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.

FUNCTIONAL MAPPING OF THE HUMAN BRAIN DURING ACUPUNCTURE WITH MAGNETIC RESONANCE IMAGINGSOMATOSENSORY CORTEX ACTIVATION

Hegu (LI 4) is one of the most frequently used and most important analgesic points in Chinese acupuncture. It is particularly effective for treating disorders of the head and face. According to the meridian theory in Traditional Chinese Medicine (TCM), the Large Intestine Meridian to which it belongs originates in the hand and terminates in the face. This theory is based, however, more on thousands of years of clinical experience rather than on scientific evidence. In our study of acupuncture effects on normal human volunteers with the non-invasive BOLD (blood oxygenation level dependant)technique for FMRI (functional magnetic resonance imaging), we demonstrated widespread effects in the brain during acupuncture at Hegu and Zusanli (ST 36). A finding of special interest was observed in the primary somatosensory cortes (SI) during Hegu acupuncture. In additlon to activation of the area representing the hand in response to the sensory impulses arising from the site of stimulation, activation also occurred in the face representation in all 3 subjects brains studied by coronal brain sections. In one of these subjects activation in the face representation was even stronger than that in the hand representation. Areas representing the neck, trunk and other parts of the upper extremity also exhibited increase in signal intensity, subject to individual variability. As compared with Hegu, such effects were either absent or much weaker with acupuncture at Zusanli (ST 36) or with other forms of sensory stimulation to the hand. Functional mapping of the brain with MRI has provided the first direct evidence in support of the important role of Hegu acupuncture in TCM.

In vivo neuronal and astrocytic activation in somatosensory cortex by acupuncture stimuli

Acupuncture is a medical treatment that has been widely pra cticed in China for over 3000 years,yet the neural mechanisms of acupuncture are not fully understood.We hypothesized that neurons and astrocytes act independently and synergistically under acupuncture stimulation.To investigate this,we used two-photon in vivo calcium reco rding to observe the effects of acupuncture stimulation at ST36(Zusanli)in mice.Acupuncture stimulation in peripheral acupoints potentiated calcium signals of pyramidal neurons and astrocytes in the somatosensory cortex and resulted in late-onset calcium transients in astrocytes.Chemogenetic inhibition of neurons augmented the astrocytic activity.These findings suggest that acupuncture activates neuronal and astrocytic activity in the somatosensory co rtex and provide evidence for the involvement of both neurons and astrocytes in acupuncture treatment.

Experimental Research PARTICIPATION OF GABA IN SH EMANATING DESCENDING MODULATION ON THE NUCLEUS CENTRUM MEDIANUM VIA MOTOR CORTEX IN ACUPUNCTURE ANALGESIA

The effects of electrical stimulation of second somatosensory area(S Ⅱ)andelectroacupuncture(EA)at Huantiao(GB 30)and Yanglinquan(GB 34)points on nociceptive re-sponses of neurons in the nucleus centrum medianum(CM)in the thalamus were respectively ob-served after topical application of bicuculline(Bic)at the motor cortex(MCtx),and the results werecompared with those obtained in the saline control group.It was found that following application ofBic either electrical stimulation of SII(n=11)or EA(n=11)yielded obvious inhibition on nocicep-tive responses of CM neurons(P【0.05),which was similar to the inhibitory effects obtained in thesaline control groups(n=11,n=10).After GABA application at MCtx electrical stimulation of SIIfailed to show inhibition on nociceptive responses in 3 CM neurons.It is indicated that GABA in MC-tx is involved in SII originating corticofugal regulation of nucleus CM in acupuncture analgesia.

Optical imaging of nociception in primary somatosensory cortex of nonhuman primates

While the activation of primary somatosensory(SI) cortex during pain perception is consistently reported in functional imaging studies on normal subjects and chronic pain patients,the specific roles of SI,particularly the subregions within SI,in the processing of sensory aspects of pain are still largely unknown.Using optical imaging of intrinsic signal(OIS) and single unit electrophysiology,we studied cortical activation patterns within SI cortex(among Brodmann areas 3a,3b and 1) and signal amplitude changes to various intensities of non-nociceptive,thermal nociceptive and mechanical nociceptive stimulation of individual distal finerpads in anesthetized squirrel monkeys.We have demonstrated that areas 3a and 1 are preferentially involved in the processing of nociceptive information while areas 3b and 1 are preferentially activated in the processing of non-nociceptive(touch) information.Nociceptive activations of individual fingerpad were organized topographically suggesting that nociceptive topographic map exits in areas 3a and 1.Signal amplitude was enhanced to increasing intensity of mechanical nociceptive stimuli in areas 3a,3b and 1.Within area 1,nociceptive response co-localizes with the non-nociceptive response.Therefore,we hypothesize that nocicepitve information is area-specifically represented within SI cortex,in which nociceptive inputs are preferentially represented in areas 3a and 1 while non-nociceptive inputs are preferentially represented in areas 3b and 1.

