Synapse loss from chronically elevated glucocorticoids: Relationship to neuropil volume and cell number in hippocampal area CA3

Chronic hypercortisolism disrupts the principal functional gradient in Cushing's disease: A multi-scale connectomics and transcriptomics study

Cushing's disease (CD) represents a state of cortisol excess, serving as a model to investigate the effects of prolonged hypercortisolism on functional brain. Potential alterations in the functional connectome of the brain may explain frequently reported cognitive deficits and affective disorders in CD patients. This study aims to elucidate the effects of chronic hypercortisolism on the principal functional gradient, which represents a hierarchical architecture with gradual transitions across cognitive processes, by integrating connectomics and transcriptomics approaches. Utilizing resting-state functional magnetic resonance imaging data from 140 participants (86 CD patients, 54 healthy controls) recruited at a single center, we explored the alterations in the principal gradient in CD patients. Further, we thoroughly explored the underlying associative mechanisms of the observed characteristic alterations with cognitive function domains, biological attributes, and neuropsychiatric representations, as well as gene expression profiles. Compared to healthy controls, CD patients demonstrated changes in connectome patterns in both primary and higher-order networks, exhibiting an overall converged trend along the principal gradient axis. The gradient values in CD patients' right prefrontal cortex and bilateral sensorimotor cortices exhibited a significant correlation with cortisol levels. Moreover, the cortical regions showing gradient alterations were principally associated with sensory information processing and higher-cognitive functions, as well as correlated with the gene expression patterns which involved synaptic components and function. The findings suggest that converged alterations in the principal gradient in CD patients may mediate the relationship between hypercortisolism and cognitive impairments, potentially involving genes regulating synaptic components and function.

Behavior, synaptic mitochondria, and microglia are differentially impacted by chronic adolescent stress and repeated endotoxin exposure in male and female rats

Early life adversity and chronic inflammation have both been associated with cognitive impairment and neural compromise. In this study, we investigated the interactions between a history of chronic adolescent stress (CAS) and repeated endotoxin exposure on behavior, synaptic mitochondria, and microglia in adult male and female Wistar rats. Adult rats from chronic stress and control conditions were exposed to either repeated endotoxin (lipopolysaccharide; LPS) or saline injections every 3 days for 9 weeks. In both sexes, repeated LPS, regardless of stress history, impaired working memory in the Y maze. Regarding spatial memory, LPS impaired function for females; whereas, CAS altered function in males. Although males had an increase in anxiety-like behavior shortly after CAS, there were no long-term effects on anxiety-like behavior or social interaction observed in males or females. Stress did not alter synaptic mitochondrial function in either sex. Repeated LPS altered synaptic mitochondrial function such that ATP production was increased in females only. There were no observed increases in IBA-1 positive cells within the hippocampus for either sex. However, LPS and CAS altered microglia morphology in females. Impact of repeated LPS was evident at the terminal endpoint with increased spleen weight in both sexes and decreased adrenal weight in males only. Circulating cytokines were not impacted by repeated LPS at the terminal endpoint, but evidence of CAS effects on cytokines in females were evident. These data suggest a long-term impact of chronic stress and an impact of repeated endotoxin challenge in adulthood; however, not all physiological and behavioral metrics examined were impacted by the paradigm employed in this study and the two environmental challenges rarely interacted.

Glucocorticoids and cognitive function: a walkthrough in endogenous and exogenous alterations

PURPOSE

The hypothalamic-pituitary-adrenal (HPA) axis exerts many actions on the central nervous system (CNS) aside from stress regulation. Glucocorticoids (GCs) play an important role in affecting several cognitive functions through the effects on both glucocorticoid (GR) and mineralocorticoid receptors (MR). In this review, we aim to unravel the spectrum of cognitive dysfunction secondary to derangement of circulating levels of endogenous and exogenous glucocorticoids.

METHODS

All relevant human prospective and retrospective studies published up to 2022 in PubMed reporting information on HPA disorders, GCs, and cognition were included.

RESULTS

Cognitive impairment is commonly found in GC-related disorders. The main brain areas affected are the hippocampus and pre-frontal cortex, with memory being the most affected domain. Disease duration, circadian rhythm disruption, circulating GCs levels, and unbalanced MR/GR activation are all risk factors for cognitive decline in these patients, albeit with conflicting data among different conditions. Lack of normalization of cognitive dysfunction after treatment is potentially attributable to GC-dependent structural brain alterations, which can persist even after long-term remission.

CONCLUSION

The recognition of cognitive deficits in patients with GC-related disorders is challenging, often delayed, or mistaken. Prompt recognition and treatment of underlying disease may be important to avoid a long-lasting impact on GC-sensitive areas of the brain. However, the resolution of hormonal imbalance is not always followed by complete recovery, suggesting irreversible adverse effects on the CNS, for which there are no specific treatments. Further studies are needed to find the mechanisms involved, which may eventually be targeted for treatment strategies.

Xanthine oxidase mediates chronic stress-induced cerebrovascular dysfunction and cognitive impairment

Xanthine oxidase (XO) mediates vascular function. Chronic stress impairs cerebrovascular function and increases the risk of stroke and cognitive decline. Our study determined the role of XO on stress-induced cerebrovascular dysfunction and cognitive decline. We measured middle cerebral artery (MCA) function, free radical formation, and working memory in 6-month-old C57BL/6 mice who underwent 8 weeks of control conditions or unpredictable chronic mild stress (UCMS) with or without febuxostat (50 mg/L), a XO inhibitor. UCMS mice had an impaired MCA dilation to acetylcholine vs. controls (p < 0.0001), and increased total free radical formation, XOR protein levels, and hydrogen peroxide production in the liver compared to controls. UCMS increased hydrogen peroxide production in the brain and cerebrovasculature compared to controls. Working memory, using the y-maze test, was impaired (p < 0.05) in UCMS mice compared to control mice. However, blocking XO using febuxostat prevented the UCMS-induced impaired MCA response, while free radical production and hydrogen peroxide levels were similar to controls in the liver and brain of UCMS mice treated with febuxostat. Further, UCMS + Feb mice did not have a significant reduction in working memory. These data suggest that the cerebrovascular dysfunction associated with chronic stress may be driven by XO, which leads to a reduction in working memory.

Xiangshao Granules reduce the aggressive behavior and hippocampal injury of premenstrual irritability in rats by regulating JIK/JNK/p38 signal pathway

ETHNOPHARMACOLOGICAL RELEVANCE

As a typical prescription for soothing the liver, Xiangshao granule has a good effect on the symptoms of irritability and anxiety. Clinical evidence suggests that it has significant efficacy in the treatment of Premenstrual dysphoria disorder (PMDD). However, the underlying mechanism remains unclear.

AIM OF THE STUDY

PMDD is a common disease in women of childbearing age, seriously affecting their family, society, and daily work life. The registered herbal medicine, Xiangshao granules, is used for relieving PMDD dysphoria and irritability symptoms with excellent efficacy in China. This study was focused on the deep intervention mechanism of Xiangshao granules in treating PMDD.

MATERIALS AND METHODS

The vaginal smear and open field test were used to screen rats in nonreception phase of estrus cycle with similar macroscopic behaviors and regular estrus cycle. The rat model of PMDD irritability was established through social isolation and residential invasion, with which, the irritability symptoms of PMDD patients with menstrual cycle dependence was also well simulated. Elevated plus Maze Test and Social interaction activities were used to measure the anxiety-like behavior of rats. TUNEL Staining and Hematoxylin-Eosin staining were used to measure apoptosis of hippocampal neurons. RT-PCR, Western blot and immunofluorescence were used to measure the expression of GR, JIK, p-JIK, p38, P-P38, JNK, caspase 3, and caspase 12.

