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 disor- der 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 ran- dom 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. Hum Brain Mapp 30:3719-3735, 2009. V C 2009 Wiley-Liss, Inc.

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

Context Although differences in clinical characteristics exist between major depressive disorder (MDD) and bipolar disorder (BD), consistent structural brain abnormalities that distinguish the disorders have not been identified. Objectives To investigate structural brain changes in MDD using meta-analysis of primary studies; assess the effects of medication, demographic, and clinical variables; and compare the findings with those of a meta-analysis of studies on BD. Data Sources The MEDLINE, EMBASE, and PsycINFO databases were searched for studies from January 1, 1980, to February 2, 2010. Study Selection Two hundred twenty-five studies that used magnetic resonance imaging or x-ray computed tomography to compare brain structure in patients with MDD with that of controls were included in an online database, and 143 that measured common brain structures were selected for meta-analysis. Data Extraction Twenty-five variables, including demographic and clinical data, were extracted from each study, when available. For the meta-analysis, mean structure size and standard deviation were extracted for continuous variables, and the proportion of patients and controls with an abnormality in brain structure was extracted for categorical variables. Data Synthesis Compared with the structure of a healthy brain, MDD was associated with lateral ventricle enlargement; larger cerebrospinal fluid volume; and smaller volumes of the basal ganglia, thalamus, hippocampus, frontal lobe, orbitofrontal cortex, and gyrus rectus. Patients during depressive episodes had significantly smaller hippocampal volume than patients during remission. Compared with BD patients, those with MDD had reduced rates of deep white matter hyperintensities, increased corpus callosum cross-sectional area, and smaller hippocampus and basal ganglia. Both disorders were associated with increased lateral ventricle volume and increased rates of subcortical gray matter hyperintensities compared with healthy controls. Conclusions The meta-analyses revealed structural brain abnormalities in MDD that are distinct from those observed in BD. These findings may aid investigators attempting to discriminate mood disorders using structural magnetic resonance imaging data.

Structural neuroimaging studies in major depressive disorder. Meta-analysis and comparison with bipolar disorder

Background
Some, although not all, studies report small hippocampal volume in patients with major depressive disorder (MDD) relative to healthy controls. Here, we explore the contribution of key demographic and clinical variables to this difference.

A meta-analysis examining clinical predictors of hippocampal volume in patients with major depressive disorder.

Major depressive disorder (MDD) has until recently been conceptualized as an episodic disorder associated with 'chemical imbalances' but no permanent brain changes. Evidence has emerged in the past decade that MDD is associated with small hippocampal volumes. This paper reviews the clinical and biological correlates of small hippocampal volumes based on literature searches of PubMed and EMBASE and discusses the ways in which these data force a re-conceptualization of MDD. Preclinical data describe the molecular and cellular effects of chronic stress and antidepressant treatment on the hippocampus, providing plausible mechanisms through which MDD might be associated with small hippocampal volumes. Small hippocampal volumes are associated with poor clinical outcome and may be a mechanism through which MDD appears to be a risk factor for Alzheimer's disease. The pathways through which stress may be linked to MDD, the emergence of chronicity or treatment resistance in MDD and the association between MDD and memory problems may be at least partially understood by dissecting the association with depression and changes in the hippocampus. MDD must be re-conceived as a complex illness, associated with persistent morphological brain changes that are detectable before illness onset and which may be modified by clinical and treatment variables.

The hippocampus in major depression: evidence for the convergence of the bench and bedside in psychiatric research?

Although referred to in passing in several places, there have been few attempts to specify the functions of the human olfactory system. This article presents an initial effort at identifying and categorizing these functions, using 3 sources of information as a guide: 1) losses experienced by anosmic participants; 2) olfactory function in other mammals; and 3) capacity, namely, whether the human olfactory system can support the suggested function and whether there is evidence that it does. Three major classes of function were identified, relating to Ingestion (Detection/identification prior to ingestion; Detection of expectancy violations; Appetite regulation; Breast orientation and feeding), Avoiding environmental hazards (Fear related; Disgust related), and Social communication (Reproductive [inbreeding avoidance, fitness detection in prospective mates]; Emotional contagion [fear contagion, stress buffering]). These suggested functions were then examined with respect to 1) issues of ecological validity in human olfactory research; 2) their impact on olfactory loss; and 3) their general and specific implications for the study of human olfaction.