原发性早泄中枢丘脑-额叶-躯体感觉皮层环路MRI研究进展

原发性早泄(lifelong premature ejaculation,LPE)是男性最常见的性功能障碍疾病,但中枢发病机制尚不明确。近年来,研究人员借助多模态磁共振成像(magnetic resonance imaging,MRI)技术检测和分析了LPE患者大脑结构和功能的特定变化,尤其是与奖赏系统相关的丘脑-额叶环路,以及参与射精周期的躯体感觉皮层。本文将基于丘脑-额叶-躯体感觉皮层环路对LPE患者的大脑MRI研究发现进行综述,探寻丘脑-额叶-躯体感觉皮层环路在LPE中枢神经系统中的作用机制,为开辟新的早泄评估和疗效评价方法提供科学依据。

缺血性神经阻滞状态下神经肌肉电刺激诱发感觉皮层活动的研究

目的基于缺血性神经阻滞(INB)技术能够成功剥离出运动阈值上神经肌肉电刺激(NMES)前臂肌肉诱发的肌梭感觉传入信息,本文旨在探究INB状态下感觉运动皮层如何感知运动阈值上NMES所诱发的肌梭感觉传入信息。方法本文设计了一个2×2因素(INB:前、后;NMES强度:运动阈值上、下)的实验任务方案,任务期间记录健康受试者大脑64通道脑电信号,并利用脑电beta频段的事件相关去同步化(beta ERD)量化感觉运动皮层区域的激活水平。通过心理物理学测试评估血压袖带施加于右手腕处后受试者右手感觉与运动的变化。结果在INB状态下,运动阈值上NMES诱发的对侧感觉运动皮层脑电beta ERD显著减弱,并且在INB施加前,运动阈值上、下NMES诱发的对侧感觉运动皮层脑电beta ERD幅值差异具有统计学意义(P<0.05),但是此差异在INB状态下消失。此外,阻滞成功后NMES诱发的感觉运动皮层脑电beta ERD的对侧优势转移到了同侧。结论INB导致运动阈值上NMES诱发的皮层活动显著减弱,对侧感觉运动皮层对NMES刺激强度的感知减弱,这可能由INB引起感觉运动皮层产生快速功能重塑造成。

抑制大鼠大脑皮层SI区对电针抑制持续性痛反应的影响

在大鼠用玻璃微电极细胞外记录的方法，观察了电针同侧前肢“合谷”、“内关”穴对皮下注射福尔马林（５％ ，５０ μｌ）诱发的脊髓背角广动力型（ＷＤＲ）神经元晚时相放电反应的影响。结果表明，低频强电针（５ Ｈｚ， ５～６ ｍ Ａ）和高频弱电针（５０ Ｈｚ， １ ｍ Ａ）都可对背角ＷＤＲ神经元的晚时相反应产生明显的抑制作用，且低频强电针的抑制作用大于高频弱电针的作用。用４％ ＭｇＳＯ４ 抑制皮层体感Ⅰ区（ＳＩ区）的活动后，低频强电针对ＷＤＲ神经元晚时相反应的抑制作用明显减弱，提示ＳＩ区在电针对持续性痛的镇痛机制中具有重要作用。

