Chronic depression as a model disease for cerebral aging

Wearable neurofeedback acceptance model for students' stress and anxiety management in academic settings

This study investigates the technology acceptance of a proposed multimodal wearable sensing framework, named mSense, within the context of non-invasive real-time neurofeedback for student stress and anxiety management. The COVID-19 pandemic has intensified mental health challenges, particularly for students. Non-invasive techniques, such as wearable biofeedback and neurofeedback devices, are suggested as potential solutions. To explore the acceptance and intention to use such innovative devices, this research applies the Technology Acceptance Model (TAM), based on the co-creation approach. An online survey was conducted with 106 participants, including higher education students, health researchers, medical professionals, and software developers. The TAM key constructs (usage attitude, perceived usefulness, perceived ease of use, and intention to use) were validated through statistical analysis, including Partial Least Square-Structural Equation Modeling. Additionally, qualitative analysis of open-ended survey responses was performed. Results confirm the acceptance of the mSense framework for neurofeedback-based stress and anxiety management. The study contributes valuable insights into factors influencing user intention to use multimodal wearable devices in educational settings. The findings have theoretical implications for technology acceptance and practical implications for extending the usage of innovative sensors in clinical and educational environments, thereby supporting both physical and mental health.

A Review on Integrated ZnO-Based SERS Biosensors and Their Potential in Detecting Biomarkers of Neurodegenerative Diseases

Surface-enhanced Raman spectroscopy (SERS) applications in clinical diagnosis and spectral pathology are increasing due to the potential of the technique to bio-barcode incipient and differential diseases via real-time monitoring of biomarkers in fluids and in real-time via biomolecular fingerprinting. Additionally, the rapid advancements in micro/nanotechnology have a visible influence in all aspects of science and life. The miniaturization and enhanced properties of materials at the micro/nanoscale transcended the confines of the laboratory and are revolutionizing domains such as electronics, optics, medicine, and environmental science. The societal and technological impact of SERS biosensing by using semiconductor-based nanostructured smart substrates will be huge once minor technical pitfalls are solved. Herein, challenges in clinical routine testing are addressed in order to understand the context of how SERS can perform in real, in vivo sampling and bioassays for early neurodegenerative disease (ND) diagnosis. The main interest in translating SERS into clinical practice is reinforced by the practical advantages: portability of the designed setups, versatility in using nanomaterials of various matter and costs, readiness, and reliability. As we will present in this review, in the frame of technology readiness levels (TRL), the current maturity reached by semiconductor-based SERS biosensors, in particular that of zinc oxide (ZnO)-based hybrid SERS substrates, is situated at the development level TRL 6 (out of 9 levels). Three-dimensional, multilayered SERS substrates that provide additional plasmonic hot spots in the z-axis are of key importance in designing highly performant SERS biosensors for the detection of ND biomarkers.

Alzheimer's disease and depression in the elderly: A trajectory linking gut microbiota and serotonin signaling

The occurrence of neuropsychiatric symptoms in the elderly is viewed as an early sign of subsequent cognitive deterioration and conversion from mild cognitive impairment to Alzheimer's disease. The prognosis in terms of both the severity and progression of clinical dementia is generally aggravated by the comorbidity of neuropsychiatric symptoms and decline in cognitive function. Undeniably, aging and in particular unhealthy aging, is a silent "engine of neuropathology" over which multiple changes take place, including drastic alterations of the gut microbial ecosystem. This narrative review evaluates the role of gut microbiota changes as a possible unifying concept through which the comorbidity of neuropsychiatric symptoms and Alzheimer's disease can be considered. However, since the heterogeneity of neuropsychiatric symptoms, it is improbable to describe the same type of alterations in the bacteria population observed in patients with Alzheimer's disease, as well as it is improbable that the variety of drugs used to treat neuropsychiatric symptoms might produce changes in gut bacterial diversity similar to that observed in the pathophysiology of Alzheimer's disease. Depression seems to be another very intriguing exception, as it is one of the most frequent neuropsychiatric symptoms in dementia and a mood disorder frequently associated with brain aging. Antidepressants (i.e., serotonin reuptake inhibitors) or tryptophan dietary supplementation have been shown to reduce Amyloid β-loading, reinstate microbial diversity and reduce the abundance of bacterial taxa dominant in depression and Alzheimer's disease. This review briefly examines this trajectory by discussing the dysfunction of gut microbiota composition, selected bacterial taxa, and alteration of tryptophan and serotonin metabolism/neurotransmission as overlapping in-common mechanisms involved with depression, Alzheimer's disease, and unhealthy aging.