RESULTS

In this study, Xiangshao granules showed consistent therapeutic effects similar with those in clinic, significantly reducing aggressive and anxiety-like behaviors with improved social skills in PMDD rats. In mechanism, Xiangshao granules lowered the apoptosis of hippocampal neurons and weakened the morphological damage of the hippocampal brain evidenced by the decreased mRNA and protein expression of glucocorticoid receptor, caspase-3, and caspase-12. In addition, administration of Xiangshao granules led to the decreased expression of JIK in the PMDD irritability rat model which agreed well with the previous studies. The JNK/p38 mitogen-activated protein kinases (MAPKs) signaling pathway is abnormally activated in the hippocampal brain region of PMDD rats, while treated with Xiangshao granules could increase JIK expression and inhibit the abnormal activation of the JNK/p38 MAPK signaling pathway, effectively reducing the stress damage in the hippocampus.

CONCLUSIONS

Xiangshao Granules Reduce the Aggressive Behavior and Hippocampal Injury of Premenstrual Irritability in Rats by Regulating JIK/JNK/p38 Signal Pathway.

Psychosocial and Trauma-Related Stress and Risk of Dementia: A Meta-Analytic Systematic Review of Longitudinal Studies

Stress has deleterious effects on brain health and yet, the prognostic value of psychosocial stress regarding the most common types of dementias, including Alzheimer disease, is still unclear. The primary aim of this systematic review was to explore the association between psychosocial stress and late onset dementia. We classified 24articles from Medline, PsycINFO, CINAHL, and Web of Science, as pertaining toxic categories of psychosocial and trauma-related stress (low socio-economic status [SES] related inequalities, marital status, posttraumatic stress disorder, work stress, "vital exhaustion" [VE], and, combined stressors). Using the Quality of Prognosis Studies in Systematic Reviews tool, we judged the quality of evidence to be low. This systematic review provided some non-robust, yet suggestive evidence that the above psychosocial types of stress are associated with increased risk of dementia in later life. Future robust, longitudinal studies with repeated validated measures of psychosocial stress and dementiaare required to strengthen or refute these findings.

Highlighting Immune System and Stress in Major Depressive Disorder, Parkinson's, and Alzheimer's Diseases, with a Connection with Serotonin

There is recognition that both stress and immune responses are important factors in a variety of neurological disorders. Moreover, there is an important role of several neurotransmitters that connect these factors to several neurological diseases, with a special focus in this paper on serotonin. Accordingly, it is known that imbalances in stressors can promote a variety of neuropsychiatric or neurodegenerative pathologies. Here, we discuss some facts that link major depressive disorder, Alzheimer’s, and Parkinson’s to the stress and immune responses, as well as the connection between these responses and serotonergic signaling. These are important topics of investigation which may lead to new or better treatments, improving the life quality of patients that suffer from these conditions.

Altered microstructural pattern of white matter in Cushing's disease identified by automated fiber quantification

A growing body of evidence suggests that altered brain structure plays a crucial role in the pathogenesis of neuropsychological abnormalities induced by hypercortisolism in patients with Cushing's disease. While most studies mainly focus on gray matter, white matter structure has been largely overlooked. In the current study, we conducted a cross-sectional diffusion tensor imaging study on 58 patients with Cushing's disease and 54 matched healthy individuals to profile the microstructural pattern using automated fiber quantification and investigate its association with neuroendocrine and neuropsychological deficits. The study revealed that microstructural pattern showed a widespread mean diffusivity, radial diffusivity increase, fractional anisotropy decrease and partial axial diffusivity increase among tracts notably in corpus callosum forceps, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, superior longitudinal fasciculus, uncinate fasciculus and arcuate fasciculus, while within the same tract abnormalities localized to specific positions. Moreover, compromised microstructural pattern of white matter in specific tracts and locations along the trajectory were associated with ACTH and cortisol concentration and cognitive decline in patients with Cushing's disease. Collectively, our study elucidates the form of white matter pathology induced by hypercortisolism and its association with cognitive decline which may provide further targets for early identification and intervention of Cushing's disease.

Corticosterone-induced Hippocampal 5-HT Responses were Muted in Depressive-like State

Interactions between the hypothalamic-pituitary-adrenal axis and the central 5-HT system in the depressive state remain largely unknown. The present study investigated corticosterone (CORT) regulations of extracellular 5-HT in the hippocampal CA3 in a mouse model of depression. Basal dialysate 5-HT, true extracellular 5-HT, 5-HT reuptake efficiency, and time courses of dialysate 5-HT following CORT injections at 10, 20, and 40 mg/kg were determined at baseline, depressive-like state and after subsequent fluoxetine (FLX) treatment using in vivo microdialysis in male C57BL/6 mice. Behavioral tests were used to determine behavioral phenotypes and therapeutic responses to FLX. Depressed mice showed decreased extracellular 5-HT, increased 5-HT reuptake efficiency, and absence of the increase in dialysate 5-HT response to CORT injections, which were all reversed in FLX-responsive mice. Surprisingly, the FLX nonresponsive mice continued to worsen behaviorally and exhibited lower extracellular 5-HT and higher 5-HT reuptake efficiency. Our study indicates that abolished-CORT induced 5-HT response, decreased extracellular 5-HT, and increased 5-HT reuptake efficiency might be the signature features associated with depressive-like state. Increased 5-HT reuptake efficiency was one of the underlying mechanisms, with target effectors remaining to be explored. The findings in the FLX nonresponsive mice suggest distinct neuromechanisms, which might be genetically predetermined.

Astrocytes in rare neurological conditions: Morphological and functional considerations

Astrocytes are a population of central nervous system (CNS) cells with distinctive morphological and functional characteristics that differ within specific areas of the brain and are widely distributed throughout the CNS. There are mainly two types of astrocytes, protoplasmic and fibrous, which differ in morphologic appearance and location. Astrocytes are important cells of the CNS that not only provide structural support, but also modulate synaptic activity, regulate neuroinflammatory responses, maintain the blood-brain barrier, and supply energy to neurons. As a result, astrocytic disruption can lead to widespread detrimental effects and can contribute to the pathophysiology of several neurological conditions. The characteristics of astrocytes in more common neuropathologies such as Alzheimer's and Parkinson's disease have significantly been described and continue to be widely studied. However, there still exist numerous rare neurological conditions in which astrocytic involvement is unknown and needs to be explored. Accordingly, this review will summarize functional and morphological changes of astrocytes in various rare neurological conditions based on current knowledge thus far and highlight remaining neuropathologies where astrocytic involvement has yet to be investigated.

Stress and Alzheimer's disease: A senescence link?

Chronic stress has been shown to promote numerous aging-related diseases, and to accelerate the aging process itself. Of particular interest is the impact of stress on Alzheimer's disease (AD), the most prevalent form of dementia. The vast majority of AD cases have no known genetic cause, making it vital to identify the environmental factors involved in the onset and progression of the disease. Age is the greatest risk factor for AD, and measures of biological aging such as shorter telomere length, significantly increase likelihood for developing AD. Stress is also considered a crucial contributor to AD, as indicated by a formidable body of research, although the mechanisms underlying this association remain unclear. Here we review human and animal literature on the impact of stress on AD and discuss the mechanisms implicated in the interaction. In particular we will focus on the burgeoning body of research demonstrating that senescent cells, which accumulate with age and actively drive a number of aging-related diseases, may be a key mechanism through which stress drives AD.