皮层SI区伤害感受神经元膜电生理特性研究

用细胞内记录技术， 在１６ 只成年健康猫， 研究了皮层第一躯体感觉区（ｐｒｉｍａｒｙ ｓｏｍａｔｏｓｅｎｓｏｒｙ ｃｏｒｔｅｘ ａｒｅａ ， Ｓ Ｉ区） 伤害感受神经元的电生理特性． Ｓ Ｉ区伤害感受神经元自发放电频率差异大， 放电形式多样． 极化电流绝对值≤１０ ｎ Ａ 时， 伤害感受神经元 Ｉ Ｖ极相关（ｒ ＝ ０９６） ， 整流作用不明显； 极化电流绝对值＞ １０ ｎ Ａ 时， 在两个方向上发生整流， Ｉ Ｖ （ 电流电压） 曲线表现为“ Ｓ”型， 其中伤害感受神经元整流作用较非伤害感受神经元明显． 伤害感受神经元 Ｒｍ 、τ、 Ｃｍ 明显大于非伤害感受神经元（ Ｐ＜ ００１ 或 Ｐ＜ ００５） ． 结果提示 Ｓ Ｉ区伤害感受神经元与非伤害感受神经元可能在细胞膜结构、细胞大小等方面存在有意义的差别， 从而反映其不同的生理功能．

创伤后应激障碍小鼠初级体感皮质神经元异常敏化的研究

目的:分析创伤后应激障碍(PTSD)小鼠胡须触觉刺激后初级躯体感觉皮质(S1)神经元的激活情况及PTSD小鼠S1皮质神经元的形态结构变化。方法:使用神经元细胞骨架相关蛋白(Arc)标记策略,结合免疫荧光染色技术,对PTSD小鼠与对照组小鼠胡须刺激后S1皮质神经元Arc进行标记并观察,通过分析Arc标记神经元的空间表达位置和阳性细胞数量差异,对比分析两组S1皮质神经元的激活水平。利用病毒稀疏标记方法标记S1皮质的锥体神经元,比较两组小鼠神经元树突数量及树突棘的形态与数量分布。结果:胡须刺激两组小鼠后发现Arc阳性神经元在S1浅层至深层均有分布,其中在Ⅱ/Ⅲ与Ⅴ层分布更密集。与对照组小鼠相比,PTSD组在不同层的阳性神经元数目均明显增多。细胞形态结构分析结果显示,与对照组神经元相比,PTSD组小鼠树突棘密度在Ⅱ/Ⅲ层异常增高,其中蘑菇型树突棘数量增多,丝状伪足型树突棘数量减少;而S1Ⅴ层蘑菇型与细长型的树突棘数量均较多,但树突棘总数没有明显差异。结论:PTSD小鼠胡须刺激后S1神经元过度激活,神经元结构及形态发生明显改变。

乙酰胆碱在刺激SⅡ区影响C类纤维传入诱发的SI区电反应中的作用

电刺激猫大脑皮层体感Ⅱ区(SⅡ)对隐神经C类纤维传入引起的体感Ⅰ区(SⅠ)诱发电位(C—CEP)有抑制和易化作用。在SⅠ区局部用阿托品能部分地阻断电刺激SⅡ区对C—CEP的抑制作用,但对易化作用的影响不明显;而用六烃季铵(C_6)能阻断易化作用,但对抑制作用的影响却不明显。在SⅠ区局部应用0.01％乙酰胆碱(ACh)对C—CEP有易化作用,用0.1％ACh则有抑制作用。结果提示,ACh可能参与SⅡ区对SⅠ区C—CEP的影响,通过SⅠ区的胆碱能M受体起抑制作用,通过N受体起易化作用。

Changes in brain activation in stroke patients after mental practice and physical exercise: a functional MRI study

Mental practice is a new rehabilitation method that reters to the mental rehearsal ot motor imagery content with the goal of improving motor performance. However, the relationship between activated regions and motor recovery after mental practice training is not well understood. In this study, 15 patients who suffered a firstever subcortical stroke with neurological deficits affecting the right hand, but no significant cognitive impairment were recruited. 10 patients underwent mental practice combined with physical practice training, and 5 patients only underwent physical practice training. We observed brain activation regions after 4 weeks of training, and explored the correlation of activation changes with functional recovery of the affected hands. The results showed that, after 4 weeks of mental practice combined with physical training, the Fugl-Meyer assessment score for the affected right hand was significantly increased than that after 4 weeks of practice training alone. Functional MRI showed enhanced activation in the left primary somatosensory cortex, attenuated activation intensity in the right primary motor cortex, and enhanced right cerebellar activation observed during the motor imagery task using the affected right hand after mental practice training. The changes in brain cortical activity were related to functional recovery of the hand. Experimental findings indicate that cortical and cerebellar functional reorganization following mental practice contributed to the improvement of hand function.

