A magnetic resonance imaging study of putamen nuclei in major depression

Focal and lateralized subcortical abnormalities in unipolar major depressive disorder: an automated multivoxel proton magnetic resonance spectroscopy study

BACKGROUND

The results of prior proton magnetic resonance spectroscopy ((1)H-MRS) studies in unipolar major depressive disorder (MDD) evaluating choline (Cho)/creatine (Cr) and N-acetyl-L-aspartate (NAA)/Cr ratios are mixed. These single-voxel or one-dimensional chemical-shift imaging (CSI) nonautomated (1)H-MRS studies has been unable to evaluate global or lateralized abnormalities in neuronal or membrane function. Using automated multivoxel two-dimensional CSI (1)H-MRS techniques, we tested the hypothesis that patients with MDD have focal neuronal and membrane abnormalities localized in the subcortical region.

METHODS

Whole brain and subcortical measures of Cho, NAA, Cr, and myo-inositol (mI) were obtained in 18 patients with MDD and 20 control subjects using automated two-dimensional CSI (1)H-MRS.

RESULTS

Compared with control subjects, MDD patients had a significantly lower mean NAA/Cr amplitude in the caudate and a significantly higher mean Cho/Cr amplitude in the putamen, particularly on the right side. No differences were observed for global whole brain measurements.

CONCLUSIONS

The findings support reduced neuronal viability or function in the caudate and altered membrane phospholipid metabolism in the putamen for patients with MDD. Our results are consistent with prior magnetic resonance imaging, positron emission tomography, and postmortem reports of focal and lateralized abnormalities of the basal ganglia in MDD.

Choice of cross size in stereology--a cautionary note

The stereological method of cross-counting based on the Cavalieri principle is widely used in neuroimaging to estimate the volume of cerebral structures. Although superficially simple, the stereological technique is validated by arcane mathematical proofs, so the cross size is determined by most investigators on a pragmatic basis with the assumption that the volume calculated is independent of the cross size used. We used three cross sizes (8x8, 5x5 and 3x3 voxels) to estimate the brain volume of six healthy control subjects. The volume estimate using a cross size of 3x3 was 9% larger than with a cross size of 5x5 and the latter was 15% larger than with a cross size of 8x8. We conclude that cross size significantly affects whole brain volume estimates and this result is presumably applicable to other structures whose cross-sectional areas form complex shapes. Investigators should be aware of this fact, especially when trying to make direct comparisons between volume estimates derived from the stereological method using different cross sizes.

Neurobiology of emotion perception II: Implications for major psychiatric disorders

To date, there has been little investigation of the neurobiological basis of emotion processing abnormalities in psychiatric populations. We have previously discussed two neural systems: 1) a ventral system, including the amygdala, insula, ventral striatum, ventral anterior cingulate gyrus, and prefrontal cortex, for identification of the emotional significance of a stimulus, production of affective states, and automatic regulation of emotional responses; and 2) a dorsal system, including the hippocampus, dorsal anterior cingulate gyrus, and prefrontal cortex, for the effortful regulation of affective states and subsequent behavior. In this critical review, we have examined evidence from studies employing a variety of techniques for distinct patterns of structural and functional abnormalities in these neural systems in schizophrenia, bipolar disorder, and major depressive disorder. In each psychiatric disorder, the pattern of abnormalities may be associated with specific symptoms, including emotional flattening, anhedonia, and persecutory delusions in schizophrenia, prominent mood swings, emotional lability, and distractibility in bipolar disorder during depression and mania, and with depressed mood and anhedonia in major depressive disorder. We suggest that distinct patterns of structural and functional abnormalities in neural systems important for emotion processing are associated with specific symptoms of schizophrenia and bipolar and major depressive disorder.

Neuroimaging studies of mood disorder effects on the brain

Studies of early-onset recurrent depression, late life depression associated with neurologic disorders, and bipolar illness have revealed structural brain changes within a neuroanatomical circuit. This circuit, originally described by, has been termed the limbic-cortical-striatal-pallidal-thalamic tract and is comprised of structures which are extensively interconnected. In three-dimensional magnetic resonance imaging studies of affective illness, many of the structures that comprise this tract have been found to have volume loss or structural abnormalities. Mechanisms proposed to explain volume loss in depression include glucocorticoid neurotoxicity, decreased brain-derived growth factor, decreased neurogenesis, and loss of plasticity.

Rapid stereological quantitation of temporal neocortex in TLE

To determine the extent of neocortical atrophy in the temporal lobe using rapid stereological analysis of magnetic resonance slices in patients with temporal lobe epilepsy and to compare the findings to those obtained by visual analysis of high-resolution magnetic resonance images. 25 patients with temporal lobe epilepsy, along with 25 age-matched controls were scanned using a 1.5 Tesla magnetic resonance imaging machine (GE signa systems Paris). Visual analysis was performed on standard high-resolution images. Volumetric analysis of hippocampus and temporal neocortex was performed using computer-aided stereology (MEASURE program, Patrick Barta, Johns Hopkins, Baltimore, USA). Stereological volumetric analysis demonstrated isolated hippocampal atrophy in only nine (36%) cases including three (12%) with bilateral disease. However, eight (32%) cases had combined hippocampal and neocortical atrophy and three (12%) had isolated neocortical atrophy. All volumetric measurements took less than 10 min. On the other hand, visual analysis suggested that 17 (68%) had hippocampal atrophy alone with only two (8%) having combined neocortical atrophy and a further two (8%) having isolated neocortical atrophy. Nearly half of the patients had temporal neocortical atrophy with or without hippocampal atrophy. This rapid, accurate and non-biased quantitative technique has wide clinical utility and is significantly more valuable in detecting neocortical atrophy than visual analysis alone. The results support the notion that abnormalities may be overlooked by current standards of routine magnetic resonance imaging.

