Synaptic noise improves detection of subthreshold signals in hippocampal CA1 neurons
Synaptic noise improves detection of subthreshold signals in hippocampal CA1 neurons
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DOI：
10.1152/jn.2001.86.3.1104
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发表时间：
2001-09-01
影响因子：
2.5
通讯作者：
Durand, DM
中科院分区：
文献类型：
--
作者：
Stacey, WC;Durand, DM
随机共振（SR）是一种通过引入噪声来增强非线性系统中低电平信号的检测的现象。对SR在神经元中的作用的研究表明，噪声在改善小信号的检测方面可以发挥突出的作用。大多数实验性SR研究都集中在使用生理刺激的感觉神经元中噪声的作用。计算机模拟表明，在海马神经元中的信号检测是通过增加施加到突触输入的细胞外的噪声的生理水平得到改善。这些结果得到了实验证实。我们现在报告说，内源性噪声源也可以改善信号检测。用阈下阴极电流调制大鼠海马脑片CA 1细胞顶树突上的随机突触活动产生噪声源。CA1细胞的细胞内记录表明，即使是很小的增加突触噪声能够大大提高检测一个独立的，突触，阈下刺激的预测模拟。CA1细胞中的噪声方差与静息方差和由几种内源性噪声源引起的方差变化进行了比较。在所有情况下，增加的噪声方差都在生理范围内。这些结果进行了补充和分析的CA 1计算机模型。改善的信号检测与少量的内源性噪声表明，不同的输入到CA 1能够提高阈下突触信号的检测，并可以提供一种手段来调制特定的输入在海马体的检测。
Stochastic resonance (SR) is a phenomenon whereby the detection of a low-level signal is enhanced in a nonlinear system by the introduction of noise. Studies of the effects of SR in neurons have suggested that noise could play a prominent role in improving detection of small signals. Most experimental SR research has focused on the role of noise in sensory neurons using physiological stimuli. Computer simulations show that signal detection in hippocampal neurons is improved by the addition of physiological levels of noise applied extracellularly to synaptic inputs. These results were confirmed experimentally. We now report that endogenous noise sources can also improve signal detection. The noise source was generated by modulating the, random synaptic activity on the apical dendrites of CA1 cells in rat hippocampal slices using subthreshold cathodic current. Intracellular recordings of CA1 cells showed that even small increases of synaptic noise are able to greatly improve the detection of an independent, synaptic, subthreshold stimulus as predicted by the simulations. The noise variance in the CA1 cell was compared with the resting variance and with variance changes caused by several endogenous noise sources. In all cases, the increased noise variance was well within the physiological range. These results were supplemented and analyzed with a CA1 computer model. The improved signal detection with small amounts of endogenous noise suggests that the diverse inputs to CA1 are able to improve detection of subthreshold synaptic signals and could provide a means to modulate detection of specific inputs in the hippocampus.