Vibration-reduced anxiety-like behavior relies on ameliorating abnormalities of the somatosensory cortex and medial prefrontal cortex

Tibetan singing bowls emit low-frequency sounds and produce perceptible harmonic tones and vibrations through manual tapping.The sounds the singing bowls produce have been shown to enhance relaxation and reduce anxiety.However,the underlying mechanism remains unclear.In this study,we used chronic restraint stress or sleep deprivation to establish mouse models of anxiety that exhibit anxiety-like behaviors.We then supplied treatment with singing bowls in a bottomless cage placed on the top of a cushion.We found that unlike in humans,the combination of harmonic tones and vibrations did not improve anxietylike behaviors in mice,while individual vibration components did.Additionally,the vibration of singing bowls increased the level of N-methyl-D-aspartate receptor 1 in the somatosensory cortex and prefrontal cortex of the mice,decreased the level ofγ-aminobutyric acid A(GABA)receptorα1 subtype,reduced the level of CaMKII in the prefrontal cortex,and increased the number of GABAergic interneurons.At the same time,electrophysiological tests showed that the vibration of singing bowls significantly reduced the abnormal low-frequency gamma oscillation peak frequency in the medial prefrontal cortex caused by stress restraint pressure and sleep deprivation.Results from this study indicate that the vibration of singing bowls can alleviate anxiety-like behaviors by reducing abnormal molecular and electrophysiological events in somatosensory and medial prefrontal cortex.

The selective 5-HTIA receptor antagonist WAY-100635 inhibits neuronal activity of the ventromedial prefrontal cortex in a rodent model of Parkinson's disease

Objective The ventral part of the medial prefrontal cortex（mPFC）plays an important role in initiation and control of voluntary movement,mood and cognition.However,after the degeneration of the nigrostriatal pathway,the neuronal activity of the ventral mPFC and the role of serotonin1A（5-hydroxytryptamine,5-HT1A）receptors in the firing of the neurons are still unknown.The present study is to investigate the change of neuronal activity in the ventral mPFC and the effect of systemic administration of the selective 5-HT1Areceptor antagonist WAY-100635 on the activity of the neurons in normal and 6-hydroxydopamine（6-OHDA）-lesioned rats.Methods Single unit responses were recorded extracellularly with glass microelectrodes from ventral mPFC neurons in normal rats and 6-OHDA unilaterally lesiond rats in vivo.Results 6-OHDA lesion of the substantia nigra pars compacta（SNc）significantly increased the firing rate with no change in the firing pattern of neurons of the ventral mPFC in rats.Systemic administration of WAY-100635（0.1 mg/kg,i.v.）did not change the mean firing rate and firing pattern of ventral mPFC neurons in normal rats.In contrast,WAY-100635 signifi- cantly decreased the mean firing rate of the neurons in rats with 6-OHDA lesion of the SNc.Conclusion These data suggest that the degeneration of the nigrostriatal pathway results in an increase of neuronal activity of ventral mPFC and dysfunction of 5-HT1Areceptor.

Lesions of mediodorsal thalamic nucleus reverse abnormal firing of the medial prefrontal cortex neurons in parkinsonian rats