猫SI、SII对尾核痛相关单位的下行调制作用初探

实验用清醒麻痹猫进行观察。结果表明,刺激SⅠ区,尾核头部痛相关单位多数受到抑制。36.36％的单位在刺激SⅠ区后表现先抑制后兴奋的现象。64.29％的单位在刺激SI区后出现抑制效应时,单位放电即刻停止一定时间。刺激SⅡ区的效应与刺激SⅠ区类同。用GABA改变SⅡ区的正常机能状态,刺激SⅠ区的效应,在26个痛相关单位中有13个单位显示激活或相反,而对照组没有改变。提示SⅠ区对痛相关单位有单独的抑制效应。而在SⅠ区对尾核头部痛相关单位的下行调制中SⅡ区起一定的协同作用。

Effects of visual information regarding tactile stimulation on the somatosensory cortical activation：a functional MRI study

Many studies have investigated the evidence for tactile and visual interactive responses to activation of various brain regions.However,few studies have reported on the effects of visuo-tactile multisensory integration on the amount of brain activation on the somatosensory cortical regions.The aim of this study was to examine whether coincidental information obtained by tactile stimulation can affect the somatosensory cortical activation using functional MRI.Ten right-handed healthy subjects were recruited for this study.Two tasks（tactile stimulation and visuotactile stimulation）were performed using a block paradigm during f MRI scanning.In the tactile stimulation task,in subjects with eyes closed,tactile stimulation was applied on the dorsum of the right hand,corresponding to the proximal to distal directions,using a rubber brush.In the visuotactile stimulation task,tactile stimulation was applied to observe the attached mirror in the MRI chamber reflecting their hands being touched with the brush.In the result of SPM group analysis,we found brain activation on the somatosensory cortical area.Tactile stimulation task induced brain activations in the left primary sensory-motor cortex（SM1）and secondary somatosensory cortex（S2）.In the visuo-tactile stimulation task,brain activations were observed in the both SM1,both S2,and right posterior parietal cortex.In all tasks,the peak activation was detected in the contralateral SM1.We examined the effects of visuo-tactile multisensory integration on the SM1 and found that visual information during tactile stimulation could enhance activations on SM1 compared to the tactile unisensory stimulation.

Neural circuits and temporal plasticity in hindlimb representation of rat primary somatosensory cortex:revisited by multi-electrode array on brain slices

Objective The well-established planar multi-electrode array recording technique was used to investigate neural circuits and temporal plasticity in the hindlimb representation of the rat primary somatosensory cortex （S1 area） . Methods Freshly dissociated acute brain slices of rats were subject to constant perfusion with oxygenated artificial cerebrospinal fluid （95% O2 and 5% CO2） , and were mounted on a Med64 probe （64 electrodes, 8×8 array） for simultaneous multi-site electrophysiological recordings. Current sources and sinks across all the 64 electrodes were transformed into two-dimensional current source density images by bilinear interpolation at each point of the 64 electrodes. Results The local intracortical connection, which is involved in mediation of downward information flow across layers II-VI, was identified by electrical stimulation （ES） at layers II-III. The thalamocortical connection, which is mainly involved in mediation of upward information flow across layers II-IV, was also characterized by ES at layer IV. The thalamocortical afferent projections were likely to make more synaptic contacts with S1 neurons than the intracortical connections did. Moreover, the S1 area was shown to be more easily activated and more intensively innervated by the thalamocortical afferent projections than by the intracortical connections. Finally, bursting conditioning stimulus （CS） applied within layer IV of the S1 area could success-fully induce long-term potentiation （LTP） in 5 of the 6 slices （83.3%） , while the same CS application at layers II-III induced no LTP in any of the 6 tested slices. Conclusion The rat hindlimb representation of S1 area is likely to have at least 2 patterns of neural circuits on brain slices： one is the intracortical circuit （ICC） formed by interlaminar connections from layers II-III, and the other is the thalamocortical circuit （TCC） mediated by afferent connections from layer IV. Besides, ICC of the S1 area is spatially limited, with less plasticity, while TCC is spatially extensive and exhibits a better plasticity in response to somatosensory afferent stimulation. The present data provide a useful experimental model for further studying microcircuit properties in S1 cortex at the network level in vitro.