/pdf/an-initial-evaluation-of-the-functions-of-human-olfaction-2weocuy188.pdf

An Initial Evaluation of the Functions of Human Olfaction

A number of studies have used magnetic resonance imaging to examine the volumetric differences in temporal lobe structures especially the hippocampus in patients suffering from major depressive disorder (MDD). Although some studies reported lower hippocampal volume, others did not. It is proposed that the inconsistency among studies may be due to the heterogeneity of patients and antidepressant treatment during scanning. In this study, we aimed to evaluate the hippocampus in drug-free patients. Twenty-four patients (6 males and 18 females) diagnosed as having MDD according to the DSM-IV criteria and 24 healthy controls (6 males and 18 females) were included in the study. Eleven of the patients had their first mood episode and were drug-naive. Other patients were drug-free for at least 4 weeks. The Hamilton depression rating scale (HAM-D) assessed the severity of depression. Magnetic resonance imaging was performed on a 1.5-T MR unit. The Cavalieri method of modern design stereology in conjunction with point counting was used to estimate hippocampal volume. The data were evaluated by a repeated measure of ANOVA and the intracranial volume was taken as a covariate. A significant hippocampal volume difference was observed between the patients and healthy controls (F=4.43, df=1.45, P 0.05). The left hippocampus of patients was significantly lower than those of controls (t=1.98, df=46, P<0.05). Correlation analysis showed a correlation between HAM-D scores and the right hippocampal volume. The results of this study indicate that hippocampus volume is reduced in depressed patients especially in the left side. This finding in the drug-free depressed outpatients without a history of alcohol dependence supports previous studies that have reported lower hippocampal volume.

Reduced hippocampal volume in drug-free depressed patients.

To reduce the risk of iatrogenic injury to sympathetic chain during anterior and anterolateral approaches to the cervical spine, its location has to be well defined and known by surgeons. We analyzed the course of sympathetic chain and its ganglia from C7 up to its entry into the cranial base and its relationship mainly with the longus colli (LC). Formalin fixed 20 human cadavers were dissected under operating microscope. Measurement of the dimensions of the ganglia, distance of the trunk to the LC, and the angles identifying the course of the chain were performed. Superior and inferior cervical/cervicothoracic ganglion were observed in all specimens, the middle cervical ganglion was observed in 48% of the specimens. The middle ganglion consisted of two ganglia in 10% of the dissected sides. Forty percent of the inferior cervical/cervicothoracic ganglion was at the C7 level, 25% was at C7-Th1 disc level, and 35% was at Th1 level. Vertebral ganglion was detected in only 8% of the specimens. The course of the sympathetic trunk converges medially descending from upper cervical levels to the lower levels. Anterior surgical approach to the cervical spine is a commonly used procedure. Although Horner syndrome due to sympathetic injury is not a common sequence of cervical operations, our findings support the current few reports on the subject and should be useful to any surgeon who operates in the cervical region to avoid this uncommon complication.

Neuroanatomy of cervical sympathetic trunk: a cadaveric study.

The aim of this study was to observe the course of the marginal mandibular branch of the facial nerve (MMBFN) in relation to the inferior border of the mandible and parotid gland and its relevance to surgical procedures such as rhytidectomy and parotid gland surgery. In this study, 50 specimens were dissected. The relationships between the MMBFN and the inferior border of the mandible were recorded and analyzed. We found that posterior to the facial artery, the MMBFN ran above the inferior border of the mandible in 37 (74%) of the specimens. In 11 (22%) specimens, below the inferior border of the mandible it was divided into two branches at the crossing point with the facial artery. In 2 (4%) specimens the MMBFN divided into two branches at the point of emergence from the parotid gland. There were no statistical differences between the left and right sides, and both sexes. The MMBFN is one of the most vulnerable branches to surgical injury because of its location. For this reason, the surgeons who are willing to operate on this area, especially for the rhytidectomies, should have a true knowledge about the anatomy of this branch.

Localization of the marginal mandibular branch of the facial nerve

BackgroundSphenopalatine artery (SPA) ligation or cauterization stands to be one of the most common management options of refractory epistaxis. Ramification pattern of SPA as it passes through sphe...

Anatomic variations of sphenopalatine artery and minimally invasive surgical cauterization procedure.

Dissection of a human body during an anatomy course raises questions about invasion of privacy, cadaver sources, dying and death for medical students. The technical orientation in any medical education process tends to motivate students towards a purely biological view of the human body. An orientation lesson was performed, including technical instructions, with particular emphasis on how to deal with emotions. Two hundred and forty-two second-year students were asked to complete a questionnaire and two State-Trait Anxiety Inventory (STAI) self-reports. One hundred and two students participated in an orientation lesson (group A) and 140 students did not (group B). Data were analyzed using SPSS. The t-test and chi-square test were used to evaluate differences between the groups. Group A students showed significantly better performance in both a verbal anatomy examination and multiple-choice test than group B students (p=0.001). There were no differences between group A and B students in the state and trait anxiety levels, willingness to donate their body or organs, belief in life after death, social activity or gender. The goal of including consideration of psychosocial factors in an anatomy course would allow students a thoughtful interpretation of their laboratory experience in the context of their professional development as physicians.

Orientation lesson in anatomy education

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