Midline brain abnormalities in established bipolar affective disorder

Exploring the impact of the interthalamic adhesion on human cognition: insights from healthy subjects and thalamic stroke patients

The interthalamic adhesion (IA) is a structure that connects the median borders of both thalami. Its anatomical variants and functions remain poorly studied. The main objective of this study was to explore the role of the IA on cognition. 42 healthy subjects and 40 patients with chronic isolated thalamic strokes underwent a neuroimaging and a neuropsychological assessment. The presence, absence, or lesion of the IA and its anatomical variants were evaluated. 76% of participants had an IA, with a higher prevalence among women (92%) than men (61%). The presence or absence of an IA did not affect the neuropsychological performance of healthy subjects nor did the type of IA variant. Across all the tests and when compared to healthy subjects using a Bayesian rmANOVA, patients exhibiting more cognitive impairments were those without an IA (n = 10, BF10 = 10,648), while those with an IA were more preserved (n = 18, BF10 = 157). More specifically, patients without an IA performed more poorly in verbal memory or the Stroop task versus healthy subjects. This was not explained by age, laterality of the infarct, volume or localization of the lesion. Patients with a lesioned IA (n = 12) presented a similar trend to patients without an IA, which could however be explained by a greater volume of lesions. The IA does not appear to play a major role in cognition in healthy subjects, but could play a compensatory role in patients with thalamic lesions.

Massa intermedia in adults: incidence, dimension, location and clinical importance

PURPOSE

This retrospective magnetic resonance imaging investigation aimed to obtain information related to the anatomy of the massa intermedia (MI) in an adult population.

METHODS

The work conducted on MRI views of 1058 (539 males and 519 females) healthy adult samples aged with 48.93 ± 17.63 years. Initially, the presence or absence of MI was noted, and then if present, its numbers and location in the third ventricle were recorded. Its horizontal (HDMI) and vertical (VDMI) diameters were measured on MRI views, while the cross-sectional area (CSAMI) was calculated using its diameters.

RESULTS

MI was missing in 2.6% (27 cases) of 1058 adult samples. Six subjects (0.6%) had a double MI. HDMI, VDMI and CSAMI were measured as 4.83 ± 1.01 mm, 4.86 ± 0.98 mm, and 19.11 ± 7.23 mm2, respectively. MI size did not show a significant alteration from 19 up to 49 years, but then its size distinctly decreased between 50 and 60 years. After age 60, MI dimension did not display an important change. MI was settled in the antero-superior quadrant in 929 cases (90.63% of 1025 subjects), in the postero-superior quadrant in 22 cases (2.15%), in the antero-inferior quadrant in 32 cases (3.12%), in the postero-inferior quadrant in 8 cases (0.78%), and in the central part in 34 cases (3.32%).

CONCLUSIONS

The size, position and incidence of MI were not affected by sex, and its position and incidence were not affected by adult age periods. In adults, MI size demonstrated a significant decrease in the middle age.

Anatomic Features of the Interthalamic Adhesion in the Pediatric Population

OBJECTIVE

The main goal of this retrospective study was to examine the morphology of the interthalamic adhesion (ITA) in normal children aged between 1 and 18 years.

METHODS

The study universe consisted of magnetic resonance images of 180 healthy pediatric subjects (age, 9.50 ± 5.20 years, sex, 90 girls and 90 boys). The cross-sectional area (CSA), vertical diameter (VD), and horizontal diameter (HD) of the ITA were measured and in addition, its location was noted.

RESULTS

HD, VD, and CSA of the ITA were measured as 8.47 ± 1.64 mm, 7.59 ± 1.57 mm, and 52.06 ± 18.51 mm2, respectively. HD did not change from infancy until postpubescence, but then significantly decreased (P < 0.001). VD increased up to early childhood but then did not alter until the end of prepubescence. After that period, it decreased in postpubescence (P < 0.001). CSA tended to decrease in an irregular pattern according to pediatric age periods (P < 0.001). The ITA was located at the anterosuperior quadrant in 138 individuals (76.70%), at the anteroinferior quadrant in 7 individuals (3.90%), and the center of the lateral wall of the third ventricle in 35 individuals (19.40%). Linear functions were calculated as y = 9.490-0.107 × age (years) for HD, y = 8.453-0.091 × age (years) for VD, and y = 63.559-1.211 × age (years) for CSA.