Brain Aging and Anesthesia

Herein, the authors review the neuroanatomical and the neurophysiological aspects of the normal aging evolution based on the recent literature and briefly describe the difference between physiological and pathological brain aging, with consideration of the currently recommended anesthesia management of older patients. The population of elderly patients is growing drastically with advances in medicine that have prolonged the life span. One of the direct consequence has been a significant increase in the request for anesthesia care for older patients despite the type of surgery (cardiac vs noncardiac and mainly orthopedic). Because the brain of this category of patients undergoes a specific triple influence (immune, metabolic, and inflammatory), some particular physiological, anatomical, and structural modifications must be taken into account because they expose these patients more specifically to postoperative cognitive disturbances. To prevent type of adverse outcome, a better knowledge and understanding of these neurosciences must be promoted. The strategies developed to prevent such adverse outcomes include the determination and detection of significant at-risk patients and improvement in the titration of anesthesia to reduce exposure of anesthesia to these patients through an adapted anesthesia-induced unconsciousness that avoids, as much as possible, the risk of toxic overdose with an overly deep brain depression. To accomplish this, the unprocessed electroencephalogram (EEG) and its spectrogram may represent a significant improvement in monitoring, first by allowing for the rapid recognition of repetitive or persistent EEG suppression by the on-line reading of the raw EEG trace and second by allowing for the accurate determination of the adequate anesthetic-induced state, obtained in general in this category of patients by substantially lowered doses of anesthetic agents. This represents a new methodology for anesthesia titration that is adjusted on a more case-by-case basis and is related to the physiology of individual patients. A better understanding of aging-induced brain transformations remains the key regarding the improvement of the anesthetic management of the always growing population of elderly patients. The promotion of the unprocessed EEG may represent the best method of preventing the risk of anesthetic toxicity, including postoperative cognitive dysfunctions.

Valproic acid withdrawal ameliorates impairments of hippocampal-spatial working memory and neurogenesis

Valproic acid (VPA), an agent that is used to treat epileptic seizures, can cause spatial memory impairment in adults and children. This effect is thought to be due to the ability of VPA to inhibit neurogenesis in the hippocampus, which is required for learning. We have previously used an animal model to show that VPA significantly impairs hippocampal-spatial working memory and inhibits neuronal generation in the sub-granular zone of the dentate gyrus. As there are patient reports of improvements in memory after discontinuing VPA treatment, the present study investigated the recovery of both spatial memory and hippocampal neurogenesis at two time points after withdrawal of VPA. Male Wistar rats were given intraperitoneal injections of 0.9% normal saline or VPA (300 mg/kg) twice a day for 10 d. At 1, 30, or 45 d after the drug treatment, the novel object location (NOL) test was used to examine spatial memory; hippocampal cell division was counted using Ki67 immunohistochemistry, and levels of brain-derived neurotrophic factor (BDNF) and Notch1 were measured using western immunoblotting. Spatial working memory was impaired 1 and 30 d after the final administration, but was restored to control levels by 45 d. Cell proliferation had increased to control levels at 30 and 45 d. Both markers of neurogenesis (BDNF and Notch1 levels) had returned to control levels at 45 d. These results demonstrate that memory recovery occurs over a period of six weeks after discontinuing VPA treatment and is preceded by a return of hippocampal neurogenesis to control levels.

Depression and risk of cognitive dysfunctions in amyotrophic lateral sclerosis

OBJECTIVES

Amyotrophic lateral sclerosis (ALS) is not only a motor disorder: More than 50% of patients have cognitive dysfunctions over the course of the disease. At the same time, mood disorders may also occur in ALS patients following diagnosis due to the fatal prognosis; however, little data are available on any depression beforehand. Starting from these considerations, the aim of our study was to investigate the occurrence of depression in Italian ALS patients prior to diagnosis, evaluating its prevalence in the subjects who have developed cognitive dysfunctions and in those who did not.