Enhancing neuronal plasticity and cellular resilience to develop novel, improved therapeutics for difficult-to-treat depression

There is growing evidence from neuroimaging and ostmortem studies that severe mood disorders, which have traditionally been conceptualized as neurochemical disorders, are associated with impairments of structural plasticity and cellular resilience. It is thus noteworthy that recent preclinical studies have shown that critical molecules in neurotrophic signaling cascades (most notably cyclic adenosine monophosphate [cAMP] response element binding protein, brain-derived neurotrophic factor, bcl-2, and mitogen activated protein [MAP] kinases) are long-term targets for antidepressant agents and antidepressant potentiating modalities. This suggests that effective treatments provide both trophic and neurochemical support, which serves to enhance and maintainnormal synaptic connectivity, thereby allowing the chemical signal to reinstate the optimal functioning of critical circuits necessary for normal affective functioning. For many refractory patients, drugs mimicking "traditional" strategies, which directly or indirectly alter monoaminergic levels, may be of limited benefit. Newer "plasticity enhancing" strategies that may have utility in the treatment of refractory depression include N-methyl-D-aspartate antagonists, alpha-amino-3-hydroxy-5-methylisoxazole propionate (AMPA) potentiators, cAMP phosphodiesterase inhibitors, and glucocorticoid receptor antagonists. Small-molecule agents that regulate the activity f growth factors, MAP kinases cascades, and the bcl-2 family of proteins are also promising future avenues. The development of novel, nonaminergic-based therapeutics holds much promise for improved treatment of severe, refractory mood disorders.

Neuroimaging and neurocircuitry models pertaining to the neurosurgical treatment of psychiatric disorders

Neurocircuitry models of obsessive-compulsive disorder (OCD) and major depression (MD) are described, focusing on relevant supporting neuroimaging data. Corticostriatothalamocortical circuitry is implicated in OCD. In MD, the relation between "dorsal" and "ventral" cortical compartments is emphasized; the amygdala, hippocampus, and pregenual anterior cingulate are implicated in the pathophysiology of MD and are potential targets for treatment. The neuroanatomy of psychiatric neurosurgical procedures and related neuroimaging findings are reviewed. Finally, anticipated future directions of research in this field are discussed.

Chronic, treatment-resistant depression and right fronto-striatal atrophy

BACKGROUND

Treatment-resistant depression (TRD) is relatively common but its neurobiological basis is poorly understood. Fronto-striatal structural brain changes have been reported in patients with depression but their association with treatment resistance and chronicity has not been established.

METHOD

Magnetic resonance images of 20 patients with TRD were compared with images of 20 recovered patients and 20 healthy controls. Images were compared using a voxel-based analysis (VBA) method; the results were validated by conventional volumetric analysis. The clinical associations of magnetic resonance imaging (MRI) changes with illness duration and severity were examined by VBA.

RESULTS

Only the TRD group exhibited right fronto-striatal atrophy, and subtle MRI changes in the left hippocampus on VBA. Atrophy was confirmed on volumetric analysis, the degree correlating with the cumulative number of electroconvulsive therapy (ECT) treatments received, suggesting an acquired deficit.

CONCLUSIONS

This is the first study to demonstrate fronto-striatal atrophy in patients with depression with poor outcome; the atrophy is more marked in those with more severe illness.

Volumetric MRI studies of mood disorders: do they distinguish unipolar and bipolar disorder?

The authors reviewed magnetic resonance imaging volumetric imaging results in major mood disorders, particularly comparing similarities and differences from studies of bipolar disorder and unipolar major depression. Abnormalities of cerebral brain regions appear inconsistently in mood disorders and, when present, typically consist of decreased frontal or prefrontal cortical volumes in both unipolar depression and bipolar disorder. In contrast, subcortical and medial temporal abnormalities are more commonly observed and are different between these two major classes of affective illness. Specifically, whereas structural enlargement of the basal ganglia and amygdala have been observed in bipolar disorder, in unipolar depression, these structures appear to be smaller in patients than healthy subjects. These findings suggest that affective illnesses may share in common an underdeveloped or atrophied prefrontal region, leading to loss of cortical modulation of limbic emotional networks. The effect of this loss results in unipolar depression or cycling (mania with depression) depending on the abnormalities of the subcortical structures involved. The cerebellum may also play a role in the presentation of mood disorders. This hypothesis remains speculative as much more research is needed to specifically examine how morphometric brain abnormalities translate into the neurophysiologic deficits that produce mood disorders.

Volumetric brain imaging findings in mood disorders

Volumetric neuroimaging is increasingly being used by researchers of affective disorders to assess potential involvement of different brain structures in mood regulation and to test neuroanatomic models of mood disorders. In unipolar depression, findings suggest abnormalities in the frontal lobe (particularly the subgenual prefrontal cortex), basal ganglia (particularly the caudate and putamen), cerebellum, and hippocampus/amygdala complex. In bipolar disorder, abnormalities in the third ventricle, frontal lobe, cerebellum, and possibly the temporal lobe are noted. We review the findings for the various regions of the brain, and discuss the implications on the understanding of mood disorders. Directions for future research in volumetric imaging is then discussed.

Anatomical MRI findings in mood and anxiety disorders

OBJECTIVE

In vivo structural magnetic resonance imaging (MRI) studies have evaluated the brain anatomy of various psychiatric disorders, allowing the investigation of putative abnormal brain circuits possibly involved in the patophysiology of psychiatric disorders. Here we reviewed the structural MRI literature in mood and anxiety disorders.

METHODS

All anatomical MRI studies evaluating mood and anxiety disorder patients were identified through a comprehensive Medline search conducted for the period from 1966 to January 2002, and a manual search of bibliographic cross-referencing complemented the Medline search.

RESULTS

Differential patterns of anatomical brain abnormalities appear to be involved in subtypes of mood disorders, with hippocampus and basal ganglia being abnormal in unipolar disorder, and amygdala and cerebellum in bipolar disorders, suggesting that these two mood disorders are biologically distinct. As for anxiety disorders, orbital frontal regions and basal ganglia have been reported to be anatomically abnormal in obsessive-compulsive disorder, temporal lobe was found to be abnormally reduced in panic disorder, and abnormal hippocampus shrinkage was shown in posttraumatic stress disorder.

CONCLUSIONS

The structural MRI findings reviewed here suggest abnormalities in specific brain regions participating in proposed neuroanatomic models possibly involved in the pathophysiology of mood disorders and anxiety disorders. Nonetheless, available MRI studies have suffered from limitations related to relatively small patient samples and involvement of medicated patients, and were largely cross-sectional investigations. Therefore, longitudinal MRI studies involving more sizeable samples of drug-free patients, patients at first episode of illness or at high risk for mood or anxiety disorders, associated to genetic studies, are likely to be extremely valuable to separate state from trait brain abnormalities and to characterize further the pathophysiology of these disorders.

