Our findings suggest that depressive symptoms in AD patients are associated with cortical thinning in temporal and parietal regions. In addition, our findings suggest that τ protein pathology in these areas may contribute to the development of depressive symptoms in AD.

Objectives: Depression is common in Alzheimer´s disease (AD) with important clinical implications, but the etiology is not known. Methods: 30 subjects (15 with depression and 15 non-depressed matched for age, gender and cognitive impairment) with mild probable AD, defined as Mini-Mental State Examination score of 20 or above, diagnosed according to NINCDS-ADRDA criteria were included in the study. Data were collected at geriatric medicine and psychiatry outpatient clinics at three hospitals in Western Norway and all subjects underwent comprehensive clinical assessment. Montgomery-Asberg Depression Rating Scale with a cutoff point of 6/7 was used to evaluate depression. Automatic preprocessing using Freesurfer included steps for white and grey matter surface reconstruction. The resulting cortical thickness measurement was used in the subsequent GLM-based analysis. Correction for multiple comparisons was carried out cluster-wise by method of Monte Carlo. Results: We found 3 clusters of significantly reduced cortical thickness in the depressed group. The first cluster (p = 0,0014) contained Left Frontal Pole and Lateral Orbitofrontal cortex. The second cluster (p = 0,0131) included Left Anterior Temporal Area; Right Medial Prefrontal, Anterior Cingulate, Subgenual Cingulate and Medial Orbitofrontal cortex were included in the third cluster (p = 0,0032). Conclusion: Depression in AD is associated with reduced cortical thickness in prefrontal and anterior temporal cortices. These areas have been found to be associated with depression in other age-related disorders as well as in major depression. This convergence of morphological profiles suggests a possible unity of depression brain mechanisms across disorders.

IntroductionDepression is common in the elderly with a significant impact on the quality of life, and increased risk for developing dementia. However, the underlying structural brain changes are not well established.ObjectivesTo investigate neuroanatomical correlates of depressive symptoms in elderly people with and without mild cognitive impairment (MCI).Methods621 subjects with (n = 395) and without (n = 226) MCI selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database were included in the study. Geriatric Depression Scale (GDS-15) with a cut-off point of 6 was used to evaluate depression. All subjects had T1 3D MRI images acquired at multiple ADNI sites using a standardized MRI protocol. Image post-processing included steps for brain segmentation and cortex reconstruction, and was performed using the software Freesurfer. General linear modeling was used to investigate depression-associated brain differences in patients with and without MCI (using age and gender as nuisance covariates).ResultsNo depression-associated differences in cortical thickness were observed in subjects without MCI, whereas MCI subjects with depressive symptoms revealed significant thinning in right parahippocampal, middle temporal, left parahippocampal and entorinal gyri compared to non-depressed MCI patients.ConclusionWe found that depressive symptoms in elderly patients with MCI are associated with more severe atrophy in medial temporal area, suggesting a possible contribution of Alzheimer's pathology in the pathogenesis of depression in this group.

IntroductionMajor depressive disorder (MDD) is associated with low frustration tolerance, which is a risk factor for suicide. Hippocampal structural and functional abnormalities have been documented to play one of the crucial roles in the pathophysiology of depression. Recent studies have revealed functional differentiation of the hippocampus. Thus, activity of the anterior part was shown to be associated with negative affect mediation.ObjectivesTo investigate brain mechanisms of frustration, comparing its impact on anterior hippocampal connectivity in MDD patients and healthy controls (HCs).Methods14 MDD and 14 HC right-handed subjects were included in the study and underwent comprehensive clinical assessment. MDD was diagnosed during psychiatric interview according to ICD-10 criteria. The Hamilton Depression Rating Scale was additionally used to assess depressive symptoms. The original Stroop test was modified to evoke a state of frustration by administrering impossible task conditions and negative feedback during 10-min functional magnetic resonance scanning session. Psychophysiological interactions were used to analyze left and right anterior hippocampal functional connectivity changes in response to frustration. The resulted Z-maps were adjusted using Z > 2.3 threshold and a (corrected) cluster significance threshold of p = 0.05.ResultsIncreased functional connectivity of the left anterior hippocampus in response to frustration was significantly higher in MDD patients compared to HCs in the pars opercularis of the right prefrontal cortex and bilateral posterior cingulate regions.ConclusionThe results revealed that depressed patients demonstrate abnormally increased anterior hippocampal response to frustration, suggesting that hippocampal-neocortical network impairment may contribute to decreased frustration tolerance associated with MDD

No abstract