Sheila C. Caetano

Smaller cingulate volumes in unipolar depressed patients

BACKGROUND The anterior cingulate cortex is a key structure in brain networks involved in mood regulation. Abnormalities in this brain region are possibly implicated in the pathophysiology of depression. This anatomical magnetic resonance imaging (MRI) study compared cingulate cortex volumes in unipolar depressed patients and age- and gender-matched healthy control subjects. METHODS Thirty-one unmedicated DSM-IV unipolar patients (24 female, aged 39.2 +/- 11.9 years [mean +/- SD]) and 31 healthy control subjects (24 female, aged 36.7 +/- 10.7 years) were studied in a 1.5-T GE Signa magnet (General Electric Medical Systems, Milwaukee, Wisconsin). Cingulate volumes were compared by analysis of covariance with intracranial volume as the covariate. RESULTS The unipolar patients had significantly smaller anterior and posterior cingulate volumes bilaterally compared with healthy control subjects. When patients were divided into currently depressed (n = 21) and remitted (n = 10) subgroups, currently depressed patients had significantly smaller anterior and posterior cingulate volumes bilaterally compared with healthy control subjects, whereas remitted patients had significantly smaller left anterior cingulate volumes compared with healthy individuals. CONCLUSIONS Gray matter abnormalities in the cingulate cortex are implicated in the pathophysiology of unipolar depression. Smaller cingulate volumes in currently depressed patients support the hypothesis that cingulate cortex abnormalities are state dependent, whereas changes in left anterior cingulate might be trait related.

MRI study of thalamic volumes in bipolar and unipolar patients and healthy individuals

The thalamus is a key structure in brain anatomic circuits potentially involved in the pathophysiology of mood disorders. Available findings from studies that examined this brain region in mood disorder patients have been conflicting. To examine the hypothesis of anatomical abnormalities in the thalamus in patients with mood disorders, we conducted a magnetic resonance imaging (MRI) study in 25 bipolar patients (mean age+/-S.D.=34.4+/-9.8 years), 17 unipolar patients (mean age+/-S.D.=42.8+/-9.2 years), and 39 healthy control subjects (mean age+/-S.D.=36.6+/-9.7 years). Thalamic volumes Gray Matter were measured blindly with a semi-automated technique. Multivariate analysis of variance, with age and gender as covariates, revealed no significant differences in left or right thalamic volumes among bipolar patients, unipolar patients and healthy individuals. There were no significant effects of gender, age at illness onset, episode type, number of episodes, length of illness, or family history of mood disorders on thalamic measurements. Although functional abnormalities in the thalamus are likely to be implicated in the pathophysiology of mood disorders, no abnormalities in thalamic size appear present in bipolar or unipolar individuals.

Prefrontal gray matter increases in healthy individuals after lithium treatment: A voxel-based morphometry study

The objective of this study was to test the hypothesis that 4 weeks of lithium administration would be associated with changes in brain gray and white matter volumes in healthy individuals. Thirteen right-handed healthy volunteers (6 females, mean age=25.9+/-10.0 years) were studied. 3D SPGR MRIs (TR=25 ms, TE=5 ms, slice-thickness=1.5 mm) were acquired using a 1.5 T GE Signa Imaging System, at baseline and after 4 weeks of lithium administration at therapeutically relevant doses. Optimized voxel-based morphometry (VBM) analyses were conducted. Left and right dorsolateral prefrontal cortex and left anterior cingulate gray matter volumes increased significantly following lithium administration. Total white matter volume was increased, whereas total brain volume and total gray matter volume were not significantly changed following 4 weeks of lithium. Lithium treatment resulted in prefrontal regional gray matter volume increases in healthy volunteers, as well as increases in total white matter volume. Whether these changes are mediated by neurotrophic/neuroprotective or osmotic effects remains unknown.