初级体感皮层星形胶质细胞参与电针治疗炎性痛的实验研究

目的:观察操纵初级体感皮层星形胶质细胞对电针治疗炎性痛的影响,探讨电针镇痛的可能机制。方法:实验一,将32只C57雄性小鼠随机分为4组:空白对照组、模型组、假电针组和电针组,每组8只。在小鼠左后足底注射完全氟氏佐剂(CFA)建立炎性痛模型。成模后,电针组进行电针治疗,针刺患侧环跳穴和阳陵泉穴,频率2 Hz,电流1 mA,每天30 min,连续7 d。造模前1 d、造模后1 d和电针第1、3、5、7天进行机械痛阈值(PWT)和热痛阈值(TL)检测。实验二,将32只C57雄性小鼠随机分为4组:模型组、星形胶质细胞抑制组、电针组和星形胶质细胞抑制复合电针组,每组8只。所有小鼠进行CFA造模,成模后星形胶质细胞抑制组和星形胶质细胞抑制复合电针组在右侧初级体感皮层后肢区(S1HL脑区)注射L-α-氨基己二酸(星形胶质细胞选择性胶质毒剂)实现特异性抑制星形胶质细胞,模型组和电针组注射人工脑脊液。脑区注射3 d后,电针组和星形胶质细胞抑制复合电针组进行电针治疗,方案同实验一。检测造模前1 d、造模后1 d和电针第1、3、5、7天PWT和TL,观察抑制星形胶质细胞对炎性痛小鼠痛阈和电针镇痛效果的影响。实验三,将16只C57雄性小鼠随机分为2组:化学遗传激活组和化学遗传对照组,每组8只。2组小鼠均在右侧S1HL脑区注射化学遗传病毒,3周后进行CFA造模,成模后进行电针治疗,方案同实验一。化学遗传激活组在每次电针前40 min腹腔注射N-氧化氯氮平(CNO),对照组腹腔注射等体积0.9%氯化钠溶液。检测造模前1 d、造模后1 d和电针第1、3、5、7天PWT和TL,观察激活星形胶质细胞对电针镇痛效果的影响。结果:实验一,造模24 h后,除空白对照组外,各组小鼠PWT和TL均较前显著下降(P<0.05),提示造模成功。与模型组比较,电针组电针治疗第3、5、7天PWT均显著上升(P<0.05),电针治疗第3、5、7天TL均显著上升(P<0.05)。实验二,与模型组比较,星形胶质细胞抑制组显著提高了炎性痛小鼠的PWT和TL(P<0.05),并可维持至电针第7天。电针第5、7天,星形胶质细胞抑制加电针组与电针组炎性痛小鼠PWT和TL均无显著差异(P>0.05)。电针第7天,与星形胶质细胞抑制组比较,星形胶质细胞抑制加电针组PWT和TL显著升高(P<0.05)。实验三,与造模后疼痛阈值比较,化学遗传对照组小鼠疼痛阈值在电针第3、5、7天均显著提高(P<0.05)。与化学遗传对照组比较,化学遗传激活组小鼠疼痛阈值在电针第3、5、7天均显著降低(P<0.05)。结论:电针环跳穴和阳陵泉穴可以有效治疗炎症性疼痛,抑制初级体感皮层星形胶质细胞可以模拟电针镇痛的效应,而激活初级体感皮层星形胶质细胞可以翻转电针镇痛作用,提示初级体感皮层星形胶质细胞参与了电针治疗炎症性疼痛的机制。

内、外侧痛觉系统——伤害性信息处理的并行通路

现代研究认为 ,完整的痛觉信号应该包括两种成分 ,即反映伤害性刺激参数 (性质、定位、强度 )的感觉辨别成分和反映情绪效应以及产生逃避行为的情感动机成分。相应地 ,在脑内存在两条平行上传的通路 ,分别传递痛的感觉和情绪信息。其中由脊髓背角深层广动力神经元发出 ,经过丘脑外侧核群投射到躯体感觉皮层的通路 ,可能传导伤害性刺激的感觉信息 ,称为外侧痛觉系统 ;由脊髓背角浅层痛觉特异性神经元发出 ,经由丘脑中线核群及板内核群投射到前扣带回和岛叶的通路 ,可能传递伤害性刺激的情绪成分 ,称为内侧痛觉系统。

