Correlación entre estado emocional y activación funcional mediante resonancia magnética / Correlation between emotional state and functional activation with magnetic resonance imaging

Resumen Objetivo: Explorar si voluntarios sanos presentarían correlación entre su puntaje en un test psicológico emocional y las activaciones de áreas cerebrales relacionadas con las emociones medidas con resonancia magnética funcional (RMf). Material y métodos: Estudio exploratorio de prueba diagnóstica, prospectivo, con diseño del propio individuo como control, con muestra de 12 participantes. Se categorizó a cada participante con un puntaje de estabilidad emocional derivado de un test psicológico y se utilizaron estímulos emocionales audiovisuales durante las adquisiciones de RMf. Resultados: La sumatoria de clusters de activación medidos en cantidad total de vóxeles durante los estímulos negativos en áreas cerebrales relacionadas con las emociones mostró una correlación negativa estadísticamente significativa para nuestro tamaño de muestra respecto de los puntajes en el test emocional, con rho de Spearman de −0,623 y p = 0,0428. Conclusiones: Los paradigmas de RMf utilizados permitieron cuantificar las activaciones cerebrales ante estímulos emocionales de valencia positiva y negativa, y los resultados obtenidos abren una perspectiva hacia la posibilidad de utilizar test psicológicos y secuencias de RMf para predecir la posibilidad de aparición de síntomas de patologías psicológicas o psiquiátricas ante factores desencadenantes en población sana que presente en estos test valores cercanos al límite de la normalidad.

Abstract Objective: To explore if healthy volunteers would present a correlation between their score in emotional psychological test and the activations of brain areas related to emotions measured with functional magnetic resonance imaging (fMRI). Material and methods: Exploratory study of a prospective diagnostic test, with the individual’s own design as a control, with a sample of 12 participants. Each participant was categorized with an emotional stability score derived from a psychological test and audiovisual emotional stimuli were used during fMRI acquisitions. Results: The sum of activation clusters measured in total number of voxels during negative stimuli in brain areas related to emotions showed a statistically significant negative correlation for our sample size with respect to the scores in the emotional test, with Spearman’s rho of −0.623 and p = 0.0428. Conclusions: The fMRI paradigms used made it possible to quantify brain activations in response to emotional stimuli of positive and negative valence, and the results obtained open a perspective towards the possibility of using psychological tests and fMRI sequences to predict the possibility of the appearance of symptoms of psychological or psychiatric pathologies in response to triggering factors in a healthy population that present values close to the normal limit in these tests.

The amygdala lesioning due to status epilepticus - Changes in mechanisms controlling chloride homeostasis

Objective: Amygdala has been demonstrated as one of the brain sites involved in the control of cardiorespiratory functioning. The structural and physiological alterations induced by epileptic activity are also present in the amygdala and reflect functional changes that may be directly associated with a sudden unexpected death. Seizures are always associated with neuronal damage and changes in the expression of cation-chloride cotransporters and Na/K pumps. In this study, the authors aimed to investigate if these changes are present in the amygdala after induction of status epilepticus with pilocarpine, which may be directly correlated with Sudden Unexpected Death in Epilepsy (SUDEP). Methods: Pilocarpine-treated wistar rats 60 days after Status Epilepticus (SE) were compared with control rats. Amygdala nuclei of brain slices immunostained for NKCC1, KCC2 and α1-Na+/K+-ATPase, were quantified by optical densitometry. Results: The amygdaloid complex of the animals submitted to SE had no significant difference in the NKCC1 immunoreactivity, but KCC2 immunoreactivity reduced drastically in the peri-somatic sites and in the dendritic-like processes. The α1-Na+/K+-ATPase peri-somatic immunoreactivity was intense in the rats submitted to pilocarpine SE when compared with control rats. The pilocarpine SE also promoted intense GFAP staining, specifically in the basolateral and baso-medial nuclei with astrogliosis and cellular debris deposition. Interpretation: The findings revealed that SE induces lesion changes in the expression of KCC2 and α1-Na + /K + -ATPase meaning intense change in the chloride regulation in the amygdaloid complex. These changes may contribute to cardiorespiratory dysfunction leading to SUDEP.