The dysfunction of the medial prefrontal cortex is associated with affective disorders and non-motor features in Parkinson’s disease.However,the exact role of the mediodorsal thalamic nucleus in the function of the prefrontal cortex remains unclear.To study the possible effects of the mediodorsal thalamic nucleus on the neurological function of the medial prefrontal cortex,a model of Parkinson’s disease was established by injecting 8μg 6-hydroxydopamine into the substantia nigra compacta of rats.After 1 or 3 weeks,0.3μg ibotenic acid was injected into the mediodorsal thalamic nucleus of the midbrain.At 3 or 5 weeks after the initial injury,neuronal discharge in medial prefrontal cortex of rat brain was determined electrophysiologically.The numbers of dopamine-positive neurons and tyrosine hydroxylase immunoreactivity in substantia nigra compacta and ventral tegmental area were detected by immunohistochemical staining.Results demonstrated that after injury,the immunoreactivity of dopamine neurons and tyrosine hydroxylase decreased in the substantia nigra compacta and ventral tegmental areas of rats.Compared with normal medial prefrontal cortical neurons,at 3 and 5 weeks after substantia nigra compacta injury,the discharge frequency of pyramidal neurons increased and the discharge pattern of these neurons tended to be a burst-discharge,with an increased discharge interval.The discharge frequency of interneurons decreased and the discharge pattern also tended to be a burst-discharge,but the discharge interval was only higher at 3 weeks.At 3 weeks after the combined lesions,the discharge frequency,discharge pattern and discharge interval were restored to a normal level in pyramidal neurons and interneurons in medial prefrontal cortex.These findings have confirmed that mediodorsal thalamic nucleus is involved in regulating neuronal activities of the medial prefrontal cortex.The changes in the function of the mediodorsal thalamic nucleus may be associated with the abnormal discharge activity of the medial prefrontal cortex neurons after substantia nigra compacta injury.All experimental procedures were approved by the Institutional Animal Care and Use Committee of Xi’an Jiaotong University,China(approval No.XJTULAC2017-067)on August 26,2017.

Neurochemical metabolites in the medial prefrontal cortex in bipolar disorder A proton magnetic resonance spectroscopy study

The aim of this study was to investigate proton magnetic resonance spectroscopy metabolite values in the medial prefrontal cortex of individuals with euthymic bipolar disorder. The subjects consisted of 15 patients with euthymic bipolar disorder type I and 15 healthy controls. We performed proton magnetic resonance spectroscopy of the bilateral medial prefrontal cortex and measured levels of N-acetyl aspartate, choline and creatine. Levels of these three metabolites in the medial prefrontal cortex were found to be lower in patients with bipolar disorder compared with healthy controls. A positive correlation was found between illness duration and choline levels in the right medial prefrontal cortex. Our study suggests that during the euthymic period, there are abnormalities in cellular energy and membrane phospholipid metabolism in the medial prefrontal cortex, and that this may impair neuronal activity and integrity.

Distinct neuronal excitability alterations of medial prefrontal cortex in early-life neglect model of rats

Object:Early-life neglect has irreversible emotional effects on the central nervous system.In this work,we aimed to elucidate distinct functional neural changes in me-dial prefrontal cortex(mPFC)of model rats.Methods:Maternal separation with early weaning was used as a rat model of early-life neglect.The excitation of glutamatergic and GABAergic neurons in rat mPFC was recorded and analyzed by whole-cell patch clamp.Results:Glutamatergic and GABAergic neurons of mPFC were distinguished by typi-cal electrophysiological properties.The excitation of mPFC glutamatergic neurons was significantly increased in male groups,while the excitation of mPFC GABAergic neurons was significant in both female and male groups,but mainly in terms of rest membrane potential and amplitude,respectively.Conclusions:Glutamatergic and GABAergic neurons in medial prefrontal cortex showed different excitability changes in a rat model of early-life neglect,which can contribute to distinct mechanisms for emotional and cognitive manifestations.

High frequency heart rate variability evoked by repetitive transcranial magnetic stimulation over the medial prefrontal cortex: A preliminary investigation on brain processing of acute stressor-evoked cardiovascular reactivity

