Overview of growth differentiation factor 15 (GDF15) in metabolic diseases.

GDF15 is a stress response cytokine and a distant member of the transforming growth factor beta (TGFß) superfamily, its levels increase in response to cell stress and certain diseases in the serum. To exert its effects, GDF15 binds to glial-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL), which was firstly identified in 2017 and highly expressed in the brain stem. Many studies have demonstrated that elevated serum GDF15 is associated with anorexia and weight loss. Herein, we focus on the biology of GDF15, specifically how this circulating protein regulates appetite and metabolism in influencing energy homeostasis through its actions on hindbrain neurons to shed light on its impact on diseases such as obesity and anorexia/cachexia syndromes. It works as an endocrine factor and transmits metabolic signals leading to weight reduction effects by directly reducing appetite and indirectly affecting food intake through complex mechanisms, which could be a promising target for the treatment of energy-intake disorders.

A Review of Cerebrospinal Fluid Circulation and the Pathogenesis of Congenital Hydrocephalus.

The brain's ventricles are filled with a colorless fluid known as cerebrospinal fluid (CSF). When there is an excessive accumulation of CSF in the ventricles, it can result in high intracranial pressure, ventricular enlargement, and compression of the surrounding brain tissue, leading to potential damage. This condition is referred to as hydrocephalus. Hydrocephalus is classified into two categories: congenital and acquired. Congenital hydrocephalus (CH) poses significant challenges for affected children and their families, particularly in resource-poor countries. Recognizing the psychological and economic impacts is crucial for developing interventions and support systems that can help alleviate the distress and burden faced by these families. As our understanding of CSF production and circulation improves, we are gaining clearer insights into the causes of CH. In this article, we will summarize the current knowledge regarding CSF circulation pathways and the underlying causes of CH. The main causes of CH include abnormalities in the FoxJ1 pathway of ventricular cilia, dysfunctions in the choroid plexus transporter Na+-K+-2Cl- contransporter isoform 1, developmental abnormalities in the cerebral cortex, and structural abnormalities within the brain. Understanding the causes of CH is indeed crucial for advancing research and developing effective treatment strategies. In this review, we will summarize the findings from existing studies on the causes of CH and propose potential research directions to further our understanding of this condition.

Effects of 90 dB pure tone exposure on auditory and cardio-cerebral system functions in macaque monkeys.

Excessive noise exposure presents significant health risks to humans, affecting not just the auditory system but also the cardiovascular and central nervous systems. This study focused on three male macaque monkeys as subjects. 90 dB sound pressure level (SPL) pure tone exposure (frequency: 500Hz, repetition rate: 40Hz, 1 min per day, continuously exposed for 5 days) was administered. Assessments were performed before exposure, during exposure, immediately after exposure, and at 7-, 14-, and 28-days post-exposure, employing auditory brainstem response (ABR) tests, electrocardiograms (ECG), and electroencephalograms (EEG). The study found that the average threshold for the Ⅴ wave in the right ear increased by around 30 dB SPL right after exposure (P < 0.01) compared to pre-exposure. This elevation returned to normal within 7 days. The ECG results indicated that one of the macaque monkeys exhibited an RS-type QRS wave, and inverted T waves from immediately after exposure to 14 days, which normalized at 28 days. The other two monkeys showed no significant changes in their ECG parameters. Changes in EEG parameters demonstrated that main brain regions exhibited significant activation at 40Hz during noise exposure. After noise exposure, the power spectral density (PSD) in main brain regions, particularly those represented by the temporal lobe, exhibited a decreasing trend across all frequency bands, with no clear recovery over time. In summary, exposure to 90 dB SPL noise results in impaired auditory systems, aberrant brain functionality, and abnormal electrocardiographic indicators, albeit with individual variations. It has implications for establishing noise protection standards, although the precise mechanisms require further exploration by integrating pathological and behavioral indicators.

Acute exposure of microwave impairs attention process by activating microglial inflammation.