Effects of betulinol on cognition, emotion and chemokine expression in amygdala of rats with chronic aluminum-induced dementia / 中国职业医学

@#Abstract: Objective - To investigate the effect of betulin on the cognition and emotion of rats with chronic aluminum induced Methods dementia and its influence on the expression of inflammatory factors in amygdala. The specific pathogen free female - - SD rats were randomly divided into control group, model group, intervention control group, low dose group and high dose group, with 10 rats in each group. The rats in the later four groups were given with 100 mg/kg body weight and 10.0 g/L aluminum chloride solution by gavage, while the rats in the control group were gavaged with the same volume of distilled water, once a day for 60 days. The rat model of dementia caused by chronic aluminum exposure was established. The rats in the intervention - - control group were given donepezil hydrochloride (0.5 g/L) by gavage, the rats in the low dose and high dose groups were given betulin (20.0 and 60.0 g/L) by gavage, and the rats in the control and model groups were given the same volume of distilled water - by gavage, once a day for four weeks. Anxiety like behavior was evaluated by Y maze new arm test and elevated cross maze test. - The depression like behavior was evaluated by forced swimming test. The amygdala of rats was isolated, and the expression of - - phosphorylated Tau (p Tau) protein andcell derived factor 1 (SDF 1), C X C chemokine receptor (CXCR) 3, CXCR4 and interferon inducible protein 10 (IP 10) was Results detected by Western blotting. In the behavioral experiments, the residence time in the new arm and the percentage of P P time in the open arm of the model group decreased (all <0.05), while the cumulative immobility time increased ( <0.05) compared with the control group. The residence time in the new arm and the percentage of time in the open arm increased in the - - P intervention control group, low dose group and high dose group (all <0.05), while the cumulative immobility time decreased (all P<0.05) compared with the model group. The residence time in the new arm and the percentage of time in the open arm increased - - P P in the low dose group and the high dose group (all <0.05), while the accumulated immobility time decreased (all <0.05) compared with the intervention control group. The residence time in the new arm and the percentage of time in the open arm P P - - increased (all <0.05), while the accumulated immobility time decreased ( <0.05) in the high dose group compared with the low - - - - - dose group. The relative expression of p Tau, βAPP, IL 1, IL 6, IL 8, CXCR3 and IP 10 increased, while the relative expression - P - of SDF 1 and CXCR4 decreased in the model group compared with the control group (all <0.05). The relative expression of p - - - - - Tau, βAPP, IL 1, IL 6, IL 8, IP 10 and CXCR3 decreased, while the relative expression of SDF 1 and CXCR4 increased in the - - P intervention control group, low dose group and high dose group compared with the model group (all <0.05). The relative - - - - - P - expression of p Tau, βAPP, IL 1, IL 6, IL 8, IP 10 and CXCR3 decreased (all <0.05), while the relative expression of SDF 1 - - and CXCR4 increased in the intervention control group, low dose group and high dose group compared with the intervention P Conclusion control group (all <0.05). Betulin can protect cognitive function and improve mood in chronic aluminum - exposure induced dementia model rats. The mechanism may be related to inhibiting the production of inflammatory factors and - chemokines in the amygdala of rats, thereby inhibiting the synthesis of p Tau protein and βAPP protein. βamyloid precursor protein (βAPP) was detected by immunohistochemistry. The

Inhibiting silence information regulator 2 and glutaminase in the amygdala can improve social behavior in autistic rats / 浙江大学学报·医学版

OBJECTIVE@#To investigate the underlying molecular mechanisms by which silence information regulator (SIRT) 2 and glutaminase (GLS) in the amygdala regulate social behaviors in autistic rats.@*METHODS@#Rat models of autism were established by maternal sodium valproic acid (VPA) exposure in wild-type rats and SIRT2-knockout ( SIRT2 -/-) rats. Glutamate (Glu) content, brain weight, and expression levels of SIRT2, GLS proteins and apoptosis-associated proteins in rat amygdala at different developmental stages were examined, and the social behaviors of VPA rats were assessed by a three-chamber test. Then, lentiviral overexpression or interference vectors of GLS were injected into the amygdala of VPA rats. Brain weight, Glu content and expression level of GLS protein were measured, and the social behaviors assessed.@*RESULTS@#Brain weight, amygdala Glu content and the levels of SIRT2, GLS protein and pro-apoptotic protein caspase-3 in the amygdala were increased in VPA rats, while the level of anti-apoptotic protein Bcl-2 was decreased (all P<0.01). Compared with the wild-type rats, SIRT2 -/- rats displayed decreased expression of SIRT2 and GLS proteins in the amygdala, reduced Glu content, and improved social dysfunction (all P<0.01). Overexpression of GLS increased brain weight and Glu content, and aggravated social dysfunction in VPA rats (all P<0.01). Knockdown of GLS decreased brain weight and Glu content, and improved social dysfunction in VPA rats (all P<0.01).@*CONCLUSIONS@#The glutamate circulatory system in the amygdala of VPA induced autistic rats is abnormal. This is associated with the upregulation of SIRT2 expression and its induced increase of GLS production; knocking out SIRT2 gene or inhibiting the expression of GLS is helpful in maintaining the balanced glutamate cycle and in improving the social behavior disorder of rats.

