A magnetic resonance imaging study of putamen nuclei in major depression

Subcortical volumes in long-term abstinent alcoholics: associations with psychiatric comorbidity

BACKGROUND

Research in chronic alcoholics on memory, decision-making, learning, stress, and reward circuitry has increasingly highlighted the importance of subcortical brain structures. In addition, epidemiological studies have established the pervasiveness of co-occurring psychiatric diagnoses in alcoholism. Subcortical structures have been implicated in externalizing pathology, including alcohol dependence, and in dysregulated stress and reward circuitry in anxiety and mood disorders and alcohol dependence. Most studies have focused on active or recently detoxified alcoholics, while subcortical structures in long-term abstinent alcoholics (LTAA) have remained relatively uninvestigated.

METHODS

Structural MRI was used to compare volumes of 8 subcortical structures (lateral ventricles, thalamus, caudate, putamen, pallidum, hippocampus, amygdala, and nucleus accumbens) in 24 female and 28 male LTAA (mean abstinence=6.3 years, mean age= 46.6 years) and 23 female and 25 male nonalcoholic controls (NAC) (mean age=45.6 years) to explore relations between subcortical brain volumes and alcohol use measures in LTAA and relations between subcortical volumes and psychiatric diagnoses and symptom counts in LTAA and NAC.

RESULTS

We found minimal differences between LTAA and NAC in subcortical volumes. However, in LTAA, but not NAC, volumes of targeted subcortical structures were smaller in individuals with versus without comorbid lifetime or current psychiatric diagnoses, independent of lifetime alcohol consumption.

CONCLUSIONS

Our finding of minimal differences in subcortical volumes between LTAA and NAC is consistent with LTAA never having had volume deficits in these regions. However, given that imaging studies have frequently reported smaller subcortical volumes in active and recently detoxified alcoholics compared to controls, our results are also consistent with the recovery of subcortical volumes with sustained abstinence. The finding of persistent smaller subcortical volumes in LTAA, but not NAC, with comorbid psychiatric diagnoses, suggests that the smaller volumes are a result of the combined effects of chronic alcohol dependence and psychiatric morbidity and suggests that a comorbid psychiatric disorder (even if not current) interferes with the recovery of subcortical volumes.

Gray matter volumes of pain-related brain areas are decreased in fibromyalgia syndrome

Fibromyalgia (FM) is a chronic, widespread musculoskeletal pain disorder that is very prevalent in the general population (approximately 5%). Accumulating evidence suggests that FM is associated with central pain processing abnormalities, ie, central sensitization. Several previous studies of chronic pain patients, including FM, have shown gray matter atrophy of brain areas associated with sensory and affective pain processing. These findings, however, have not been confirmed in all FM studies. In this study, we investigated gray matter volumes of brain areas associated with pain-related areas of FM patients identified by functional brain imaging. Using voxel-based morphometric (VBM) analysis of magnetic resonance brain images, we compared 19 pain-related brain areas of 14 female FM patients and 11 healthy controls (NC). We found that FM patients had significantly less gray matter volumes than NC in 3 of these brain regions, including the anterior and mid-cingulate, as well as mid-insular cortices. Importantly, FM patients demonstrated neither global gray matter atrophy nor gray matter changes associated with depression, as shown in some studies. Using a more stringent analysis than other VBM studies, we provide evidence for decreased gray matter volumes in a number of pain-related brain areas in FM. Although the mechanisms for these gray matter changes are presently unclear, they may contribute to some of the core features of this chronic disorder including affective disturbances and chronic widespread pain.

PERSPECTIVE

Increasing evidence supports the association of chronic pain with accelerated gray matter atrophy in pain disorders like low back pain, IBS, and FM syndrome. However, cause-effect relationships between chronic pain and decreased gray matter volumes have not been established yet and will require future prospective studies.

Global and regional putamen volume loss in patients with heart failure

AIMS

Heart failure (HF) is accompanied by diminished cognitive, motor, learning, emotional, and planning deficits, which are associated with increased morbidity and mortality. A basal ganglia structure, the putamen, serves many functions that are affected in HF, but its global or localized structural integrity is unknown. Our aim was to evaluate global and regional putamen volume differences in HF over control subjects.

METHODS AND RESULTS

We collected two high-resolution T1-weighted scans from 16 HF patients (age, 54.1 ± 8.3 years; 12 males; left ventricular ejection fraction, 27.8 ± 6.8%) and 32 control subjects (52.4 ± 7.3 years; 24 males) using a 3.0 T magnetic resonance imaging scanner. After realigning, averaging, and reorienting the T1-weighted volumes into a common space, the structures were manually outlined, tracings were normalized for head size, volumes calculated, and surface models generated. Demographic data were compared between groups with χ(2) and independent samples t-tests, global putamen volumes were evaluated using independent samples t-tests, and regional differences were examined with surface morphometry. No significant differences in age or sex appeared between groups, but body mass index differed significantly (P = 0.008). Heart failure patients showed significantly lower left (controls vs. HF; 4842.1 ± 740.0 vs. 4224.1 ± 894.4 mm(3), P = 0.014) and right (4769.3 ± 651.9 vs. 4193.7 ± 876.2 mm(3), P = 0.014) global putamen volumes than controls, with localized reductions in bilateral rostral, mid-dorsal, and medial-caudal regions (left, P < 0.003; right, P < 0.0002).

CONCLUSION

Putamen structures showed global and localized volume reductions in HF over controls. The localized volume losses suggest deficits in motor and neuropsychological functions, which are evident in HF subjects, and may be due to hypoxic and ischaemic processes targeting these areas.

Striatal structure and function in mood disorders: a comprehensive review

OBJECTIVES

  A large and diverse literature has implicated abnormalities of striatal structure and function in both unipolar and bipolar disorder. Recent functional imaging studies have greatly expanded this body of research. The aim of this review is to provide a comprehensive and critical appraisal of the relevant literature.

METHODS

  A total of 331 relevant articles were reviewed to develop an integrated overview of striatal function in mood disorders.

RESULTS

  There is compelling evidence from multiple studies that functional abnormalities of the striatum and greater corticostriatal circuitry exist in at least some forms of affective illness. The literature does not yet provide data to determine whether these aberrations represent primary pathology or they contribute directly to symptom expression. Finally, there is considerable evidence that bipolar disorder may be associated with striatal hyperactivity and some suggestion that unipolar illness may be associated with hypoactivation.

CONCLUSIONS

  Additional research investigating striatal function in affective disorders will be critical to the development of comprehensive models of the neurobiology of these conditions.

Orbitofrontal volume reductions during emotion recognition in patients with major depression

BACKGROUND

Major depressive disorder is associated with both structural and functional alterations in the emotion regulation network of the central nervous system. The relation between structural and functional changes is largely unknown. Therefore, we sought to determine the relation between structural differences and functional alterations during the recognition of emotional facial expressions.

METHODS

We examined 13 medication-free patients with major depression and 15 healthy controls by use of structural T1-weighted high-resolution magnetic resonance imaging (MRI) and functional MRI during 1 session. We set the statistical threshold for the analysis of imaging data to p < 0.001 (uncorrected).