BACKGROUND: Attention provides the foundation for cognitions, which was shown to be affected by microwave (MW) radiation. With the ubiquitous of microwaves, public concerns regarding the impact of MW radiation on attention has hence been increased. Our study aims to investigate the potential effect and mechanism of acute microwave exposure on attention. RESULTS: We identified obvious impairment of attention in mice by the five-choice serial reaction time (5-CSRT) task. Proteomic analysis of the cerebrospinal fluid (CSF) revealed neuroinflammation and microglial activation potentially due to acute MW exposure. Moreover, biochemical analysis further confirmed microglial activation in the prefrontal cortex (PFC) of mice subjected to acute MW exposure. Finally, minocycline, a commercially available anti-inflammatory compound, attenuated neuroinflammation, inhibited the upregulation of N-methyl-D-aspartic acid receptor (NMDAR) including NR2A and NR2B, and also accelerated the attentional recovery after MW exposure. CONCLUSIONS: We believe that microglial activation and NMDAR upregulation likely contribute to inattention induced by acute MW exposure, and we found that minocycline may be effective in preventing such process.

Characterization of key aroma compounds in soy sauce flavor baijiu by molecular sensory science combined with aroma active compounds reverse verification method.

The distinctive flavor profile of soy sauce flavor baijiu (SAB) is shaped by its unique aroma compounds. The characteristic aroma compounds in Langjiu soy sauce flavor baijiu (LSAB) were explored based on molecular sensory science. A total of 66 aroma active compounds were identified by gas chromatography-olfactometry (GC-O) combined with aroma extract dilution analysis (AEDA), and 6 important unknown sulfur compounds were identified using the aroma active compounds reverse verification method (ACRVW). A total of 39 key aroma compounds were determined to have odor activity values (OAVs) ≥ 1. The aroma contribution of aroma components was verified by aroma recombination and aroma omission experiments. 15 characteristic aroma compounds were identified in LSAB. Meanwhile, a simple and easy-to-understand sensory expression language was described to fully understand the style characteristics of LSAB. Overall, the present paper offers insights into research uncovering the key "sauce flavor" of soy sauce flavor baijiu.

Prefrontal cortex activity of active motion, cyclic electrical muscle stimulation, assisted motion, and imagery of wrist extension in stroke using fNIRS.

OBJECTIVES: This study aimed to determine whether the prefrontal cortex (PFC) was activated during four training approaches for wrist extension in patients with stroke, including active motion, cyclic electrical muscle stimulation (EMS), assisted motion, and motor imagery (MI). MATERIALS AND METHODS: We conducted a cross-sectional study involving 16 patients with stroke, and adopted functional near-infrared spectroscopy (fNIRS) to observe PFC activity during four treatment paradigms. The beta value of 53 channels in fNIRS under each paradigm, compared to the baseline, was evaluated using single sample t-test. The one-way analysis of variance with post hoc analysis was employed to compare the difference of significantly activated channels among four treatment paradigms. RESULTS: This study revealed that the active motion (t values ranging from 2.399 to 4.368, p values <0.05), as well as MI of wrist extension (t values ranging from 2.161 to 4.378, p values <0.05), significantly increased HBO concentration across the entire PFC. The cyclic EMS enhanced the activation of Broca's area and frontal pole (FP) (t values ranging from -2.540 to 2.303, p values <0.05). The assisted motion induced significant activation in Broca's area, dorsolateral prefrontal cortex, and FP (t values ranging from -2.226 to 3.056, p values <0.05). The difference in ΔHBO among the four tasks was seen in Broca's area, FP, and frontal eye field. CONCLUSIONS: Active wrist extension and MI activate most PFC areas, whereas assisted motion and single-use of cyclic EMS have limited effectiveness for PFC activation in stroke patients.

Update on neurobiological mechanisms of fear: illuminating the direction of mechanism exploration and treatment development of trauma and fear-related disorders.

Fear refers to an adaptive response in the face of danger, and the formed fear memory acts as a warning when the individual faces a dangerous situation again, which is of great significance to the survival of humans and animals. Excessive fear response caused by abnormal fear memory can lead to neuropsychiatric disorders. Fear memory has been studied for a long time, which is of a certain guiding effect on the treatment of fear-related disorders. With continuous technological innovations, the study of fear has gradually shifted from the level of brain regions to deeper neural (micro) circuits between brain regions and even within single brain regions, as well as molecular mechanisms. This article briefly outlines the basic knowledge of fear memory and reviews the neurobiological mechanisms of fear extinction and relapse, which aims to provide new insights for future basic research on fear emotions and new ideas for treating trauma and fear-related disorders.