CONCLUSIONS

ITA size irregularly decreases with advancing age from 1 to 18 years. Our calculated linear functions, showing the growth dynamics of the ITA by pediatric ages, may be helpful in estimating its dimension.

Absence of the interthalamic adhesion (ITA) as a neuroanatomical association or risk factor for neuropsychiatric disorders: A systemic review and meta-analysis

Background

This study aimed to provide an up-to-date account of the frequency of "the absence of interthalamic adhesion (AITA) as a risk factor or association" in healthy subjects and neuropsychiatric patients. Owing to the increased interest in the contribution of ITA to neurological function in previous literature, a meta-analysis of its frequency and sex dependency is required.

Aim

This study aimed to study whether the AITA is associated with neuropsychiatric disorders.

Settings and Design

This study is a meta-analysis and systemic review.

Methods and Material

Literature searches were conducted in PubMed, Web of Science, and Google Scholar using the keywords "interthalamic adhesion," "massa intermedia," "adhesio interthalamica," and "adhesion" along with the Boolean operators (OR, AND, and NOT). Three reviewers independently assessed the abstracts and full texts for validation based on the inclusion criteria. The meta-analysis was performed using Microsoft Excel 2019 for descriptive studies and RevMan 5.2 for comparative studies.

Results

The incidence of absent ITA was 15.3% in healthy subjects and 28.76% in neuropsychiatric subjects. The relative probability of AITA was 2.30 [95% confidence interval (CI), 1.96-2.70] in neuropsychiatric illness. Healthy men were 1.91 times more likely, and men with neuropsychiatric disorders were 1.82 times more likely to have absent ITA than women.

Conclusions and Relevance

In this study, a consistent association of AITA with psychiatric disorders was observed, rendering the condition to be treated as an associated risk factor affecting the function of the habenula nuclear complex via the stria medullaris thalami. A cohort or longitudinal study is needed to compare the incidence of psychiatric disorders in individuals with or without ITA and to calculate the attributed risk.

Examining for Cavum Septum Pellucidum and Ventricular Enlargement in Retired Elite-Level Rugby League Players

Objective

A cavum septum pellucidum (CSP) has been reported as a visible brain anomaly in normal individuals as well in some former combat and collision sport athletes. The appearance of CSP with fenestrations and ventricular enlargement are considered associated features of the neuropathological diagnosis of chronic traumatic encephalopathy. The current study examined CSP anatomic features and lateral ventricle size in retired elite rugby league players and controls.

Methods

Forty-one retired rugby league players and 41 healthy community controls, similar in age and education, underwent structural MRI scans. CSP grade, CSP length, corpus callosum septal length, and Evans' ratio (for lateral ventricle size) were rated by two of the current study authors. All participants also self-reported concussion exposure histories, depressive symptoms, daytime sleepiness, and impulsivity. They completed a neuropsychological test battery assessing premorbid intellectual functioning, attention, processing speed, language, visuospatial skills, memory, and aspects of executive functioning.

Results

The two raters had high agreement for CSP grade (Cohen's κ = 0.80), CSP length [intraclass correlation (ICC) = 0.99], corpus callosum septal length (ICC = 0.73), the CSP/septal ratio (ICC = 0.99), and the Evans' ratio (ICC = 0.75). Twenty-five retired players (61.0%) had an abnormal CSP compared to 17 controls [41.5%; χ(1, 82)2 = 3.12, p = 0.08, odds ratio = 2.21]. The CSP/septal ratio was larger for retired players than for the controls. The Evans' ratio did not differ between the two groups. In the retired rugby league players (n = 41), those with normal (n = 16) and abnormal (n = 25) CSP grades did not differ across age, age of first exposure to collision sport, years of sport exposure, concussion history, or 23 clinical and cognitive variables.