Facial emotion recognition in bipolar disorder: a critical review

OBJECTIVE Literature review of the controlled studies in the last 18 years in emotion recognition deficits in bipolar disorder. METHOD A bibliographical research of controlled studies with samples larger than 10 participants from 1990 to June 2008 was completed in Medline, Lilacs, PubMed and ISI. Thirty-two papers were evaluated. RESULTS Euthymic bipolar disorder presented impairment in recognizing disgust and fear. Manic BD showed difficult to recognize fearful and sad faces. Pediatric bipolar disorder patients and children at risk presented impairment in their capacity to recognize emotions in adults and children faces. Bipolar disorder patients were more accurate in recognizing facial emotions than schizophrenic patients. DISCUSSION Bipolar disorder patients present impaired recognition of disgust, fear and sadness that can be partially attributed to mood-state. In mania, they have difficult to recognize fear and disgust. Bipolar disorder patients were more accurate in recognizing emotions than depressive and schizophrenic patients. Bipolar disorder children present a tendency to misjudge extreme facial expressions as being moderate or mild in intensity. CONCLUSION Affective and cognitive deficits in bipolar disorder vary according to the mood states. Follow-up studies re-testing bipolar disorder patients after recovery are needed in order to investigate if these abnormalities reflect a state or trait marker and can be considered an endophenotype. Future studies should aim at standardizing task and designs.

Proton spectroscopy study of the left dorsolateral prefrontal cortex in pediatric depressed patients

The dorsolateral prefrontal cortex (DLPFC) plays an essential role in mood regulation and integration of cognitive functions that are abnormal in major depressive disorder (MDD). Few neuroimaging studies have evaluated the still maturing DLPFC in depressed children and adolescents. We conducted single voxel proton magnetic resonance spectroscopy ((1)H MRS) of the left DLPFC in 14 depressed children and adolescents (13.3 +/- 2.3 years old, 10 males) and 22 matched healthy controls (13.6 +/- 2.8 years old, 13 males). Depressed subjects had significantly lower levels of glycerophosphocholine plus phosphocholine (GPC + PC; or choline-containing compounds) and higher myo-inositol levels in the left DLPFC compared to healthy controls. In the depressed subjects, we found significant inverse correlations between glutamate levels and both duration of illness and number of episodes. In healthy controls there was a significant direct correlation between age and glutamine levels, which was not present in the patient group. Lower GPC + PC levels in pediatric MDD may reflect lower cell membrane content per volume in the DLPFC. Increased myo-inositol levels in MDD may represent a disturbed secondary messenger system. GPC + PC and myo-inositol abnormalities further demonstrate the involvement of DLPFC in pediatric MDD.

Medial temporal lobe abnormalities in pediatric unipolar depression

In vivo anatomical magnetic resonance imaging (MRI) studies in adults with major depressive disorder (MDD) have implicated neurocircuitries involved in mood regulation in the pathophysiology of mood disorders. Specifically, abnormalities in the medial temporal lobe structures have been reported. This study examined a sample of children and adolescents with major depressive disorder to investigate anatomical abnormalities in these key medial temporal brain regions. Nineteen children and adolescents with DSM-IV major depression (mean age +/- S.D.=13.0 +/- 2.4 years; 10 unmedicated) and 24 healthy comparison subjects (mean age +/- S.D.=13.9 +/- 2.9 years) were studied using a 1.5T Philips MRI scanner. We measured hippocampus and amygdala gray matter volumes. MRI structural volumes were compared using analysis of covariance with age and total brain volumes as covariates. Pediatric depressed patients had significantly smaller left hippocampal gray matter volumes compared to healthy controls (1.89 +/- 0.16 cm(3) versus 1.99 +/- 0.18 cm(3), respectively; F=5.0, d.f.=1/39, p=0.03; effect size: eta2(p) =0.11). Unmedicated depressed patients showed a trend towards smaller left hippocampal volumes compared to medicated patients and healthy subjects (F=2.8, d.f.=2/38, p=0.07; effect size: eta2(p) =0.13). There were no statistically significant differences in mean volumes for left or right amygdala. Smaller left hippocampal volumes in children and adolescents with MDD are in agreement with findings from adult studies and suggest that such abnormalities are present early in the course of the illness. Amygdala volumes are not abnormal in this age group. Smaller hippocampal volumes may be related to an abnormal developmental process or HPA axis dysfunction.