Perspectives of B-mode transcranial ultrasound

Transcranial color coded sonography has proved valuable in the diagnostic work-up of cerebrovascular disorders in adults. More recently, evidences have converged that transcranial sonography is also useful in the diagnosis of brain parenchymal disorders. Here, a new field of application is the visualization of signal intensity shift in specific brain areas in some neurodegenerative disorders (Parkinson's disease, idiopathic dystonia, and depression). Findings obtained by transcranial ultrasound complement information from other neuroimaging data in these disorders and have led to the generation of new pathophysiological concepts. In this review we summarize the application fields of transcranial sonography with special emphasis on recent findings in neurodegenerative disorders and their implications for future research. As new application and processing techniques are being developed transcranial color coded sonography will gain increasing impact on both diagnosis and research of neurological disorders.

Reduced volume of orbitofrontal cortex in major depression

BACKGROUND

Functional neuroimaging studies have implicated dysfunction of orbitofrontal cortex in the symptoms of depression, and a recent postmortem study of depressed patients found reduced density of neurons and glia in this area. The purpose of this study was to measure volume of orbitofrontal cortex and other frontal cortical subregions in patients with major depression.

METHODS

Magnetic resonance imaging was used to measure volume of the orbitofrontal cortex and other frontal cortical regions in patients with major depression in remission (n = 15) and comparison subjects (n = 20).

RESULTS

Patients with depression had a statistically significant 32% smaller medial orbitofrontal (gyrus rectus) cortical volume, without smaller volumes of other frontal regions including anterior cingulate Brodmann's area 24 (subgenual gyrus), anterior cingulate Brodmann's area 32, subcallosal gyrus (Brodmann's area 25), or whole brain volume. The findings were significant after statistically controlling for brain size.

CONCLUSIONS

These findings are consistent with smaller orbitofrontal cortical volume in depression.

Structural changes in the brain in depression and relationship to symptom recurrence

Depression is an important public health problem affecting about 15% of the general population; however, little is known about possible changes in the brain that might underlie the disorder. Neuroimaging has been a powerful tool to map actual changes in the brain structure of depressed patients that might be directly related to their symptoms of depression. Some imaging studies of brain structure have shown smaller hippocampal volume with the chronicity of depression correlating to a reduction in volume. Although the meaning of these findings is unclear, other studies have shown increased amygdala volume. Studies have found reductions in volume of the frontal cortex, with some studies showing specific reductions in subregions of the frontal cortex, including the orbitofrontal cortex. Findings of an increase in white matter lesions in elderly patients with depression have been replicated and correlated with late-onset depression, as well as impairments in social and cognitive function. These findings point to alterations in a circuit of brain regions hypothesized to include the frontal cortex, hippocampus, amygdala, striatum, and thalamus, that underlie symptoms of depression.

Alcohol misuse among college athletes: self-medication for psychiatric symptoms?

A collegiate athlete population was surveyed for alcohol abuse as well as self-reported depression, anxiety, and other psychiatric symptoms. This study revealed that in a group of 262 athletes there were 21 percent who reported high alcohol use and problems associated with its use. Significant correlations were found between reported alcohol abuse and self-reported symptoms of depression and general psychiatric symptoms. Subjects with positive depression and psychiatric symptom ratings in the "severe" range had a significantly higher rate of alcohol abuse than subjects who had low depression and low or mild symptom ratings. Conversely, subjects reporting higher rates of alcohol misuse had more psychiatric symptoms. These findings suggest a possible causal link between psychopathology and serious alcohol abuse among college athletes. They also point to the need for routine depression and anxiety screening in college students who are typically beginning a significant exposure to alcohol.

A controlled study of MRI signal hyperintensities in older depressed patients with and without hypertension

OBJECTIVES

To compare the frequency/severity of signal hyperintensities--likely markers of cerebrovascular disease--in the subcortical gray and deep white matter on magnetic resonance imaging (MRI) scans of brains of hypertensive and normotensive older depressed and nondepressed comparison subjects.

DESIGN

Between-groups comparison of cross-sectional MRI data employing analyses of covariance controlling for the effects of age, gender, and height.

SETTING

A comprehensive inpatient-outpatient geriatric psychiatry service in a university hospital.

PARTICIPANTS

Nondemented older depressed (n = 81) and nondepressed comparison (n = 70) subjects divided into four groups (hypertensive depressed (n = 40), hypertensive normals (n = 21), normotensive depressed (n = 41), normotensive normals (n = 49)).

MEASUREMENTS

Signal hyperintensities were rated on T-2 weighted MRI scans blind to patient diagnoses employing two standardized hyperintensity rating systems (Fazekas, Boyko).

RESULTS

Hypertensive depressives had significantly more- severe hyperintensity ratings in both subcortical gray and deep white matter than did normotensive depressives and controls (P < .05) and significantly more-severe hyperintensity ratings only in subcortical gray matter (P < .05) than did hypertensive controls. Hypertensive controls had significantly more-severe ratings in deep white matter than either normotensive group (P < .05).

CONCLUSIONS

Findings suggest a relationship between deep white matter hyperintensities and hypertension (regardless of depressive state), and a particular role of subcortical gray matter hyperintensities (possibly interacting with more-severe deep white matter lesions) in older depressed hypertensives, as compared with older depressed normotensives of similar ages and severity of depression. These data support possible heterogeneous pathogenic contributions in late-life depression subgroups, one of which appears to be influenced by cerebrovascular disease.

Anatomical MRI study of basal ganglia in bipolar disorder patients

This study examined possible anatomical abnormalities in basal ganglia structures in bipolar disorder patients. Caudate and putamen gray matter volumes, and globus pallidus total volume were measured with magnetic resonance imaging (MRI) in 22 DSM-IV bipolar patients (age+/-S.D.=36+/-10 years; eight drug-free and 14 lithium monotherapy patients) and 22 matched healthy control subjects (age+/-S.D.=38+/-10 years). No significant differences were found between bipolar patients and healthy control subjects for any of the basal ganglia measures (t-tests, P>0.05). Age was inversely correlated with left putamen volumes in patients (R=-0.44, P=0.04), but not in healthy control subjects (R=-0.33, P=0.14). Older patients (>36 years old) had a significantly larger left globus pallidus than younger ones (< or =36 years old) (ANOVA, P=0.01). In a multiple regression analysis, after entering age as independent variable, the length of illness predicted smaller left putamen volumes, explaining 10.4% of the variance (F=4.07, d.f.=2, P=0.03). No significant effects of episode type, number of prior episodes, or gender were found in any basal ganglia measurements (ANOVA, P>0.05). In conclusion, our findings indicate that the basal ganglia may be anatomically preserved in bipolar patients. This is in contrast to available findings for unipolar disorder. However, our findings also suggest that age and length of illness may have significant effects on basal ganglia structures in bipolar patients, which may be more pronounced among bipolar I patients, and of relevance for the pathophysiology of the disorder.