Conclusion

This study revealed a difference in the size of the CSP between retired professional rugby league players and controls. There was no significant difference in the size of the ventricles between the two groups. There were no significant differences between those with vs. without an abnormal CSP on age of first exposure to rugby league, years of exposure to repetitive neurotrauma, number of lifetime concussions, depression, impulsivity, perceived cognitive decline, or on any neuropsychological test.

Prevalence of the interthalamic adhesion in the human brain: a review of literature

The interthalamic adhesion (IA) is a midline structure connecting the two thalami. Though it has been studied for centuries its exact function remains elusive. Early studies had noted its peculiar absence even among some healthy individuals. Population studies have investigated the differences in prevalence of IA in pathologic conditions and healthy controls. However, there is a general lack of consensus on IA prevalence in the healthy population. Understanding the true prevalence is critical in providing context for future studies, as well as uncovering further clues regarding IA's function. We systematically reviewed the existing literature to evaluate the prevalence of IA. The average prevalence among reviewed studies was higher than previously reported, at 87.3%. Studies utilizing magnetic resonance imaging rather than cadaveric specimens reported higher rates of IA prevalence. A higher prevalence among females was noted throughout the literature that persisted regardless of acquisition modality utilized.

The adhesio interthalamica as a neuroanatomical marker of structural differences in healthy adult population

The adhesio interthalamica (AI) is a small midline brain structure that connects the left and right thalamus. According to in vivo data, between 2.3 and 22.3% of the general population lack the AI, and the question of whether this absence is more prevalent in males than in females is a matter of debate. Despite the existence of these demographic figures, it remains unclear how this distinctive feature affects healthy people, or what specific anatomic profile is related to the presence or absence of the AI. The aim of this study was to investigate whole-brain gray matter (GM) volumetric differences depending on the presence or absence of the AI. A total of 240 healthy adult volunteers completed one MRI scanning session. After the AI assessment, the data from 110 participants were included in the final sample, of which 12.9% of the participants (n = 31) presented complete AI absence vs. 32.9% of participants (n = 79) who presented complete AI presence. Then, whole-brain group comparison analysis revealed that the absent AI brain, compared to the present AI brain, was associated with lower GM volume in the premotor cortex, inferior frontal gyrus, and anterior temporal cortex. Interestingly, neuroscience research has linked emotional and cognitive control brain processing to the latter two regions. The importance of these findings lies in providing a neuroanatomical profile for the absent AI brain in healthy human adults.

The Prevalence of Cavum Septum Pellucidum in Mental Disorders Revealed by MRI: A Meta-Analysis

OBJECTIVE

The prevalence of cavum septum pellucidum (CSP) in mental disorders, particularly schizophrenia spectrum disorders and mood disorders, remains uncertain. The authors used a meta-analytical approach to determine the prevalence of CSP in mental disorders and to compare these with the prevalence of CSP in psychiatrically healthy comparison subjects.

METHODS

PubMed and Embase were systematically searched for relevant articles published as of January 9, 2018. After a quality assessment of individual studies using the Newcastle-Ottawa Scale, a random-effects model within Stata statistical software was used to synthesize 25 eligible studies that included 2,392 patients with mental disorders and 1,445 psychiatrically healthy comparison subjects.

RESULTS

The prevalence of CSP of any size and large CSP was found to be significantly higher in individuals with mental disorders compared with healthy comparison subjects, and the prevalence of CSP in schizophrenia spectrum and mood disorders did not differ between the groups.

CONCLUSIONS

The meta-regression with predefined covariance indicated that imaging parameters were not associated with the heterogeneity among original studies; however, the mean age of enrolled subjects was identified as a possible source of heterogeneity. No publication bias was found.