Neural Oscillation Disorder in the Hippocampal CA1 Region of Different Alzheimer's Disease Mice.

BACKGROUND: Alzheimer's disease (AD) is a well-known neurodegenerative disease that gradually induces neural network dysfunction and progressive memory deficits. Neural network activity is represented by rhythmic oscillations that influence local field potentials (LFPs). However, changes in hippocampal neural rhythmic oscillations in the early stage of AD remain largely unexplored. OBJECTIVE: This study investigated neural rhythmic oscillations in 3-month-old APP/PS1 and 5x- FAD mice to assess early neural connectivity in AD. METHODS: LFPs were recorded from the hippocampal CA1 region with implanted microelectrode arrays while the mice were in the awake resting stage. Welch fast Fourier transforms, continuous wavelet transforms, and phase-amplitude coupling analyses were used to compute the power density of different frequency bands and phase-amplitude modulation indices in the LFPs. RESULTS: Our results showed impaired theta, low gamma, and high gamma frequency band power in APP/PS1 and 5xFAD mice during the awake resting stage. AD mice also showed decreased delta, alpha, and beta frequency band power. Impaired theta-low gamma and theta-high gamma phaseamplitude coupling were observed in 5xFAD mice. CONCLUSION: This study revealed neural network activity differences in oscillation power and cross-frequency coupling in the early stage of AD, providing a new perspective for developing biomarkers for early AD diagnosis.

900 MHZ electromagnetic field exposure relieved AD-like symptoms on APP/PS1 mice: A potential non-invasive strategy for AD treatment.

BACKGROUND: Evidence shows that microwaves radiation may have various biological effects on central nervous system. Role of electromagnetic fields in neurodegenerative diseases, especially AD, has been widely studied, but results of these studies are inconsistent. Therefore, the above effects were verified again and the mechanism was preliminarily discussed. METHODS: Amyloid precursor protein (APP/PS1) and WT mice were exposed to long-term microwave radiation for 270 days (900 MHz, SAR: 0.25-1.055 W/kg, 2 h/day, alternately), and related indices were assessed at 90, 180 and 270 days. Cognition was evaluated by Morris water maze, Y maze and new object recognition tests. Congo red staining, immunohistochemistry and ELISA were used to analyze Aß plaques, Aß40 and Aß42 content. Differentially expressed proteins in hippocampus between microwave-exposed and unexposed AD mice were identified by proteomics. RESULTS: Spatial and working memory was improved in AD mice after long-term 900 MHz microwave exposure compared with after sham exposure. Microwave radiation (900 MHz) for 180 or 270 days did not induce Aß plaque formation in WT mice but inhibited Aß accumulation in the cerebral cortex and hippocampus in 2- and 5-month-old APP/PS1 mice. This effect mainly occurred in the late stage of the disease and may have been attributed to downregulation of apolipoprotein family member and SNCA expression and excitatory/inhibitory neurotransmitter rebalance in the hippocampus. CONCLUSIONS: The present results indicated that long-term microwave radiation can retard AD development and exert a beneficial effect against AD, suggesting that 900 MHz microwave exposure may be a potential therapy for AD.

Distal Humeral Trochlear Geometry Associated With the Spatial Variation of the Dynamic Elbow Flexion Axis.