Considering the Microbiome in Stress-Related and Neurodevelopmental Trajectories to Schizophrenia

Early life adversity and prenatal stress are consistently associated with an increased risk for schizophrenia, although the exact pathogenic mechanisms linking the exposures with the disease remain elusive. Our previous view of the HPA stress axis as an elegant but simple negative feedback loop, orchestrating adaptation to stressors among the hypothalamus, pituitary, and adrenal glands, needs to be updated. Research in the last two decades shows that important bidirectional signaling between the HPA axis and intestinal mucosa modulates brain function and neurochemistry, including effects on glucocorticoid hormones and brain-derived neurotrophic factor (BDNF). The intestinal microbiome in earliest life, which is seeded by the vaginal microbiome during delivery, programs the development of the HPA axis in a critical developmental window, determining stress sensitivity and HPA function as well as immune system development. The crosstalk between the HPA and the Microbiome Gut Brain Axis (MGBA) is particularly high in the hippocampus, the most consistently disrupted neural region in persons with schizophrenia. Animal models suggest that the MGBA remains influential on behavior and physiology across developmental stages, including the perinatal window, early childhood, adolescence, and young adulthood. Understanding the role of the microbiome on critical risk related stressors may enhance or transform of understanding of the origins of schizophrenia and offer new approaches to increase resilience against stress effects for preventing and treating schizophrenia.

Stress-Induced Neurodegeneration: The Potential for Coping as Neuroprotective Therapy

Stress responses are essential for survival, but become detrimental to health and cognition with chronic activation. Chronic hypothalamic-pituitary-adrenal axis release of glucocorticoids induces hypothalamic-pituitary-adrenal axis dysfunction and neuronal loss, decreases learning and memory, and modifies glucocorticoid receptor/mineralocorticoid receptor expression. Elderly who report increased stress are nearly 3 times more likely to develop Alzheimer's disease, have decreased global cognition and faster cognitive decline than those reporting no stress. Patients with mild cognitive impairment are more sensitive to stress compared to healthy elderly and those with Alzheimer's disease. Stress may also transduce neurodegeneration via the gut microbiome. Coping styles determine hippocampal mineralocorticoid receptor expression in mice, indicating that coping modifies cortisol's effect on the brain. Identifying neuroprotective coping strategies that lessen the burden of stress may prevent or slow cognitive decline. Treatments and education designed to reduce stress should be recognized as neuroprotective.

Hippocampal Volume, Cognitive Functions, Depression, Anxiety, and Quality of Life in Patients With Cushing Syndrome

CONTEXT

Cushing syndrome (CS) is associated with hippocampal atrophy and psychopathology.

OBJECTIVE

The primary objective of this systematic review was to assess hippocampal volume (HV) in patients with CS. The secondary objectives were to assess patients' cognitive functioning, depressive and anxiety symptoms, and quality of life.

DATA SOURCES

PubMed, Embase, Cochrane, LILACs, and Scopus databases were searched for relevant studies until 1 May 2019.

STUDY SELECTION

Case-control studies comparing patients with CS with healthy control subjects, or studies assessing patients with CS before and after surgery were included. The initial search resulted in 18 studies fulfilling the inclusion criteria.

DATA EXTRACTION

Data extraction regarding all outcomes was performed independently by two reviewers. Quality assessment was assessed with the Newcastle-Ottawa Scale for case-control studies.

DATA SYNTHESIS

Meta-analysis was performed using a random effect model. The right-side HV in patients with CS was reduced by a standard mean difference of 0.68 (95% CI, -1.12 to -0.24; P = 0.002; I2 = 0%) compared with healthy control subjects, but with no increase in HV after surgery. Patients had more depressive symptoms, impaired cognitive functions, and reduced health-related QoL (HRQoL), which all responded favorably to surgery. The data did not support the presence of anxiety in patients with CS.

CONCLUSION

An overall reduction of HV in patients with CS was not suggested by the study findings. However, most cognitive domains were significantly affected and responded favorably to surgery. Depressive symptoms and reduced HRQoL were present in patients with CS and improved after surgery.

Health-Promoting Strategies for the Aging Brain

As the world's population ages and people live longer, the changes in the aging brain present substantial challenges to our health and society. With greater longevity come age-related diseases, many of which have direct and indirect influences on the health of the brain. Although there is some degree of predictable decline in brain functioning with aging, meaningful cognitive decline is not inevitable and is perhaps preventable. In this review, we present the case that the course of aging-related brain disease and dysfunction can be modified. We present the evidence for conditions and risk factors that may contribute to cognitive decline and dementia and for interventions that may mitigate their impact on cognitive functioning later in life, or even prevent them and their cognitive sequelae from developing. Although much work remains to be done to meet the challenges of the aging brain, strategies to promote its health have been demonstrated and offer much promise, which can only be realized if we mount a vigorous public health effort to implement these strategies.

Levels of Cortisol in CSF Are Associated With SNAP-25 and Tau Pathology but Not Amyloid-β

Objective: Preclinical studies have found both hyperactivity of hypothalamic- pituitary- adrenal (HPA) axis and synaptic degeneration are involved in the pathogenesis of Alzheimer's disease (AD). However, the data on the relationship of activity of HPA axis and synaptic degeneration in humans are limited. Methods: We compared CSF cortisol levels in 310 subjects, including 92 cognitively normal older people, 149 patients with mild cognitive impairment (MCI), and 69 patients with mild AD. Several linear and logistic regression models were conducted to investigate associations between CSF cortisol and synaptosomal-associated protein 25 (SNAP-25, reflecting synaptic degeneration) and other AD-related biomarkers. Results: We found that levels of cortisol in CSF were associated with SNAP-25 levels and tau pathologies but not amyloid-β protein. However, there were no significant differences in CSF cortisol levels among the three diagnostic groups. Conclusion: The HPA axis may play a crucial role in synaptic degeneration in AD pathogenesis.

Perceived Stress and Mild Cognitive Impairment among 32,715 Community-Dwelling Older Adults across Six Low- and Middle-Income Countries

BACKGROUND

Perceived stress may be a modifiable risk factor for mild cognitive impairment (MCI) and ultimately dementia, but studies on this topic from low- and middle-income countries (LMICs) are lacking.

OBJECTIVE

We assessed the association between perceived stress and MCI in six LMICs (China, Ghana, India, Mexico, Russia, and South Africa) using nationally representative data.

METHODS

Cross-sectional, community-based data on individuals aged ≥50 years from the World Health Organization's Study on Global Ageing and Adult Health were analyzed. The definition of MCI was based on the National Institute on Ageing-Alzheimer's Association criteria. A perceived stress score (range 0 [lowest stress] to 10 [highest stress]) was computed based on two questions from the Perceived Stress Scale. Multivariable logistic regression analysis was conducted to assess the as-sociation between perceived stress and MCI.

RESULTS

The mean (SD) age of the 32,715 participants was 62.1 (15.6) years and 51.7% were females. After adjustment for potential confounders including depression, in the overall sample, a one-unit increase in the perceived stress score was associated with a 1.14 (95% CI = 1.11-1.18) times higher odds for MCI. The association was similar among those aged 50-64 and ≥65 years. Countrywise analysis showed that there was a moderate level of between-country heterogeneity in this association (I2 = 59.4%), with the strongest association observed in Russia (OR = 1.33, 95% CI = 1.15-1.55).