Neuroanatomical substrates of depression in the elderly

The etiology of depression in the elderly is poorly understood. In this study, magnetic resonance imaging was used to evaluate the role of subcortical structures in the pathophysiology of depression in the elderly. Elderly depressed patients were found to have smaller caudate nuclei, smaller putaminal complexes and in increased frequency of subcortical hyperintensities compared with normal, healthy controls. These findings were more pronounced in patients with late-onset depression. Based on these findings, the authors discuss the role of the basal ganglia in the pathophysiology of depression in the elderly.

3D MRI studies of neuroanatomic changes in unipolar major depression: the role of stress and medical comorbidity

Increasing evidence has accumulated for structural brain changes associated with unipolar recurrent major depression. Studies of neuroanatomic structure in early-onset recurrent depression have only recently found evidence for depression-associated structural change. Studies using high-resolution three-dimensional magnetic resonance imaging (MRI) are now available to examine smaller brain structures with precision. Brain changes associated with early-onset major depression have been reported in the hippocampus, amygdala, caudate nucleus, putamen, and frontal cortex, structures that are extensively interconnected. They comprise a neuroanatomic circuit that has been termed the limbic-cortical-striatal-pallidal-thalamic tract. Of these structures, volume loss in the hippocampus is the only consistently observed change to persist past the resolution of the depression. Possible mechanisms for tissue loss include neuronal loss through exposure to repeated episodes of hypercortisolemia; glial cell loss, resulting in increased vulnerability to glutamate neurotoxicity; stress-induced reduction in neurotrophic factors; and stress-induced reduction in neurogenesis. Many depressed patients, particularly those with late-onset depression, have comorbid physical illnesses producing a high rate of hyperintensities in deep white matter and subcortical gray matter and brain damage to key structures involved in the modulation of emotion. Combining MRI studies with functional studies has the potential to localize abnormalities in blood flow, metabolism, and neurotransmitter receptors and provide a better integrated model of depression.

Accuracy and validity of stereology as a quantitative method for assessment of human temporal lobe volumes acquired by magnetic resonance imaging

The object of this study was to compare the accuracy and validity of stereology as a method for determining whole temporal lobe volume with the more established technique of semi-automated thresholding and tracing. Ten, fixed, post-mortem human brains, were imaged using a three dimensional (3D) acquisition protocol. The volume of the left temporal lobe, dissected from each brain, was determined by fluid displacement. Each volume was compared to measurements obtained from magnetic resonance images (MRI) of the post-mortem brain using each of the two segmentation methods. Post-acquisition processing was performed using MEASURE software. Three investigators performed each measurement three times using each method, yielding a total of 180 measurements. Stereology took, on average, half the time of thresholding/tracing. Using a clinically acceptable variation for 95% of repeat measures; both intra-observer and inter-observer variation were acceptable for each technique. However, validity, as demonstrated by graphs of agreement against water displacement showed that the "limits of agreement" using stereology were within the acceptable range, while those using the thresholding/tracing technique were not. Quantitative estimates of variation and a graphical representation of the limits of agreement show that stereology is at least as precise as the thresholding/tracing method but is superior in terms of speed and validity. This has broad implications for published estimates of brain region volumes in human diseases such as epilepsy, dementia and other neurodegenerative disorders.

Changes in cerebral blood flow associated with premenstrual syndrome: a preliminary study

The purpose of this study was to determine changes in regional cerebral blood flow (rCBF) associated with premenstrual syndrome (PMS). Regional CBF was examined using single photon emission computed tomography (SPECT) in seven women who sought treatment for PMS and seven control subjects. Confirmation of PMS was based on the Daily Symptom Report (DSR) of 17 common symptoms associated with PMS. A first SPECT scan was performed near the peak of premenstrual symptoms based on DSR reports from the two previous cycles. A second scan was performed in the postmenstrual period. Prior to scanning, each subject had a Hamilton Depression Rating Scale (Ham-D) obtained. Regions of interest were drawn on the images to generate mean counts per pixel, and normalized to the cerebellum. Activity in the frontal, temporal and parieto-occipital cortices, and the thalami and basal ganglia, were compared between the two scans. Correlations between activity in each region of interest and Ham-D values were also determined. There were marked decreases in rCBF in the temporal lobes on the premenstrual scan compared to the postmenstrual scan in PMS patients. Significant correlations were observed between the change in rCBF in the right and left temporal lobes and the changes in Ham-D scores (r = 0.91, p < 0.01 and r = 0.86, p = 0.01 respectively). No rCBF changes were observed in controls. We conclude that SPECT imaging demonstrates modest decreases in rCBF in the temporal lobes that correlate with the level of depression in subjects with PMS.

The benefit of stereology for quantitative radiology

A knowledge of stereology (i.e. proper sampling), the opportunities provided by computers for image analysis (i.e. image segmentation, image registration, data base exploration, 3D reconstruction), and the strengths (i.e. non-invasive) and limitations (i.e. finite resolution, image artefacts) of medical imaging equipment must all be combined for reliable quantitative magnetic resonance imaging (MRI), the goal of which is to obtain a deeper understanding of the structure, function, life cycle and evolution of the human body, especially the brain, and a more objective diagnosis of disease and assessment of its response to treatment. In this article we illustrate the first of these requirements. We describe the application of proper sampling strategies and efficient computer-based counting procedures for obtaining unbiased estimates of volume by the Cavalieri method and of surface area from vertical sections. In particular, we estimate the volume of a brain tumour from Cavalieri sections, the volume of grey matter in the cerebral hemispheres from Cavalieri slices and the surface area of the cerebral cortex from vertical sections. The estimates obtained are mathematically unbiased. In each case, we assess the precision of the estimates empirically. Application of formulae available for predicting the precision of volume estimates obtained using the Cavalieri sections and slices methods is also described.