Background: The complexity of the spatial dynamic flexion axis (DFA) of the elbow joint makes the elbow prosthesis design and humeral component alignment challenging. This study aimed to 1) investigate the variations of the spatial DFA during elbow flexion and 2) investigate the relationship between the distal humeral trochlear geometry and the in vivo spatial variation of the DFA. Methods: Ten healthy subjects participated in this study. Each subject performed a full elbow extension to maximum flexion with hand supination under dual fluoroscopic imaging system (DFIS) surveillance. The 2D fluoroscopic images and the 3D bone models were registered to analyze the in vivo elbow kinematics and DFAs. The spatial DFA positions were defined as inclination with the medial and lateral epicondyle axes (MLA) in the transverse and coronal planes. The range of the DFA positions was also investigated during different flexion phases. The Spearman correlation method was used to analyze the relationship between the distal humeral trochlear's morphological parameters and the position of DFAs during different flexion phases. Results: The pathway of the DFAs showed an irregular pattern and presented individual features. The medial trochlear depth (MTD) (r = 0.68, p = 0.03) was positively correlated with the range of the DFA position (2.8° ± 1.9°) in the coronal plane from full extension to 30° of flexion. Lateral trochlear height (LTH) (r = -0.64, p = 0.04) was negatively correlated with the DFA position (-1.4° ± 3.3°) in the transverse plane from 30° to 60° of flexion. A significant correlation was found between LTH with the DFA position in the coronal (r = -0.77, p = 0.01) and transverse planes (r = -0.76, p = 0.01) from 60° to 90° of flexion. Conclusion: This study showed that the pathway of the dynamic flexion axis has an individual pattern. The medial and lateral trochlear sizes were the key parameters that might affect the elbow joint flexion function. When recovering complex distal humeral fractures or considering the implant design of total elbow arthroplasty, surgeons should pay more attention to the medial and lateral trochlea's geometry, which may help restore normal elbow kinematics.

Associations Between a Polymorphism in the Rat 5-HT1A Receptor Gene Promoter Region (rs198585630) and Cognitive Alterations Induced by Microwave Exposure.

The nervous system is a sensitive target of electromagnetic radiation (EMR). Chronic microwave exposure can induce cognitive deficits, and 5-HT system is involved in this effect. Genetic polymorphisms lead to individual differences. In this study, we evaluated whether the single-nucleotide polymorphism (SNP) rs198585630 of 5-HT1A receptor is associated with cognitive alterations in rats after microwave exposure with a frequency of 2.856 GHz and an average power density of 30 mW/cm2. Rats were exposed to microwaves for 6 min three times a week for up to 6 weeks. PC12 cells and 293T cells were exposed to microwaves for 5 min up to 3 times at 2 intervals of 5 min. Transcriptional activity of 5-HT1A receptor promoter containing rs198585630 C/T allele was determined in vitro. Electroencephalograms (EEGs), spatial learning and memory, and mRNA and protein expression of 5-HT1A receptor were evaluated in vivo. We demonstrated that transcriptional activity of 5-HT1A receptor promoter containing rs198585630 C allele was higher than that of 5-HT1A receptor promoter containing T allele. The transcriptional activity of 5-HT1A receptor promoter was stimulated by 30 mW/cm2 microwave exposure, and rs198585630 C allele was more sensitive to microwave exposure, as it showed stronger transcriptional activation. Rats carrying rs198585630 C allele exhibited increased mRNA and protein expression of 5-HT1A receptor and were more susceptible to 30 mW/cm2 microwave exposure, showing cognitive deficits and inhibition of brain electrical activity. These findings suggest SNP rs198585630 of the 5-HT1A receptor is an important target for further research exploring the mechanisms of hypersensitivity to microwave exposure.

Acute High Level Noise Exposure Can Cause Physiological Dysfunction in Macaque Monkeys: Insight on the Medical Protection for Special Working Environmental Personnel.

The high level noise caused by intense acoustic weapons and blasting is a common source of acute acoustic trauma faced by some special environmental personnel. Studies have shown that high level noise can cause auditory and non-auditory effects. However, there are few reports on the biological effects, especially the non-auditory effects of acute high level noise exposure in simulated special working environments, and the great differences between experimental animals and human beings make it difficult to extrapolate from research conclusions. In this study, macaque monkeys were used to detect the effects of acute high level noise exposure on hearing, cognition, and cardiovascular function. Auditory brainstem response, auditory P300, and electrocardiogram (ECG) of macaque monkeys were measured. Results showed that acute high level noise exposure caused permanent hearing threshold shifts; partial hearing loss which couldn't recover to normal levels in the detection period; pathological changes in T wave and QRS complexes; and large fluctuations in cognitive ability after exposure, which finally recovered to normal. These alterations may be a combination of effects caused by stress-induced neuroendocrine dysfunction and mechanical damage of auditory organs. To elaborate the exact mechanism, further studies are still needed. Meanwhile, positive measures should be taken to reduce the incidence of acute high level noise injury.