Effects of Chronic Restraint Stress on Apoptosis of Amygdala Cells in Rats / 法医学杂志

OBJECTIVES@#To explore the damage effects of chronic restraint stress (CRS) on amygdala cells through the rat CRS model.@*METHODS@#The rat CRS model was established, and the changes in body weight and adrenal mass in control group and CRS group were monitored at 1 d, 7 d, 14 d and 21 d. The behavior changes were evaluated by the percentage of retention time of open arms and open arm entries using the elevated plus maze (EPM). ELISA was used to detect the concentrations of rat's corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol. The changes of expression of glucocorticoid receptor (GR) and glial fibrillary acidic protein (GFAP) in amygdala were determined by immunohistochemistry and Western blotting. Ultrastructure changes of glial cell were observed by transmission electron microscopy. The apoptosis rate of amygdala was measured by flow cytometry.@*RESULTS@#Compared with the control group at the same time points, body weight of CRS 1 d, 7 d, 14 d and 21 d groups increased slowly, but adrenal mass increased significantly; the serum level of CRH, cortisol and ACTH increased significantly at 7 d, 14 d and 21 d respectively; the expression of GR in amygdala was increased while that of GFAP was decreased; EPM test suggested that the percentage of retention time of open arms and open arm entries decreased significantly after 14 d. The CRS group showed different degrees of glial cell damage in amygdala, and the apoptosis rate of glial cell was significantly increased in 21 d group.@*CONCLUSIONS@#This study successfully established a CRS model in rats, and anxiety-like behavioral changes in model rats may be caused by apoptosis of amygdala astrocytes.

The antiepileptic activity of Safranal in kindling model of epilepsy in male rats

Abstract Recent studies suggested that safranal exerts anticonvulsant properties. The present study aimed to investigate the effect of safranal on epileptic activities in the amygdala electrical kindling model in male rats. Animals were implanted with a recording electrode on the skull and a tripolar in the amygdala. After 10 days of recovery, the afterdischarge (AD) threshold of each animal was determined and stimulated once daily the AD threshold for full kindling development. Then, parameters including afterdischarge duration (ADD), stage 4 latency (S4L), stage 5 duration (S5D), and stimulation threshold were determined before and after injection of safranal (0.05, 0.1, 0.2 ml/ kg; i.p). While the dose of 0.05 ml/kg had no significant effect, the dose of 0.1 ml/kg increased the AD threshold as well as S4L and decreased the S5D (P<0.05). Injection of 0.2 ml/kg of the safranal significantly decreased the ADD and S5D (P<0.05) and 83.3% of animals had no stage 4 and stage 5 of kindling (P<0.001). Based on the obtained data safranal has anticonvulsant effects dosedependently. It seems that a dose of 0.2 ml/kg is the minimum effective dose. Further investigation is warranted to conduct the clinical implications for the treatment of epileptic disorders

Establishment of A Mouse Model of Obesity and Depression Comorbidity and Its Application in Pharmacological Study of Tripterine / 中国实验方剂学杂志

ObjectiveTo establish a neuroinflammation-based obesity and depression comorbidity （COM） model in mice and explore the pharmacodynamics and preliminary pharmacological mechanism of tripterine on COM mice. MethodC57BL/6J mice were randomly divided into a normal group （Chow）， a diet-induced obesity group （DIO）， and a COM group. The mice in the COM group were fed on a high-fat diet and chronically stressed with moist litter for 12 weeks to establish the COM model. C57BL/6J mice were randomly divided into a Chow group， a COM group， and a tumor necrosis factor-α（TNF-α） knock-down group. In the TNF-α knock-down group， TNF-α shRNA adeno-associated virus was injected into the amygdala through brain stereotaxis， and the expression of TNF-α in the amygdala was down-regulated. C57BL/6J mice were randomly divided into a Chow group， a DIO group， a DIO + low-dose tripterine group （0.5 mg·kg-1）， a DIO + high-dose tripterine group （1.0 mg·kg-1）， a COM group， a COM + low-dose tripterine group （0.5 mg·kg-1）， and a COM + high-dose tripterine group （1.0 mg·kg-1）. The body weight， food intake， glucose tolerance， white/brown fat ratio， serum total cholesterol （TC）， triglyceride （TG）， and high-/low-density lipoprotein cholesterol （HDL-C and LDL-C） content were recorded， and obesity of mice in each group was evaluated. Forced swimming test （FST）， tail suspension test （TST）， and open field test were used to evaluate the degree of depression of mice in each group. Immunofluorescence staining was used to detect the protein expression levels of neuropeptide Y， tryptophan hydroxylase 2 （TPH2）， and brain-derived neurotrophic factor （BDNF） in various brain nuclei of mice. Correlation analysis was used to detect the correlation of obesity and depression indexes. ResultThe comparison of the Chow group and the DIO group indicated that COM mice showed obesity and depression. To be specific， obesity was manifested as increased body weight and food intake （P<0.05， P<0.01）， as well as increased NPY expression in the central amygdala， and depression was manifested as prolonged immobility time in FST and TST （P<0.01）， and reduced TPH2-positive 5-hydroxytryptamine neurons in the dorsal raphe nucleus （DRN） and basolateral nucleus of the amygdala （BLA）. The down-regulation of TNF-α protein in BLA of COM mice shortened the immobility time in FST and TST （P<0.05， P<0.01）， increased TPH2/BDNF-positive neurons in BLA， and showed no significant changes in obesity. In DIO mice， the administration of 0.5 mg·kg-1 tripterine for 9 days significantly decreased the 60 min blood glucose in glucose tolerance （P<0.01） and food intake （P<0.05）. In COM mice， 1.0 mg·kg-1 tripterine was administered for 14 days to significantly decrease 30 min blood glucose in glucose tolerance （P<0.01）， and food intake （P<0.05）， and immobility time in TST （P<0.01）， increase TPH2-BDNF double-labeled cells in BLA and DRN， and reduce the area of TMEM119-stained cells. ConclusionThe model of obesity and depression comorbidity can be properly induced in mice under the condition of dual stress of energy environment. Tripterine can effectively interfere with obesity-depression comorbidity， and its mechanism may be related to the inhibition of central nervous system inflammation.