CONCLUSION

If our study results are confirmed in prospective studies, addressing perceived stress may have an impact in reducing the risk for MCI and subsequent dementia in LMICs.

Prolonged Grief and Cognitive Decline: A Prospective Population-Based Study in Middle-Aged and Older Persons

OBJECTIVE

Bereavement can result in unresolved and prolonged grief, often termed prolonged grief disorder (PGD). The impact of PGD on cognitive functioning is poorly understood. The aim of the study was to compare the cognitive decline, assessed by repeated measures of different cognition domains, between persons with normal and PGD and a non-grieving reference population in a 7-year follow-up study.

METHODS

The study sample comprised 3126 non-demented persons, mean age: 64 years, of the Rotterdam Study. Participants were classified into three groups: no grief (reference group, N = 2,582), normal grief (N = 418), and prolonged grief disorder (N = 126). Participants were assessed with the Complicated Grief Inventory and underwent cognitive testing (Mini-Mental State Examination [MMSE], Letter-Digit Substitution test, Stroop test, Word fluency task, Word learning test). Analyses were adjusted for baseline cognition and depressive symptoms; persons with major depressive disorders were excluded.

RESULTS

Compared with the reference group, participants with PGD showed a decrease in global cognitive function, MMSE scores, and World learning test (immediate and delayed) over time. Participants with normal grief did not show a stronger cognitive decline in any of cognitive tests than the reference group.

CONCLUSIONS

Participants with PGD showed a stronger cognitive decline than the reference group during 7 years of follow-up. This suggests that PGD is a risk factor for cognitive decline, but this study cannot detect the psychobiological mechanism underlying this longitudinal association.

Neuroanatomical pathways underlying the effects of hypothalamo-hypophysial-adrenal hormones on exploratory activity

When injected via the intracerebroventricular route, corticosterone-releasing hormone (CRH) reduced exploration in the elevated plus-maze, the center region of the open-field, and the large chamber in the defensive withdrawal test. The anxiogenic action of CRH in the elevated plus-maze also occurred when infused in the basolateral amygdala, ventral hippocampus, lateral septum, bed nucleus of the stria terminalis, nucleus accumbens, periaqueductal grey, and medial frontal cortex. The anxiogenic action of CRH in the defensive withdrawal test was reproduced when injected in the locus coeruleus, while the amygdala, hippocampus, lateral septum, nucleus accumbens, and lateral globus pallidus contribute to center zone exploration in the open-field. In addition to elevated plus-maze and open-field tests, the amygdala appears as a target region for CRH-mediated anxiety in the elevated T-maze. Thus, the amygdala is the principal brain region identified with these three tests, and further research must identify the neural circuits underlying this form of anxiety.

Stress and Cognitive Reserve as independent factors of neuropsychological performance in healthy elderly

Exposure to high levels of cortisol and self-reported stress, as well as cognitive reserve, have been linked to Alzheimer's disease pathology. However, there are no studies on the interaction of these variables. The present study aims to assess the associations of measures of cortisol, self-reported stress, and cognitive reserve with neuropsychological performance in healthy elderly people; besides, to test the interactions between these variables. Cross-sectional analyzes were conducted using data on stress, cognitive reserve and clinical conditions in 145 healthy elderly adults. A neuropsychological battery was used to assess executive functions, verbal memory and processing speed. Measurement of salivary cortisol at the circadian nadir was taken. A negative association between different stress measures and performance on tasks of memory, executive functions and processing speed was observed. Elderly people with higher cognitive reserve showed superior performance on all neuropsychological measures. No significant interaction between stress and cognitive reserve to neuropsychological performance was observed. These results indicate that older adults with high levels of stress and reduced cognitive reserve may be more susceptible to cognitive impairment.

Stress and Loss of Adult Neurogenesis Differentially Reduce Hippocampal Volume

BACKGROUND

Hippocampal volume loss is a hallmark of clinical depression. Chronic stress produces volume loss in the hippocampus in humans and atrophy of CA3 pyramidal cells and suppression of adult neurogenesis in rodents.

METHODS

To investigate the relationship between decreased adult neurogenesis and stress-induced changes in hippocampal structure and volume, we compared the effects of chronic unpredictable restraint stress and inhibition of neurogenesis in a rat pharmacogenetic model.

RESULTS

Chronic unpredictable restraint stress over 4 weeks decreased total hippocampal volume, reflecting loss of volume in all hippocampal subfields and in both dorsal and ventral hippocampus. In contrast, complete inhibition of adult neurogenesis for 4 weeks led to volume reduction only in the dentate gyrus. With prolonged inhibition of neurogenesis for 8 or 16 weeks, volume loss spread to the CA3 region, but not CA1. Combining stress and inhibition of adult neurogenesis did not have additive effects on the magnitude of volume loss but did produce a volume reduction throughout the hippocampus. One month of chronic unpredictable restraint stress and inhibition of adult neurogenesis led to atrophy of pyramidal cell apical dendrites in dorsal CA3 and to neuronal reorganization in ventral CA3. Stress also significantly affected granule cell dendrites.

CONCLUSIONS

The findings suggest that adult neurogenesis is required to maintain hippocampal volume but is not responsible for stress-induced volume loss.

Posttraumatic Stress Disorder and Depression Symptom Severities Are Differentially Associated With Hippocampal Subfield Volume Loss in Combat Veterans

Background

Two decades of human neuroimaging research have associated volume reductions in the hippocampus with posttraumatic stress disorder. However, little is known about the distribution of volume loss across hippocampal subfields. Recent advances in neuroimaging methods have made it possible to accurately delineate 10 gray matter hippocampal subfields. Here, we apply a volumetric analysis of hippocampal subfields to data from a group of combat-exposed Veterans.

Method

Veterans (total, n = 68, posttraumatic stress disorder, n = 36; combat control, n = 32) completed high-resolution structural magnetic resonance imaging. Based on previously validated methods, hippocampal subfield volume measurements were conducted using FreeSurfer 6.0. The Clinician-Administered PTSD Scale assessed posttraumatic stress disorder symptom severity; Beck Depression Inventory assessed depressive symptom severity. Controlling for age and intracranial volume, partial correlation analysis examined the relationship between hippocampal subfields and symptom severity. Correction for multiple comparisons was performed using false discovery rate. Gender, intelligence, combat severity, comorbid anxiety, alcohol/substance use disorder, and medication status were investigated as potential confounds.

Results

In the whole sample, total hippocampal volume negatively correlated with Clinician-Administered PTSD Scale and Beck Depression Inventory scores. Of the 10 hippocampal subfields, Clinician-Administered PTSD Scale symptom severity negatively correlated with the hippocampus–amygdala transition area (HATA). Beck Depression Inventory scores negatively correlated with dentate gyrus, cornu ammonis 4 (CA4), HATA, CA2/3, molecular layer, and CA1. Follow-up analysis limited to the posttraumatic stress disorder group showed a negative correlation between Clinician-Administered PTSD Scale symptom severity and each of HATA, CA2/3, molecular layer, and CA4.

Conclusion

This study provides the first evidence relating posttraumatic stress disorder and depression symptoms to abnormalities in the HATA, an anterior hippocampal region highly connected to prefrontal-amygdala circuitry. Notably, dentate gyrus abnormalities were associated with depression severity but not posttraumatic stress disorder symptoms. Future confirmatory studies should determine the extent to which dentate gyrus volume can differentiate between posttraumatic stress disorder- and depression-related pathophysiology.