Well-Placed Acetabular Component Oriented Outside the Safe Zone During Weight-Bearing Daily Activities.

Background: A comprehensive and thorough understanding of functional acetabular component orientation is essential for optimizing the clinical outcome after total hip arthroplasty (THA). This study aimed to quantify the functional acetabular anteversion and inclination of unilateral THA patients during walking and static standing and to determine whether the functional acetabular orientation falls within the Lewinnek safe zone. Methods: Seventeen patients with unilateral THA received a CT scan and dual fluoroscopic imaging during level walking and static standing to evaluate in vivo hip kinematics. The pelvic functional coordinate system of the 3D CT-based computer model was defined by the line of gravity and anterior pelvic plane (APP) to measure functional acetabular anteversion and inclination in different postures. The Lewinnek safe zone was used to determine the acetabular malposition during functional activities. Results: The THA side demonstrated an average of 10.1° (± 9.6°, range -7.5° to 29.9°) larger functional anteversion and 16.0° (± 9.2°, range -7.2° to 29.9°) smaller inclination than native hips during level walking. Functional acetabular anteversion in the THA side during level walking and static standing was significantly larger than anatomical measurements (p < 0.05). Acetabular orientation of most well-placed THA components anatomically in the Lewinnek safe zone fell outside the safe zone during more than half of the gait cycle and static standing. Conclusion: The current study revealed that an anatomically well-placed acetabular cup does not guarantee a well-functional orientation during daily activities. The in vivo mechanical performance and loading conditions of the THA component during other weight-bearing activities should be investigated in further studies.

Effectiveness of different types of skin grafting for treating venous leg ulcers: A protocol for systematic review and network meta-analysis.

BACKGROUND: Venous leg ulcers (VLUs) are the most common ulcer on the lower extremity, with 4% of patients over the age of 65 suffering from VLUs worldwide. As a recurrent, chronic, disabling disease, VLUs are associated with prolonged disability, substantial socioeconomic impact, and significant psychosocial morbidity. At present, Skin grating is one of the most effective treatments for non-healing ulcers. However, there are still no new studies based on the latest research and new research methods to evaluate and compare the effect of different types of skin grafts for treating venous leg ulcers. Therefore, a Bayesian network meta-analysis (NMA) will be conducted to systematically assess skin grafting efficacy for VLUs. METHODS: We will include randomized controlled trials (RCTs) involving patients with VLUs treated by skin grafts. Electronic databases and clinical trials registries will be searched from their inception until June 2021, without language or publication restrictions on status. The search strategy mainly includes Medical Subject Headings (MeSH) and free-text terms. Two review authors will independently perform data extraction and assessment of study quality. And We will use Bayesian NMA to evaluate all available evidence in STATA 14.0 and WinBUGS software. RESULTS: This protocol will use Bayesian NMA to assess the effectiveness of different types of skin grafting for treating venous leg ulcers. CONCLUSION: This study aims to synthesize the available evidence from RCTs in a network meta-analysis to summarize the best research available and provide consistency among treatment protocols given to patients, resulting in improved efficacy and the quality of care and reduced cost.

Optimizing the Femoral Offset for Restoring Physiological Hip Muscle Function in Patients With Total Hip Arthroplasty.