RESULTS

As shown by voxel-based morphometry, depressed patients had reductions in orbitofrontal cortex volume and increases in cerebellar volume. Additionally, depressed patients showed increased activity during emotion recognition in the middle frontal cortex, caudate nucleus, precuneus and lingual gyrus. Within this cerebral network, the orbitofrontal volumes were negatively correlated in depressed patients but not in healthy controls with changes in blood oxygen level-dependent signal in the middle frontal gyrus, caudate nucleus, precuneus and supplementary motor area.

LIMITATIONS

Our results are limited by the relatively small sample size.

CONCLUSIONS

This combined functional and structural MRI study provides evidence that the orbitofrontal cortex is a key area in major depression and that structural changes result in functional alterations within the emotional circuit. Whether these alterations in the orbitofrontal cortex are also related to persistent emotional dysfunction in remitted mental states and, therefore, are related to the risk of depression needs further exploration.

Brain volume abnormalities in major depressive disorder: a meta-analysis of magnetic resonance imaging studies

OBJECTIVE

So far, there have been no attempts to integrate the growing number of all brain volumetric magnetic resonance imaging studies in depression. In this comprehensive meta-analysis the magnitude and extent of brain volume differences between 2,418 patients with major depressive disorder and 1,974 healthy individuals from 64 studies was determined.

METHODS

A systematic research was conducted for volumetric magnetic resonance imaging studies of patients with major depressive disorder in relation to healthy control subjects. Studies had to report sufficient data for computation of effect sizes. For each study, the Cohen's d was calculated. All analyses were performed using the random effects model. Additionally, meta-regression analyses were done to explore the effects of potential sources of heterogeneity.

RESULTS

Patients showed large volume reductions in frontal regions, especially in the anterior cingulate and orbitofrontal cortex with smaller reductions in the prefrontal cortex. The hippocampus, the putamen and caudate nucleus showed moderate volume reductions.

CONCLUSIONS

This is the first comprehensive meta-analysis in major depressive disorder demonstrating structural brain abnormalities, particularly in those brain areas that are involved in emotion processing and stress-regulation.

Neurocircuitry of mood disorders

This review begins with a brief historical overview of attempts in the first half of the 20th century to discern brain systems that underlie emotion and emotional behavior. These early studies identified the amygdala, hippocampus, and other parts of what was termed the 'limbic' system as central parts of the emotional brain. Detailed connectional data on this system began to be obtained in the 1970s and 1980s, as more effective neuroanatomical techniques based on axonal transport became available. In the last 15 years these methods have been applied extensively to the limbic system and prefrontal cortex of monkeys, and much more specific circuits have been defined. In particular, a system has been described that links the medial prefrontal cortex and a few related cortical areas to the amygdala, the ventral striatum and pallidum, the medial thalamus, the hypothalamus, and the periaqueductal gray and other parts of the brainstem. A large body of human data from functional and structural imaging, as well as analysis of lesions and histological material indicates that this system is centrally involved in mood disorders.

Demonstration of disturbed activity of external globus pallidus projecting neurons in depressed patients by the AgNOR staining method

BACKGROUND

The external globus pallidus (EGP) is thought to play the most important integrating and conveying role in the striatopallidal system involved in the transfer from motivation to action. The aim to find a morphological biomarker of disturbed EGP activity in depression was approached by the karyometric analysis of large projecting neurons.

METHODS

The study was performed on paraffin-embedded brains from 19 depressed patients from both the major depressive disorder (MDD) and the bipolar disorder (BD) diagnostic groups encompassing 10 suicides and from 24 controls. The karyometric parameters of EGP neurons bilaterally were evaluated by argyrophilic nucleolar organiser (AgNOR) silver staining method.

RESULTS

A significantly decreased AgNOR area was found in the left EGP neurons in depressed patients compared to controls. The distinctness of the diagnostic groups and suicidal vs non-suicidal patients was not shown in the statistical comparisons. The AgNOR parameter which was decreased correlated positively with the mean dose of benzodiazepines in non-suicidal patients.

LIMITATIONS

A major limitation of this study is the relatively small number of cases. A further limitation is given by the lack of data on drug exposure across the whole lifespan of patients.

CONCLUSION

The results suggest disturbed, most likely decreased, activity of the left EGP projecting neurons in depressed patients, a disturbed activity that should hypothetically be counteracted by the applied pharmacotherapy in non-suicidal patients.

Exercise increases BDNF levels in the striatum and decreases depressive-like behavior in chronically stressed rats

Early life stress in humans can affect the development of neurons and neurotransmitter systems and predispose an individual to the subsequent development of depression. Similarly, in rats, maternal separation causes anxiety and depressive-like behavior and decreased corticosterone levels. Patients receiving pharmacological treatment for depression often experience negative side-effects or do not respond optimally and therefore the use of exercise as alternative antidepressant treatment is investigated. The aim of the study was to see whether rats subjected to both early life stress and chronic stress later in life show differences in depressive-like behavior, neurotrophin levels, stress hormone levels and antioxidant capacity of serum after chronic voluntary exercise as treatment. Rat pups were maternally separated and one group were allowed access to running wheels for 6 weeks while control rats were also handled and put in cages without running wheels. All rats were subjected to chronic restraint stress during adulthood. A forced swim test was done to test for depressive-like behavior. Neurotrophins were measured in the ventral hippocampus and striatum; baseline stress hormones were measured in blood plasma as well as the anti-oxidative potential of serum. Compared to controls, rats that exercised had no difference in baseline stress hormones, but had decreased immobility times in the forced swim test, increased brain derived neurotrophic factor (BDNF) levels in the striatum and decreased anti-oxidative potential of their serum. The mechanism by which depressive-like behavior was improved may have been mediated through increased striatal BDNF levels, resulting in increased neuroplasticity and the prevention of neuronal death.

Implicit and explicit procedural learning in patients recently remitted from severe major depression

In acute depression a high prevalence of deficits in learning and memory performance has been reported. Still, it is unclear whether these cognitive deficits are present after remission of clinical symptoms of depression. The present study compared 20 inpatients recently remitted from severe major depressive disorder (MDD) with 20 healthy matched control participants on two sequence learning tasks: a modified serial reaction-time task (SRT) for implicit learning, which is sensitive to subcortical and frontal impairments, and a serial generation task (SGT) for explicit learning. As compared with performance in healthy controls, implicit and explicit learning were not impaired in recently remitted inpatients with depression. Intentional acquisition of new information was related to the severity of depressive symptoms as patients with higher scores on Beck's Depression Inventory (BDI) showed poorer explicit learning. In contrast to findings in acute depression, our results suggest a normal degree of learning in remitted depression; these findings are consistent with unimpaired fronto-striatal functioning. However, although not statistically significant, patients remitted from melancholic MDD revealed poorer implicit learning performance compared with patients remitted from non--melancholic MDD. Longitudinal studies in patients with melancholic vs. non-melancholic MDD are needed to investigate the course of cognitive functioning during the recovery from MDD.

