SYNCHRONIZED EXCITATION AND INHIBITION DRIVEN BY INTRINSICALLY BURSTING NEURONS IN NEOCORTEX
SYNCHRONIZED EXCITATION AND INHIBITION DRIVEN BY INTRINSICALLY BURSTING NEURONS IN NEOCORTEX
复制标题
DOI：
10.1152/jn.1989.62.5.1149
复制
发表时间：
1989-11-01
影响因子：
2.5
通讯作者：
CONNORS, BW
中科院分区：
文献类型：
--
作者：
CHAGNACAMITAI, Y;CONNORS, BW
1.同步突触活动的细胞机制进行了研究，在大鼠SmI新皮层，γ-氨基丁酸（GABA）介导的抑制轻微抑制隔离片。从单个神经元进行细胞内测量，并且细胞外记录监测群体事件的时间和强度。2.皮质层II-VI中的神经元通过其单个动作电位和在细胞内电流脉冲注入期间的重复放电模式的属性进行分类。规则尖峰（RS）细胞发生在所有层，并具有较长的持续时间和较强的频率适应尖峰。内部爆发（IB）细胞只发生在IV和V层，并产生大于或等于3个尖峰的爆发;低层V的一些IB细胞在长去极化脉冲过程中产生重复的爆发。快速尖峰（FS）细胞有短暂的尖峰，很少或没有适应，并以高频率发射。3.当GABAA介导的抑制与低剂量的荷包牡丹碱methiodide（BMI，0.8-1.0 μ M）略有减少，同步事件诱发的刺激层VI与单次电击。同步事件的特点是突出的，通常是全或无细胞外场电位，水平传播的可变距离高达几毫米。大场电位总是与兴奋性和抑制性突触后电位（EPSP和IPSP）在单个神经元。PSP和场电位通常都有长的（长达250 ms）和可变的潜伏期，有时两个或多个事件由单一刺激产生。在所有情况下，PSP和场电位是同步的。场电位和单个细胞有时在20-50 Hz产生短时期（3-7个峰）的节律事件。4.单个神经元的生理类别与每个同步事件中兴奋和抑制的相对优势相关。在每个同步事件的阶段，大多数RS细胞被非常强烈的抑制，只有少量的并发兴奋。相比之下，IB细胞强烈且持续地兴奋，抑制相对较小。FS细胞也是相性兴奋的。5.解剖学研究已确定RS和IB细胞为锥体细胞，FS细胞为GABA能非锥体细胞。这意味着，在本研究的同步事件，大多数锥体细胞占主导地位的IPSPs。FS细胞（假定的抑制性中间神经元）的同步兴奋与此一致。只有一个子集的锥体神经元，几乎所有的中间层的IB细胞，表现出强烈的，同步的兴奋和动作电位簇。（400字处截断摘要）
1. The cellular mechanisms of synchronous synaptic activity were studied in isolated slices of rat SmI neocortex in which gamma-aminobutyric acid (GABA)-mediated inhibition was slightly suppressed. Intracellular measurements were made from single neurons, and extracellular recordings monitored the timing and intensity of population events. 2. Neurons in cortical layers II-VI were classified by the attributes of their single action potentials and repetitive firing patterns during injection of intracellular current pulses. Regular-spiking (RS) cells occurred in all layers and had relatively long-duration spikes and strong frequency adaptation. Intrinsically bursting (IB) cells occurred only in layers IV and V and generated bursts of greater than or equal to 3 spikes; some IB cells of lower-layer V produced repetitive bursts during long depolarizing pulses. Fast-spiking (FS) cells had brief spikes and little or no adaptation and fired at high frequencies. 3. When GABAA-mediated inhibition was slightly reduced with low doses of bicuculline methiodide (BMI, 0.8-1.0 microM), synchronous events were evoked by stimulating layer VI with single shocks. Synchronous events were characterized by prominent, often all-or-none extracellular field potentials that propagated horizontally for variable distances up to several millimeters. Large field potentials were invariably correlated with excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) in single neurons. Both PSPs and field potentials often had long (up to 250 ms) and variable latencies, and sometimes two or more events were generated by single stimuli. In all cases the PSPs and field potentials were synchronous. Both field potentials and single cells sometimes generated short epochs (3-7 peaks) of rhythmic events at 20-50 Hz. 4. The physiological class of single neurons was correlated with the relative dominance of excitation and inhibition during each synchronous event. In phase with each synchronous event, most RS cells were very strongly inhibited with only small amounts of concurrent excitation. By contrast, IB cells were strongly and consistently excited, with relatively little inhibition. FS cells were also phasically excited. 5. Anatomic studies have identified RS and IB cells as pyramidal cells and FS cells as GABAergic nonpyramidal cells. This implies that, during the synchronous events of the present study, the majority of pyramidal cells were dominated by IPSPs. Synchronous excitation of FS cells, the presumed inhibitory interneurons, is consistent with this. Only a subset of the pyramidal neurons, almost all of them IB cells of the middle layers, displayed strong, synchronous excitation and clusters of action potentials.(ABSTRACT TRUNCATED AT 400 WORDS)