Microglia under psychosocial stressors along the aging trajectory: Consequences on neuronal circuits, behavior, and brain diseases

Mounting evidence indicates the importance of microglia for proper brain development and function, as well as in complex stress-related neuropsychiatric disorders and cognitive decline along the aging trajectory. Considering that microglia are resident immune cells of the brain, a homeostatic maintenance of their effector functions that impact neuronal circuitry, such as phagocytosis and secretion of inflammatory factors, is critical to prevent the onset and progression of these pathological conditions. However, the molecular mechanisms by which microglial functions can be properly regulated under healthy and pathological conditions are still largely unknown. We aim to summarize recent progress regarding the effects of psychosocial stress and oxidative stress on microglial phenotypes, leading to neuroinflammation and impaired microglia-synapse interactions, notably through our own studies of inbred mouse strains, and most importantly, to discuss about promising therapeutic strategies that take advantage of microglial functions to tackle such brain disorders in the context of adult psychosocial stress or aging-induced oxidative stress.

Strategies for dementia prevention: latest evidence and implications

Dementia is a common and debilitating syndrome with enormous impact on individuals and societies. Preventing disease onset or progression would translate to public health and societal benefits. In this review, we discuss the latest evidence on interventions that may show promise for the prevention of cognitive decline. We appraise existing evidence primarily drawn from randomized controlled trials, systematic reviews, and meta-analyses, but also highlight observational studies in humans and relevant work in model organisms. Overall, there is currently limited evidence to support a cause-effect relationship between any preventive strategy and the development or progression of dementia. However, studies to date suggest that a multifactorial intervention comprising regular exercise and healthy diet, along with the amelioration of vascular risk factors, psychosocial stress, and major depressive episodes may be most promising for the prevention of cognitive decline. We discuss the challenges, future directions, and implications of this line of research.

Psychiatric Symptoms in Patients with Cushing's Syndrome: Prevalence, Diagnosis and Management

Cushing's syndrome (CS) results from chronic exposure to cortisol excess, produced by the adrenal cortex. Hypercortisolism predisposes to psychiatric and neurocognitive disorders, mainly to depression and anxiety disorders. Screening tools to identify psychiatric symptoms are available for clinicians in their daily practice, although a specific diagnosis should be performed by specialists. Even if psychiatric symptoms improve after remission of hypercortisolism, complete recovery may not be achieved. Given the burden of these symptoms, psychiatric or psychological monitoring and treatment should be offered through all phases of CS, with a multidisciplinary approach. The aim of this article is to review data on the prevalence, diagnosis and management of psychiatric symptoms seen in patients with CS and to propose therapeutic approaches that may be followed in clinical practice. The prevalence of different psychiatric disorders has been described in both the active phase and after CS remission. Patients may not talk spontaneously about psychiatric symptoms they present, thus clinicians should ask directly about them. We recommend the use of screening tools in clinical practice to detect and treat these symptoms promptly. Even if reference endocrinologists cannot perform a definite psychiatric diagnosis, it will be important to ask patients directly about the presence of symptoms and refer if necessary to a psychiatrist. Additionally, patient information and educational programmes could be useful to manage psychiatric symptoms and to improve quality of life in patients with CS.

Depression and Anxiety Scores Are Associated with Amygdala Volume in Cushing's Syndrome: Preliminary Study

Introduction

Cushing's syndrome (CS) has repeatedly been associated with hippocampal volume reductions, while little information is available on the amygdala, another structure rich in glucocorticoid receptors. The aim of the study was to analyze amygdala volume in patients with CS and its relationship with anxiety, depression, and hormone levels.

Material and Methods

39 CS patients (16 active and 23 patients in remission) and 39 healthy controls matched for age, sex, and education level completed anxiety (STAI) and depression tests (BDI-II) and underwent a 3 Tesla brain MRI and endocrine testing. Amygdala volumes were analysed with FreeSurfer software.

Results

Active CS patients had smaller right (but not left) amygdala volumes when compared to controls (P = 0.045). Left amygdala volumes negatively correlated with depression scores (r = −0.692, P = 0.003) and current anxiety state scores (r = −0.617, P = 0.011) in active CS patients and with anxiety trait scores (r = −0.440, P = 0.036) in patients in remission. No correlations were found between current ACTH, urinary free cortisol or blood cortisol levels, and amygdala volumes in either patient group.

Conclusion

Patients with active CS have a smaller right amygdala volume in comparison to controls, while left amygdala volumes are associated with mood state in both patient groups.

Repeated threat (without direct harm) alters metabolic capacity in select regions that drive defensive behavior

To understand the behavioral consequences of intermittent anticipatory stress resulting from threats without accompanying physiological challenges, we developed a semi-naturalistic rodent housing and foraging environment that can include threats that are unpredictable in timing. Behavior is automatically recorded while rats forage for food or water. Over three weeks, the threats have been shown to elicit risk assessment behaviors, increase defensive burying and increase adrenal gland weight. To identify brain regions activated by this manipulation, we measured cytochrome c oxidase (COX), which is tightly coupled to neural activity. Adolescent male Sprague-Dawley rats were randomly assigned to control (CT) or unpredictable threat/stress (ST) housing conditions consisting of two tub cages, one with food and another with water, separated by a tunnel. Over three weeks (P31-P52), the ST group received randomly timed (probability of 0.25), simultaneous presentations of ferret odor, an abrupt light, and sound at the center of the tunnel. The ST group had consistently fewer tunnel crossings than the CT group, but similar body weights. Group differences in COX activity were detected in regions implicated in the control of defensive burying. There was an increase in COX activity in the hypothalamic premammillary dorsal nucleus (PMD) and lateral septum (LS), whereas a decrease was observed in the periaqueductal gray (PAG) and CA3 region of the hippocampus. There were no significant differences in the anterior cingulate cortex, prefrontal cortex, striatum or motor cortex. The sites with changes in metabolic capacity are candidates for the sites of plasticity that may underlie the behavioral adaptations to intermittent threats.

Long-term depression-associated signaling is required for an in vitro model of NMDA receptor-dependent synapse pruning

Activity-dependent pruning of synaptic contacts plays a critical role in shaping neuronal circuitry in response to the environment during postnatal brain development. Although there is compelling evidence that shrinkage of dendritic spines coincides with synaptic long-term depression (LTD), and that LTD is accompanied by synapse loss, whether NMDA receptor (NMDAR)-dependent LTD is a required step in the progression toward synapse pruning is still unknown. Using repeated applications of NMDA to induce LTD in dissociated rat neuronal cultures, we found that synapse density, as measured by colocalization of fluorescent markers for pre- and postsynaptic structures, was decreased irrespective of the presynaptic marker used, post-treatment recovery time, and the dendritic location of synapses. Consistent with previous studies, we found that synapse loss could occur without apparent net spine loss or cell death. Furthermore, synapse loss was unlikely to require direct contact with microglia, as the number of these cells was minimal in our culture preparations. Supporting a model by which NMDAR-LTD is required for synapse loss, the effect of NMDA on fluorescence colocalization was prevented by phosphatase and caspase inhibitors. In addition, gene transcription and protein translation also appeared to be required for loss of putative synapses. These data support the idea that NMDAR-dependent LTD is a required step in synapse pruning and contribute to our understanding of the basic mechanisms of this developmental process.