Bipolar and major depressive disorder: neuroimaging the developmental-degenerative divide

Both major depressive disorder and bipolar disorder are the subject of a voluminous imaging and genetics literature. Here, we attempt a comprehensive review of MRI and metabolic PET studies conducted to date on these two disorders, and interpret our findings from the perspective of developmental and degenerative models of illness. Elevated activity and volume loss of the hippocampus, orbital and ventral prefrontal cortex are recurrent themes in the literature. In contrast, dorsal aspects of the PFC tend to display hypometabolism. Ventriculomegaly and white matter hyperintensities are intimately associated with depression in elderly populations and likely have a vascular origin. Important confounding influences are medication, phenotypic and genetic heterogeneity, and technological limitations. We suggest that environmental stress and genetic risk variants interact with each other in a complex manner to alter neural circuitry and precipitate illness. Imaging genetic approaches hold out promise for advancing our understanding of affective illness.

Neuropsychiatric disorders related to interferon and interleukins treatment

Certain cytokines such as interferon-alpha and interleukin-2 are often used in the treatment certain cancers and chronic diseases such as melanoma, hepatitis C infection and multiple sclerosis. Several neuropsychiatric side effects such as depression, anxiety, psychosis, suicidal ideation, hypomanic mood and cognitive impairment were reported in those patients who received those medications. In certain patients with those neuropsychiatric side effects, the symptoms ceased when the medication was stopped. However, in some cases, the cognitive impairment persisted even for years after cessation of the medication. In animal studies, those cytokines could induce sickness behaviour, anxiety behaviour and social anhedonia. The increased in pro-inflammatory cytokines in certain neuropsychiatric disorders was widely reported. In addition, in animal studies, the treatment with interferon-alpha or interleukin-1 could induce depressive like behaviour. Recently, the role of certain pro-inflammatory cytokines that could enhance the activity of the enzyme, indoleamine 2-3, dioxygenase (IDO) which in turn would increase tryptophan degradation into kynurenine and decrease tryptophan availability of tryptophan in the brain to synthesize serotonin, a neurotransmitter which is necessary for the normal mood state became of interest in pathophysiology of psychiatric disorders. Furthermore, the imbalance in the further downward catabolic kynurenine pathway and their interactions with other neurotransmitters has been proposed to play an important role. The presence of such an imbalance in patients being treated with cytokines and in patients with psychiatric disorders and the possible consequence of those changes on the neuroprotective function in the brain are discussed in this review.

Serial susceptibility weighted MRI measures brain iron and microbleeds in dementia

A new iron sensitive MR sequence (susceptibility weighted imaging - SWI) enabling the simultaneous quantitation of regional brain iron levels and brain microbleeds (BMB) has been acquired serially to study dementia. Cohorts of mildly cognitively impaired (MCI) elderly (n = 73) and cognitively normal participants (n = 33) have been serially evaluated for up to 50 months. SWI phase values (putative iron levels) in 14 brain regions were measured and the number of BMB were counted for each SWI study. SWI phase values showed a left putaminal mean increase of iron (decrease of phase values) over the study duration in 27 participants who progressed to dementia compared to Normals (p = 0.035) and stable MCI (p = 0.01). BMB were detected in 9 out of 26 (38%) MCI participants who progressed to dementia and are a significant risk factor for cognitive failure in MCI participants [risk ratio = 2.06 (95% confidence interval 1.37-3.12)]. SWI is useful to measure regional iron changes and presence of BMB, both of which may be important MR-based biomarkers for neurodegenerative diseases.

Neuroimaging genetics: new perspectives in research on major depression?

OBJECTIVE

Stress-related changes in the hippocampus are influenced by genetic factors. To enhance our understanding of both the interaction between the brain, behaviour and genetics and of biological mechanisms in mood disorders neuroimaging genetics provide a good opportunity.

METHOD

A MEDLINE search was conducted to identify articles on neuroimaging genetics in major depression (MD).

RESULTS

Hippocampal volumes were found to be associated with polymorphisms in the promotor region of the serotonin transporter (5-HTTLPR) in patients with MD. Met-allele carriers of the BDNF (val66met) polymorphism had smaller hippocampal volumes in both patients and healthy controls when compared with homozygous val-allele carriers. Polymorphisms of the serotonin transporter (5-HTTLPR) and 5-HT1a receptor are associated with increased amygdala activation investigated with functional MRI in patients with MD.

CONCLUSION

Genetic variants seem to modulate the effects of stress on hippocampal volumes as well as amygdala activity as well as the development of the brain.

Gray matter changes in late life depression--a structural MRI analysis

Multiple brain morphometric changes have been reported in late-life depression (LLD), mostly in studies comparing volumes of circumscribed brain areas. The aim of our study is to characterize the volumetric changes of multiple gray matter regions in relation to age of onset/duration of illness. We predicted that the association of gray matter volumes with total duration of illness and age of onset would differ depending on whether the region was susceptible to the toxic effects of chronic exposure to cortisol or to the vascular/neurodegenerative changes accompanying prodromal dementia. Seventy-one elderly depressed subjects were studied along with thirty-two comparison subjects. High-resolution T1-weighted brain MRIs were processed using an automated labeling pathway technique. To protect against type-I error, we combined the right and left hemisphere volume data. We sampled 24 regions of interest (ROIs). We used the primary visual cortex volume to normalize for individual variations in brain size. LLD Subjects had smaller volumes than non-depressed subjects in 17 of the 24 examined ROIs. Shorter duration of illness and later age of onset was correlated with smaller volumes of parahippocampal area and parietal inferior area. A later age of onset was also correlated with smaller volumes of several frontal and temporal areas, cingulum, and putamen. Our findings support a dementia prodrome model more strongly than a toxic stress model in this group of subjects. However, it remains likely that both processes as well as other factors contribute to the heterogeneity of volumetric brain changes in LLD.

The MRI brain correlates of depressed mood, anhedonia, apathy, and anergia in older adults with and without cognitive impairment or dementia

OBJECTIVES

We examined the magnetic resonance imaging (MRI) correlates of depressed mood, apathy, anhedonia, and anergia in older adults with and without cognitive impairment or dementia.

METHODS

This analysis included 270 community-dwelling older adults (59% male; 79% Caucasian; mean age 74.4 years) who were recruited into a multi-center longitudinal observational study of subcortical ischemic vascular disease (SIVD).The distribution of cognitive status included: cognitively intact (38%), cognitively impaired (27%), or demented (35%). All subjects underwent MRI and 41% were classified as having subcortical lacunes. MRI measures included cortical gray and white matter volumes, lacunar volumes in subcortical white and gray matter structures, volume of white matter hyperintensities, and total hippocampal volume. Depressed mood, anhedonia, anergia, and apathy apparent at the time of assessment were assessed using a behavioral assessment Associations between neuropsychiatric symptoms and MRI variables were evaluated using logistic regression.

RESULTS

Subjects with neuropsychiatric symptoms were more likely to be cognitively impaired or demented than those without neuropsychiatric symptoms. In multivariate models controlling for cognitive status, age, gender, and education, higher lacunar volume in white matter was independently associated with the presence of all four neuropsychiatric symptoms.

CONCLUSIONS

We report an association between the lacunar volumes in the white matter and depressed mood, anhedonia, apathy, and anergia, thus supporting the role of subcortical ischemic vascular disease in the pathogenesis of late-life neuropsychiatric disorders.