Thalamic Massa Intermedia in Children with and without Midline Brain Malformations

BACKGROUND AND PURPOSE

The massa intermedia is a normal midline transventricular thalamic connection. Massa intermedia aberrations are common in schizophrenia, Chiari II malformation, X-linked hydrocephalus, Cornelia de Lange syndrome, and diencephalic-mesencephalic junction dysplasia, among others. We have noticed that massa intermedia abnormalities often accompany other midline malformations. The massa intermedia has never been formally evaluated in a group of exclusively pediatric patients, to our knowledge. We sought to compare and contrast the prevalence, size, and location of the massa intermedia in pediatric patients with and without congenital midline brain abnormalities.

MATERIALS AND METHODS

Successive 3T brain MR imaging examinations from pediatric patients with and without midline malformations were procured from the imaging data base at a pediatric hospital. Massa intermedia presence, size, morphology, and position were determined using 3D-TIWI with 1-mm isotropic resolution. The brain commissures, septum pellucidum, hypothalamus, hippocampus, vermis, and brain stem were evaluated to determine whether alterations were related to or predictive of massa intermedia abnormalities.

RESULTS

The massa intermedia was more frequently absent, dysmorphic, and/or displaced in patients with additional midline abnormalities than in those without. The massa intermedia was absent in 40% of patients with midline malformations versus 12% of patients with normal findings (P < .001). Massa intermedia absence, surface area, and morphology were predictable by various attributes and alterations of the commissures, hippocampus, hypothalamus, vermis, brain stem, and third ventricle.

CONCLUSIONS

Most pediatric patients have a thalamic massa intermedia centered in the anterior/superior third ventricle. Massa intermedia abnormalities are commonly associated with other midline malformations. Normal-variant massa intermedia absence is a diagnosis of exclusion.

Neuroanatomical Risk Factors for Posttraumatic Stress Disorder in Recent Trauma Survivors

BACKGROUND

Low hippocampal volume could serve as an early risk factor for posttraumatic stress disorder (PTSD) in interaction with other brain anomalies of developmental origin. One such anomaly may well be the presence of a large cavum septum pellucidum (CSP), which has been loosely associated with PTSD. We performed a longitudinal prospective study of recent trauma survivors. We hypothesized that at 1 month after trauma exposure the relation between hippocampal volume and PTSD symptom severity will be moderated by CSP volume, and that this early interaction will account for persistent PTSD symptoms at subsequent time points.

METHODS

One hundred seventy-one adults (87 women, average age 34.22 years [range, 18-65 years of age]) who were admitted to a general hospital's emergency department after a traumatic event underwent clinical assessment and structural magnetic resonance imaging within 1 month after trauma. Follow-up clinical evaluations were conducted at 6 (n = 97) and 14 (n = 78) months after trauma. Hippocampal and CSP volumes were measured automatically by FreeSurfer software and verified manually by a neuroradiologist (D.N.).

RESULTS

At 1 month after trauma, CSP volume significantly moderated the relation between hippocampal volume and PTSD severity (p = .026), and this interaction further predicted symptom severity at 14 months posttrauma (p = .018). Specifically, individuals with a smaller hippocampus and larger CSP at 1 month posttrauma showed more severe symptoms at 1 and 14 months after trauma exposure.

CONCLUSIONS

Our study provides evidence for an early neuroanatomical risk factors for PTSD, which could also predict the progression of the disorder in the year after trauma exposure. Such a simple-to-acquire neuroanatomical signature for PTSD could guide early management as well as long-term monitoring.

Cavum Septum Pellucidum in the General Pediatric Population and Its Relation to Surrounding Brain Structure Volumes, Cognitive Function, and Emotional or Behavioral Problems

BACKGROUND AND PURPOSE

The cavum septum pellucidum, a cavity filled with CSF, is localized between the 2 lateral ventricles of the brain. The cavum is present in all neonates, but it typically closes within 5 months after birth. In some cases, this closure does not occur and a persistent or enlarged cavum septum pellucidum has been linked, in some studies, to psychiatric disorders. However, the clinical relevance in the general population is unknown. In this study, we examined the relationship between the cavum septum pellucidum and volumes of brain structures, cognitive function, and emotional and behavioral problems in children.