Volumetric measurement of renal cysts and parenchyma using MRI: phantoms and patients with polycystic kidney disease

We have developed an MR method to measure the volumes of renal cysts and parenchyma in patients with polycystic kidney disease. Phantoms were designed to simulate polycystic kidneys. Four patients were recruited. MR scans were performed on the phantoms and patients. A stereology technique was applied for image segmentation and volume measurement. Volumetric measurement of renal cysts and parenchyma was accurate in phantom studies and reliable in both phantom and patient studies in these limited examples.

Motor and cognitive aspects of motor retardation in depression

BACKGROUND

Motor retardation is a common feature of major depressive disorder having potential prognostic and etiopathological significance. According to DSM-IV, depressed patients who meet criteria for psychomotor retardation, must exhibit motor slowing of sufficient severity to be observed by others. However, overt presentations of motor slowing cannot distinguish slowness due to cognitive factors from slowness due to neuromotor disturbances.

METHODS

We examined cognitive and neuromotor aspects of motor slowing in 36 depressed patients to test the hypothesis that a significant proportion of patients exhibit motor programming disturbances in addition to psychomotor impairment. A novel instrumental technique was used to assess motor programming in terms of the subject's ability to program movement velocity as a function of movement distance. A traditional psychomotor battery was combined with an instrumental measure of reaction time to assess the cognitive aspects of motor retardation.

RESULTS

The depressed patients exhibited significant impairment on the velocity scaling measure and longer reaction times compared with nondepressed controls. Approximately 40% of the patients demonstrated abnormal psychomotor function as measured by the traditional battery; whereas over 60% exhibited some form of motor slowing as measured by the instruments. Approximately 40% of the patients exhibited parkinsonian-like motor programming deficits. A five-factor model consisting of motor measures predicted diagnosis among bipolar and unipolar depressed patients with 100% accuracy.

LIMITATIONS

The ability of motor measures to discriminate bipolar from unipolar patients must be viewed with caution considering the relatively small sample size of bipolar patients.

CONCLUSIONS

These findings suggest that a subgroup of depressed patients exhibit motor retardation that is behaviorally similar to parkinsonian bradykinesia and may stem from a similar disruption within the basal ganglia.

Neo-striatal rCBF correlates of psychomotor slowing in patients with major depression

Psychomotor slowing is a fundamental clinical feature of severe depression and is thought to reflect dysfunction within prefrontal-subcortical circuits. This study utilised a split-dose single photon emission computerised tomography (SPECT) scanning technique in association with a two-stage test of psychomotor speed. Twenty-five patients with primary depressive disorders were injected with technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) whilst performing each component of a two-stage psychomotor task. The first stage, 'simple reaction time' (RT) and the second stage, 'choice reaction time' (CRT), were each followed by 30-min SPECT scans. Regions of interest (ROIs) corresponding to the left and right neo-striatum (caudate-putamen) were drawn, and regional cerebral blood flow (rCBF) values were calculated. Importantly, the change in rCBF measure in the left neo-striatum was inversely correlated with RT (r = -0.48, P < 0.05). That is, the patients with the greatest psychomotor slowing initially showed the least increase in rCBF during the CRT condition. This effect was independent of age. The study demonstrates that a simple two-stage motor paradigm can be used to elicit rCBF correlates of psychomotor slowing in patients with primary depression. Such rCBF findings may implicate the neo-striatum in the neurobiology of major depression.

Absence of striatal volume differences between depressed subjects with no comorbid medical illness and matched comparison subjects

OBJECTIVE

The striatum (caudate and putamen) appears to be important in the pathogenesis of depression. Some studies show smaller than normal striatal structure volumes in depressed subjects. This study compared striatal volumes in depressed and nondepressed women, screened to exclude major cerebrovascular disease risk factors and comorbid medical illness.

METHOD

Caudate and putamen volumes were measured from magnetic resonance imaging scans of 24 depressed women and 24 matched nondepressed comparison subjects.

RESULTS

Caudate and putamen volumes were not significantly different between depressed and nondepressed groups.

CONCLUSIONS

These findings differ from those of previous studies, possibly because of the exclusion of subjects with cerebrovascular risk factors in this study.

The pathomorphology of schizophrenia and mood disorders: similarities and differences

In this article, post-mortem neurohistological and structural imaging studies of schizophrenia and mood disorders are briefly reviewed. In contrast to the large number of post-mortem studies on schizophrenia published during the last 20 years, very few histological studies of affective disorders are available. After commenting on CT and MRI studies, as well as on neuropathological findings on whole-brain size, cortex, frontal and temporal lobes, limbic system, basal ganglia, thalamus, brain stem, and cortical asymmetry, it is concluded that despite a broad overlap in structural findings in the so-called endogenous psychoses, heteromodal association cortex, limbic system, and structural asymmetry are more affected in schizophrenia, while subtle structural abnormalities in the basal ganglia, especially in the nucleus accumbens and in hypothalamic areas, might play a crucial role in mood disorders.

Declarative and procedural memory in bipolar disorder

BACKGROUND

Memory function is an important but under researched area for neuropsychological investigation in persons with bipolar disorder. Previous studies have reported cognitive deficits on tasks of declarative memory in bipolar patients in the euthymic state.

METHODS

This study extended these findings by investigating declarative as well as procedural learning and memory in bipolar patients (with and without alcohol abuse) who were examined in the euthymic state. The California Verbal Learning Test, Star Mirror Tracing Task, Pursuit Rotor Task, American National Adult Reading Test, and the Vocabulary Subtest of the WAIS-R, were administered to bipolar patients and control subjects by researchers who were blind to the subject's group.

RESULTS

Bipolar patients performed worse than control subjects on a measure of declarative memory (California Verbal Learning Test) but did not differ from the performance of control subjects on either of the two procedural learning tasks (Pursuit Rotor Task and Star Mirror Task).

CONCLUSIONS

These results suggest disturbed function of temporal lobe, but not basal ganglia, structures in persons with bipolar disorder.