Brain structural and functional abnormalities in mood disorders: implications for neurocircuitry models of depression

The neural networks that putatively modulate aspects of normal emotional behavior have been implicated in the pathophysiology of mood disorders by converging evidence from neuroimaging, neuropathological and lesion analysis studies. These networks involve the medial prefrontal cortex (MPFC) and closely related areas in the medial and caudolateral orbital cortex (medial prefrontal network), amygdala, hippocampus, and ventromedial parts of the basal ganglia, where alterations in grey matter volume and neurophysiological activity are found in cases with recurrent depressive episodes. Such findings hold major implications for models of the neurocircuits that underlie depression. In particular evidence from lesion analysis studies suggests that the MPFC and related limbic and striato-pallido-thalamic structures organize emotional expression. The MPFC is part of a larger "default system" of cortical areas that include the dorsal PFC, mid- and posterior cingulate cortex, anterior temporal cortex, and entorhinal and parahippocampal cortex, which has been implicated in self-referential functions. Dysfunction within and between structures in this circuit may induce disturbances in emotional behavior and other cognitive aspects of depressive syndromes in humans. Further, because the MPFC and related limbic structures provide forebrain modulation over visceral control structures in the hypothalamus and brainstem, their dysfunction can account for the disturbances in autonomic regulation and neuroendocrine responses that are associated with mood disorders. This paper discusses these systems together with the neurochemical systems that impinge on them and form the basis for most pharmacological therapies.

Depressive symptoms, vascular risk factors, and Alzheimer's disease

BACKGROUND

Depressive symptoms in the elderly are associated with an increased Alzheimer's disease (AD) risk. We sought to determine whether the association between depressive symptoms and AD is explained by a history of vascular risk factors and stroke.

METHODS

Five hundred and twenty-six elderly persons from New York City without dementia at baseline were followed for a mean of 5 years. Depressive symptoms were assessed using the 17-item Hamilton Depression Rating Scale (HAM). Incident AD was ascertained using standard criteria. Diabetes, hypertension, heart disease, current smoking and stroke were ascertained by self-report. Proportional hazards regression was used to relate HAM scores to incident AD.

RESULTS

HAM scores were higher in persons with hypertension, heart disease, and stroke, which in turn were related to higher AD risk. AD risk increased with increasing HAM scores as a continuous logarithmically transformed variable (HR for one point increase=1.4; 95% CI=1.1,1.8) and as a categorical variable (HR for HAM >or= 10=3.4; 95% CI=1.5,8.1; p for trend=0.004 with HAM=0 as the reference). These results were virtually unchanged after adjustment for vascular risk factors and stroke, individually (HR for HAM >or= 10=3.4; 95% CI=1.5,8.1; p for trend = 0.004), and in a composite measure (HR for HAM >or= 10=3.0; 95% CI=1.2,7.8; p for trend=0.02).

CONCLUSION

The prospective relation between depressive symptoms and AD is not explained by a history of vascular risk factors and stroke, suggesting that other mechanisms may account for this association.

Brain structural and functional abnormalities in mood disorders: implications for neurocircuitry models of depression

The neural networks that putatively modulate aspects of normal emotional behavior have been implicated in the pathophysiology of mood disorders by converging evidence from neuroimaging, neuropathological and lesion analysis studies. These networks involve the medial prefrontal cortex (MPFC) and closely related areas in the medial and caudolateral orbital cortex (medial prefrontal network), amygdala, hippocampus, and ventromedial parts of the basal ganglia, where alterations in grey matter volume and neurophysiological activity are found in cases with recurrent depressive episodes. Such findings hold major implications for models of the neurocircuits that underlie depression. In particular evidence from lesion analysis studies suggests that the MPFC and related limbic and striato-pallido-thalamic structures organize emotional expression. The MPFC is part of a larger "default system" of cortical areas that include the dorsal PFC, mid- and posterior cingulate cortex, anterior temporal cortex, and entorhinal and parahippocampal cortex, which has been implicated in self-referential functions. Dysfunction within and between structures in this circuit may induce disturbances in emotional behavior and other cognitive aspects of depressive syndromes in humans. Further, because the MPFC and related limbic structures provide forebrain modulation over visceral control structures in the hypothalamus and brainstem, their dysfunction can account for the disturbances in autonomic regulation and neuroendocrine responses that are associated with mood disorders. This paper discusses these systems together with the neurochemical systems that impinge on them and form the basis for most pharmacological therapies.

Morphometric magnetic resonance imaging in psychiatry

Although advances in the clinical criteria of various axis I psychiatric disorders are continually being made, there is still considerable overlap in the clinical features, and diagnosis is often challenging. As a result, there has been substantial interest in using morphometric magnetic resonance imaging to better characterize these diseases and inform diagnosis. Region of interest and voxel-based morphometry studies are reviewed herein to examine the extent to which these goals are being met across various psychiatric disorders. It is concluded based on the studies reviewed that specific patterns of regional loss, although present in certain axis I disorders, are not, as yet, diagnostically useful. However, advances in outcome and treatment monitoring show considerably more promise for rapid application in psychiatry.

Anterior cingulate dysfunction in geriatric depression

BACKGROUND

Although several brain abnormalities have been identified in geriatric depression, their relationship to the pathophysiological mechanisms leading to the development and perpetuation of this syndrome remain unclear.

METHODS

This paper reviews findings on the anterior cingulate cortex (ACC) function and on the relationship of ACC abnormalities to the clinical presentation and the course of geriatric depression in order to elucidate the pathophysiological role of ACC in this disorder.

RESULTS

The ACC is responsible for conflict detection and emotional evaluation of error and is connected to brain structures that regulate mood, emotional valence of thought and autonomic and visceral responses, which are functions disturbed in depression. Geriatric depression often is accompanied by abnormalities in some executive functions and has a clinical presentation consistent with ACC abnormalities. Indices of ACC dysfunction are associated with adverse outcomes of geriatric depression.

CONCLUSIONS

Converging findings suggest that at least some ACC functions are abnormal in depression and these abnormalities are pathophysiologically meaningful. Indices of ACC dysfunction may be used to identify subgroups of depressed elderly patients with distinct illness course and treatment needs and serve as the theoretical background for novel treatment development.

Maternal separation of rat pups increases the risk of developing depressive-like behavior after subsequent chronic stress by altering corticosterone and neurotrophin levels in the hippocampus

Children that are abused have an increased risk for developing psychiatric disorders later in life, because of the negative effects of stress on the developing brain. We used a maternal separation model in rats to see how neurotrophins, stress hormones, behavior and the anti-oxidant potential of serum are affected. Rat pups were separated from their mothers for 3h/day on days 2-14. Maternal separation caused changes in levels of NGF and NT-3 in the dorsal and ventral hippocampus, increased basal corticosterone levels and decreased ACTH levels after acute restraint stress. The anti-oxidant potential of the rat serum was significantly lower in the maternal separation group. Depressive-like behavior, measured during a forced swim test, was seen in maternally separated rats after additional chronic stress during adulthood. Maternal separation caused downregulation of neurotrophins in the ventral hippocampus, possibly as an effect of high corticosterone levels, but compensatory mechanisms against cell death may be involved as neurotrophin levels increased in the dorsal hippocampus. Decreased anti-oxidant potential of serum could have been an effect of downregulated neurotrophin levels.