运动双手食指后应用磁源性影像对运动皮质及体感皮质定位

目的确定运动双手食指后应用磁源性影像对运动皮质及体感皮质功能区定位的价值并探讨其成像方法。方法6例受试者接受左、右侧视觉光刺激后运动相应侧食指,双手食指下方各放置一块垫板,垫板上有一个光电偶合器,食指抬起后数据采集计算机即可将光电偶合的一刻为“零”对脑反应信号进行叠加。应用脑磁图记录运动及体感反应叠加后的脑电磁波并将其与相应受试者头MRI叠加形成磁源性影像。结果食指运动后,每个受试者双侧半球均出现一个最高的波峰,左右半球潜伏期分别为(41.5±7.8)ms和(35.5±3.6)ms。受试者之间左、右半球皮质兴奋的潜伏期(W1)差异无显著意义(t=2.046,P=0.096)。将其ECD叠加到MRI上可见ECD均位于中央后回。每个受试者在最高波峰之前出现一个小的波峰,潜伏期为负值,左、右半球分别为-(52.9±25.9)ms和-(63.8±19.5)ms。受试者之间左、右半球皮质兴奋的潜伏期(W2)差异无显著意义(t=1.342,P=0.237)。由磁源性影像显示兴奋的皮质位于中央前回。结论磁源性影像可很好地显示健康受试者运动皮质及体感皮质,可对运动皮质及体感皮质进行精确定位。

体感诱发电位在神经性瘫痪中的定位价值

目的检测及分析小儿神经性瘫痪体感诱发电位(SEP),探讨SEP在小儿神经性瘫痪定位诊断中的价值。方法以180例0～14岁小儿刺激正中神经和胫后神经体感诱发电位正常值为标准,对临床有肢体瘫痪的335例年龄49d～13岁小儿的体感诱发电位进行分析比较。结果266例临床有痉挛性肢体瘫痪小儿,SEP异常率共为86.5%(230/266)。表现为脊髓和/或皮层SEP峰潜伏期记录延长或消失,而周围神经电位正常;脊髓疾病及脑性瘫痪SEP异常率较其他中枢神经疾病高,分别为92.6%(25/27)和86.3%(139/161);颅内病变中天幕上SEP异常较天幕下常见;69例临床周围性肢瘫SEP异常率20.3%(14/69);3岁以下年龄组与3岁以上年龄组之间异常率差异意义无显著性。结论体感诱发电位对小儿肢体瘫痪定位,特别是对临床工作中较难判断的小婴儿瘫痪定位诊断具有实用价值。

去甲肾上腺素和刺激隐神经对大鼠体感皮层Ⅰ区神经元自发活动的调制

目的 :探讨去甲肾上腺素是否对体感皮层Ⅰ区神经元的自发活动具有调制作用 ,以及这种调制作用是否影响体感皮层对传入信息的感受。方法 :以SD大鼠为实验对象 ,采用多管玻璃微电极刺激记录技术和微电泳注射的方法 ,观察了不同剂量的去甲肾上腺素和刺激隐神经单独作用和共同作用于体感皮层Ⅰ区神经元时自发活动平均放电率的变化。结果 :去甲肾上腺素能易化体感皮层Ⅰ区电泳部位神经元的自发活动 ,使平均放电率增大。当微电泳电流强度从 5nA逐渐加大至 145nA时 ,平均放电率的增加值从 (0 .5 2± 0 .47)脉冲 /s增大到 (2 4.1± 6 .9)脉冲 /s ,表明易化作用逐渐加强 ,且呈剂量———效应正相关依赖关系。去甲肾上腺素对体感皮层Ⅰ区神经元的自发活动有抑制效应 ,但无剂量依赖关系。刺激隐神经的电流强度较弱 ,单纯A类纤维传入时对记录部位神经元的自发活动有抑制作用 ;刺激强度较强 ,A类和C类纤维共同传入时 ,能易化记录部位的自发活动。而且发现 ,去甲肾上腺素与传入信息对体感皮层Ⅰ区神经元自发活动的调制有相互作用 :去甲肾上腺素既能取消传入信息对体感皮层Ⅰ区神经元自发活动的兴奋效应 ;又能使其抑制作用减弱。结论 :去甲肾上腺素通过调制体感皮层Ⅰ区神经元的自发活动来改变信号一噪声比 。