本文選題：體感刺激　切入點(diǎn)：海馬　出處：《浙江大學(xué)》2014年博士論文

【摘要】：感覺信號的處理一直是神經(jīng)科學(xué)領(lǐng)域研究的熱點(diǎn),體感感覺因其遍布全身的感受器以及在觸摸技術(shù)領(lǐng)域的廣泛應(yīng)用越來越受到重視。海馬作為學(xué)習(xí)和記憶的中樞結(jié)構(gòu),從內(nèi)嗅皮質(zhì)接收有關(guān)外界體感刺激的信號,并將其按某種模式編碼,以便信息在大腦中的傳播和儲存。早先的研究發(fā)現(xiàn)體感刺激可以使海馬CA1區(qū)的多單元放電活動(multiple unit activity, MUA)發(fā)生變化,但其對CA1區(qū)具體的作用效果和機(jī)制并不明確。由于對體感信息的處理與動物的生存和活動息息相關(guān),因此研究體感信息在海馬區(qū)中的信號響應(yīng)和處理機(jī)制具有重要意義。 本文通過對麻醉大鼠施加夾尾刺激,利用記錄位點(diǎn)高密度分布的微電極陣列,記錄海馬CA1區(qū)的各種神經(jīng)活動信號。主要研究了場電位、鋒電位以及正向誘發(fā)電位對體感刺激的響應(yīng),考察了刺激對海馬CA1區(qū)的作用效果；并且建立了包含體感輸入和局部抑制回路的CA1區(qū)神經(jīng)網(wǎng)絡(luò)模型,利用計算機(jī)仿真驗(yàn)證了動物實(shí)驗(yàn)結(jié)果的產(chǎn)生機(jī)制；最后對海馬中體感信息的處理與編碼進(jìn)行了探討。 本文的主要研究結(jié)果如下： (1)體感刺激對大鼠海馬CA1區(qū)的主神經(jīng)元活動具有抑制作用 在夾尾的體感刺激作用下,CA1區(qū)的場電位變成以θ節(jié)律為主要功率成分,同時伴隨有不一致的MUA響應(yīng)(發(fā)放減少或者不變)；其中,錐體細(xì)胞的鋒電位發(fā)放頻率減小,中間神經(jīng)元的發(fā)放頻率增加；錐體細(xì)胞爆發(fā)式發(fā)放頻率減小,每個爆發(fā)式發(fā)放所包含的鋒電位數(shù)量無明顯變化；Schaffer側(cè)支上施加正向脈沖刺激所誘發(fā)的CA1區(qū)群峰電位的幅值顯著減��；CA1區(qū)的MUA、錐體細(xì)胞的發(fā)放對重復(fù)體感刺激產(chǎn)生了適應(yīng)性現(xiàn)象(adaptation)。這些結(jié)果表明體感刺激對海馬CA1區(qū),尤其是錐體細(xì)胞興奮性有明顯的抑制作用。 (2)數(shù)學(xué)模型的仿真結(jié)果表明體感刺激可以增強(qiáng)海馬CA1區(qū)局部抑制性回路的作用 利用NEURON軟件建立CA1區(qū)神經(jīng)網(wǎng)絡(luò)模型,以研究海馬對體感刺激響應(yīng)的機(jī)制。模型的仿真結(jié)果與動物實(shí)驗(yàn)的結(jié)果一致,證明了體感刺激后CA1區(qū)錐體細(xì)胞興奮性降低是中間神經(jīng)元通過局部抑制回路作用的結(jié)果,其中前饋抑制回路和反饋抑制回路共同發(fā)揮作用,但以前饋抑制回路的作用為主導(dǎo)。為了進(jìn)一步考察這種抑制作用是否能夠用于控制異常的神經(jīng)活動,我們還仿真了體感刺激對于過度興奮狀態(tài)下(癲癇發(fā)作時)錐體細(xì)胞興奮性的影響,結(jié)果表明體感刺激可以減弱單側(cè)顳葉癲癇活動,但無法減弱雙側(cè)顳葉癲癇活動。 (3)鋒電位與場電位之間的相位鎖定可能是CA1區(qū)編碼體感信息的方式 本文利用Rayleigh檢驗(yàn)分析了神經(jīng)元鋒電位與場電位θ節(jié)律之間的時間相關(guān)性,揭示了一種可能的CA1區(qū)對體感信息編碼的方式。研究結(jié)果表明：夾尾刺激前,少部分神經(jīng)元(3/22)展現(xiàn)出與0節(jié)律周期相位鎖定的特性；夾尾刺激作用下,呈現(xiàn)相位鎖定特性的神經(jīng)元數(shù)量顯著增加(10/22),其鋒電位發(fā)放集中在0節(jié)律周期的負(fù)相位附近。 總之,本文結(jié)合了大鼠在體實(shí)驗(yàn)記錄和建模仿真兩種研究方法,考察了海馬CA1區(qū)神經(jīng)活動對體感刺激的響應(yīng),證明了體感刺激的抑制性作用,并且表明這種作用的內(nèi)在機(jī)制是中間神經(jīng)元通過局部抑制回路降低了錐體細(xì)胞的興奮性。本文為海馬是如何處理體感信息的研究提供了實(shí)驗(yàn)和理論依據(jù),對海馬的學(xué)習(xí)功能和神經(jīng)編碼的研究具有重要意義。
[Abstract]:Processing of sensory signals is always the research focus in the field of neuroscience, body sensation throughout the body because of its receptors as well as in touch technology widely used more and more attention. As the central structure of hippocampus in learning and memory, the received signal on the external cortical somatosensory stimulation from the entorhinal, and by a certain mode encoding, so that information is transmitted and stored in the brain. Previous studies found that somatosensory stimulation can make the multi unit discharge of hippocampal CA1 region (multiple unit, activity, MUA) change, but its CA1 region specific effects and mechanism is not clear. To deal with the animal because of somatosensory information. Life and activities, so the research has important significance to signal somatosensory information in the hippocampus in response and processing mechanism.
In this paper, by applying clamping tail stimulation in anesthetized rats, recorded by the microelectrode array site of high density distribution, various neural activity signals recorded in hippocampal CA1 region. The main research field potential, and a positive response of the spike evoked potentials on somatosensory stimulation, investigated the stimulation effect on the hippocampal CA1 region; and the establishment of the CA1 neural network model contains somatosensory input and local inhibitory circuits, which verified the mechanism of animal experiments using computer simulation; at the end of the processing and encoding somatosensory information in the hippocampus were discussed.
The main results of this paper are as follows:
(1) somatosensory stimulation inhibits the activity of main neurons in the CA1 region of the hippocampus of rats
In the tail clamp somatosensory stimulation, field potential CA1 region into a theta rhythm as the main power components, with inconsistent MUA response (payment is reduced or unchanged); among them, pyramidal cell spikes firing frequency decreases the firing frequency of interneurons increased; pyramidal cells burst firing frequency decreases each spike number type, the outbreak of issue contains no obvious change; positive pulse amplitude applied CA1 peaks potentials evoked by stimulation of the Schaffer collaterals significantly decreased; CA1 area MUA pyramidal cells release sense stimulate the adaptation of repeats (adaptation). These results suggest that somatosensory stimulation of the hippocampus CA1, especially can significantly inhibit the excitability of pyramidal cells.
(2) the simulation results of the mathematical model show that the somatosensory stimulation can enhance the role of the local inhibitory loop in the hippocampal CA1 region.
A CA1 neural network model by using NEURON software, to investigate the mechanism of hippocampal somatosensory stimulation response. The simulation results and the results of animal experiments, proved that somatosensory stimulation excited CA1 pyramidal cells is decreased as the result of interneurons by local inhibitory circuits, including feedforward inhibition and feedback loop together play the role of inhibitory loop, but with feedforward inhibitory circuits leading role. In order to further investigate whether this inhibition can be used to control the abnormal neuronal activity, we also simulated somatosensory stimulation for over excited state (seizure) affect the excitability of pyramidal cells. The results show that somatosensory stimulation can weaken unilateral temporal lobe epileptic activity, but not weaken the bilateral temporal lobe epilepsy.
(3) the phase locking between the front potential and the field potential may be the way of encoding the body sense information in the CA1 region.
This paper uses the Rayleigh test to analyze the time correlation between spikes and field potentials of the theta rhythm, reveals the way of somatosensory information encoding a putative CA1 region. The results show that: the tail clipping before stimulation, a few neurons (3/22) show the characteristics of 0 phase locking and rhythm cycle; stimulate tail under the action of the number of neurons showed phase locking characteristics significantly increased (10/22), the spike potentials are concentrated in the vicinity of the negative phase 0 rhythm cycle.
In conclusion, this paper combines the rat in vivo recording and modeling and Simulation of two kinds of research methods, investigated the response of neural activity in hippocampal CA1 area of somatosensory stimulation, that somatosensory stimulation of inhibitory effect, and indicates the inherent mechanism of the role of the interneurons reduces excitability of pyramidal cells by local inhibitory circuits this is how to deal with the hippocampus. Study on somatosensory information provides experimental and theoretical basis, it is important to study on hippocampal learning function and neural encoding.

【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TN911.7

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

1 韓春曉;王江;常莉;車艷秋;;外電場作用下改進(jìn)的Leaky Integrate-And-Fire模型的峰放電頻率適應(yīng)性研究[J];動力學(xué)與控制學(xué)報;2013年01期

2 王靜;封洲燕;;多通道神經(jīng)元鋒電位檢測和分類的新方法[J];生物化學(xué)與生物物理進(jìn)展;2009年05期

3 柳玉倩;趙凌云;洪波;;大鼠下丘神經(jīng)元對重復(fù)刺激適應(yīng)性的時頻表征[J];生物物理學(xué)報;2009年03期

相關(guān)博士學(xué)位論文 前1條

1 鄭曉靜;大鼠海馬區(qū)電刺激抑制癲癇的作用機(jī)制研究[D];浙江大學(xué);2011年

，

本文編號：1688104