Making sense of neuroimaging in psychiatry

OBJECTIVE

Neuroimaging of psychiatric disorders has increased exponentially in the last decade; however, much of the uptake thus far has been in the realm of research. We anticipate that clinical use of neuroimaging modalities in psychiatry will increase dramatically in the near future and suggest that clinicians need to be aware of the potential applications.

METHOD

The authors conducted an extensive MEDLINE, EMBASE, PubMED and PsychInfo search of the published literature (1965-2007) using a variety of search terms to find relevant articles. Bibliographies of retrieved papers were further scrutinised for publications of interest, as were indices of books. Articles that reported clinically significant findings and research reports conducted using pertinent neuroimaging modalities were reviewed in detail.

RESULTS

The review suggests that exciting neuroimaging advances are being made that have relevance to psychiatry. Novel neuroimaging applications with potential clinical utility are rapidly emerging and the accessibility and use of these technologies will increase in coming years. Clinically meaningful findings have begun to emerge in mood disorders, post-traumatic stress disorder, schizophrenia and dementia. Coupling multimodal imaging with genetics and pharmacotherapeutic studies will further assist in understanding the pathophysiology of neuropsychiatric disorders.

CONCLUSION

It is important that clinicians understand the benefits and limitations of modern neuroimaging techniques and are also suitably equipped to appraise future developments. The use of neuroimaging in evaluating psychopathology is likely to impact upon the future nosology of psychiatric disorders, and assist in diagnosis and clinical management. The integrated use of neuroimaging in conjunction with clinical assessments promises to improve clinical care and markedly alter psychiatric practice.

Volumetric neuroimaging investigations in mood disorders: bipolar disorder versus major depressive disorder

BACKGROUND

As patients with mood disorders manifest heterogeneity in phenomenology, pathophysiology, etiology, and treatment response, a biological classification of mental disease is urgently needed to advance research. Patient and methodological variability complicates the comparison of neuroimaging study results and limits heuristic model development and a biologically-based diagnostic schema.

OBJECTIVE

We have critically reviewed and compared the magnetic resonance neuroimaging literature to determine the degree and directionality of volumetric changes in brain regions putatively implicated in the pathophysiology of major depressive disorder (MDD) versus bipolar disorder (BD).

METHODS

A total of 140 published magnetic resonance imaging investigations evaluating subjects with BD or MDD were selected to provide a summary and interpretation of volumetric neuroimaging results in MDD and BD. Further commentary on the pathophysiological implications, and putative cellular and pharmacological mechanisms, is also provided.

RESULTS

While whole brain volumes of patients with mood disorders do not differ from those of healthy controls, regional deficits in the frontal lobe, particularly in the anterior cingulate and the orbitofrontal cortex, appear to consistently differentiate subjects with mood disorders from the general population. Preliminary findings also suggest that subcortical structures, particularly the striatum, amygdala, and hippocampus, may be differentially affected in MDD and BD.

CONCLUSIONS

Structural neuroimaging studies have consistently identified regional abnormalities in subjects with mood disorders. Future studies should strive to definitively establish the influence of age and medication.

Striatal dopamine transporter levels correlate with apathy in neurodegenerative diseases

OBJECTIVES

The aim of the present study was to stress the relationship between neuropsychiatric symptoms and most particularly apathy and striatal dopamine uptake in patients with Alzheimer's disease (AD) or dementia with Lewy body (DLB).

PATIENTS AND METHODS

Twenty-two patients (AD n=14; DLB n=8) were included. All patients had neuropsychological and behavioral examination including Mini Mental Test Examination (MMSE), Neuropsychiatric Inventory (NPI), and UPDRS for the motor activity assessment. Apathy dimensions, emotional blunting, lack of initiative and lack of interest were assessed using the Apathy Inventory (AI). Dopamine transporter (DAT) striatal uptake was assessed using (123)I-FP-CIT (DaTSCAN) SPECT. Quantitative measurements were obtained in 3D using a method which compensates for physical detection biases including partial volume effect.

RESULTS

We observed a correlation between DAT uptake and NPI's domains only for apathy. More specifically using the AI, lack of initiative significantly correlated with bilateral putamen DAT uptake. Using partial correlation coefficients controlling for the UPDRS score, the correlation remained significant between lack of initiative and right and left putamen DAT uptake.

CONCLUSION

These results demonstrate a relationship between apathy and DAT levels independent from motor activity. They suggest that the patients with neurodegenerative diseases presenting with apathy are characterized by some degree of dopaminergic neuronal loss.

Alcoholism and judgments of affective stimuli

This study sought to differentiate alcoholism-related changes in judgments of emotional stimuli from those of other populations in which such changes have been documented. Two sets of visual stimuli, one containing words and the other containing drawings of faces (representing a range of emotional content), were presented to abstinent alcoholic adults with and without Korsakoff's syndrome, as well as to a healthy control group and four groups of patients with other neurobehavioral disorders: Parkinson's disease, schizophrenia, depression, and posttraumatic stress disorder. Participants rated the stimuli according to emotional valence and intensity of emotion. Results implicated bi-hemispheric frontal and subcortical involvement in the abnormalities of emotion identification associated with alcoholism, and they also support the notion of age-related vulnerabilities in conjunction with alcoholism.

Kynurenine pathway in major depression: evidence of impaired neuroprotection

The neurodegeneration hypothesis proposed major depression as a consequence of the imbalance between neuroprotective and neurodegenerative metabolites in the kynurenine pathway. To test the hypothesis, plasma tryptophan and kynurenine pathway metabolites were studied in 58 patients with major depression and 189 normal controls. The mean tryptophan breakdown index was higher (p=0.036), and mean kynurenic acid concentration and mean neuroprotective ratios were lower, in depressed patients (p=0.003 and 0.003, respectively). In receiver operating characteristic analysis, the kynurenic acid concentrations and the neuroprotective ratio showed clear discrimination between depressed patients and controls with area under the curve 79% and 76.3% respectively. The neuroprotective ratio did not change after treatment in those with repeated episodes of depression but it increased significantly (p=0.044) in those with first episodes. The results suggested that the reduction in neuroprotective markers, which indicated an impaired neuroprotection, might play an important role in pathophysiology of major depression.

Subcortical and medial temporal MR-detectable metabolite abnormalities in unipolar major depression

The purpose of the present study was to determine whether MR-detectable alterations of choline-containing compounds in two key neural systems involved in major depression disorder namely the hippocampus and the basal ganglia can be detected. Multislice proton magnetic resonance spectroscopic imaging was applied in 11 patients with major depressive disorder (MDD) and ten matched healthy subjects. Voxels were selected from the left and right side of the hippocampus and the putamen. Significantly lower choline-containing compounds in the hippocampus and significantly higher choline-containing compounds in the putamen of patients with MDD compared to healthy subjects were found. No significant differences were found for the other metabolites in the two regions evaluated. Abnormal levels of choline-containing compounds most likely reflect altered membrane phospholipid metabolism. A reduced level in the hippocampus and an increased level in the putamen suggest regionally opponent membrane abnormalities.