Regulatory Effect of Wenyang Prescription， Jieyu Prescription， and Wenyang Jieyu Prescription on Pain Sensitivity and Depression-like Behaviors in Mice Induced by Maternal Separation and Chronic Neuropathic Pain / 中国实验方剂学杂志

ObjectiveTo observe the behavioral and pain threshold alterations， as well as the changes in indexes related to depression and pain in the serum and central system in mice stressed by maternal separation and chronic neuropathic pain， and explore the underlying mechanism of Wenyang prescription （WY）， Jieyu prescription （JY）， and Wenyang Jieyu prescription （WYJY） in improving depression and pain sensitivity. MethodThe birth date of mice was recorded as PD0. After birth， the mice were divided into a blank group and an experimental group. The neonatal mice in the experimental group underwent maternal separation in PD5-14 at 8 h·d-1. After ablactation， the mice were divided into a maternal separation group， a WY group （Erxian decoction， 5.84 g·kg-1）， a JY group （Xiaoyaosan， 12.00 g·kg-1）， a WYJY group （16.68 g·kg-1）， and a fluoxetine group （2.60 mg·kg-1）， with 15 mice in each group. Meanwhile， 15 male mice of the same age without maternal separation were assigned to the normal control group. Mice in the blank group and the maternal separation group were fed on a regular chow diet in PD21-PD90， while the remaining groups were fed on the corresponding drugs. In PD91， sciatic nerve ligation was performed to induce a model of maternal separation and chronic neuropathic pain. The open field test was used to observe the depression-like behaviors of mice in each group， and the mechanical and temperature pain thresholds were measured to detect the pain sensitivity of mice in each group. The serum levels of corticosterone （CORT）， substance P， and β-endorphin （β-EP） were determined by enzyme-linked immunosorbent assay （ELISA）， and the expression of the glucocorticoid receptor （GR） in the amygdala and β-EP protein in the hypothalamus was detected by immunohistochemistry. The mRNA expression levels of amygdala GR gene （Nr3c1）， FK506 binding protein 5 gene （FKBP5）， metabolic glutamate receptor 5 gene （GRM5）， and brain-derived neurotrophic factor （BDNF） were detected by real-time fluorescence quantitative polymerase chain reaction（Real-time PCR）. ResultCompared with the blank group， the maternal separation group showed reduced stay time and total distance traveled in the 5-min open field test （P<0.01）， reduced mechanical pain threshold （P<0.01）， increased serum CORT and β-EP （P<0.01）， declining FKBP5 mRNA expression （P<0.01）， and increased hypothalamic β-EP expression （P<0.05）. Compared with the maternal separation group， the groups with drug intervention showed prolonged stay time （P<0.05， P<0.01） and up-regulated pain thresholds to different degrees. The total distance traveled in the 5-min open field test increased in the WY group， the WYJY group， and the fluoxetine group （P<0.05， P<0.01）. The JY group showed decreased serum CORT （P<0.01）， reduced β-EP ， and increased BDNF mRNA （P<0.01）. Nr3c1 and GRM5 mRNA decreased in the WY group （P<0.05， P<0.01）. The WYJY group showed decreased serum CORT （P<0.05）and decreased Nr3c1， GRM5， and BDNF mRNA （P<0.05， P<0.01）. The levels of β-EP expression were elevated to different degrees in the groups with drug intervention， but the differences were not significant. The levels of GR expression in the WY group， the JY group， and the WYJY group increased （P<0.05）. ConclusionWYJY can inhibit central pain sensitization and regulate hypothalamic-pituitary-adrenal gland （HPA） axis function by enhancing the expression of GR in the amygdala and inhibiting neuroplasticity and excitability in the amygdala to relieve depression-like behaviors and improve somatic hyperalgesia.