OBJECTIVE: Femoral offset (FO) restoration is significantly correlated with functional recovery following total hip arthroplasty (THA). Accurately assessing the effects of FO changes on hip muscles following THA would help improve function and optimize functional outcomes. The present study aimed to (1) identify the impact of FO side difference on the hip muscle moment arms following unilateral THA during gait and (2) propose the optimal FO for a physiological hip muscle function. METHODS: In vivo hip kinematics from eighteen unilateral THA patients during gait were measured with a dual-fluoroscopic imaging system. The moment arms of thirteen hip muscles were calculated using CT-based 3D musculoskeletal models with the hip muscles' lines of actions. The correlation coefficient (R) between FO and hip muscle moment arm changes compared with the non-implanted hip was calculated. We considered that the FO reconstruction was satisfactory when the abductor moment arms increased, while the extensor, adductor, and flexor moment arms decreased less than 5%. RESULTS: A decreased FO following THA was significantly correlated with a decrease of the abductor and external rotator moment arms during the whole gait (R > 0.5) and a decrease of extensor moment arms during the stance phase (R > 0.4). An increased FO following THA was significantly associated with shorter flexor moment arms throughout the gait (R < -0.5) and shorter adductor moment arms in the stance phase (R < -0.4). An increase in FO of 2.3-2.9 mm resulted in increased abductor moment arms while maintaining the maximum decrease of the hip muscles at less than 5.0%. CONCLUSION: An increase of 2-3 mm in FO could improve the abductor and external rotator function following a THA. Accurate surgical planning with optimal FO reconstruction is essential to restoring normal hip muscle function in THA patients.

Low p-SYN1 (Ser-553) Expression Leads to Abnormal Neurotransmitter Release of GABA Induced by Up-Regulated Cdk5 after Microwave Exposure: Insights on Protection and Treatment of Microwave-Induced Cognitive Dysfunction.

With the wide application of microwave technology, concerns about its health impact have arisen. The signal transmission mode of the central nervous system and neurons make it particularly sensitive to electromagnetic exposure. It has been reported that abnormal release of amino acid neurotransmitters is mediated by alteration of p-SYN1 after microwave exposure, which results in cognitive dysfunction. As the phosphorylation of SYN1 is regulated by different kinases, in this study we explored the regulatory mechanisms of SYN1 fluctuations following microwave exposure and its subsequent effect on GABA release, aiming to provide clues on the mechanism of cognitive impairment caused by microwave exposure. In vivo studies with Timm and H&E staining were adopted and the results showed abnormality in synapse formation and neuronal structure, explaining the previously-described deficiency in cognitive ability caused by microwave exposure. The observed alterations in SYN1 level, combined with the results of earlier studies, indicate that SYN1 and its phosphorylation status (ser-553 and ser62/67) may play a role in the abnormal release of neurotransmitters. Thus, the role of Cdk5, the upstream kinase regulating the formation of p-SYN1 (ser-553), as well as that of MEK, the regulator of p-SYN1 (ser-62/67), were investigated both in vivo and in vitro. The results showed that Cdk5 was a negative regulator of p-SYN1 (ser-553) and that its up-regulation caused a decrease in GABA release by reducing p-SYN1 (ser-553). While further exploration still needed to elaborate the role of p-SYN1 (ser-62/67) for neurotransmitter release, MEK inhibition had was no impact on p-Erk or p-SYN1 (ser-62/67) after microwave exposure. In conclusion, the decrease of p-SYN1 (ser-553) may result in abnormalities in vesicular anchoring and GABA release, which is caused by increased Cdk5 regulated through Calpain-p25 pathway after 30 mW/cm2 microwave exposure. This study provided a potential new strategy for the prevention and treatment of microwave-induced cognitive dysfunction.

Adverse effects of total hip arthroplasty on the hip abductor and adductor muscle lengths and moment arms during gait.

BACKGROUND: Precise evaluation of the hip abductor and adductor muscles function in total hip arthroplasty (THA) patients during gait could help prevent postoperative complications and optimize the rehabilitation training program. The purpose of this study was to elucidate the effects of THA on the hip abductor and adductor muscle lengths and moment arms of in vivo patients during gait. METHODS: Ten unilateral THA patients received CT scans and dual fluoroscopic imaging for the hip kinematics during gait. The hip abductor and adductor muscle insertions were digitized on the 3D hip model for the determination of their dynamic lines of action and moment arms. Changes in the hip abductor and adductor muscle lengths and moment arms of THA patients between the implanted and non-implanted sides were quantified during gait. RESULTS: The adductor longus, adductor brevis, and pectineus of the implanted hips had significantly (P < 0.05) less elongation than that of the non-implanted side during the stance phase. The gluteus medius, gluteus minimus, and piriformis moment arms of the implanted side were significantly shorter. The piriformis muscle moment arm was significantly larger. In the double support phase, the adductor magnus and adductor longus moment arms of the implanted sides were significantly decreased. CONCLUSIONS: Results suggested that the adverse effects of THA on hip stability. Development of a rehabilitation program considering the effects of THA is essential. Accurate surgical techniques may reduce the impact of THA on the peripheral muscles.