Psychological distress in migrants in Australia over 50 years old: a longitudinal investigation

BACKGROUND

Although it is a well-known fact that migration is a risk factor contributing to psychopathology, little is known in migrants who migrated in their old age. The present study examined whether origin of countries and visa types predicted psychological distress over a period of 1 year and whether their association changed after factors in health, social roles, cohort effect and social support were adjusted.

METHODS

A nationwide representative sample of 431 migrants who aged 50 and above were interviewed in 2000-2001 and 359 of them were re-interviewed 1 year after the baseline assessment. 12-item General Health Questionnaire (GHQ-12) was used measure psychological distress and a series of questions regarding socio-demographic characteristics (age, gender, living alone), days in Australia, origin of countries, visa types, health, social role, cohort effect, and social support were also included.

RESULTS

GHQ-12 scores did deteriorate over a period of 1 year among older migrants to Australia. In multiple regression analyses, origin of countries and visa types were significant predictors of future GHQ-12 scores. Baseline GHQ-12 scores, age, gender, living alone, days in Australia, poor self-rated health, the presence of heart disease, diabetes, and asthma, being a student or economically inactive, widowhood or divorce, as well as education were also significant predictors of GHQ-12 scores at 1-year follow-up.

CONCLUSIONS

The status of refugees predicts future psychological distress in older migrants even when other known correlates of psychological distress are controlled.

Structural neuroimaging research methods in geriatric depression

Geriatric depression consists of complex and heterogeneous behaviors unlikely to be caused by a single brain lesion. However, there is evidence that abnormalities in specific brain structures and their interconnections confer vulnerability to the development of late-life depression. Structural magnetic resonance imaging methods can be used to identify and quantify brain abnormalities predisposing to geriatric depression and in prediction of treatment response. This article reviews several techniques, including morphometric approaches, study of white matter hyperintensities, diffusion tensor imaging, magnetization transfer imaging, t2 relaxography, and spectroscopy, that have been used to examine these brain abnormalities with a focus on the type of information obtained by each method as well as each method's limitations. The authors argue that the available methods provide complementary information and that, when combined judiciously, can increase the knowledge gained from neuroimaging findings and conceptually advance the field of geriatric depression.

Depression in Parkinson's disease. Diffusion tensor imaging study

OBJECTIVES

The pathophysiology of depression and anxiety in Parkinson's disease remains obscure. We aimed to compare the fractional anisotropy (FA) values of Parkinson's disease (PD) patients with and without depression to investigate the nature of depression in PD.

METHODS

Twenty-eight patients were divided into two groups: those with depression and those without. Diagnosis of depression was made using the DSM-IV criteria. Patients in the two groups were matched for Hoehn Yahr stage.

RESULTS

There were significant reductions in FA values in the bilateral frontal ROIs possibly representing anterior cingulate bundles.

CONCLUSIONS

The anterior cingulate bundles play an important role in depression in PD, and some aspects of depression in PD have pathological processes in common with de novo depression.

Volumetric brain imaging studies in the elderly with mood disorders

Volumetric neuroimaging studies of the elderly with affective disorders provide important insights into the underlying physiology of the illnesses. Advantages of studying the elderly include the ability to make various assessments and obtain a history differentiating subtypes of illness. However, challenges to studying the elderly include the heterogeneity of affective illnesses and confounds of medical comorbidity and medications. Volumetric assessments have provided important information in the neural mechanisms of mood regulation, especially in the overlap of cognitive disorders. This article reviews articles describing findings of volumetric analyses in elderly with unipolar depression and bipolar disorders, and compares and contrasts these findings with the larger volumetric research in affective disorders.

Minor depression and brain perfusion images in Parkinson's disease

Depression is common in individuals with Parkinson's disease. However, the pathophysiology of depression in Parkinson's disease remains obscure. Here we compared brain perfusion images of Parkinson's disease patients with and without depression to investigate correlations between depression and brain perfusion images in Parkinson's disease. We divided 40 consecutive patients with Parkinson's disease into two groups: patients with minor depression (n = 22) and patients without depression (n = 18). We then compared brain perfusion images between the two groups. As a result, hypoperfusion of the left superior and inferior frontal gyrus was demonstrated in depressed patients. These results were partially in agreement with previous studies on de novo and parkinsonian major depression. We could not conclude on whether pathophysiological mechanisms differed between de novo depression and depression with Parkinson's disease, and between major and minor depressions.

Volume deficits of subcortical nuclei in mood disorders A postmortem study

Structural changes in subcortical nuclei may underlie clinical symptoms of mood disorders. The goal was to determine whether macrostructural changes exist in brain areas assumed to be involved in regulation of mood and whether such changes differ between major depressive disorder and bipolar disorder. A case-control design was used to compare volumes of all major subcortical nuclei. Brains of patients with major depressive disorder (n = 9) or bipolar disorder (n = 11) or of individuals without a neuropsychiatric disorder (n = 22) were included. Exclusion criteria were a history of substance abuse or histological signs of neurodegenerative disorders. Volumes of the striato-pallidal nuclei, of the hypothalamus, thalamus, amygdala, hippocampus and basal limbic forebrain were determined in the right and left hemisphere by planimetry of 20 mum whole brain serial paraffin sections. Comparisons between patients with bipolar disorder, major depressive disorder and controls showed a significant (Lambda = 0.35, F(20,56) = 1.93, P = 0.028) overall difference in volumes of all investigated regions with strong effect sizes ( f > 0.40) contributed by the hypothalamus, external pallidum, putamen and thalamus. As compared to controls, a strong effect size (f > 0.40) was found in the bipolar group for smaller volumes of the hypothalamus, external pallidum, putamen and thalamus,whereas in patients with major depressive disorder a strong effect size was only found for a smaller volume of the external pallidum. In conclusion our data suggest that pathways presumably involved in mood regulation have structural pathology in affective disorders with more pronounced abnormalities in bipolar disorder.

Basal ganglia volumetric studies in affective disorder: what did we learn in the last 15 years?

Until today, morphometric neuroimaging studies on affective disorders concentrate on the limbic system, especially the hippocampus, amygdala, and anterior cingulate. In most of the studies and reviews available today, the basal ganglia are of secondary interest. It seems that the basal ganglia are interest of neurologist, whereas the limbic system is reserved for psychiatric neuroimaging studies. We follow a different approach in this review, studying all available papers on MRI research of the basal ganglia in unipolar depression and bipolar disorder. We found a possibly larger neostriatum in bipolar and possibly smaller one in unipolar patients. None of the unipolar studies found any larger basal ganglion, and only one out of 12 bipolar studies found smaller basal ganglia. Both findings seemed to depend on age (tendency toward smaller volumes in unipolar and bipolar with older age), sex (men tending to pathology in both disorders) and bipolar patients show a possible influence of medication, which is not assessed so far in unipolar depression. We conclude that several methodological shortcomings in volumetric MRI research on the basal ganglia in affective disorders make it necessary to imply more research in this area. We suggest (a) better MRI methods (we do not have a single volumetric 3 Tesla study in this patient group); (b) studies of medication-naïve patients (thus ruling out the medication effect); (c) Studies that directly compare unipolar depressed and bipolar patients are needed to determine whether these apparent differences in morphometric abnormalities, as observed through the mediating comparison with healthy subjects, are real.