MATERIALS AND METHODS

This study was embedded in the Generation R Study, a prospective cohort in Rotterdam, the Netherlands. MR imaging studies of 1070 children, 6-10 years of age, were systematically evaluated for the presence and length of a persistent cavum septum pellucidum. An enlarged cavum septum pellucidum was defined as a cavum length of ≥6 mm. Groups without, with persistent, and with enlarged cavum septi pellucidi were compared for brain structure volumes, nonverbal intelligence, and emotional and behavioral problems.

RESULTS

The prevalence of cavum septi pellucidi in our sample was 4.6%. Children with an enlarged cavum septum pellucidum had a larger corpus callosum, greater thalamic and total white matter-to-total brain volume ratio, and smaller lateral ventricle volumes. We did not find a relationship between cavum septi pellucidi and cognitive function or emotional and behavioral problems.

CONCLUSIONS

The cavum septum pellucidum is a normal structural brain variation without clinical implications in this population-based sample of school-aged children.

Meta-analyses of cavum septum pellucidum in mood disorders in comparison with healthy controls or schizophrenia

The cavum septum pellucidum (CSP) is a neurodevelopmental abnormality significantly more prevalent in subjects with schizophrenia (SCZ) than in healthy controls (HC). Using meta-analyses, we tested the hypotheses whether CSP would be more frequent in subjects with mood disorders when compared with HC or SCZ. We performed a search in MEDLINE and EMBASE followed by 10 meta-analyses of magnetic resonance imaging studies which examined the association of CSP in bipolar disorders (BD), major depressive disorder (MDD) or mood disorders (MD; considering MDD and BD combined) with either HC or SCZ. Nine studies were included, comprising 692 cases (363 with BD, 182 with MDD and 147 with MD), 463 with SCZ and 630 HC. CSP of any size was significantly associated with BD (OR = 2.07, 95% CI: 1.48-2.90) when compared with HC. Large CSP showed a trend to be associated with BD when compared with HC, but the association was not statistically significant (OR = 1.92, 95% CI 0.64-5.78). Large CSP was significantly associated with subjects with SCZ when compared with subjects with MD (OR = 0.57, 95% CI: 0.36-0.92). There was no association between CSP and MDD in comparison to HC or subjects with SCZ. Cortical structures are known to be altered in mood disorders. The present metanalysis found that certain midline brain abnormalities, such as CSP, are also associated with BD.

Brain morphologic changes in early stages of psychosis: Implications for clinical application and early intervention

To date, a large number of magnetic resonance imaging (MRI) studies have been conducted in schizophrenia, which generally demonstrate gray matter reduction, predominantly in the frontal and temporo-limbic regions, as well as gross brain abnormalities (e.g., a deviated sulcogyral pattern). Although the causes as well as timing and course of these findings remain elusive, these morphologic changes (especially gross brain abnormalities and medial temporal lobe atrophy) are likely present at illness onset, possibly reflecting early neurodevelopmental abnormalities. In addition, longitudinal MRI studies suggest that patients with schizophrenia and related psychoses also have progressive gray matter reduction during the transition period from prodrome to overt psychosis, as well as initial periods after psychosis onset, while such changes may become almost stable in the chronic stage. These active brain changes during the early phases seem to be relevant to the development of clinical symptoms in a region-specific manner (e.g., superior temporal gyrus atrophy and positive psychotic symptoms), but may be at least partly ameliorated by antipsychotic medication. Recently, increasing evidence from MRI findings in individuals at risk for developing psychosis has suggested that those who subsequently develop psychosis have baseline brain changes, which could be at least partly predictive of later transition into psychosis. In this article, we selectively review previous MRI findings during the course of psychosis and also refer to the possible clinical applicability of these neuroimaging research findings, especially in the diagnosis of schizophrenia and early intervention for psychosis.