Association of Increased Amygdala Activity with Stress-Induced Anxiety but not Social Avoidance Behavior in Mice / 神经科学通报·英文版

Chronic stress leads to many psychiatric disorders, including social and anxiety disorders that are associated with over-activation of neurons in the basolateral amygdala (BLA). However, not all individuals develop psychiatric diseases, many showing considerable resilience against stress exposure. Whether BLA neuronal activity is involved in regulating an individual's vulnerability to stress remains elusive. In this study, using a mouse model of chronic social defeat stress (CSDS), we divided the mice into susceptible and resilient subgroups based on their social interaction behavior. Using in vivo fiber photometry and in vitro patch-clamp recording, we showed that CSDS persistently (after 20 days of recovery from stress) increased BLA neuronal activity in all the mice regardless of their susceptible or resilient nature, although impaired social interaction behavior was only observed in susceptible mice. Increased anxiety-like behavior, on the other hand, was evident in both groups. Notably, the CSDS-induced increase of BLA neuronal activity correlated well with the heightened anxiety-like but not the social avoidance behavior in mice. These findings provide new insight to our understanding of the role of neuronal activity in the amygdala in mediating stress-related psychiatric disorders.

Progress in the mechanism of acupuncture intervention on pain emotion and pain cognition mediated by limbic system / 针灸推拿医学（英文版）

Pain is a complex physiological and psychological activity, involving at least three dimensions, including pain sensation, pain emotion, and pain cognition. Acupuncture can clearly relieve the pain sensation of patients and improve pain emotion and pain cognition induced by pain; acupuncture participates in the multi-dimensional regulation of pain through brain regions of the limbic system such as anterior cingulate cortex (ACC), amygdala (AMY), and hippocampus. By analyzing relevant literature, it has been found that the regulation of acupuncture on pain emotion is mainly related to the activation of pertinent opioid receptors in the ACC, the decrease of the expression of extracellular signal-regulated kinase (ERK), and the promotion of the expression of glutamic acid (Glu) A1, metabotropic glutamate receptor-1 (mGluR1), and γ-aminobutyric acid aminobutyric acid (GABA) B2 protein in the AMY. The regulation of acupuncture on pain cognition is mainly related to the elevation of the expression of protein kinase A (PKA) and phospho-p38 mitogen-activated protein kinase (phospho-p38 MAPK) and the inhibition of cyclic adenosine monophosphate (cAMP)/PKA/cAMP response element-binding protein (CREB) signaling pathway in the ACC.

A Deep Mesencephalic Nucleus Circuit Regulates Licking Behavior / 神经科学通报·英文版

Licking behavior is important for water intake. The deep mesencephalic nucleus (DpMe) has been implicated in instinctive behaviors. However, whether the DpMe is involved in licking behavior and the precise neural circuit behind this behavior remains unknown. Here, we found that the activity of the DpMe decreased during water intake. Inhibition of vesicular glutamate transporter 2-positive (VGLUT2+) neurons in the DpMe resulted in increased water intake. Somatostatin-expressing (SST+), but not protein kinase C-δ-expressing (PKC-δ+), GABAergic neurons in the central amygdala (CeA) preferentially innervated DpMe VGLUT2+ neurons. The SST+ neurons in the CeA projecting to the DpMe were activated at the onset of licking behavior. Activation of these CeA SST+ GABAergic neurons, but not PKC-δ+ GABAergic neurons, projecting to the DpMe was sufficient to induce licking behavior and promote water intake. These findings redefine the roles of the DpMe and reveal a novel CeASST-DpMeVGLUT2 circuit that regulates licking behavior and promotes water intake.

Association between poor tolerability of antidepressant treatment and brain functional activation in youth at risk for bipolar disorder

Objective: To investigate whether poor antidepressant tolerability is associated with functional brain changes in children and adolescents of parents with bipolar I disorder (at-risk youth). Methods: Seventy-three at-risk youth (ages 9-20 years old) who participated in a prospective study and had an available baseline functional magnetic resonance imaging (fMRI) scan were included. Research records were reviewed for the incidence of adverse reactions related to antidepressant exposure during follow-up. The sample was divided among at-risk youth without antidepressant exposure (n=21), at-risk youth with antidepressant exposure and no adverse reaction (n=12), at-risk youth with antidepressant-related adverse reaction (n=21), and healthy controls (n=20). The fMRI task was a continuous performance test with emotional distracters. Region-of-interest mean activation in brain areas of the fronto-limbic emotional circuit was compared among groups. Results: Right amygdala activation in response to emotional distracters significantly differed among groups (F3,66 = 3.1, p = 0.03). At-risk youth with an antidepressant-related adverse reaction had the lowest amygdala activation, while at-risk youth without antidepressant exposure had the highest activation (p = 0.004). Conclusions: Decreased right amygdala activation in response to emotional distracters is associated with experiencing an antidepressant-related adverse reaction in at-risk youth. Further studies to determine whether amygdala activation is a useful biomarker for antidepressant-related adverse events are needed.