Introduction: Transcranial Magnetic Stimulation (TMS) is a non-invasive technique for brain stimulation. Repetitive TMS (rTMS) over the medial Prefrontal Cortex (mPFC), Broadman Area 10 (BA10) may stimulate transynaptically perigenual Anterior Cingulate Cortex (pACC, BA 33), insula, amigdala, hypothalamus and connected branches of the Autonomic Nervous System (ANS) involved in stressorevoked cardiovascular reactivity. Stressors are associated with an increase in sympathetic cardiac control, a decrease in parasympathetic control, or both, and, consequently, an increase in systolic/stroke volume, total vascular impedance/resistance and heart rate, a decrease of baroreflex sensitivity, i.e., an increase in blood pressure/arterial tension. Objectives and Aims: The present work aims, using TMS and accordingly to Gianaros modeling, based on functional neuroimaging studies and previous neuroanatomical data from animal models, to probe the connectivity of brain systems involved in stressor-evoked cardiovascular reactivity and to explore TMS potential as a tool for detection and stratification of individual differences concerning this reactivity and hemorreological risk factors correlated with the development of Coronary Heart Disease (CHD). Methods: Both subjects, a 52 years old male and a 40 years old female with previous increased Low Frequency (LF)/High Frequency (HF) Heart Rate Variability (HRV) ratios (respectively, 4.209/3.028) without decompensated cardiorespiratory symptoms, gave informed consent, and ethico-legal issues have been observed. Electroencephalographic (EEG) monitoring has been performed for safety purposes. Immediately after administration, over the mPFC, of 15 pulses of rTMS, during 60 second, with an inductive electrical current, at the stimulating coil, of 85.9 Ampère per μsecond and 66 Ampère per μsecond, respectively, for male and female subjects (a “figure-of-eight” coil and magnetic stimulator MagLite, Dantec/Medtronic, have been used), HRV spectrum analysis (cStress software) has been performed (during 5 minutes, in supine position). Results: In both subjects, LF power, HF power and LF/HF ratio results, before and after rTMS administration, pointed towards sympathetic attenuation and parasympathetic augmentation (respectively, in male/female subject: decreased LF power—65.1 nu/69.3 nu, before rTMS;56.1 nu/41.6 nu, after rTMS;increased HF power—15.5 nu/22.9 nu, before rTMS;30.9 nu/45.5 nu, after rTMS). Conclusions: In this preliminary investigation, the existence of a link between “mind” and heart’s function has been put in evidence, through a reversible “virtual” lesion, of brain systems involved in cardiovascular control, caused by TMS. Repetitive TMS over mPFC decreased brain function involved in stressorevoked cardiovascular reactivity, suggesting the importance of TMS in the management of stress-related cardiovascular disorders.

七氟醚麻醉过程中mPFC脑区不同类型神经元胞外腺苷递质动态变化研究

目的探究在七氟醚麻醉致意识消失与恢复过程中内侧前额叶皮层(mPFC)中谷氨酸能的锥体(Pyr)神经元与γ-氨基丁酸(GABA)能神经元的两种亚型:小清蛋白(PV)阳性神经元与生长抑素(SST)阳性神经元胞外腺苷释放的动态变化情况。方法在C57小鼠(n=6)mPFC脑区注射AAV-CaMkⅡα-Cre与AAV-DIO-Ado1.0混合病毒,SST-IRES-Cre小鼠(n=6)与PV-IRES-Cre小鼠(n=6)mPFC脑区注射AAV-DIO-Ado1.0病毒,待病毒转染3周。在本实验中主要使用多通道光纤记录系统记录腺苷的荧光信号强度。记录给予2.3%七氟醚麻醉时小鼠从清醒到翻正反射消失,以及翻正反射恢复到完全苏醒过程中腺苷的动态变化情况。结果七氟醚能够引起mPFC中锥体神经元、SST神经元、PV神经元胞外腺苷的增加,并随着七氟醚的停止吸入未立即下降。结论mPFC脑区可能通过调控腺苷传递参与七氟醚麻醉致意识的改变。

Brain region-specific roles of brain-derived neurotrophic factor in social stress-induced depressive-like behavior

Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response.Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region–specific,particularly involving the corticolimbic system,including the ventral tegmental area,nucleus accumbens,prefrontal cortex,amygdala,and hippocampus.Determining how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress psychopathology.In this review,we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of depression.We focused on associated molecular pathways and neural circuits,with special attention to the brain-derived neurotrophic factor–tropomyosin receptor kinase B signaling pathway and the ventral tegmental area–nucleus accumbens dopamine circuit.We determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature,severity,and duration of stress,especially in the above-mentioned brain regions of the corticolimbic system.Therefore,BDNF might be a biological indicator regulating stress-related processes in various brain regions.