Late-life depression: a model for medical classification

Geriatric psychiatric syndromes might serve as the starting point for a medical classification of psychiatric disorders, because their medical and neurological comorbidity and their clinical, neuropsychological, and neuroimaging features often reflect specific brain abnormalities. Geriatric syndromes, however, consist of complex behaviors that are unlikely to be caused by single lesions. We propose a model in which aging-related changes in specific brain structures increase the propensity for the development of certain psychiatric syndromes. The predisposing factors are distinct from the mechanisms mediating the expression of a syndromic state, much like hypertension is distinct from stroke, but constitutes a morbid vulnerability. We argue that research seeking to identify both brain abnormalities conferring vulnerability as well as the mediating mechanisms of symptomatology has the potential to lead to a medical classification of psychiatric disorders. In addition, a medical classification can guide the effort to improve treatment and prevention of psychiatric disorders as it can direct therapeutic efforts to the underlying predisposing abnormalities, the syndrome-mediating mechanisms, and to development of behavioral skills needed for coping with adversity and disability.

IDO and interferon-alpha-induced depressive symptoms: a shift in hypothesis from tryptophan depletion to neurotoxicity

Studies show that administration of interferon (IFN)-alpha causes a significant increase in depressive symptoms. The enzyme indoleamine 2,3-dioxygenase (IDO), which converts tryptophan (TRP) into kynurenine (KYN) and which is stimulated by proinflammatory cytokines, may be implicated in the development of IFN-alpha-induced depressive symptoms, first by decreasing the TRP availability to the brain and second by the induction of the KYN pathway resulting in the production of neurotoxic metabolites. Sixteen patients with chronic hepatitis C, free of psychiatric disorders and eligible for IFN-alpha treatment, were recruited. Depressive symptoms were measured using the Montgomery Asberg Depression Rating Scale (MADRS). Measurements of TRP, amino acids competing with TRP for entrance through the blood-brain barrier, KYN and kynurenic acid (KA), a neuroprotective metabolite, were performed using high-performance liquid chromatography. All assessments were carried out at baseline and 1, 2, 4, 8, 12 and 24 weeks after treatment was initiated. The MADRS score significantly increased during IFN-alpha treatment as did the KYN/TRP ratio, reflecting IDO activity, and the KYN/KA ratio, reflecting the neurotoxic challenge. The TRP/CAA (competing amino acids) ratio, reflecting TRP availability to the brain, did not significantly change during treatment. Total MADRS score was significantly associated over time with the KYN/KA ratio, but not with the TRP/CAA ratio. Although no support was found that IDO decreases TRP availability to the brain, this study does support a role for IDO activity in the pathophysiology of IFN-alpha-induced depressive symptoms, through its induction of neurotoxic KYN metabolites.

Effects of exposure to a predator on behaviour and serotonergic neurotransmission in different brain regions of C57bl/6N mice

Clinical studies and animal models have provided evidence that stress and serotonin may play a role in the aetiology of psychiatric diseases such as depression and anxiety. In addition, reciprocal interactions between stress and serotonergic neurotransmission have been demonstrated. However, the relationships between stress, serotonin and behaviour are far from completely understood. In this integrative study, we aimed to elucidate the effect of the psychological stress model predator exposure on behaviour and serotonergic neurotransmission in mice. We used a high time-resolution microdialysis method to measure extracellular levels of serotonin (5-hydroxytryptamine, 5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in the hippocampus, prefrontal cortex, lateral septum and caudate putamen of C57BL/6N [corrected] mice, before (08:30-10:30 h), during (10:30-11:00 h) and after exposure (11:00-14:00 h) to a rat. Detailed behavioural observations were also made. Rat exposure resulted in behavioural activation, with predominant risk-assessment activities, and in increases in hippocampal, cortical, septal but not striatal 5-HT and 5-HIAA. When rat exposure was repeated on the consecutive day, small behavioural differences and reductions in 5-HIAA levels, but no differences in the 5-HT response, as compared with the first exposure were observed. As increases in 5-HT often coincide with behavioural activation, it was particularly interesting to find that 5-HT also increased in periods when mice only made minor movements such as sniffing, and that an effect of predator stress was absent in the caudate putamen. Our results indicate that the presence of the rat leads to differential activation of serotonergic neurotransmission in higher brain structures, probably involved in the coping response to this potentially life-threatening situation.

Developmental abnormalities in striatum in young bipolar patients: a preliminary study

OBJECTIVES

Anatomical abnormalities in the basal ganglia of adult mood disorder patients have been reported. To investigate whether these abnormalities are present early in illness course, we compared the volume of striatal structures in young bipolar patients and healthy controls.

METHODS

Brain magnetic resonance images of 15 children and adolescents who met DSM-IV criteria for bipolar disorders and 21 healthy controls were obtained. Measurements were performed manually, by trained evaluators, who were blind to subjects' diagnosis. The volumes of caudate and putamen were compared in patients and controls.

RESULTS

The volumes of striatal structures were not significantly different in patients and controls (ANCOVA, p > 0.05). However, we found a significant inverse relationship between age and the volumes of left caudate (r = -0.72, p < 0.01), right caudate (r = -0.66, p = 0.02) and left putamen (r = -0.71, p = 0.01) in bipolar patients, not present in healthy controls.

CONCLUSIONS

Abnormalities in striatal development may be involved in the pathophysiology of bipolar disorder.

Topography of cortico-striatal connections in man: anatomical evidence for parallel organization

Tracing studies in non-human primates support the existence of several parallel neuronal circuits involving cerebral cortex, basal ganglia and thalamus. Distinct functional loops were proposed to underlie multiple aspects of normal and pathological behaviour in man. We present here the first anatomical evidence for separate corticostriatal systems in humans. Neural connections of the sensorimotor and prefrontal cortex to the striatum were studied in one human brain using the Nauta method for anterogradely degenerating axons. Axons originating from a lesion in the left sensorimotor cortex, including the face area, were found to terminate in the superolateral part of the ipsilateral putamen, forming a narrow band in its posterior part. Inside the band, the distribution of degenerating axons was inhomogeneous; high-density clusters of approximately 2.5 mm in diameter were separated by regions with less dense cortical projections. Axons originating from a small lesion in the fundus of the right superior frontal sulcus were found in the upper part of the ipsilateral caudate nucleus. The existence of discrete and anatomically segregated terminal patches originating from distinct cortical regions suggests parallel organization of cortico-striatal connections in man.

Is major depression a neurologic disorder with psychiatric symptoms?