Projections from Infralimbic Cortex to Paraventricular Thalamus Mediate Fear Extinction Retrieval / 神经科学通报·英文版

The paraventricular nucleus of the thalamus (PVT), which serves as a hub, receives dense projections from the medial prefrontal cortex (mPFC) and projects to the lateral division of central amygdala (CeL). The infralimbic (IL) cortex plays a crucial role in encoding and recalling fear extinction memory. Here, we found that neurons in the PVT and IL were strongly activated during fear extinction retrieval. Silencing PVT neurons inhibited extinction retrieval at recent time point (24 h after extinction), while activating them promoted extinction retrieval at remote time point (7 d after extinction), suggesting a critical role of the PVT in extinction retrieval. In the mPFC-PVT circuit, projections from IL rather than prelimbic cortex to the PVT were dominant, and disrupting the IL-PVT projection suppressed extinction retrieval. Moreover, the axons of PVT neurons preferentially projected to the CeL. Silencing the PVT-CeL circuit also suppressed extinction retrieval. Together, our findings reveal a new neural circuit for fear extinction retrieval outside the classical IL-amygdala circuit.

The Amygdala Responds Rapidly to Flashes Linked to Direct Retinal Innervation: A Flash-evoked Potential Study Across Cortical and Subcortical Visual Pathways / 神经科学通报·英文版

Rapid detection and response to visual threats are critical for survival in animals. The amygdala (AMY) is hypothesized to be involved in this process, but how it interacts with the visual system to do this remains unclear. By recording flash-evoked potentials simultaneously from the superior colliculus (SC), lateral posterior nucleus of the thalamus, AMY, lateral geniculate nucleus (LGN) and visual cortex, which belong to the cortical and subcortical pathways for visual fear processing, we investigated the temporal relationship between these regions in visual processing in rats. A quick flash-evoked potential (FEP) component was identified in the AMY. This emerged as early as in the LGN and was approximately 25 ms prior to the earliest component recorded in the SC, which was assumed to be an important area in visual fear. This quick P1 component in the AMY was not affected by restraint stress or corticosterone injection, but was diminished by RU38486, a glucocorticoid receptor blocker. By injecting a monosynaptic retrograde AAV tracer into the AMY, we found that it received a direct projection from the retina. These results confirm the existence of a direct connection from the retina to the AMY, that the latency in the AMY to flashes is equivalent to that in the sensory thalamus, and that the response is modulated by glucocorticoids.

Role of BDNF in basolateral amygdala-prelimbic cortex in perioperative neurocognitive disorders and relationship with TrkB receptors in mice / 中华麻醉学杂志

Objective:To evaluate the role of basolateral amygdala (BLA)-prelimbic cortex (PL) brain-derived neurotrophic factor (BDNF) in perioperative neurocognitive disorders (PND) and its relationship with tyrosine kinase B (TrkB) receptors in mice.Methods:Forty-eight clean-grade healthy C57BL/6J mice, aged 6 months, weighing 25-30 g, were divided into 4 groups ( n=12 each) using a random number table method: control group (group C), surgery group (group S), BDNF overexpression in BLA group (group B) and BDNF overexpression in BLA+ ANA-12 injection in PL group (group A). In group S, at 30 min after the end of training session of fear conditioning system, exploratory laparotomy was performed.In group B, recombinant adenovirus 0.3 μl was injected in BLA, fear conditioning test was performed 3 weeks later, and exploratory laparotomy was performed at 30 min after the end of the training session of fear conditioning system.In group A, recombinant adenovirus 0.3 μl was injected in BLA, catheterization was performed in PL, the fear conditioning test used performed 3 weeks later, TrkB receptor antagonist ANA-12 0.25 μg was given in PL starting from 30 min before training session, and exploratory laparotomy was performed at 30 min after training session.Test session was started at 24 h after the end of training session of fear conditioning system, and the percentage of time spent freezing was calculated in all groups.At 30 min after the end of the behavioral test, the expression of BDNF in brain areas, phosphorylated TrkB (p-TrkB) and phosphorylated extracellular signal-regulated kinase 1/2 (p-ERKl/2) was determined by Western blot, and the expression BDNF mRNA in BLA was detected using reverse transcription fluorescence quantitative polymerase chain reaction assay. Results:Compared with group C, the percentage of time spent freezing was significantly decreased, and expression of BNDF protein and its mRNA in BLA and BDNF, p-TrkB and p-ERK1/2 in PL was down-regulated in group S ( P<0.05). Compared with group S, the percentage of time spent freezing was significantly increased, and expression of BNDF protein and its mRNA in BLA and BDNF, p-TrkB and p-ERK1/2 in PL was up-regulated in group B ( P<0.05). Compared with group B, the percentage of time spent freezing was significantly decreased, and expression of p-TrkB and p-ERK1/2 in PL was down-regulated in group A ( P<0.05). Conclusion:The mechanism of PND is probably related to reduction of BDNF secretion from BLA to PL caused by down-regulation of BDNF expression in BLA, and decreasing of post-synaptic phosphorylation of TrkB receptors in mice.