电刺激大鼠mPFC对听皮层神经元听反应的影响

实验在40只成年SD大鼠上进行,使用常规电生理学方法,观察了电刺激大鼠内侧额叶前皮质(medial prefrontal cortex,mPFC)对听皮层神经元听反应的影响.在122个神经元上观察了电刺激mPFC对听反应的影响.对其中93个神经元作了详细分析发现,有73个神经元的听反应受到易化(39个,41.9%)或抑制(34个,36.6%).刺激mPFC对听反应的影响存在最佳刺激间隔,大多数神经元(51个,69%)在10～15ms之间.结果提示,大鼠mPFC可对听皮层神经元的听反应调制,这种调制可能是通过多级神经元环路实现的.

NPY受体在急性束缚应激大鼠mPFC和下丘脑中的表达及其与炎性因子的相关性

目的观察神经肽Y(NPY)受体及炎性因子在急性束缚应激(RES)大鼠前额叶内侧皮层(mPFC)和下丘脑中的表达,探讨NPY受体Y5R在急性RES大鼠mPFC中可能的作用机制。方法将SD雄性大鼠随机分为对照组(CTL组)和模型组(RES组)。采用专业大鼠固定器束缚RES组大鼠2 h制备急性RES模型,CTL组不进行处理。造模结束后处死大鼠,实时定量PCR检测各组大鼠mPFC及下丘脑NPY受体及炎性因子mRNA表达情况;蛋白质印迹检测NPY受体Y5R及炎性因子IL-1β的蛋白表达情况;免疫荧光染色检测NPY受体Y5R及小胶质细胞标志物Iba-1的分布和定位。结果与CTL组相比,RES组大鼠mPFC NPY受体Y5R的mRNA和蛋白水平均显著降低(P<0.05或P<0.01);炎性因子mRNA水平显著升高(P<0.05),蛋白水平差异无统计学意义(P>0.05)。RES组大鼠下丘脑NPY受体Y5R及炎性因子mRNA和蛋白水平与CTL组相比差异均无统计学意义(P>0.05)。免疫荧光染色检测结果显示NPY受体Y5R及小胶质细胞标志物Iba-1不存在共定位。结论NPY受体Y5R参与了急性束缚应激大鼠mPFC的病理过程,但其作用机制与小胶质细胞神经炎性反应无相关性。

Effects of Melatonin Levels on Neurotoxicity of the Medial Prefrontal Cortex in a Rat Model of Parkinson＇s Disease

Background： Damage of the medial prefrontal cortex （mPFC） results in similar characteristics to the cognitive deficiency seen with the progress of Parkinson＇s disease （PD）. Since the course of mPFC damage is still unclear, our study aimed to investigate the effects of melatonin （MT） on neurotoxicity in the mPFC of a rat model of PD. Methods： One hundred and fifty-four normal, male Wistar rats were randomly divided into the following five groups： normal ＋ normal saline （NS）, normal ＋ 6-hydroxydopamine （6-OHDA）, sham pinealectomy （PX） ＋ 6-OHDA, PX ＋ 6-OHDA, and MT ＋ 6-OHDA. 6-OHDA was injected into the right substantia nigra pars compacta （SNc） and ventral tegmental area （VTA） of each group, except normal ＋ NS, 60 days after the PX. In the MT treatment group, MT was administered immediately after the intraperitoneal injection at 4 p.m. every day, for 14 days. Neuronal apoptosis in the mPFC was exalnined using the TUNEL method, while the expression oftyrosine hydroxylase （TH）, Bax, and Bcl-2 in this region was measured using immunohistochemistry. The concentration of malondialdehyde （MDA） in the mPFC was examined using the thioharbituric acid method. Results： Rats in the normal ＋ 6-OHDA and sham PX ＋ 6-OHDA groups were combined into one group （Group N ＋ 6-OHDA） since there was no significant discrepancy between the groups for all the detected parameters. Apoptosis of cells in the NS, MT ＋ 6-OHDA, N ＋ 6-OH DA, and PX ＋ 6-OHDA groups was successively significantly increased （Hc = 256.25, P 〈 0.001 ）. The gray value of TH （＋） fibers in the NS, MT ＋ 6-OHDA, N ＋ 6-OHDA, and PX ＋ 6-OHDA groups was also successively significantly increased （F= 99.33, P 〈 0.001 ）. The staining intensities of Bax and Bcl-2 were as follows： Group NS ＋/＋, Group MT ＋ 6-OHDA ＋＋/＋, Group N ＋ 6-OHDA ＋＋/＋, and PX ＋ 6-OHDA ＋＋＋/＋. The concentrations of MDA in the NS, MT ＋ 6-OHDA, N ＋ 6-OHDA, and PX ＋ 6-OHDA groups were significantly increased in sequence （Hc = 296.309, P 〈 0.001 ）. Conclusions： Neuronal damage of the VTA by 6-OHDA might induce VTA-mPFC nerve fibers to undergo anterograde nerve damage, in turn inducing transneuronal damage of the mPFC. PX significantly exacerbated the neurotoxicity in the mPFC, which was induced by the neuronal injury of the VTA. However, MT replacement therapy significantly alleviated the neurotoxicity in the mPFC.