Magnetic-resonance morphometry in patients with major depression

Magnetic-resonance morphometry performed on 72 patients with major depression compared with 38 control subjects replicated previously reported, statistically significant reductions in the volumes of the caudate (P < 0.03) and putamen (P < 0.05) in depressed patients. Borderline statistical significance was observed for whole-brain (P < 0.07) and frontal volume (P < 0.10) in a subsample of 32 patients matched on age and sex with 32 control subjects, whereas statistical significance was observed for the full sample (P < 0.007 and P < 0.03, respectively). Chronological age was related to volume of the frontal lobes (P < 0.0002), caudate (P < 0.0001), putamen (P < 0.008), thalamus (P < 0.002), cerebellum (P < 0.007), lateral ventricles (P < 0.0001), and ratios of [whole brain]/[whole brain + cerebrospinal fluid (CSF)] (P < 0.0001) and [frontal]/[frontal + CSF] (P < 0.0001). Age of first depressive episode was related to putamen volume after accounting for chronological age (R2= 0.16, P < 0.005), and a correlation of 0.26 (P < 0.04) was observed between caudate volume and global mental status. Results are in accord with previous reports of basal-ganglia abnormalities in depressed patients and support the role of subcortical structures in mediating affective disorder.

Frontostriatal deficits in unipolar major depression

Recent accounts of major depression have tended to focus on dysfunction of frontothalamic-striatal reentrant circuits as a possible source of the disorder. Evidence of frontostriatal involvement in unipolar major depression from lesion and neuropsychological studies, and functional and structural imaging studies is examined. The high incidence of depressive symptomatology following left frontal and basal ganglia lesions implicate these as possible sites of dysfunction. Neuropsychological evidence indicates similar deficits in patients with major depression, perhaps with dorsolateral prefrontal deficits most prominent. Structural imaging studies report frontal and basal ganglia (BG) abnormalities particularly in cases of late-age onset depression. Resting state functional imaging studies show deficits in dorsolateral, anterior cingulate (medial frontal), and BG structures. Activation imaging studies show less consistent evidence of dorsolateral deficit, while anterior cingulate deficit is more consistently demonstrated. Variability in findings across studies may reflect differences between subtypes of depression and differences in methodology. Possible involvement of the BG in the psychomotor retardation of depression is examined. It is concluded that, while there is evidence of frontostriatal deficit in major depression, the exact nature of such deficits is uncertain. Issues such as component vs. system dysfunction need to be addressed.

Magnetic resonance imaging signal hypointensity and iron content of putamen nuclei in elderly depressed patients

We previously introduced a semiquantitative scale for assessment of iron content of putamen nuclei as determined by magnetic resonance imaging (MRI)--the Signal Hypointensity in the Putamen (SHIP) scale. Such hypointensity may be related to putamen nuclei iron content, although this suggestion remains controversial, especially in the elderly. In the present study, we apply the SHIP scale to a sample of 68 elderly depressed patients (diagnosed with DSM-IV major depression using the Diagnostic Interview Schedule and clinical interview) and a group of 28 age-matched non-depressed control subjects. MRI scans were conducted on a single 1.5-T General Electric Signa system with axial acquisitions obtained parallel to the canthomeatal line. Technical parameters were as follows: (1) repetition time (TR) = 500 ms and echo time (TE) = 15 ms for T1-weighted images; (2) TR = 2500 ms and TE = 30 ms for proton-density-weighted images; and (3) TR = 2500 ms and TE = 80 ms for T2-weighted images. Among depressed patients, older age of depression onset and greater severity of depression were associated with increased putamen nuclei iron deposition. When depressed patients were compared with control subjects, the patient group demonstrated greater putamen nuclei iron, but the finding was significant only for the left hemisphere. Our findings support previous neuroimaging studies linking both changes in the basal ganglia and greater left-sided brain pathology to late-life depression.

Major depression and the basal ganglia

In the last decade, major changes in our understanding of basal ganglia functions have occurred. Traditionally the basal ganglia were considered to be involved only in the modulation of movement. Recent research has suggested that the basal ganglia also take part in complex fronto-subcortical networks that have an important role in cognition reward, and mood regulation. The authors review recent findings that implicate basal ganglia abnormalities in the pathophysiology of mood disorders and discuss their potential implications for future developments in the pharmacotherapy of depressive disorder.

Does neuroanatomy predict ECT response?

1. Structural neuropathologic abnormalities have been associated with severe psychiatric illnesses, including bipolar disorder, major depressive disorder, and schizophrenia. In the latter, ventricular enlargement has been variably associated with symptom severity and poor treatment response. In patients with severe depressive disorders, the relationship between cortical and subcortical pathology and ventricle enlargement, symptom severity, and response to treatment is far from clear. 2. The present study investigated the relationship between structural CNS pathology, symptom severity and treatment response in patients undergoing ECT. It was hypothesized that patients with greater neuroanatomic abnormalities would demonstrate greater initial symptom severity and poorer response to ECT. 3. The subjects were 57 patients with unipolar or bipolar depression admitted for ECT treatment. Symptom severity was quantified using the Hamilton Depression Rating Scale (HRSD) at baseline and post-ECT. 4. Lateral and third ventricle-brain ratio (LVBR, 3VBR) were determined from CT scans and cortical atrophy was rated by a faculty neuroradiologist. 5. Contrary to our first hypothesis, structural pathology was not associated with baseline symptom severity. In terms of treatment response, the number of treatments required to achieve benefit was correlated with larger 3VBR; CT variables were not related to total post-treatment or change in HRSD score. Third ventricle enlargement may be an index of generalized pathology or regional brainstem abnormalities that influence ECT response rate by limiting individual seizure efficacy or neurochemical responsiveness, thereby necessitating a greater number of ECT treatments, without significant impact on overall response.

Subcortical hyperintensities on magnetic resonance imaging in patients with severe depression--a longitudinal evaluation

In a longitudinal evaluation of 37 patients with severe depression who had undergone brain magnetic resonance imaging (MRI) 6 months-2 years (mean 14.1 months) previously, the degree of residual dysfunction was predicted by the extent of subcortical white matter hyperintensities (WMHS, p < .01), longer time elapsed since the MRI scan (p < .05), older age (p < .05), and older age at onset of affective disorder (p < .05). Ten (27%) patients developed "probable" dementia syndromes of the vascular type, with such syndromes being predicted by WMHS (p < .01) and older age of onset of affective disorder (p < .05). Institutionalization of patients was predicted largely by the combination of chronic depression, progressive cognitive decline, and advanced age. The study supports the notion that a subgroup of patients with late-onset depressive disorders, without a family history of depression, and with risk factors to cerebrovascular disease, have extensive WMHS on MRI, and that such structural brain changes predispose to chronic depression and progressive cognitive decline.