Endogenous cortisol-related alterations of right anterior insula functional connectivity under acute stress.

BACKGROUND: Previous studies have suggested that the right anterior insula (rAI) plays a vital role in salience processing and stress-related disorders. In this study, we aimed to investigate the relationship between rAI functional connectivity changes and individual differences in cortisol responses after acute stress, in order to provide insights into psychiatric illness vulnerabilities. METHODS: Thirty-five young men were enrolled in a randomized, counterbalanced two-session study, with aversive movie clip combined with electrical shocks as stress stimulation and the neutral movie clip as control stimulation. Resting-state fMRI data was acquired after movie exposure. The rAI was chosen as seed for functional connectivity analysis. We then examined the effect of acute stress on rAI functional connectivity and its association with individuals' cortisol response. RESULTS: We found decreased rAI functional connectivity in the fronto-parietal regions, but increased functional connectivity in the visual and somatosensory areas following acute stress. Moreover, stress-induced cortisol response was significantly positively correlated with the rAI functional connectivity in the medial prefrontal cortex, and negatively correlated with the orbital-frontal cortex, lingual gyrus, and middle temporal gyrus. LIMITATIONS: Only young Chinese males without any trauma experience were recruited in this study. CONCLUSIONS: The results suggested tight link between specific rAI functional connectivity alterations and individual stress reactivity, which may help elucidate the potential neurobiological mechanism underlying vulnerability to stress-related disorders.

Neuroticism is associated with altered resting-state functional connectivity of amygdala following acute stress exposure.

The amygdala, a subcortical structure responsible for fear and vigilance, is central to the stress circuitry. Aberrant amygdala connectivity with the cortical and subcortical regions is found in patients with stress-related disorders, and in healthy subjects following acute stress exposure. However, the extent to which the stress-induced alteration of amygdala functional connectivity correlates with risk-related personality measures remains unclear. Using resting-state functional magnetic resonance imaging, we evaluated the effect of acute stress, induced by aversive movies accompanied by a mild electric shock, on the functional connectivity of the basolateral amygdala (BLA) and centromedial amygdala (CMA) in 35 healthy men, and assessed the association between changes in amygdala functional connectivity and individual differences in neuroticism. We found increased BLA functional connectivity with the posterior cingulate cortex/retrosplenial and increased CMA functional connectivity with the medial prefrontal cortex following acute stress exposure. Moreover, neuroticism was positively correlated with altered functional coupling of the basolateral subregions with the anterior insular cortex, dorsal anterior cingulate cortex, and pregenual anterior cingulate cortex, which are involved in salience processing. These findings suggest that neurotic individuals may be more prone to hypervigilance following acute stress, which may potentially link neuroticism to the neurobiology underlying increased susceptibility to stress-related disorders.

Microwave radiation leading to shrinkage of dendritic spines in hippocampal neurons mediated by SNK-SPAR pathway.

The popularization of microwave raised concerns about its influence on health including cognitive function which is associated greatly with dendritic spines plasticity. SNK-SPAR is a molecular pathway for neuronal homeostatic plasticity during chronically elevated activity. In this study, Wistar rats were exposed to microwaves (30 mW/cm2 for 6 min, 3 times/week for 6 weeks). Spatial learning and memory function, distribution of dendritic spines, ultrastructure of the neurons and their dendritic spines in hippocampus as well as the related critical molecules of SNK-SPAR pathway were examined at different time points after microwave exposure. There was deficiency in spatial learning and memory in rats, loss of spines in granule cells and shrinkage of mature spines in pyramidal cells, accompanied with alteration of ultrastructure of hippocampus neurons. After exposure to 30 mW/cm2 microwave radiation, the up-regulated SNK induced decrease of SPAR and PSD-95, which was thought to cause the changes mentioned above. In conclusion, the microwave radiation led to shrinkage and even loss of dendritic spines in hippocampus by SNK-SPAR pathway, resulting in the cognitive impairments.