Anticipatory activity in rat medial prefrontal cortex during a working memory task

Objective Working memory is a key cognitive function in which the prefrontal cortex plays a crucial role. This study aimed to show the firing patterns of a neuronal population in the prefrontal cortex of the rat in a working memory task and to explore how a neuronal ensemble encodes a working memory event. Methods Sprague-Dawley rats were trained in a Y-maze until they reached an 80% correct rate in a working memory task. Then a 16-channel microelectrode array was implanted in the prefrontal cortex. After recovery, neuronal population activity was recorded during the task, using the Cerebus data-acquisition system. Spatio-temporal trains of action potentials were obtained from the original neuronal population signals. Results During the Y-maze working memory task, some neurons showed significantly in- creased firing rates and evident neuronal ensemble activity. Moreover, the anticipatory activity was associated with the delayed alternate choice of the upcoming movement. In correct trials, the averaged pre-event firing rate （10.86 ± 1.82 spikes/ bin） was higher than the post-event rate （8.17 ± 1.15 spikes/bin） （P 〈0.05）. However, in incorrect trials, the rates did not differ. Conclusion The results indicate that the anticipatory activity of a neuronal ensemble in the prefrontal cortex may play a role in encoding working memory events.

Reversal of Social Recognition Deficit in Adult Mice with MECP2 Duplication via Normalization of MeCP2 in the Medial Prefrontal Cortex

Methyl-CpG binding protein 2(MeCP2) is a basic nuclear protein involved in the regulation of gene expression and microRNA processing.Duplication of MECP2-containing genomic segments causes MECP2 duplication syndrome,a severe neurodevelopmental disorder characterized by intellectual disability,motor dysfunction,heightened anxiety,epilepsy,autistic phenotypes,and early death.Reversal of the abnormal phenotypes in adult mice with MECP2 duplication(MECP2-TG) by normalizing the MeCP2 levels across the whole brain has been demonstrated.However,whether different brain areas or neural circuits contribute to different aspects of the behavioral deficits is still unknown.Here,we found that MECP2-TG mice showed a significant social recognition deficit,and were prone to display aversive-like behaviors,including heightened anxiety-like behaviors and a fear generalization phenotype.In addition,reduced locomotor activity was observed in MECP2-TG mice.However,appetitive behaviors and learning and memory were comparable in MECP2-TG and wild-type mice.Functional magnetic resonance imaging illustrated that the differences between MECP2-TG and wild-type mice were mainly concentrated in brain areas regulating emotion and social behaviors.We used the CRISPR-Cas9 method to restore normal MeCP2 levels in the medial prefrontal cortex(mPFC) and bed nuclei of the stria terminalis(BST) of adult MECP2-TG mice,and found that normalization of MeCP2 levels in the mPFC but not in the BST reversed the social recognition deficit.These data indicate that the mPFC is responsible for the social recognition deficit in the transgenic mice,and provide new insight into potential therapies for MECP2 duplication syndrome.