MATERIALS AND METHODS

We included 318 patients, establishing the presence of depression in the 5 years before ALS diagnosis. Patients underwent a complete battery of neuropsychological tests with the aim to evaluate the executive functions, behavior, language, and memory.

RESULTS

Before diagnosis, 40 patients with ALS had been diagnosed with depression: Among them, 29 patients had cognitive impairment over the course of the disease and only 11 did not develop any cognitive alteration (OR 1.46; 95% CI: 1.26-1.66, adjusted for sex, age, and disease phenotype, P: 0.038). Moreover, there is a significant difference in survival time between ALS patients with depression before ALS, compared to ALS patients without previous depression (P: 0.006).

CONCLUSIONS

We reported a high prevalence of depression in the past in patients with ALS and cognitive impairment, as compared to patients without cognitive deficits, showing also that patients with both had a shorter survival time. These aspects require multidisciplinary approach at disease onset.

Persistent depressive disorder has long-term negative impacts on depression, anxiety, and somatic symptoms at 10-year follow-up among patients with major depressive disorder

OBJECTIVE

The study aimed to investigate the impacts of persistent depressive disorder (PDD) and pharmacotherapy on depression, anxiety, and somatic symptoms among patients with major depressive disorder (MDD) over a ten-year period.

METHODS

290 outpatients with MDD were enrolled, including 117 with PDD, at baseline. Subjects were followed-up at six-month, two-year, and 10-year points. MDD and dysthymic disorder were diagnosed using the Structured Clinical Interview for DSM-IV-TR. The Hamilton Depression Rating Scale, the Hospital Anxiety and Depression Scale, and the Depression and Somatic Symptoms Scale were used. Generalized Estimating Equation models were used to investigate the impacts.

RESULTS

MDD patients with PDD had greater severities of depression, anxiety, and somatic symptoms at the three follow-up points as compared with those without; however, these results were of statistical significance only in patients without pharmacotherapy. MDD patients with PDD had a longer duration of pharmacotherapy and a lower remission rate as compared with those without. After controlling for depression and anxiety at baseline, PDD was independently associated with more severe depression, anxiety, and somatic symptoms.

LIMITATION

At the ten-year follow-up, approximately half of the subjects were lost to follow-up; this, in addition to the unequal follow-up intervals, might have caused bias.

CONCLUSIONS

Among the patients, PDD continued to have negative impacts on depression, anxiety, and somatic symptoms over the subsequent ten years. Differences in symptomatology between the patients with and without PDD were statistically insignificant when pharmacotherapy was utilized; however, pharmacotherapy did not fully compensate for the negative impacts of PDD.

Intranasal Cotinine Plus Krill Oil Facilitates Fear Extinction, Decreases Depressive-Like Behavior, and Increases Hippocampal Calcineurin A Levels in Mice

Failure in fear extinction is one of the more troublesome characteristics of posttraumatic stress disorder (PTSD). Cotinine facilitates fear memory extinction and reduces depressive-like behavior when administered 24 h after fear conditioning in mice. In this study, it was investigated the behavioral and molecular effects of cotinine, and other antidepressant preparations infused intranasally. Intranasal (IN) cotinine, IN krill oil, IN cotinine plus krill oil, and oral sertraline were evaluated on depressive-like behavior and fear retention and extinction after fear conditioning in C57BL/6 mice. Since calcineurin A has been involved in facilitating fear extinction in rodents, we also investigated changes of calcineurin in the hippocampus, a region key on contextual fear extinction. Short-term treatment with cotinine formulations was superior to krill oil and oral sertraline in reducing depressive-like behavior and fear consolidation and enhancing contextual fear memory extinction in mice. IN krill oil slowed the extinction of fear. IN cotinine preparations increased the levels of calcineurin A in the hippocampus of conditioned mice. In the light of the results, the future investigation of the use of IN cotinine preparations for the extinction of contextual fear memory and treatment of treatment-resistant depression (TRD) in PTSD is discussed.