Anatomical measurements of the orbitofrontal cortex in child and adolescent patients with bipolar disorder

Imaging studies indicate smaller orbitofrontal cortex (OFC) volume in mood disorder patients compared with healthy subjects. We sought to determine whether child and adolescent patients with bipolar disorder have smaller OFC volumes than healthy controls. Fourteen children and adolescents meeting DSM-IV criteria for bipolar disorder (six males and eight females with a mean age+/-S.D.=15.5+/-3.2 years) and 20 healthy controls (11 males and nine females with mean age+/-S.D.=16.9+/-3.8 years) were studied. Orbitofrontal cortex volume was measured using magnetic resonance imaging. Male bipolar patients had smaller gray matter volumes in medial (p=0.044), right medial (0.037) and right (p=0.032) lateral OFC subdivisions compared to male controls. In contrast, female patients had larger gray matter volumes in left (p=0.03), lateral (p=0.012), left lateral (p=0.007), and trends for larger volumes in right lateral and left medial OFC subdivisions compared with female controls. Male patients exhibit smaller gray matter volumes, while female patients exhibit larger volumes in some OFC sub-regions. Gender differences in OFC abnormalities may be involved in illness pathophysiology among young bipolar patients.

Striatal volume abnormalities in treatment-naïve patients diagnosed with pediatric major depressive disorder.

OBJECTIVE The striatum, including the putamen and caudate, plays an important role in executive and emotional processing and may be involved in the pathophysiology of mood disorders. Few studies have examined structural abnormalities of the striatum in pediatric major depressive disorder (MDD) patients. We report striatal volume abnormalities in medication-naïve pediatric MDD compared to healthy comparison subjects. METHOD Twenty seven medication-naïve pediatric Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) MDD and 26 healthy comparison subjects underwent volumetric magnetic resonance imaging (MRI). The putamen and caudate volumes were traced manually by a blinded rater, and the patient and control groups were compared using analysis of covariance adjusting for age, sex, intelligence quotient, and total brain volumes. RESULTS MDD patients had significantly smaller right striatum (6.0% smaller) and right caudate volumes (7.4% smaller) compared to the healthy subjects. Left caudate volumes were inversely correlated with severity of depression in MDD subjects. Age was inversely correlated with left and right putamen volumes in MDD patients but not in the healthy subjects. CONCLUSIONS These findings provide fresh evidence for abnormalities in the striatum of medication-naïve pediatric MDD patients and suggest the possible involvement of the striatum in the pathophysiology of MDD.

Fronto-limbic brain abnormalities in juvenile onset bipolar disorder

BACKGROUND Advances in brain imaging techniques and cognitive neuropsychology have brought new possibilities for the in vivo study of the pathophysiology of neuropsychiatric disorders, including bipolar disorder (BD). Recently, such studies have been extended to the pediatric age range. Here we review the neuroimaging and neuropsychological studies conducted in BD children and adolescents. METHODS A review of the peer-reviewed published literature was conducted in Medline for the period of 1966 to April 2005. RESULTS Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) studies suggest abnormalities in fronto-limbic structures in pediatric BD patients, similar to those found in adults. A notable exception in pediatric BD patients is smaller amygdala volumes compared to healthy controls, contrary to what has been reported in most adult studies. CONCLUSIONS Further research evaluating children and adolescents is needed to study the normal neurodevelopmental process and to answer how and when the illness processes that result in bipolar disorder exert their effects on the developing brain.

Normal metabolite levels in the left dorsolateral prefrontal cortex of unmedicated major depressive disorder patients: A single voxel 1H spectroscopy study

Few proton magnetic resonance spectroscopy ((1)H spectroscopy) studies have investigated the dorsolateral prefrontal cortex (DLPFC), a key region in the pathophysiology of major depressive disorder (MDD). We used (1)H spectroscopy to verify whether MDD patients differ from healthy controls (HC) in metabolite levels in this brain area. Thirty-seven unmedicated DSM-IV MDD patients were compared with 40 HC. Subjects underwent a short echo-time (1)H spectroscopy examination at 1.5 T, with an 8-cm(3) single voxel placed in the left DLPFC. Reliable absolute metabolite levels of N-acetyl aspartate (NAA), phosphocreatine plus creatine (PCr+Cr), choline-containing compounds (GPC+PC), myo-inositol, glutamate plus glutamine (Glu+Gln), and glutamate were obtained using the unsuppressed water signal as an internal reference. Metabolite levels in the left DLPFC did not statistically differ between MDD patients and HC. We found an interaction between gender and diagnosis on PCr+Cr levels. Male MDD patients presented lower levels of PCr+Cr than male HC, and female MDD patients presented higher levels of PCr+Cr than female HC. Moreover, length of illness was inversely correlated with NAA levels. These findings suggest that there is not an effect of diagnosis on the left DLPFC neurochemistry. Possible effects of gender on PCr+Cr levels of MDD patients need to be further investigated.