Effect of reward alteration following acupuncture for morphine withdrawal rats on neuronal discharges in the ventral medial prefrontal cortex

Objective：To observe the effect of reward alteration following acupuncture for morphine withdrawal rats on the behavior and neuronal discharges in the medial prefrontal cortex （mPFC）. Methods：The Sprague-Dawley （SD） rats were randomly allocated into a model group, a confinement group, an electroacupuncture （EA） group, and a control group. Rats with morphine addiction were made by intraperitoneal injection of naloxone （same dose injection of saline for rats in the control group）, followed by a 2-week morphine withdrawal. Acupuncture and confinement were completed during the morphine withdrawal period. Upon withdrawal, the rats received conditioned place preference （CPP） training and open field test. The multi-channel neural signal processor was used in the electrophysiological experiment to measure the neuronal discharges in different subareas of prefrontal cortex in CPP box and aversion box. Results：Rats in the model group and the confinement group spent longer period of time in CPP box than those in the EA group and the control group （allP〈0.01）; there was no statistically significant difference between the EA group and the control group. The total distances of movement by rats in the model group and the confinement group were longer than those in the EA group and the control group （allP〈0.01）. The mPFC neuronal discharge frequencies were compared between morphine preference box and aversion box. The mPFC neuronal discharge frequencies in the model group and the confinement group were higher than those in the EA group and the control group （allP〈0.05）; there was no statistically significant difference between the EA group and the control group. Conclusion：Acupuncture can effectively interfere with the reward alteration following morphine withdrawal, possibly because of its involvement with the mPFC neuronal discharges.

Dopamine D2 receptors in the dorsomedial prefrontal cortex modulate social hierarchy in male mice

Social hierarchy greatly influences behavior and health.Both human and animal studies have signaled the medial prefrontal cortex(mPFC)as specifically related to social hierarchy.Dopamine D1 receptors(D1Rs)and D2 receptors(D2Rs)are abundantly expressed in the mPFC,modulat-ing its functions.However,it is unclear how DR-expressing neurons in the mPFC regulate social hierarchy.Here,using a confrontation tube test,we found that most adult C57BL/6J male mice could establish a linear social rank after 1 week of cohabitation.Lower rank individuals showed social anxiety together with decreased serum testosterone levels.D2R expression was significantly downregulated in the dorsal part of mPFC(dmPFC)in lower rank individuals,whereas D1R expression showed no significant difference among the rank groups in the whole mPFC.Virus knockdown of D2Rs in the dmPFC led to mice being particularly prone to lose the contests in the confrontation tube test.Finally,simultaneous D2R activation in the subordinates and D2R inhibition in the dominants in a pair switched their dominant-subordinate relationship.The above results indicate that D2Rs in the dmPFC play an important role in social dominance.Our findings provide novel insights into the divergent func-tions of prefrontal D1Rs and D2Rs in social dominance,which may contribute to ameliorating social dysfunctions along with abnormal social hierarchy.