In the last decade, multiple investigator groups have identified structural changes of various neuroanatomic structures in patients with idiopathic major depression and bipolar disorders. Using high-resolution MRI of the brain and functional neuroimaging studies (i.e., PET, SPECT), researchers have described decreases in the volume of hippocampal formation, amygdala, entorhinal cortex, various frontal lobe structures, and basal ganglia, in addition to abnormal cerebral blood flow and metabolic activity in these structures as well as in thalamic nuclei. Similar structural and functional changes have been identified in patients with depression associated with a variety of neurologic disorders (i.e., stroke, Parkinson's disease, epilepsy, Alzheimer's dementia). In addition, recent data have shown that depression is a risk factor for the development of several neurologic disorders, including epilepsy, stroke, and Parkinson's disease and bears a negative impact on the course and outcome of most neurologic disorders. This article reviews these data and provides evidence that major depressive and bipolar disorders may in fact be neurologic disorders with psychiatric symptoms.

Neurocognitive profiles in elderly patients with frontotemporal degeneration or major depressive disorder

Major depressive disorder (MDD) and frontotemporal dementia (FTD) are both disorders in elderly populations that involve the prefrontal cortex and appear to have similar neurocognitive deficits. This review examined whether there are testable deficits in cognition that are consistent across individuals within the same neuropathological condition that could be used to facilitate early diagnoses. Medline and PsychInfo databases were searched for cognitive studies of depressed and FTD patients that used a matched control group and reported findings with means and standard deviations (N = 312). Effect sizes for FTD patients with mild and moderately advanced disease were compared to effect sizes within subgroups of depressed patients, such as inpatients, outpatients and community volunteers. Moderately advanced FTD patients were more impaired than depressed patients over all domains, particularly in language ability, although depressed inpatients appeared similar to FTD patients in some domains. Effect sizes for FTD patients who were in the mild, or early, stage of the disease (MMSE = 28) were similar to those of depressed outpatients but slightly worse than those of community volunteers in all domains except semantic memory and executive ability. In the latter two domains, even mild FTD patients had notably large deficits. All FTD patients showed more severe deficits in some domains relative to other domains. In contrast, depressed patients tended to vary by clinical presentation or disease severity, but the magnitude of impairment for each subgroup remained relatively consistent across domains and they did not have the severe focal deficits in one or two domains demonstrated by FTD patients.

Volumes of the caudate nuclei in women with somatization disorder and healthy women

Very little is known about the pathophysiology of somatization disorder. This study was designed to analyze the volumes of some brain structures possibly involved in somatization based on the observation of glucose metabolism of the brain in these patients. We studied 10 female patients with a diagnosis of somatization disorder or undifferentiated somatoform disorder with no comorbid current DSM-IV Axis I disorder and compared them to 16 healthy female volunteers using brain MRI (1.5 T instrument). The patients had bilateral enlargement of caudate nuclei volumes compared with healthy volunteers. These volume differences in the caudate nuclei could be associated with the pathophysiology of somatization.

Cognitive and neurological impairment in mood disorders

Disorders of mood are accompanied by a range of cognitive and neurological impairments. Similar types of cognitive deficits are shared by patients with unipolar depression and bipolar disorder. Given the disparate clinical nature of these two disorders, it is interesting and informative to understand that they share common impairments in cognition. Neuro-imaging studies indicate that these impairments in both patient populations may be subserved by disruptions of the dorsal lateral and ventral medial PFC. An important problem that remains for clinicians is that some neurological symptoms are linked specifically to the adverse pharmacological effects of antidepressant agents, mood stabilizers, and neuroleptic agents. Research has shown a relation between mood and cognitive ability. Studies also have shown an association between mood and specific types of neurological dysfunction. Although few studies have examined all three symptom domains within one investigation, preliminary reports indicate that mood, cognition, and motor function may be linked to one another by complex mechanisms. Moreover, either type of abnormality that persists in the euthymic state suggests that a fundamental neural dysfunction is unaffected by treatment with existing means. Understanding the neural mechanisms that underlie mood, cognition, and movements may help to devise better treatments that do not influence cognitive or neurological functions,yet treat mood successfully.

Structural MRI changes of the brain in depression

For many years, investigators have been trying to identify the neuroanatomical structures responsible for the development of neuropsychiatric disorders, specifically depression and schizophreniform disorders. The available data were based on observations made in neurological patients who developed a psychiatric comorbid disorder following the neurologic insult. With the advances in high-resolution magnetic resonance imaging and functional neuroimaging studies, we have witnessed in the last decade a wealth of new data that identify structural neuroimaging changes in mesial temporal structures, prefrontal cortex and basal ganglia in major depressive disorders. The purpose of this article is to briefly review the published data on neuroanatomical structural changes associated with major depressive and bipolar disorders.

Mood disorders - review of structural MRI studies

BACKGROUND

Mood disorders are related to considerable morbidity and mortality, and although there is little doubt that they are brain-based disorders, their neural correlates still remain elusive. A neuro-anatomic model of mood regulation comprising the prefrontal cortex, amygdala-hippocampus complex, thalamus, basal ganglia, and connections among these areas has been proposed.

OBJECTIVE

We reviewed the evidence for regional brain abnormalities in bipolar disorder, and attempted to integrate available findings into a comprehensive pathophysiological model of illness.

METHODS

A computerized Medline Ovid search was conducted for the period 1966-2002, and complemented by a manual search of bibliographical references from recent reviews. Articles meeting specified criteria were included.

RESULTS

Hyperintense lesions in cortical and subcortical regions are the most consistently reported and widely studied structural abnormalities. Smaller prefrontal cortical volume is a common finding in bipolar disorder and unipolar depression. Enlarged amygdala (in bipolar disorder) and smaller hippocampus (in unipolar depression) have been reported by several groups. Decreased volumes (in unipolar depression) and increased or unaltered volumes (in bipolar disorder) of striatal structures have been reported.

CONCLUSIONS

Bipolar and unipolar mood disorders are associated with detectable structural brain abnormalities. The histopathology underlying such anatomical changes remains to be elucidated. To reach more definitive conclusions about neuroanatomical changes that take place during the course of mood disorders, prospective longitudinal studies are needed. Also, integration with functional imaging is necessary in order to elucidate the relevance of identified structural abnormalities.

Anatomical MRI study of basal ganglia in major depressive disorder

The basal ganglia form a part of the brain neuroanatomic circuits that may be involved in mood regulation. Decreases in basal ganglia volumes have been previously reported in major depressive disorder patients in comparison to healthy controls. In this study, we measured caudate, putamen, and globus pallidus volumes in 25 patients with major depressive disorder (4 M; age+/-S.D.=41+/-11 years) and 48 healthy controls (29 M; age+/-S.D.=35+/-10 years), using high-resolution magnetic resonance imaging (MRI), in an attempt to replicate prior findings. Unlike most previous studies, we did not find significant differences between patient and control groups in basal ganglia volumetric measures. Nonetheless, there was a significant interaction between diagnosis and cerebral hemisphere, with MDD patients showing decreased asymmetry in globus pallidus volumes in comparison with healthy controls. Furthermore, in the patient group, left putamen volumes correlated inversely with length of illness, and left globus pallidus volume correlated directly with number of prior depressive episodes. These findings suggest that abnormalities in lateralization and possibly neurodegenerative changes in basal ganglia structures participate in the pathophysiology of major depressive disorder.