Identification of the stria medullaris thalami using diffusion tensor imaging

Background

Deep brain stimulation (DBS) via anatomical targeting of white matter tracts defined by diffusion tensor imaging (DTI) may be a useful tool in the treatment of pathologic neurophysiologic circuits implicated in certain disease states like treatment resistant depression (TRD). We sought to determine if DTI could be used to define the stria medullaris thalami (SM), the major afferent white matter pathway to the lateral habenula (LHb), a thalamic nucleus implicated in the pathophysiology of TRD.

Methods

Probabilistic DTI was performed on ten cerebral hemispheres in five patients who underwent preoperative MRI for DBS surgery. Manual identification of the LHb on axial T1 weighted MRI was used for the initial seed region for tractography. Variations in tractography depending on chosen axial slice of the LHb and chosen voxel within the LHb were also assessed.

Results

In all hemispheres the SM was reliably visualized. Variations in chosen axial seed slice as well as variations in single seed placement did not lead to significant changes in SM tractography.

Conclusions

Probabilistic DTI can be used to visualize the SM which may ultimately provide utility for direct anatomic targeting in DBS surgery.

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Diffusion tensor imaging based probabilistic fiber tracking can reliably identify the stria medullaris fiber bundles.

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The seeding of habenula reliably and consistently identifies the stria medullaris fiber tracks.

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Identification of the stria medullaris is useful in deep brain stimulation surgery.

Dietary total antioxidant capacity is associated with plasmatic antioxidant capacity, nutrient intake and lipid and DNA damage in healthy women

Dietary total antioxidant capacity (DTAC) seems to be associated with reducing risk of diseases. However, data about the influence of the DTAC on oxidative stress parameters are scarce. The aim of this study was to estimate the DTAC and its influence on plasma total antioxidant capacity (PTAC), and damage to lipids, proteins and DNA in healthy women. It was found a positive correlation between DTAC and PTAC in young and healthy subjects, where presumably the endogenous defenses are fully functional. DTAC and PTAC were positively correlated with the intake of known antioxidants, including vitamin C and polyphenols. The DTAC exhibited a negative correlation with lipid oxidative damage, while PTAC showed a negative correlation with DNA damage. This data contributes to better understanding of the recommended dietary antioxidant intake for promoting health.

Cortical correlates of affective syndrome in dementia due to Alzheimer's disease

Neuropsychiatric symptoms in Alzheimer's disease (AD) are prevalent, however their relationship with patterns of cortical atrophy is not fully known. Objectives To compare cortical atrophy's patterns between AD patients and healthy controls; to verify correlations between neuropsychiatric syndromes and cortical atrophy. Method 33 AD patients were examined by Neuropsychiatric Inventory (NPI). Patients and 29 controls underwent a 3T MRI scanning. We considered four NPI syndromes: affective, apathy, hyperactivity and psychosis. Correlations between structural imaging and neuropsychiatric scores were performed by Freesurfer. Results were significant with a p-value < 0.05, corrected for multiple comparisons. Results Patients exhibited atrophy in entorhinal cortices, left inferior and middle temporal gyri, and precuneus bilaterally. There was correlation between affective syndrome and cortical thickness in right frontal structures, insula and temporal pole. Conclusion Cortical thickness measures revealed atrophy in mild AD. Depression and anxiety symptoms were associated with atrophy of right frontal, temporal and insular cortices.

The neuroscience of depression: implications for assessment and intervention

Major Depressive Disorder (MDD) is among the most prevalent of all psychiatric disorders and is the single most burdensome disease worldwide. In attempting to understand the profound deficits that characterize MDD across multiple domains of functioning, researchers have identified aberrations in brain structure and function in individuals diagnosed with this disorder. In this review we synthesize recent data from human neuroimaging studies in presenting an integrated neural network framework for understanding the impairments experienced by individuals with MDD. We discuss the implications of these findings for assessment of and intervention for MDD. We conclude by offering directions for future research that we believe will advance our understanding of neural factors that contribute to the etiology and course of depression, and to recovery from this debilitating disorder.