Role of glutamate receptors and glial cells in the pathophysiology of treatment-resistant depression

Treatment-resistant depression (TRD) causes substantial socioeconomic burden. Although a consensus on the definition of TRD has not yet been reached, it is certain that classic monoaminergic antidepressants are ineffective for TRD. One decade ago, many researchers found ketamine, an N-methyl-d-aspartate receptor (NMDAR) antagonist, to be an alternative to classic monoaminergic antidepressants. The major mechanisms of action of ketamine rapidly induce synaptogenesis in the brain-derived neurotrophic factor (BDNF) pathway. Although excessive glutamatergic neurotransmission and consequent excitotoxicity were considered a major cause of TRD, recent evidence suggests that the extrasynaptic glutamatergic receptor signal pathway mainly contributes to the detrimental effects of TRD. Glial cells such as microglia and astrocytes, early life adversity, and glucocorticoid receptor dysfunction participate in complex cross-talk. An appropriate reuptake of glutamate at the astrocyte is crucial for preventing 'spill-over' of synaptic glutamate and binding to the extrasynaptic NMDA receptor. Excessive microglial activation and the inflammatory process cause astrocyte glutamatergic dysfunction, which in turn activates microglial function. Early life adversity and glucocorticoid receptor dysfunction result in vulnerability to stress in adulthood. A maladaptive response to stress leads to increased glutamatergic release and pro-inflammatory cytokines, which then activate microglia. However, since the role of inflammatory mediators such as pro-inflammatory cytokines is not specific for depression, more disease-specific mechanisms should be identified. Last, although much research has focused on ketamine as an alternative antidepressant for TRD, its long-lasting effectiveness and adverse events have not been rigorously demonstrated. Additionally, evidence suggests that substantial brain abnormalities develop in ketamine abusers. Thus, more investigations for ketamine and other novel glutamatergic agents are needed.

Adiponectin Exerts Neurotrophic Effects on Dendritic Arborization, Spinogenesis, and Neurogenesis of the Dentate Gyrus of Male Mice

The hippocampus, a brain region critical for learning, memory and emotional processing, maintains its capacity to undergo structural plasticity throughout life. Hippocampal structural plasticity can be modulated by a number of intrinsic and extrinsic factors. This study investigated the effects of adiponectin, an adipocyte-derived hormone, on dendritic growth, arborization, and spinogenesis in mature granule neurons of the hippocampal dentate gyrus generated during embryonic (early-born) or early postnatal (late-born) stages. We found that adiponectin deficiency reduced dendritic length, branching and spine density of granule neurons. The reduction was more evident in early-born granule neurons than in late-born granule neurons. Intracerebroventricular infusion of adiponectin for 1 week increased of dendritic spines and arbor complexity in late-born granule neurons. Moreover, adiponectin deficiency decreased the production of adult-born new granule neurons through suppressing neural progenitor cell proliferation and differentiation, whereas intracerebroventricular adiponectin infusion increased the proliferation of neural progenitor cells in adult dentate gyrus. These results suggest that adiponectin plays an important role in dendritic spine remodeling and neurogenesis in the dentate gyrus.

The role of macrophage polarization on bipolar disorder: Identifying new therapeutic targets

OBJECTIVE

Bipolar disorder is a chronic, severe and disabling disease; however, its pathophysiology remains poorly understood. Recent evidence has suggested that inflammation and immune dysregulation play a significant role in the pathophysiology of bipolar disorder. This review is aimed to highlight the importance of systemic inflammation in modulating the inflammatory response of microglia and hence its potential involvement with bipolar disorder. We also discuss novel therapeutic strategies that emerge from this new research.

METHOD

This article presents a theoretical synthesis of the effects of systemic inflammation on the immune response of the central nervous system in bipolar disorder. The complex relationship between stress, pro-inflammatory cytokines and microglial dysfunction is summarized, emphasizing the role of the kynurenine pathway in this process and, consequently, their effects on neuronal plasticity.

RESULTS

Bipolar patients demonstrate increased serum levels of pro-inflammatory cytokines (interleukin-1β, interleukin-6 and tumor necrosis factor-α) and lower hypothalamic-pituitary-adrenal axis sensitivity. This imbalance in the immune system promotes a change in blood-brain barrier permeability, leading to an inflammatory signal spread in the central nervous system from the periphery, through macrophages activation (M1 polarization). Chronic microglial activation can result in neuronal apoptosis, neurogenesis inhibition, hippocampal volume reduction, lower neurotransmitters synthesis and cytotoxicity, by increasing glutamate production and kynurenine metabolism.

CONCLUSIONS

This review provides an overview of the mechanisms involved in the immune system imbalance and its potential involvement in the pathophysiology of bipolar disorder. Consequently, new strategies that normalize the immune-inflammatory pathways may provide a valuable therapeutic target for the treatment of these disorders.

Altered brain morphology and functional connectivity reflect a vulnerable affective state after cumulative multigenerational stress in rats

Prenatal stress is a risk factor for abnormal neuroanatomical, cognitive, behavioral and mental health outcomes with potentially transgenerational consequences. Females in general seem more resilient to the effects of prenatal stress than males. Here, we examined if repeated stress across generations may diminish stress resiliency and cumulatively enhance the susceptibility for adverse health outcomes in females. Pregnant female rats of three successive generations were exposed to stress from gestational days 12-18 to generate multigenerational prenatal stress (MPS) in the maternal lineage. Stress response was measured by plasma corticosterone levels and open-field exploration in each generation. Neuromorphological consequences of MPS were investigated in the F3 generation using in vivo manganese-enhanced magnetic resonance imaging (MEMRI), T2-relaxometry, and cytoarchitectonics in relation to candidate gene expression involved in brain plasticity and mental health. Each additional generation of prenatal stress incrementally elevated hypothalamic-pituitary-adrenal axis activation, anxiety-like and aversive behaviors in adult female offspring. Elevated stress responses in the MPS F3 generation were accompanied by reduced neural density in prefrontal cortex, hippocampus and whole brain along with altered brain activation patterns in in vivo MEMRI. MPS increased ephrin receptor A5 (Epha5), neuronal growth regulator (Negr1) and synaptosomal-associated protein 25 (Snap25) gene expression and reduced fibroblast growth factor 12 (Fgf12) in prefrontal cortex. These genes regulate neuronal maturation, arborization and synaptic plasticity and may explain altered brain cytoarchitectonics and connectivity. These findings emphasize that recurrent stress across generations may cumulatively increase stress vulnerability and the risk of adverse health outcomes through perinatal programing in females.

Cushing Disease Presenting as Primary Psychiatric Illness: A Case Report and Literature Review

We report the case of a woman with long-standing refractory depression and psychotic features who was eventually diagnosed with Cushing disease. After surgical treatment of a pituitary adenoma, she experienced gradual psychiatric recovery and was eventually able to discontinue all psychotropic medication. We review the psychiatric components of Cushing disease, implications of psychiatric illnesses for the treatment and prognosis of Cushing disease, and potential pathophysiological mechanisms linking glucocorticoid excess to psychiatric illness.

