Electrical properties affecting discharge of units of the mid and posterolateral thalamus of conscious cats.
Electrical properties affecting discharge of units of the mid and posterolateral thalamus of conscious cats.
复制标题
电特性影响有意识的猫的中丘脑和后外侧丘脑单位的放电。
DOI：
10.1016/j.neuroscience.2003.08.011
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发表时间：
2003
期刊：
影响因子：
3.3
通讯作者：
Wang,XF
中科院分区：
文献类型：
--
作者：
Woody,CD;Gruen,E;Wang,XF
放电特性响应于胞内施加，矩形电流测量单位的中间（背外侧核和中央外侧核）和后外侧（外侧后和枕核）丘脑的清醒猫。一个单独的目的是确定神经元兴奋性的变化与刺激诱发的活动的变化后，动物进行训练，以区分两个声学刺激时，执行条件运动反应。低阈值尖峰（l.t.s.）在272个细胞中的3个中观察到放电，所述细胞给予1nA的胞内、40 ms持续时间的超极化电流脉冲。这一发现支持了这样的观点，即有意识的动物的丘脑神经元主要在继电器，而不是振荡模式。在细胞中应用更大和更长的超极化电流产生反弹l.t.s.这支持了大多数丘脑神经元能够产生这种类型的放电的预期。在丘脑的每个研究区域，也观察到重复放电时的棘波后超极化（AHP）的减少和棘波基底的增宽。条件反射后，在施加去极化电流（RSD）时，丘脑后外侧区（中丘脑区）出现自发、快速（≥50 Hz）、重复放电（RRD）和频率≥100 Hz的快速、持续放电（RSD）的细胞比例发生变化。在后外侧丘脑中，对RSD为1 nA的去极化反应的单位百分比从调节前的71%下降到调节后的45%。具有RRD的细胞百分比从69%下降到46%。这些变化伴随着细胞膜电位的3 mV超极化和基线活性的降低。条件反射后，兴奋性的增加被发现在中丘脑的细胞，选择性地响应点击条件刺激（CS），引起条件反射，和兴奋性的降低被发现在后外侧丘脑的细胞，响应于辨别性的声刺激（DS），动物被训练不作出反应。早期的一项研究表明，类似的条件反射后，中丘脑单位的CS放电增强，后外侧丘脑单位的DS响应单位和DS峰值放电的比例减少。我们的结论是，放电特性的中间和后外侧丘脑的单位可以改变，以支持不同的功能意义的声刺激条件反射后的歧视。
Discharge properties in response to intracellularly applied, rectangular currents were measured in units of the mid (lateralis dorsalis and centrolateral nuclei) and posterolateral (lateralis posterior and pulvinar nuclei) thalamus of conscious cats. A separate aim was to determine if neuronal excitability changed in association with changes in stimulus-evoked activity after the animals were trained to discriminate between two acoustic stimuli when performing a conditioned motor response. Low threshold spike (l.t.s.) discharges were observed in three of 272 cells given 1 nA intracellular, hyperpolarizing current pulses of 40 ms duration. This finding supports the view that thalamic neurons of conscious animals operate mainly in the relay as opposed to the oscillatory mode. Application of larger and longer hyperpolarizing currents in the cells produced rebound l.t.s. discharges, supporting the expectation that most thalamic neurons are capable of producing this type of discharge. Decrements of spike afterhyperpolarizations (AHP) and broadening of spike bases upon repeated discharge also were observed in each area of the thalamus studied. After conditioning, changes were found in the posterolateral thalamus (but not in the mid-thalamus) in the proportions of cells with spontaneous, rapid (≥50 Hz), repetitive, discharges (RRD) and rapid, sustained discharges at rates ≥100 Hz during application of depolarizing current (RSD). In the posterolateral thalamus the percentage of units responding to 1 nA depolarization with RSD fell from 71% before conditioning to 45% after conditioning. The percentage of cells with RRD decreased from 69% to 46%. The changes were accompanied by a 3 mV hyperpolarization of the membrane potentials of the cells and a decrease in baseline activity. After conditioning, increases in excitability were found in cells of the mid thalamus that responded selectively to the click conditioned stimulus (CS) that elicited the conditioned response, and decreases in excitability were found in cells of the posterolateral thalamus that responded to the discriminative acoustic stimulus (DS) to which the animals were trained not to respond. An earlier study showed a potentiation of discharge in response to the CS in units of the midthalamus after similar conditioning and a reduction of the proportion of DS responsive units and peak discharge to the DS in units of the posterolateral thalamus. We conclude that the discharge properties of units of the mid and posterolateral thalamus can change to support discrimination between acoustic stimuli of different functional significance after conditioning.