Deep brain stimulation for treatment-resistant depression: systematic review of clinical outcomes

Major depressive disorder (MDD) is a widespread, severe, debilitating disorder that markedly diminishes quality of life. Medication is commonly effective, but 20-30 % of patients are refractory to medical therapy. The surgical treatment of psychiatric disorders has a negative stigma associated with it owing to historical abuses. Various ablative surgeries for MDD have been attempted with marginal success, but these studies lacked standardized outcome measures. The recent development of neuromodulation therapy, especially deep brain stimulation (DBS), has enabled controlled studies with sham stimulation and presents a potential therapeutic option that is both reversible and adjustable. We performed a systematic review of the literature pertaining to DBS for treatment-resistant depression to evaluate the safety and efficacy of this procedure. We included only studies using validated outcome measures. Our review identified 22 clinical research papers with 5 unique DBS approaches using different targets, including nucleus accumbens, ventral striatum/ventral capsule, subgenual cingulate cortex, lateral habenula, inferior thalamic nucleus, and medial forebrain bundle. Among the 22 published studies, only 3 were controlled trials, and 2, as yet unpublished, multicenter, randomized, controlled trials evaluating the efficacy of subgenual cingulate cortex and ventral striatum/ventral capsule DBS were recently discontinued owing to inefficacy based on futility analyses. Overall, the published response rate to DBS therapy, defined as the percentage of patients with > 50 % improvement on the Hamilton Depression Rating Scale, is reported to be 40-70 %, and outcomes were comparable across studies. We conclude that DBS for MDD shows promise, but remains experimental and further accumulation of data is warranted.

The aging brain and anesthesia

PURPOSE OF REVIEW

To review the neurophysiology and neuroanatomy of normal aging and the recent recommendations for the clinical management of general anesthesia and sedation in the elderly.

RECENT FINDINGS

As the population ages, the number of elderly patients having surgery is likewise increasing and with it, the prevalence of postoperative cognitive disorders. Postoperative cognitive disorders including delirium and postoperative cognitive dysfunction are common postanesthesia complications in elderly patients. Several risk factors for postoperative disorders have been identified, and anesthesiologists commonly adapt their practice habits when taking care of elderly patients to try to mitigate the effects of the anesthetics on postoperative cognitive function. These practices are reasonable and prudent; yet, they are not well supported by an understanding of the aging brain and specifics of how the anesthetic effects on the brain change with age. Through functional imaging and electrophysiological studies, much is being learned about the neurophysiology and the neuroanatomy of normal aging.

SUMMARY

Our analysis suggests that understanding the neurophysiology and neuroanatomy should be part of the standard working knowledge of anesthesiologists and that this knowledge can guide their use of the electroencephalogram to track more accurately the brain states of elderly patients receiving anesthesia care.

Accelerated aging in major depression: the role of nitro-oxidative stress

Nitro-oxidative stress (NOS) plays a fundamental role in aging, as well as in the pathogenesis of neurodegenerative disorders, and major depression (MD). The latter is a very frequent psychiatric illness characterized by accelerated aging, neurodegeneration, high comorbidity with age-related disorders, and premature mortality; all of these conditions find an explanation in an altered redox homeostasis. If aging, neurodegeneration, and major depression share a common biological base in their pathophysiology, common therapeutic tools could be investigated for the prevention and treatment of these disorders. As an example, antidepressants have been demonstrated to present neuroprotective and anti-inflammatory properties and to stimulate neurogenesis. In parallel, antioxidants that stimulate the antioxidant defense systems and interact with the monoaminergic system show an antidepressant-like activity. Further research on this topic could lead, in the near future, to the expansion of the therapeutic possibilities for the treatment of NOS-related disorders.

Aging and neuroplasticity

Neuroplasticity can be defined as a final common pathway of neurobiological processes, including structural, functional or molecular mechanisms, that result in stability or compensation for age- or disease-related changes. The papers in this issue address the aging process, as well as depression, dementia, and stroke and a range of interventions, including manipulations in behavior (physical and cognitive activity/exercise), physiological factors (caloric restriction, cholesterol), pharmacologic treatments (AMPA receptors) and manipulation of brain magnetic fields and electrical activity (transcranial magnetic stimulation, magnetic seizure therapy, and deep brain stimulation).This editorial will address different facets of neuroplasticity, the need for translational research to interpret neuroimaging data thought to reflect neuroplasticity in the human brain, and the next steps for testing interventions in aging and in disease.