内侧前额叶皮质区核氧化还原蛋白对卒中后抑郁小鼠抑郁样行为的影响及其机制

目的:探讨内侧前额叶皮质(mPFC)区核氧化还原蛋白(NXN)对小鼠卒中后抑郁(PSD)的影响,并阐明其可能的作用机制。方法:80只C57BL/6小鼠,随机选取42只分为NXN过表达腺相关病毒感染组(AAV-NXN-OE组,n=21)和阴性对照腺相关病毒感染组(AAV-NC组,n=21),剩余小鼠分为假手术组(n=20)和PSD组(n=18),注射NXN过表达腺相关病毒后,将AAV-NXN-OE组和AAV-NC组剩余小鼠分为PSD+AAV-NC组(n=18)和PSD+AAV-NXN-OE组(n=18)。术前3周,采用脑立体定位法向小鼠脑组织mPFC区注射NXN过表达腺相关病毒,显微镜下观察病毒在小鼠脑组织mPFC区表达情况,Western blotting法检测小鼠脑组织中NXN蛋白表达水平。采用线栓法建立大脑中动脉闭塞(MCAO)卒中模型,术后1周使用慢性不可预见的中等应激(CUMS)结合孤养法持续干预3周,构建PSD模型小鼠。造模期间监测小鼠体质量变化,造模结束后采用糖水偏好实验、悬尾实验和强迫游泳实验观察各组小鼠抑郁样行为学表现,生化法检测各组小鼠脑组织mPFC区中丙二醛(MDA)和还原型谷胱甘肽(GSH)水平及超氧化物歧化酶(SOD)活性,2',7'-二氯荧光素二乙酸酯(DCFH-DA)荧光探针标记法检测各组小鼠脑组织mPFC区中活性氧(ROS)水平,Western blotting法检测各组小鼠脑组织mPFC区、杏仁核区和海马组织中NXN蛋白表达水平。结果:PSD小鼠脑组织mPFC区有大量绿色荧光,表明携带ZsGreen绿色荧光蛋白标签的AAVs病毒在PSD小鼠脑组织mPFC区成功感染并表达。与AAV-NC组比较,AAV-NXN-OE组小鼠脑组织mPFC区中NXN蛋白表达水平明显升高(P<0.05)。与假手术组比较,PSD组小鼠体质量增长缓慢(P<0.05),糖水偏好率明显降低(P<0.05),小鼠在悬尾实验和强迫游泳实验中不动时间均明显增加(P<0.05);与假手术组比较,PSD+AAV-NC组小鼠糖水偏好率明显降低(P<0.05),小鼠在悬尾实验和强迫游泳实验中不动时间均明显增加(P<0.05);与PSD+AAV-NC组比较,PSD+AAV-NXN-OE组小鼠糖水偏好率明显升高(P<0.05),小鼠在悬尾实验和强迫游泳实验中不动时间均明显减少(P<0.05)。与假手术组比较,PSD+AAV-NC组小鼠脑组织mPFC区中MDA和ROS水平均明显升高(P<0.05),GSH水平和SOD活性均明显降低(P<0.05);与PSD+AAV-NC组比较,PSD+AAV-NXN-OE组小鼠脑组织mPFC区中MDA和ROS水平均明显降低(P<0.05),GSH水平和SOD活性均明显升高(P<0.05)。与假手术组比较,PSD组小鼠脑组织mPFC区中NXN蛋白表达水平明显降低(P<0.05),杏仁核区和海马组织中NXN蛋白表达水平差异无统计学意义(P>0.05)。结论:小鼠脑组织mPFC区中NXN过表达可改善PSD小鼠抑郁样行为,其作用机制可能与调节氧化还原平衡有关。

自主跑步运动对APP/PS1小鼠内侧前额叶皮质少突胶质细胞的作用

目的:研究自主跑步运动对APP/PS1双转基因AD(Alzheimer’s disease,AD)模型小鼠内侧前额叶皮质(medial prefrontal cortex,mPFC)内少突胶质细胞数量,少突胶质细胞分化、成熟以及髓鞘形成的作用。方法:将10月龄雄性转基因AD模型小鼠随机分为AD组和AD跑步(AD+RUN)组,另外将同月龄同窝生野生型小鼠随机分为正常(WT)组和正常跑步(WT+RUN)组。其中跑步组于跑步笼内给予3个月自主跑步锻炼,AD组和WT组不做处理。跑步锻炼结束后4组小鼠同时给予行为学测试,用Morris水迷宫检测小鼠空间学习、记忆能力;用Y迷宫检测小鼠工作记忆能力;用新物体识别实验检测小鼠的认知记忆功能;利用无偏体视学技术和免疫组化技术相结合精确定量小鼠大脑mPFC内成熟少突胶质细胞(CC1^(+))总数量;同时分析小鼠mPFC内边缘皮层、Ⅱ、Ⅲ、Ⅵ、Ⅵ层成熟少突胶质细胞密度;利用免疫荧光和激光共聚焦显微镜分析小鼠mPFC内未成熟少突胶质细胞(PDGFα^(+)/Olig2^(+))密度、髓鞘标志物髓鞘碱性蛋白(myelin basic protein,MBP)荧光强度。结果:AD+RUN组和WT组在Morris水迷宫、Y迷宫以及新物体识别实验中的表现优于AD组,AD组mPFC内MBP荧光强度明显低于WT组(P<0.05),而AD+RUN组mPFC内MBP荧光强度明显大于AD组(P<0.001)。AD+RUN组mPFC内CC1^(+)细胞总数较AD组明显增加(P<0.05)。AD+RUN组mPFC内第Ⅲ层和第Ⅴ层CC1^(+)细胞密度较AD组明显增高(P<0.05),AD组mPFC内第Ⅴ层和第Ⅵ层CC1^(+)细胞密度较WT组明显降低(P<0.05)。AD组mPFC内PDGFα^(+)/Olig2^(+)细胞密度明显大于WT组,而AD+RUN组mPFC内PDGFα^(+)/Olig2^(+)细胞密度明显小于AD组(P<0.05)。结论:自主跑步运动能促进AD小鼠少突胶质细胞分化和髓鞘形成,这可能与运动能改善APP/PS1转基因AD小鼠的学习记忆能力有关。