MRI findings in patients with affective disorder: a meta-analysis

A review of the literature on primarily magnetic resonance imaging (MRI) scans of patients with affective disorders is presented. Several studies have indicated an increased ventricle/brain ratio and other signs of cerebral atrophy, as well as an increased frequency of lesions (so-called signal hyperintensities) in the brains of unipolar and bipolar patients. This notion is strongly supported by two meta-analyses performed in the present study. The lesions are often localized in the frontal lobes and the basal ganglia, indicating a defective basal ganglia/frontal circuit, and are correlated with the degree of cognitive impairment seen in these conditions. No studies have indicated that psychoactive drugs or electroconvulsive therapy (ECT) might cause the lesions, but on the other hand they can probably increase the risk of delirium complicating the treatment.

Improving stereological estimates for the volume of structures identified in three-dimensional arrays of spatial data

Investigators frequently measure the volumes of anatomic structures. These volumes can answer important scientific questions such as whether a structure differs between two groups, which structures a disease affects, or how the size of a structure relates to its function. Magnetic resonance (MR) imaging, X-ray computed tomography and confocal microscopy are used more and more frequently in anatomic studies; each yields information that is spatially organized as a three-dimensional array. We describe how to improve an efficient stereological technique for estimating the volumes of structures that are identifiable in these arrays. As an example, we apply the technique to measuring brain volumes by MR imaging. We then show how the results of the technique may be used for solving a typical problem in experimental design. This technique is applicable to a wide range of experimental problems. We discuss its limitations and offer some suggestions and observations relating to its use.

A quantitative magnetic resonance imaging study of cerebral and cerebellar gray matter volume in primary unipolar major depression: relationship to treatment response and clinical severity

The authors investigated whether there were differences in cerebral and cerebellar gray and white matter volumes in depressed patients compared to controls, and whether this was associated with treatment response to fluoxetine. Brain magnetic resonance images were obtained from 38 unipolar depressed patients and 20 age, gender, and educationally matched comparison subjects. Patients were divided into groups of "responders" and "nonresponders" based on change in 17-item Hamilton Depression Rating Scale (HDRS) after an 8-week standardized trial of fluoxetine, 20 mg/day. There were no group mean differences in cerebral or cerebellar tissue volumes between patients and controls, or responders and nonresponders. For nonresponders to fluoxetine treatment, cerebral and cerebellar gray matter volume, and total cerebellar tissue volume decreased as baseline HDRS increased. The results suggest an association between gray matter volume and severity of illness in nonresponders to fluoxetine treatment.

The functional neuroanatomy of mood disorders

Mood disorders may be associated with global and regional changes in cerebral blood flow and metabolism. The accumulated functional neuroimaging findings in mood disorders were reviewed in order to examine a proposed neuroanatomic model of pathophysiology. Global cerebral blood flow and glucose metabolism appear normal, but may be decreased in late-life depression. Regional cerebral blood flow and glucose metabolism deficits are present, and may be indicators of brain regions participating in neuroanatomic circuits involved in mood disorders. Decreased pre-frontal cortex blood flow and metabolism in depressed unipolar and bipolar patients are the most consistently replicated findings, and correlate with severity of illness. Basal ganglia abnormalities have been found in depressed unipolar and bipolar patients, involving decreased blood flow and metabolism. Temporal lobe abnormalities are present in bipolar disorder patients, and perhaps unipolar depression. There is conflicting evidence of abnormalities in other limbic regions. Cognitive impairment may correlate with decreased metabolism in frontal and cerebellar areas. The relationship between functional neuroimaging findings and clinical course, and therefore state and trait characteristics, has not been systematically investigated. Antidepressant medications, but not ECT, seem to reverse some of the identified functional brain changes in the depressed state. The structural, neurotransmitter and neuropathological correlates of these functional abnormalities are yet to be determined. Functional abnormalities in frontal, subcortical and limbic structures appear to be part of the pathophysiology of mood disorders.

Basal ganglia choline levels in depression and response to fluoxetine treatment: an in vivo proton magnetic resonance spectroscopy study

We have investigated proton magnetic resonance spectra of the basal ganglia in 41 medication-free outpatients with major depression, prior to starting an 8-week standardized trial of open-label fluoxetine, and 22 matched comparison subjects. Upon completing the trial, depressed subjects were classified as treatment responders (n = 18) or nonresponders (n = 23), based on changes in the Hamilton Depression Rating Scale. Depressed subjects had a lower area ratio of the choline resonance to the creatine resonance (Cho/Cr) than comparison subjects. This statistically significant difference between the depressed subjects and comparison subjects was more pronounced in the treatment responders than in the nonresponders. There were no differences in the relative volumes of gray matter or white matter in the voxel used for proton spectroscopy in depressed subjects relative to comparison subjects. These results are consistent with an alteration in the metabolism of cytosolic choline compounds in the basal ganglia of depressed subjects and, in particular, those who are responsive to fluoxetine.

Utilising molecular biological and histopathological techniques to study the dopaminergic system in patients with melancholia

OBJECTIVE

To describe the rationale for investigating the dopaminergic system in patients with melancholia by applying molecular biological (notably, in situ hybridisation) and histopathological techniques in postmortem brain tissue.

METHOD

Relevant advances in the functional neuroanatomy of frontostriatal circuits, as well as insights from clinical neuroimaging studies in primary and secondary depressive disorders, are presented. These are integrated with developments in the pharmacological and molecular characteristics of dopamine receptor subtypes and recognition of their selective anatomical distribution.

RESULTS

Converging data from the basic and clinical neurosciences suggest that the pathophysiology of depressive disorders characterised by psychomotor phenomena, such as melancholia, may involve dysregulation of dopaminergic mechanisms within complex frontostriatal circuits.

CONCLUSIONS

The key feature of in situ hybridisation is its capacity to test for variations in the functional components of designated biochemical systems within highly specific anatomical regions. We utilise this approach, in combination with relevant histopathological techniques, to test the structural and functional integrity of the dopaminergic system within key fronto-striatal circuits in patients who had exhibited psychomotor phenomena. The same approach can also be used to study the integrity of other relevant biochemical systems, such as the serotoninergic and noradrenergic systems, in patients with other mood disorders.