Brain change trajectories that differentiate the major psychoses

BACKGROUND

Bipolar disorder and schizophrenia are highly heritable, often chronic and debilitating psychotic disorders that can be difficult to differentiate clinically. Their brain phenotypes appear to overlap in both cross-sectional and longitudinal structural neuroimaging studies, with some evidence to suggest areas of differentiation with differing trajectories. The aim of this review was to investigate the notion that longitudinal trajectories of alterations in brain structure could differentiate the two disorders.

DESIGN

Narrative review. We searched MEDLINE and Web of Science databases in May 2016 for studies that used structural magnetic resonance imaging to investigate longitudinal between-group differences in bipolar disorder and schizophrenia. Ten studies met inclusion criteria, namely longitudinal structural magnetic resonance studies comparing bipolar disorder (or affective psychosis) and schizophrenia within the same study.

RESULTS

Our review of these studies implicates illness-specific trajectories of morphological change in total grey matter volume, and in regions of the frontal, temporal and cingulate cortices. The findings in schizophrenia suggest a trajectory involving progressive grey matter loss confined to fronto-temporal cortical regions. Preliminary findings identify a similar but less severely impacted trajectory in a number of regions in bipolar disorder, however, bipolar disorder is also characterized by differential involvement across cingulate subregions.

CONCLUSION

The small number of available studies must be interpreted with caution but provide initial evidence supporting the notion that bipolar disorder and schizophrenia have differential longitudinal trajectories that are influenced by brain maturation.

3D shape analysis of the brain's third ventricle using a midplane encoded symmetric template model

BACKGROUND

Structural changes of the brain's third ventricle have been acknowledged as an indicative measure of the brain atrophy progression in neurodegenerative and endocrinal diseases. To investigate the ventricular enlargement in relation to the atrophy of the surrounding structures, shape analysis is a promising approach. However, there are hurdles in modeling the third ventricle shape. First, it has topological variations across individuals due to the inter-thalamic adhesion. In addition, as an interhemispheric structure, it needs to be aligned to the midsagittal plane to assess its asymmetric and regional deformation.

METHOD

To address these issues, we propose a model-based shape assessment. Our template model of the third ventricle consists of a midplane and a symmetric mesh of generic shape. By mapping the template's midplane to the individuals' brain midsagittal plane, we align the symmetric mesh on the midline of the brain before quantifying the third ventricle shape. To build the vertex-wise correspondence between the individual third ventricle and the template mesh, we employ a minimal-distortion surface deformation framework. In addition, to account for topological variations, we implement geometric constraints guiding the template mesh to have zero width where the inter-thalamic adhesion passes through, preventing vertices crossing between left and right walls of the third ventricle. The individual shapes are compared using a vertex-wise deformity from the symmetric template.

RESULTS

Experiments on imaging and demographic data from a study of aging showed that our model was sensitive in assessing morphological differences between individuals in relation to brain volume (i.e. proxy for general brain atrophy), gender and the fluid intelligence at age 72. It also revealed that the proposed method can detect the regional and asymmetrical deformation unlike the conventional measures: volume (median 1.95ml, IQR 0.96ml) and width of the third ventricle. Similarity measures between binary masks and the shape model showed that the latter reconstructed shape details with high accuracy (Dice coefficient ≥0.9, mean distance 0.5mm and Hausdorff distance 2.7mm).

CONCLUSIONS

We have demonstrated that our approach is suitable to morphometrical analyses of the third ventricle, providing high accuracy and inter-subject consistency in the shape quantification. This shape modeling method with geometric constraints based on anatomical landmarks could be extended to other brain structures which require a consistent measurement basis in the morphometry.