内侧前额叶皮质谷氨酸能神经元参与CD1小鼠攻击行为的机制研究

目的研究CD1小鼠发动攻击行为的内在神经机制。方法通过驻地入侵实验筛选出具有攻击行为的CD1小鼠,攻击配对偏好进一步验证后使用c-Fos标记全脑激活的脑区,通过免疫荧光双标实验分析攻击行为激活了哪种类型的神经元,最后使用光遗传学调控该类神经元的活性,观察其对攻击行为的影响。结果通过c-Fos筛选,约82%的CD1小鼠表现出攻击行为;攻击行为发生后主要激活内侧前额叶皮质(medial prefrontal cortex,mPFC),免疫荧光双标结果显示mPFC脑区c-Fos阳性神经元主要是谷氨酸能神经元;最后,我们通过光遗传激活mPFC脑区谷氨酸能神经元,发现其能够抑制CD1小鼠的攻击行为;相反,光遗传抑制mPFC脑区谷氨酸能神经元,能够促进CD1小鼠的攻击行为。结论mPFC脑区谷氨酸能神经元是调控CD1小鼠发动攻击行为的重要组成部分。

In vivo imaging reveals a synchronized correlation among neurotransmitter dynamics during propofol and sevoflurane anesthesia

General anesthesia is widely applied in clinical practice.However,the precise mechanism of loss of consciousness induced by general anesthetics remains unknown.Here,we measured the dynamics of five neurotransmitters,includingγ-aminobutyric acid,glutamate,norepinephrine,acetylcholine,and dopamine,in the medial prefrontal cortex and primary visual cortex of C57BL/6 mice through in vivo fiber photometry and genetically encoded neurotransmitter sensors under anesthesia to reveal the mechanism of general anesthesia from a neurotransmitter perspective.Results revealed that the concentrations of γ-aminobutyric acid,glutamate,norepinephrine,and acetylcholine increased in the cortex during propofol-induced loss of consciousness.Dopamine levels did not change following the hypnotic dose of propofol but increased significantly following surgical doses of propofol anesthesia.Notably,the concentrations of the five neurotransmitters generally decreased during sevoflurane-induced loss of consciousness.Furthermore,the neurotransmitter dynamic networks were not synchronized in the non-anesthesia groups but were highly synchronized in the anesthetic groups.These findings suggest that neurotransmitter dynamic network synchronization may cause anesthetic-induced loss of consciousness.

视觉记忆中工作记忆与长时记忆的交互

记忆作为我们认知系统的核心功能之一,在人类行为中起着不可或缺的作用。通常认为,长时记忆和工作记忆是记忆系统中两个重要的组成部分。本文梳理了长时记忆和工作记忆交互的主要证据,发现两者并非是完全独立或兼容的,而是存在共同的机制。此外,两者同样共享着类似的神经机制。综上,虽然我们认为工作记忆与长时记忆存在交互,但关于交互作用产生的过程仍有许多未解之谜。因此,未来研究应对此着重探讨。研究要点1.长时记忆和工作记忆间存在交互作用。2.内侧颞叶和前额皮层中的神经活动支持两记忆系统交互作用的产生。3.提出未来围绕两记忆系统交互关系的研究应重点关注的问题。