Quantitative magnetic resonance imaging in geriatric depression and primary degenerative dementia

Quantitative magnetic resonance imaging (MRI) was used to investigate volumes of different brain structures in 19 patients with late-onset major depression (DSM-III-R), 27 patients with Alzheimer's disease (NINCDS-ADRDA criteria) and 13 age matched controls. 3-D MRI sequences were acquired using a Siemens 1.5 T scanner. Whole brain volume, CSF volume, volume of the frontal and temporal lobes and the volume of the amygdala-hippocampus complex were assessed using the software NMR Win. Compared to the controls, depressed patients showed a significantly lower whole brain volume and a significantly higher CSF volume, whereas volumes of the frontal and temporal lobes as well as the amygdala-hippocampus complex volumes were not significantly decreased. In addition, depressed patients exhibited a higher ventricle-brain ratio suggesting a higher degree of central atrophy compared to healthy individuals. In contrast, Alzheimer patients showed significantly lower volumes than depressed patients and controls with respect to all volumetric parameters. Although the findings indicate the presence of brain atrophy in patients with late-onset depression, the pattern of volumetric changes in these patients differs markedly from that observed in patients with primary degenerative dementia.

The anatomy of mood disorders--review of structural neuroimaging studies

The structural neuroimaging findings in mood disorders were reviewed, to evaluate evidence for a neuroanatomic model of pathophysiology, involving the prefrontal cortex, the basal ganglia, the amygdala-hippocampus complex, thalamus, and connections among these structures. Global atrophy is not consistently found. The best replicated finding is an increased rate of white matter and periventricular hyperintensities. A smaller frontal lobe, cerebellum, caudate, and putamen appear present in unipolar depression. A larger third ventricle, and smaller cerebellum and perhaps temporal lobe appear present in bipolar disorder. These localized structural changes involve regions that may be critical in the pathogenesis of mood disorders. Generalized and localized anatomic alterations may be related to age or vascular disease. The clinical and biological correlates of these changes need to be investigated to allow development of a more complete model of pathophysiology of mood disorders.

Magnetic resonance imaging changes in putamen nuclei iron content and distribution in normal subjects

To study patterns of iron deposition in the putamen in aging, we reviewed brain magnetic resonance imaging (MRI) scans of 56 normal subjects. We developed the Signal Hypointensity in the Putamen (SHIP) Scale, a semiquantitative measure, to evaluate putamen nuclei for extent of iron deposition relative to the globus pallidus. The SHIP score was highly reliable (kappa = 0.76) and significantly correlated with age (P < 0.0001). We found that age-related iron deposition in putamen nuclei follows a characteristic pattern along a posterolateral-to-anteromedial gradient. This gradient may be related to the microvasculature of the putamen. Other studies are needed to replicate our findings in patients with affective and other neuropsychiatric disorders and to clarify the pathophysiological mechanisms that govern these changes.

Accuracy and reproducibility of brain and tissue volumes using a magnetic resonance segmentation method

Magnetic resonance (MR) imaging now allows the qualitative and quantitative assessment of the human brain in vivo. As MR imaging resolution has improved, precise measurement of small brain structures has become possible. Methods of measuring brain regions from MR images include both manual and semiautomated methods. Despite the development of numerous volumetric methods, there have been only limited attempts so far to evaluate the accuracy and reproducibility of these methods. In this study we used phantoms to assess the accuracy of the segmentation process. Our results with simple and complex phantoms indicate an error of 3-5% using either manual or semiautomated techniques. We subsequently used manual and semiautomated volumetric methodologies to study human brain structures in vivo in five normal subjects. Supervised segmentation is a semiautomated method that accomplishes the division of MR images into several tissue types based on differences in signal intensity. This technique requires the operator to manually identify points on the MR images that characterize each tissue type, a process known as seeding. However, the use of supervised segmentation to assess the volumes of gray and white matter is subject to pitfalls. Inhomogeneities of the radiofrequency or magnetic fields can result in misclassification of tissue points during the tissue seeding process, limiting the accuracy and reliability of the segmentation process. We used a structured seeding protocol that allowed for field inhomogeneity that produced reduced variation in measured tissue volumes. We used repeated segmentations to assess intra- and inter-rater reliability, and were able to measure small and large regions of interest with a small degree of variation. In addition, we demonstrated that measurements are reproducible with repeat MR acquisitions, with minimal interscan variability. Segmentation methods can accurately and reliably measure subtle morphometric changes, and will prove a boon to the study of neuropsychiatric disorders.

Stereological MRI volumetry of the frontal lobe

Stereology was used to measure frontal lobe volume on magnetic resonance imaging (MRI) scans in a multi-observer repeated-measures trial in 17 adults. Prior to measurement, MR image volumes were reoriented into coronal sections perpendicular to the bicommissural plane. Three observers blinded to subject identify repeatedly used fixed grid stereology to estimate frontal lobe volumes, defined as all sections of the frontal lobe anterior to the anterior commissure. The lateral ventricles were excluded. Stereological measurement yielded high repeatability and precision, and was time efficient for the raters. The coefficient of error was 0.03. The inter-rater correlation coefficient = 0.95 for three raters; intra-rater correlation coefficients = 0.95-0.98. A comparison was made between stereological and traditional edge tracing measurement of the frontal lobe volumes. The overall correlation between the two methods was 0.95. The use of internal landmarks to define orientation and 3-D orthogonal views to define frontal lobe boundaries on 3-D images was critical to obtaining repeatable measurements. Frontal lobe volumetry by brain MR used to estimate small differences postulated to occur in certain psychiatric and neurologic disorders requires high precision and repeatability. Stereology, a semi-automated method, can reliably estimate frontal lobe volumes. This method may distinguish small frontal lobe volume differences within individuals and between groups.

Treatment-resistant depression in children and adolescents

Treatment resistance in depressed children and adolescents cannot yet be defined fully because of the paucity of controlled studies that demonstrate efficacy. Therefore, this article addresses several of the age-specific, developmental considerations that may impinge upon treatment response. Areas covered include familial-genetic, psychosocial, and neuroimaging studies in addition to a review of controlled studies to date.