Temporomandibular inflammation mobilizes parvalbumin and FosB/deltaFosB neurons of amygdala and dorsal raphe

Pathophysiological mechanisms involved in orofacial pain and their relationship with emotional disorders have emerged as an important research area for multidisciplinary studies. In particular, temporomandibular disorders (TMD) have been evaluated clinically from both physiological and psychological perspectives. We hypothesized that an altered neuronal activity occurs in the amygdala and the dorsal raphe nucleus (DR), encephalic regions involved in the modulation of painful and emotional information. Adult male Wistar rats were used in an experimental complete Freund's adjuvant (CFA)-induced temporomandibular joint (TMJ) inflammation model. CFA was applied for 1 or 10 days, and the animals were euthanized for brain samples dissection for FosB/ΔFosB and parvalbumin (PV) immunostaining. Our results were consistent in showing that the amygdala and DR were activated in the persistent inflammatory phase (10 days) and that the expression of PV+ interneurons in the amygdala was decreased. In contrast, in the DR, the expression of PV+ interneurons was increased in persistent states of CFA-induced TMJ inflammation. Moreover, at 10 days of inflammation, there was an increased co-localization of PV+ and FosB/ΔFosB+ neurons in the basolateral and central nucleus of the amygdala. Different nuclei of the amygdala, as well as portions of the DR, were activated in the persistent phase (10 days) of TMJ inflammation. In conclusion, altered activity of the amygdala and DR was detected during persistent inflammatory nociception in the temporomandibular joint. These regions may be essential for both sensory and affective dimensions of orofacial pain.

Effect of electroacupuncture on expression of CREB and its ability to bind to synaptic proteins in amygdala and hippocampus of rats with post-traumatic stress disorder / 针刺研究

OBJECTIVE: To observe the effect of electroacupuncture (EA) on the expression of cAMP-response element binding protein (CREB, a key protein for BDNF-TrkB signaling) and it's blinding ability to synaptic key protein in the amygdala and hippocampus of rats with post-traumatic stress disorder (PTSD), so as to lay a foundation for further study of the interaction mechanism between BDNF-TrkB signaling and synaptic plasticity. METHODS: Twenty-four male SD rats were randomly divided into blank, model and electroacupuncture (EA) groups, with 8 rats in each group. The PTSD model was established by psychological stress (bondage) and physiological stress (forced swimming and anesthesia). After modeling, EA (2 Hz/100 Hz, 1 mA) was applied to "Baihui"(GV20) "Shenting"(GB24) and bilateral "Shenshu"(BL23) for 20 min, once daily for 21 days. The behavioral changes (spontaneous locomotor within 30 min and contextual fear conditioning tests in 7 days) were detected by using a spontaneous locomotor detection box, and a conditioned fear response test chamber, respectively. The expression of CREB was detected by immunohistochemistry and Western blot, separately. The binding abilities of CREB to synaptic proteins (post synaptic density 95 [PSD95], synaptophysin [SYN] and growth-associated protein 43 [GAP43]) were verified by chromatin-immunoprecipitation (CHIP) technique. RESULTS: After modeling, the spontaneous locomotor distance, the expression levels of CREB and the binding ability of CREB to PSD95 protein in the amygdala and hippocampus were significantly decreased (P0.05). CONCLUSION: EA can improve the motor activity in PTSD rats, which may be associated with its effect in increasing the binding ability of CREB to the synaptic key protein PSD95 to regulate the interaction between the synaptic plasticity and BDNF-TrkB signaling pathway of the amygdala and hippocampus.

Effect of electroacupuncture on expression of GABA receptor mRNA in different brain regions in rats with chronic inflammatory pain / 中国针灸