A critical evaluation of the activity-regulated cytoskeleton-associated protein (Arc/Arg3.1)'s putative role in regulating dendritic plasticity, cognitive processes, and mood in animal models of depression

Major depressive disorder (MDD) is primarily conceptualized as a mood disorder but cognitive dysfunction is also prevalent, and may limit the daily function of MDD patients. Current theories on MDD highlight disturbances in dendritic plasticity in its pathophysiology, which could conceivably play a role in the production of both MDD-related mood and cognitive symptoms. This paper attempts to review the accumulated knowledge on the basic biology of the activity-regulated cytoskeleton-associated protein (Arc or Arg3.1), its effects on neural plasticity, and how these may be related to mood or cognitive dysfunction in animal models of MDD. On a cellular level, Arc plays an important role in modulating dendritic spine density and remodeling. Arc also has a close, bidirectional relationship with postsynaptic glutamate neurotransmission, since it is stimulated by multiple glutamatergic receptor mechanisms but also modulates α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor internalization. The effects on AMPA receptor trafficking are likely related to Arc's ability to modulate phenomena such as long-term potentiation, long-term depression, and synaptic scaling, each of which are important for maintaining proper cognitive function. Chronic stress models of MDD in animals show suppressed Arc expression in the frontal cortex but elevation in the amygdala. Interestingly, cognitive tasks depending on the frontal cortex are generally impaired by chronic stress, while those depending on the amygdala are enhanced, and antidepressant treatments stimulate cortical Arc expression with a timeline that is reminiscent of the treatment efficacy lag observed in the clinic or in preclinical models. However, pharmacological treatments that stimulate regional Arc expression do not universally improve relevant cognitive functions, and this highlights a need to further refine our understanding of Arc on a subcellular and network level.

Examining the levels of BDNF and cortisol in children and adolescent victims of sexual abuse--a preliminary study

BACKGROUND

Previous reports have suggested the biological and psychological effects of trauma induced by cortisol and brain-derived neurotrophic factor (BDNF). The present study compared the levels of BDNF, cortisol, and adrenocorticotropic hormone (ACTH) in children and adolescent victims of sexual abuse to those without a trauma history.

METHODS

The study was conducted in the Department of Child Psychiatry at Dicle University. The study included 44 children (M/F: 12/32) aged between 8 and 17years who experienced sexual abuse with 42 age-and gender-matched children who did not have a history of trauma. Cortisol, ACTH, and BDNF levels were measured using ELISA.

RESULTS

Cortisol levels were higher and BDNF levels were significantly lower in the victims of sexual abuse compared to the control group. The mean time that elapsed from the initial sexual abuse occurrence until the date of examination was 22.7±21.7months. The evaluation of the relationship between this time span and cortisol levels revealed that cortisol levels decreased with increasing time after trauma. Cortisol and BDNF levels were lower in the victims who experienced multiple sexual assaults.

CONCLUSIONS

The results of the present study suggest that cortisol and BDNF could be biological molecular mediators of the effects of trauma on biological and psychological systems. This is the first report on the effects of cortisol and BDNF induced trauma in child and adolescent victims of sexual abuse.

Cognition, structural brain changes and complicated grief. A population-based study

BACKGROUND

Several psychosocial risk factors for complicated grief have been described. However, the association of complicated grief with cognitive and biological risk factors is unclear. The present study examined whether complicated grief and normal grief are related to cognitive performance or structural brain volumes in a large population-based study.

METHOD

The present research comprised cross-sectional analyses embedded in the Rotterdam Study. The study included 5501 non-demented persons. Participants were classified as experiencing no grief (n = 4731), normal grief (n = 615) or complicated grief (n = 155) as assessed with the Inventory of Complicated Grief. All persons underwent cognitive testing (Mini-Mental State Examination, Letter-Digit Substitution Test, Stroop Test, Word Fluency Task, word learning test - immediate and delayed recall), and magnetic resonance imaging to measure general brain parameters (white matter, gray matter), and white matter lesions. Total brain volume was defined as the sum of gray matter plus normal white matter and white matter lesion volume. Persons with depressive disorders were excluded and analyses were adjusted for depressive symptoms.

RESULTS

Compared with no-grief participants, participants with complicated grief had lower scores for the Letter-Digit Substitution Test [Z-score -0.16 v. 0.04, 95% confidence interval (CI) -0.36 to -0.04, p = 0.01] and Word Fluency Task (Z-score -0.15 v. 0.03, 95% CI -0.35 to -0.02, p = 0.02) and smaller total volumes of brain matter (933.53 ml v. 952.42 ml, 95% CI -37.6 to -0.10, p = 0.04).

CONCLUSIONS

Participants with complicated grief performed poorly in cognitive tests and had a smaller total brain volume. Although the effect sizes were small, these findings suggest that there may be a neurological correlate of complicated grief, but not of normal grief, in the general population.

Organic changes in the central nervous system in children on chronic inhaled corticosteroid therapy

Treatment of asthma, the most common chronic respiratory disease in children, includes long-term inhaled corticosteroids (ICS). The purpose of this study was to analyze the impact of chronic inhaled steroids in children with asthma on changes in the central nervous system (CNS). Eleven children (8-17 years) on at least 4 years inhaled corticosteroid therapy were assessed with magnetic resonance imaging (MRI). All participants underwent a pediatric and neurological examination and spirometry. MRI data were obtained using a 1.5 T scanner with parallel imaging capability. Structural images consisted of axial T1, T2 using turbo spin echo, FLAIR and DWI sequences using typical parameters. Images were assessed in three planes (axial, coronal, and sagittal). Pediatric and neurological examination were normal in all children. In six, the MRI studies revealed small subcortical hyperintense foci. Three had more than five lesions, all of which were smaller than 3 mm. Features of mild supratentorial cortical atrophy were apparent in four. The cerebellum was unremarkable in all children imaged. In conclusion, patients receiving chronic inhaled corticosteroids had small subcortical hyperintense foci and features of mild supratentorial cortical atrophy. These findings suggest that ICS exposure may be associated with the development of organic changes in CNS. Further studies are needed to detail the extent of brain ICS-induced changes in children on chronic inhalative corticosteroid therapy as well as delayed impact of these changes on psychomotor functioning in adulthood.

Is Dysregulation of the HPA-Axis a Core Pathophysiology Mediating Co-Morbid Depression in Neurodegenerative Diseases?

There is increasing evidence of prodromal manifestation of neuropsychiatric symptoms in a variety of neurodegenerative diseases such as Parkinson's disease (PD) and Huntington's disease (HD). These affective symptoms may be observed many years before the core diagnostic symptoms of the neurological condition. It is becoming more apparent that depression is a significant modifying factor of the trajectory of disease progression and even treatment outcomes. It is therefore crucial that we understand the potential pathophysiologies related to the primary condition, which could contribute to the development of depression. The hypothalamic-pituitary-adrenal (HPA)-axis is a key neuroendocrine signaling system involved in physiological homeostasis and stress response. Disturbances of this system lead to severe hormonal imbalances, and the majority of such patients also present with behavioral deficits and/or mood disorders. Dysregulation of the HPA-axis is also strongly implicated in the pathology of major depressive disorder. Consistent with this, antidepressant drugs, such as the selective serotonin reuptake inhibitors have been shown to alter HPA-axis activity. In this review, we will summarize the current state of knowledge regarding HPA-axis pathology in Alzheimer's, PD and HD, differentiating between prodromal and later stages of disease progression when evidence is available. Both clinical and preclinical evidence will be examined, but we highlight animal model studies as being particularly useful for uncovering novel mechanisms of pathology related to co-morbid mood disorders. Finally, we purpose utilizing the preclinical evidence to better inform prospective, intervention studies.

