Ranganathan Gayathri Nattar, Koester Helmut J
Section of Neurobiology, Center for Learning and Memory, The University of Texas at Austin, USA.
J Vis Exp. 2012 Sep 5(67):e4052. doi: 10.3791/4052.
Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also propagation of suprathreshold spiking activity involves populations of neurons. Empirical studies addressing cortical function directly thus require recordings from populations of neurons with high resolution. Here we describe an optical method and a deconvolution algorithm to record neural activity from up to 100 neurons with single-cell and single-spike resolution. This method relies on detection of the transient increases in intracellular somatic calcium concentration associated with suprathreshold electrical spikes (action potentials) in cortical neurons. High temporal resolution of the optical recordings is achieved by a fast random-access scanning technique using acousto-optical deflectors (AODs). Two-photon excitation of the calcium-sensitive dye results in high spatial resolution in opaque brain tissue. Reconstruction of spikes from the fluorescence calcium recordings is achieved by a maximum-likelihood method. Simultaneous electrophysiological and optical recordings indicate that our method reliably detects spikes (>97% spike detection efficiency), has a low rate of false positive spike detection (< 0.003 spikes/sec), and a high temporal precision (about 3 msec). This optical method of spike detection can be used to record neural activity in vitro and in anesthetized animals in vivo.
在脊椎动物中枢神经系统中，信息传递通常由神经元群体而非单个神经元来完成。此外，阈上峰电位活动的传播也涉及神经元群体。因此，直接研究皮层功能的实证研究需要对神经元群体进行高分辨率记录。在此，我们描述一种光学方法和一种反卷积算法，以单细胞和单峰分辨率记录多达100个神经元的神经活动。该方法依赖于检测与皮层神经元阈上电峰电位（动作电位）相关的细胞内体钙浓度的瞬时增加。通过使用声光偏转器（AOD）的快速随机存取扫描技术实现光学记录的高时间分辨率。钙敏感染料的双光子激发在不透明脑组织中实现高空间分辨率。通过最大似然法从荧光钙记录中重建峰电位。同时进行的电生理和光学记录表明，我们的方法能可靠地检测峰电位（峰电位检测效率>97%），假阳性峰电位检测率低（<0.003个峰电位/秒），且时间精度高（约3毫秒）。这种峰电位检测的光学方法可用于在体外和麻醉动物体内记录神经活动。