Midline Brain Abnormalities Across Psychotic and Mood Disorders

Patients with schizophrenia are known to have increased prevalence of abnormalities in midline brain structures, such as a failure of the septum pellucidum to fuse (cavum septum pellucidum) and the absence of the adhesio interthalamica. This is the first study to investigate the prevalence of these abnormalities across a large multidiagnostic sample. Presence of cavum septum pellucidum and absence of the adhesio interthalamica was assessed in 639 patients with chronic schizophrenia, delusional disorder, schizoaffective disorder, bipolar disorder, major depressive disorder, or a first episode of psychosis, mania or unipolar depression. This was compared with 223 healthy controls using logistic-regression-derived odds ratios (OR). Patients with psychotic or mood disorders showed an increased prevalence of both abnormalities (OR of cavum septum pellucidum = 2.1, OR of absence of the adhesio interthalamica = 2.6, OR of both cavum septum pellucidum and absence of the adhesio interthalamica = 3.8, all P < .001). This increased prevalence was separately observed in nearly all disorders as well as after controlling for potential confounding factors. This study supports a general increased prevalence of midline brain abnormalities across mood and psychotic disorders. This nonspecificity may suggest that these disorders share a common neurodevelopmental etiology.

Prevalence of cavum vergae in psychosis and mood spectrum disorders

BACKGROUND

Midline brain abnormalities might increase susceptibility to both first-episode and chronic mental disorder. Evidence of cavum vergae (CV) abnormality in mental disorders is scarce.

METHODS

The presence of CV was assessed by a researcher blind to clinical information in a cross-disorder sample of 639 patients with mood and psychotic disorders and in 223 healthy controls. Homogeneous magnetic resonance imaging methods of acquisition and assessment were applied.

RESULTS

Seven out of 639 patients with mood or psychotic disorders were detected with CV which corresponds to a prevalence of 1.1%. There were no concurrent cases of CV in the healthy control group. Identified cases which are briefly described were diagnosed from bipolar I disorder (n=2), delusional disorder (n=1), brief psychotic disorder (n=1) and schizoaffective disorder (n=3). Patients with CV had descriptively lower current IQ, executive functioning and memory scores in relation to patients without CV but this was not statistically significant.

LIMITATIONS

Effects of medication and lack of statistical power of the CV patient group.

CONCLUSIONS

Midline brain abnormalities, such as CV, might represent an unspecific risk factor for the development of severe mental disorders.

Olfactory sulcus morphology in established bipolar affective disorder

This MRI study examined the morphology of the olfactory sulcus, a potential marker of early neurodevelopment in 26 patients with bipolar I disorder and 24 matched controls. Bipolar patients had significantly shallower olfactory sulci bilaterally compared to controls, suggesting that neurodevelopmental abnormalities contribute to the neurobiology of bipolar disorder.

A developmental study on the neural circuitry mediating response flexibility in bipolar disorder

Cross-sectional neuroimaging studies are an important first step in examining developmental differences in brain function between adults and youth with bipolar disorder (BD). Impaired response flexibility may contribute to reduced ability to modify goal-directed behavior in BD appropriately. We compared neural circuitry mediating this process in child (CBD) vs. adult BD (ABD) and age-matched healthy subjects. fMRI data from 15 CBD, 23 ABD, 20 healthy children, and 27 healthy adults were acquired during a response flexibility paradigm, a task where subjects inhibit a prepotent response and execute an alternative response. When successfully executing an alternate response, CBD showed frontal, parietal, and temporal hyperactivation relative to healthy children and ABD, while ABD hypoactivated these regions relative to healthy adults. Previous studies of response flexibility in healthy volunteers revealed frontal, temporal, and parietal cortex hyperactivation in children and hypoactivation in adults. Relative to age-matched healthy subjects, we found hyperactivation in these regions in CBD and hypoactivation in ABD. This suggests that our findings in patients may represent the extreme extension of the age-related response flexibility activation differences found in healthy subjects. Future studies should use longitudinal fMRI to examine the developmental trajectory of the neural circuitry mediating response flexibility in BD.

Effects of medication on neuroimaging findings in bipolar disorder: an updated review

OBJECTIVE

Neuroimaging is an important tool for better understanding the neurobiological underpinnings of bipolar disorder (BD). However, potential study participants are often receiving psychotropic medications which can possibly confound imaging data. To better interpret the results of neuroimaging studies in BD, it is important to understand the impact of medications on structural magnetic resonance imaging (sMRI), functional MRI (fMRI), and diffusion tensor imaging (DTI).

