Chen Xiao-Mo, Qiao Zhi-Mei, Gao Shang-Kai, Hong Bo
Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084, China.
Sheng Li Xue Bao. 2007 Dec 25;59(6):851-7.
Neural network plasticity is fundamental for learning and memory. Its abnormal change underlies some neural diseases. Measurement of the plasticity of cortex can help understand the mechanism of plasticity, and provide a quantitative way to observe the neural process of natural aging and neurodegenerative diseases, which may lead to a new approach for evaluation of anti-aging drugs and new medical treatments for neurodegenerative diseases. In this study, a systematic method was established based on whisker pairing (WP) experiment to measure the network plasticity in the barrel cortex in rat. WP experiment is a classical experiment to study the effect of innocuous bias of the flow of sensory activity from the whiskers for certain periods in awake and behaving rats on the receptive field organization in S1 barrel cortex neurons. In the experiment, one pair of adjacent whiskers D2 and D3 remained intact while others were being trimmed throughout a certain period. After that, receptive fields of single cells in the contralateral barrel were analyzed by post-stimulus time histogram after certain days of WP and compared with the controls. In the control group, response magnitudes to surrounding whiskers D1 and D3 deflection were not significantly different. However, after WP, a bias occurred in response to paired surrounding whisker D3 relative to the opposite trimmed surrounding whisker D1. In this study, by comparing the bias degree in rats in different groups after WP, a quantitative method was established to compare cortical plasticity. Example of corical plasticity comparison between adolescent and mature rats was employed in this paper to illustrate our method. The key techniques of this method such as the identification of D2 barrels, supragranular (L2-3) and barrel layer (L4) in real-time were described in details. The feasibility of this approach was further verified by compendious report of results and our previous study regarding cortical plasticity comparison between adolescent and mature rats.
神经网络可塑性是学习和记忆的基础。其异常变化是一些神经疾病的根源。测量皮层可塑性有助于理解可塑性机制，并提供一种定量方法来观察自然衰老和神经退行性疾病的神经过程，这可能会带来一种评估抗衰老药物的新方法以及神经退行性疾病的新治疗方法。在本研究中，基于触须配对（WP）实验建立了一种系统方法来测量大鼠桶状皮层中的网络可塑性。WP实验是一项经典实验，用于研究在清醒且行为活跃的大鼠中，特定时间段内来自触须的感觉活动流的无害偏差对初级体感皮层（S1）桶状皮层神经元感受野组织的影响。在实验中，一对相邻的触须D2和D3保持完整，而在特定时间段内其他触须被修剪。之后，在WP进行若干天后，通过刺激后时间直方图分析对侧桶状区单个细胞的感受野，并与对照组进行比较。在对照组中，对周围触须D1和D3偏转的反应幅度没有显著差异。然而，在WP之后，相对于相对的修剪后的周围触须D1，对配对的周围触须D3的反应出现了偏差。在本研究中，通过比较WP后不同组大鼠的偏差程度，建立了一种比较皮层可塑性的定量方法。本文采用了青春期和成年大鼠皮层可塑性比较的实例来说明我们的方法。详细描述了该方法的关键技术，如实时识别D2桶、颗粒上层（L2 - 3）和桶状层（L4）。通过简洁的结果报告以及我们之前关于青春期和成年大鼠皮层可塑性比较的研究，进一步验证了该方法的可行性。
