray matter deficits in nonpsychotic siblings of patients with childhood-onset schizophrenia

OBJECTIVE

Cortical gray matter (GM) abnormalities in patients with childhood-onset schizophrenia (COS) progress during adolescence ultimately localizing to prefrontal and temporal cortices by early adult age. A previous study of 52 nonpsychotic siblings of COS probands had significant prefrontal and temporal GM deficits that appeared to "normalize" by age 17 years. Here we present a replication with nonoverlapping groups of healthy full siblings and healthy controls.

METHOD

Using an automated measure and prospectively acquired anatomical brain magnetic resonance images, we mapped cortical GM thickness in nonpsychotic full siblings (n = 43, 68 scans; ages 5 through 26 years) of patients with COS, contrasting them with age-, gender-, and scan interval-matched healthy controls (n = 86, 136 scans). The false-discovery rate procedure was used to control for type I errors due to multiple comparisons.

RESULTS

As in our previous study, young nonpsychotic siblings (<17 years) showed significant GM deficits in bilateral prefrontal and left temporal cortices and, in addition, smaller deficits in the parietal and right inferior temporal cortices. These deficits in nonpsychotic siblings normalized with age with minimal abnormalities remaining by age 17.

CONCLUSIONS

Our results support previous findings showing nonpsychotic siblings of COS probands to have early GM deficits that ameliorate with time. At early ages, prefrontal and/or temporal loss may serve as a familial/trait marker for COS. Late adolescence appears to be a critical period for greatest localization of deficits in probands or normalization in nonpsychotic siblings.

Developmental cortical thinning in fetal alcohol spectrum disorders

Regional cortical thickness was evaluated using CIVET processing of 3D T1-weighted images (i) to compare the variation in cortical thickness between 33 participants with fetal alcohol spectrum disorders (FASD) aged 6-30 years (mean age 12.3 years) versus 33 age/sex/hand-matched controls, and (ii) to examine developmental changes in cortical thickness with age from children to young adults in both groups. Significant cortical thinning was found in the participants with FASD in large areas of the bilateral middle frontal lobe, pre- and post- central areas, lateral and inferior temporal and occipital lobes compared to controls. No significant cortical thickness increases were observed for the FASD group. Cortical thinning with age in a linear model was observed in both groups, but the locations were different for each group. FASD participants showed thinning with age in the left middle frontal, bilateral precentral, bilateral precuneus and paracingulate, left inferior occipital and bilateral fusiform gyri; while controls showed decreases with age in the bilateral middle frontal gyrus, right inferior frontal gyrus, bilateral precuneus gyrus, and bilateral occipital gyrus. A battery of cognitive assessments of memory, attention, motor, and verbal abilities was conducted with many of the FASD participants, but no significant correlations were found between these cognitive scores and regional cortical thickness. Non-invasive measurements of cortical thickness in children to young adults with FASD have identified both key regions of cortex that may be more deleteriously affected by prenatal alcohol exposure as well as cortical changes with age that differ from normal developmental thinning.

Subcortical brain volumes relate to neurocognition in schizophrenia and bipolar disorder and healthy controls

BACKGROUND

Similar patterns of subcortical brain abnormalities and neurocognitive dysfunction have been demonstrated in schizophrenia and bipolar disorder, with more extensive findings in schizophrenia. It is unknown whether relationships between subcortical volumes and neurocognitive performance are similar or different between schizophrenia and bipolar disorder.

METHODS

MRI scans and neuropsychological test performance were obtained from 117 schizophrenia or 121 bipolar spectrum disorder patients and 192 healthy control subjects. Using the FreeSurfer software, volumes of 18 selected subcortical structures were automatically segmented and analyzed for relationships with results from 7 neurocognitive tests.

RESULTS

In schizophrenia, larger left ventricular volumes were related to poorer motor speed, and bilateral putamen volumes were related to poorer verbal learning, executive functioning and working memory performance. In bipolar disorder, larger left ventricular volumes were related to poorer motor speed and executive functioning. The relationship between left putamen volume and working memory was specific to schizophrenia. The relationships between left inferior lateral ventricles and motor speed and between right putamen volumes and executive functioning were similar in schizophrenia and bipolar disorder, and different from healthy controls. The results remained significant after corrections for use of antipsychotic medication. Significant structure-function relationships were also found when all subjects were combined into one group.

CONCLUSION

The present findings suggest that there are differences as well as similarities in subcortical structure/function relationships between patients with schizophrenia or bipolar disorder and healthy individuals. The observed differences further suggest that ventricular and putamen volume sizes may reflect severity of cognitive dysfunction in these disorders.