OBJECTIVE@#To observe the expression of GABA receptor mRNA in different brain regions of the central nervous system in chronic inflammatory pain rats and the intervention effect of electroacupuncture (EA).@*METHODS@#A total of 48 SPF male SD rats were randomly divided into a blank control group, a model control group, an EA group and a sham EA group, 12 rats in each group. The model of chronic inflammatory pain was established by injecting Freund's complete adjuvant into the foot. The EA group was treated with EA 28 days after the model establishment. The "Housanli" (ST 36) and "Kunlun" (BL 60) were selected and treated with dilatational wave, 2 Hz/100 Hz in frequency, 0.5-1.5 mA for 30 min; EA was given only once. In the sham EA group, the same acupoints were selected but the needles were only inserted into subcutaneous area; EA was connected for 30 min without electrical stimulation. The behavior changes of mechanical pain threshold and thermal pain threshold before model establishment, 1 day, 3 days, 7 days, 14 days, 21 days and 28 days after the model establishment as well as emotional behavior 29 days after the model establishment were observed; the relative expressions of GABA receptor mRNA in anterior cingulate cortex, amygdala and hypothalamus were observed.@*RESULTS@#Compared with the blank control group, the change rates of mechanical pain threshold and thermal pain threshold in the model control group were decreased significantly 1 day, 3 days, 7 days, 14 days, 21 days, 28 days after model establishment (0.05). Compared with the blank control group, the expression of GABA receptor mRNA in the amygdala was decreased significantly in the model control group (<0.01); compared with the model control group and the sham EA group, the expression of GABA receptor mRNA in amygdala was increased after intervention in the EA group (<0.01).@*CONCLUSION@#Single treatment of EA could significantly increase the mechanical pain threshold and thermal pain threshold, improve abnormal emotional behavior in rats with chronic inflammatory pain, which may be related to the increasing of expression of GABA receptor mRNA in the amygdala.

Áreas exofocales de lesión a mediano y largo término post-isquemia cerebral / Exofocal areas of medium- and long-term injury after cerebral ischemia

La isquemia cerebral es el tipo de accidente cerebrovascular más común, generando altas tasas de mortalidad y morbilidad a nivel mundial. El entendimiento de la fisiopatología de la lesión cerebral ha requerido de la implementación de modelos experimentales que permitan evaluar los fenómenos celulares, sobre todo aquellos a largo plazo. Por tal razón, el objetivo del presente trabajo fue evaluar las áreas exofocales a un mes y cuatro meses post-isquemia cerebral en un modelo experimental. Ratas Wistar fueron sometidas a una isquemia focal transitoria (t-MCAo) y un grupo fueron sacrificados al mes y otro grupo a los cuatro meses post-isquemia para su posterior análisis histológico. Los cortes fueron teñidos con Nissl y se realizó inmunohistoquímica de la proteína Tau. Nuestros resultados muestran tres áreas de lesión exofocal tanto al mes como a los cuatro meses post-isquemia: el giro dentado, la amígdala y el tálamo. Estas regiones se han asociado al control emocional, lo cual sugiere que a largo término post-isquemia se tengan en cuenta hallazgos clínicos que evalúen cambios emocionales en los pacientes que han sufrido un evento isquémico cerebral.

Cerebral ischemia is the most common type of stroke, which generates high mortality and morbidity rates worldwide. The understanding of the pathophysiology of brain injury has required the implementation of experimental models that allow the evaluation of cellular phenomena, especially those in the long-term. For this reason, the objective of the present work was to evaluate the exofocal areas at one month and four months after cerebral ischemia. Wistar rats were subjected to transient focal ischemia (t-MCAo) and one group was sacrificed one month and another group at four months' post-ischemia for subsequent histological analysis. The cuts were stained with Nissl and immunohistochemistry of the Tau protein was performed. Our results show three areas of exofocal lesion both one month and four months' post-ischemia: the thalamus, the dentate gyrus, and the amygdala. These regions have been associated with emotional control, which suggests that in the long-term post-ischemia clinical findings that evaluate emotional changes in patients who have suffered a cerebral ischemic event should be considered.

Effects of Androgen on Social Behavior of Mice and Underlying Mechanisms / 中国药学杂志

OBJECTIVE: To investigate the effect of androgen on social behavior of male mice and underlying mechanisms. METHODS: After sham or gonadectomy (GDX) operation under deep anesthesia, adolescent (4-week-old) ICR male mice were divided into sham operation group (Sham), gonadectomy group (GDX), and gonadectomy with testosterone propionate (TP, 0.5, 1 mg•kg-1•d-1) supplementation group (GDX+TP)(TP supplementation was continued until the end of the experiment). By 13-week-old, social behaviors were tested. Testosterone levels in serum and the brain as well as arginine vasopressin (AVP) level in the brain were analyzed by ELISA. Androgen receptor (AR) level in the brain was analyzed by Western blot. Morphology of accessory olfactory bulb was detected by paraffin section. AVP expression in amygdala was detected by immunofluorescence. RESULTS: TP supplementation reversed GDX-induced inhibition of sexual behavior and invasive aggressive behavior. TP improved the social recognition ability rather than the general sense of smell of GDX mice. TP supplementation increased the level of testosterone in the brain and in serum and the expression of AR in the brain of GDX mice. TP increased the cell density of mitral cell layer, a projecting neuron in accessory olfactory bulb and elevated the level of AVP in the amygdala brain area. CONCLUSION: Androgen promotes social recognition by increasing the expression of AR in the brain, cell density in the mitral cell layer in accessory olfactory bulb, and AVP level in the amygdala, thus affecting social behavior of adult male mice.