METHODS

To better understand the impact of medications on imaging data, we conducted a literature review and searched MEDLINE for papers that included the key words bipolar disorder and fMRI, sMRI, or DTI. The search was limited to papers that assessed medication effects and had not been included in a previous review by Phillips et al. (Medication effects in neuroimaging studies of bipolar disorder. Am J Psychiatry 2008; 165: 313-320). This search yielded 74 sMRI studies, 46 fMRI studies, and 15 DTI studies.

RESULTS

Medication appeared to influence many sMRI studies, but had limited impact on fMRI and DTI findings. From the structural studies, the most robust finding (20/45 studies) was that lithium was associated with increased volumes in areas important for mood regulation, while antipsychotic agents and anticonvulsants were generally not. Regarding secondary analysis of the medication effects of fMRI and DTI studies, few showed significant effects of medication, although rigorous analyses were typically not possible when the majority of subjects were medicated. Medication effects were more frequently observed in longitudinal studies designed to assess the impact of particular medications on the blood oxygen level-dependent (BOLD) signal. With a few exceptions, the observed effects were normalizing, meaning that the medicated individuals with BD were more similar than their unmedicated counterparts to healthy subjects.

CONCLUSIONS

The effects of psychotropic medications, when present, are predominantly normalizing and thus do not seem to provide an alternative explanation for differences in volume, white matter tracts, or BOLD signal between BD participants and healthy subjects. However, the normalizing effects of medication could obfuscate differences between BD and healthy subjects, and thus might lead to type II errors.

Adhesio interthalamica alterations in schizophrenia spectrum disorders: A systematic review and meta-analysis

Magnetic resonance imaging (MRI) studies have reported a variety of brain abnormalities in association with schizophrenia. These include a higher prevalence of an absent adhesio interthalamica (AI; also known massa intermedia), a gray matter junction that is present between the two thalami in approximately 80% of healthy subjects. In this meta-analytic review, we describe and discuss the main AI MRI findings in schizophrenia spectrum disorders (SSDs) to date. The MEDLINE and ISI Web of Knowledge databases were searched up to December 2010, for studies that used MRI to assess AI in patients with SSD and controls. From fourteen potential reports, eleven were eligible to be part of the current review. These studies included 822 patients with SSD and 718 healthy volunteers. There was a large degree of variability in the MRI methods they employed. Patients with SSD had a higher prevalence of absent AI than healthy volunteers (odds ratio = 1.98; 95% confidence interval 1.33-2.94; p = 0.0008). This association was evident in both male and female SSD subjects, and there was no evidence that the prevalence was related to age or duration of illness. The significance of the absence of an AI for SSD may be clarified by studies in large, longitudinal community-based samples using standardized methods.

A morphometric analysis of the septal nuclei in schizophrenia and affective disorders: reduced neuronal density in the lateral septal nucleus in bipolar disorder

The septal nuclei are assumed to play a significant role in the pathophysiology of schizophrenia and affective disorders. The aim of this study was to morphometrically characterize the septal nuclei in patients with schizophrenia, bipolar disorder, and major depressive disorder, when compared with healthy control subjects. We analyzed the septal nuclei by determining the density and size of the neurons in postmortem brains in 17 patients with schizophrenia, 8 patients with bipolar disorder, 7 patients with major depressive disorder, and 14 control subjects matched for age and gender. There was a significant reduction in the neuronal density, but not in the mean cross-sectional area, in the lateral septal nucleus (P = 0.013) in patients with bipolar disorder when compared with control subjects. There were no significant changes in the neuronal density of the septal nuclei of the medial and lateral cell groups in patients with schizophrenia and major depressive disorder when compared with control subjects. There was a significant negative correlation between neuronal density in the lateral septal nucleus and disease duration in patients with major depressive disorder (P = 0.037, r = -0.9). The histopathological abnormality of the decreased neuronal density in the lateral septal nucleus, which is an important limbic region involved in emotions, might be a neuropathological correlate of bipolar disorder.