Early life inflammatory pain induces long-lasting deficits in hippocampal-dependent spatial memory in male and female rats

The present experiment tested the hypothesis that neonatal injury disrupts adult hippocampal functioning and that normal aging or chronic stress during adulthood, which are known to have a negative impact on hippocampal function, exacerbate these effects. Male and female Sprague-Dawley rats were given an intraplantar injection of the inflammatory agent carrageenan (1%) on the day of birth and their memory was tested in the hippocampal-dependent spatial water maze in adulthood and again in middle age. We found that neonatal injury impaired hippocampal-dependent memory in adulthood, that the effects of injury on memory were more pronounced in middle-aged male rats, and that chronic stress accelerated the onset of these memory deficits. Neonatal injury also decreased glucocorticoid receptor mRNA in the dorsal CA1 area of middle-aged rats, a brain region critical for spatial memory. Morphine administration at the time of injury completely reversed injury-induced memory deficits, but neonatal morphine treatments in the absence of injury produced significant memory impairments in adulthood. Collectively, these findings are consistent with our hypothesis that neonatal injury produces long-lasting disruption in adult hippocampal functioning.

Small cerebellar cortex volume in patients with active Cushing's syndrome

OBJECTIVE

Cushing's syndrome (CS) is associated with neuropsychological deficits. As the cerebellum plays a key role in neuropsychological functions it may be affected in CS. The aim of this study was to investigate whether patients with CS have a smaller cerebellar volume than healthy controls, and to analyse whether cerebellar volume is associated with neuropsychological performance and clinical parameters.

DESIGN

A cross-sectional study was performed.

METHODS

Thirty-six CS patients (15 with active CS and 21 with CS in remission) and 36 controls matched for age, sex, and education underwent neuropsychological testing, quality of life assessment, clinical evaluation, and magnetic resonance imaging brain scan. Cerebellar volumes (white matter and cortex, bilateral) were calculated using FreeSurfer Software.

RESULTS

Patients with active CS showed smaller bilateral cerebellar cortex volumes than controls (left, P=0.035 and right, P=0.034), as well as a trend toward smaller right cerebellar cortex volumes than patients in remission CS (P=0.051). No differences were observed in the volume of cerebellar white matter between the three groups. Both right and left cerebellar cortex volumes correlated negatively with triglyceride levels (right: r=-0.358, P=0.002 and left: r=-0.317, P=0.005) and age at diagnosis (right: r=-0.433, P=0.008 and left: r=-0.457, P=0.005). Left cerebellar cortex volume also correlated positively with visual memory performance (r=0.245, P=0.038). Right cerebellar cortex volume positively correlated with quality-of-life scores (r=0.468, P=0.004).

CONCLUSIONS

The cerebellar cortex volume is smaller in active CS patients than in controls. This finding is associated with poor visual memory and quality of life and is mostly pronounced in patients with higher triglyceride levels and older age at diagnosis.

Depression in the elderly: brain correlates, neuropsychological findings, and role of vascular lesion load

PURPOSE OF REVIEW

Late-life depression (LLD) presents in older adults as a heterogeneous mood disorder. Because of the diverse outcomes and symptomatology of LLD, several theories, especially the vascular depression hypothesis, have been proposed to identify its cause. This review outlines the features of LLD and explores the recent advances in characterizing this disorder through studies of brain functioning and cognition, with an emphasis on how vascular changes may mediate this disorder.

RECENT FINDINGS

LLD is associated with brain changes, including atrophy of hippocampus, independent of other neurodegenerative states. White matter lesions (WMLs) are frequently found in patients with LLD. Functional imaging has revealed both distinct characteristics of LLD and overlap of some cognitive symptoms with other dementias. Executive dysfunction and impaired processing speeds are at the core of the cognitive deficits in LLD and are associated with the development of WMLs in specific fiber tracts in the brain.

SUMMARY

LLD is associated with brain changes in both gray matter and white matter, including cerebrovascular changes, atrophy, and loss of myelin integrity. These brain changes are associated with age of onset of depression, as well as cumulative life-time depression burden, and can explain the increased dementia risk associated with LLD.

Gastrodiae Rhizoma (tiān má): a review of biological activity and antidepressant mechanisms

Gastrodiae Rhizoma, also called chì jiàn (赤箭), guǐ dū yóu (鬼督郵), or tiān má (天麻) in Chinese, is considered a top grade (上品 shàng pǐn) medicine described to enter liver channel (肝經 gān jīng) in classic literatures of traditional Chinese medicine and has been used for centuries. Many studies investigating its various bioactivities and active compounds have been conducted worldwide. This article reviews these biological activities and details the antidepressant pharmacology of Gastrodiae Rhizoma. Gastrodiae Rhizoma treatment exerts an effective inhibition of diverse diseases and disorders, including convulsion, oxidative stress, mental disorders, amnesia, cardio-cerebral-vascular diseases, and inflammation, among others. The antidepressant effect of Gastrodiae Rhizoma was evaluated in animal models and several mechanisms of activity were found, including the modulation and regulation of monoamine oxidase activity, monoamine concentration and turnover, antioxidatant activity, GABAergic system induction, BDNF induction, neuroprotection and anti-inflammatory activity.

Altered expression of glial and synaptic markers in the anterior hippocampus of behaviorally depressed female monkeys

The anterior hippocampus is associated with emotional functioning and hippocampal volume is reduced in depression. We reported reduced neuropil volume and number of glia in the dentate gyrus (DG) and cornu ammonis (CA)1 of the anterior hippocampus in behaviorally depressed adult female cynomolgus macaques. To determine the biochemical correlates of morphometric and behavioral differences between behaviorally depressed and nondepressed adult female monkeys, glial and synaptic transcripts and protein levels were assessed in the DG, CA3 and CA1 of the anterior hippocampus. Glial fibrillary acidic protein (GFAP) was increased whereas spinophilin and postsynaptic density (PSD)-95 protein were decreased in the CA1 of depressed monkeys. GFAP was reciprocally related to spinophilin and PSD-95 protein in the CA1. Gene expression of GFAP paralleled the protein changes observed in the CA1 and was inversely related to serum estradiol levels in depressed monkeys. These results suggest that behavioral depression in female primates is accompanied by astrocytic and synaptic protein alterations in the CA1. Moreover, these findings indicate a potential role for estrogen in modulating astrocyte-mediated impairments in synaptic plasticity.

Neuropathology of stress

Environmental challenges are part of daily life for any individual. In fact, stress appears to be increasingly present in our modern, and demanding, industrialized society. Virtually every aspect of our body and brain can be influenced by stress and although its effects are partly mediated by powerful corticosteroid hormones that target the nervous system, relatively little is known about when, and how, the effects of stress shift from being beneficial and protective to becoming deleterious. Decades of stress research have provided valuable insights into whether stress can directly induce dysfunction and/or pathological alterations, which elements of stress exposure are responsible, and which structural substrates are involved. Using a broad definition of pathology, we here review the "neuropathology of stress" and focus on structural consequences of stress exposure for different regions of the rodent, primate and human brain. We discuss cytoarchitectural, neuropathological and structural plasticity measures as well as more recent neuroimaging techniques that allow direct monitoring of the spatiotemporal effects of stress and the role of different CNS structures in the regulation of the hypothalamic-pituitary-adrenal axis in human brain. We focus on the hypothalamus, hippocampus, amygdala, nucleus accumbens, prefrontal and orbitofrontal cortex, key brain regions that not only modulate emotions and cognition but also the response to stress itself, and discuss disorders like depression, post-traumatic stress disorder, Cushing syndrome and dementia.