Demontis Gian Carlo, Sbrana Andrea, Gargini Claudia, Cervetto Luigi
Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, I-56126 Pisa, Italy.
J Neurosci Methods. 2005 Jul 15;146(1):13-21. doi: 10.1016/j.jneumeth.2005.01.007.
Investigating the properties of light responsive neurons and their networks requires appropriate control of stimulus parameters, such as intensity, spectral composition, spatial and temporal profile. In the present paper, we describe how to build a simple, versatile and low-cost light source for use in visual neuroscience. The light source is a InGaN-based ultrabright light-emitting diode (LED), which may generate conventional light flashes as well as a variety of time varying stimuli to be used in quantitative studies of the visual system. In particular, with this instrument one may generate light stimuli sinusoidally modulated in time at frequencies ranging from 0.05 to 50 Hz, with less than 1% harmonic distortion at a contrast exceeding 85%. The relationship between applied voltage and energy emitted by the source is linear over an intensity range that exceeds 4.5 log-units, up to the full suppression of the light-sensitive currents in mammalian rods. The light source has minimal space requirement and does not generate appreciable radiating heat and hum, allowing its use for single cell work "in vitro" as well as for "in vivo" recording of the electroretinogram (ERG).
研究光响应神经元及其网络的特性需要对刺激参数进行适当控制，如强度、光谱组成、空间和时间分布。在本文中，我们描述了如何构建一个简单、通用且低成本的光源，用于视觉神经科学研究。该光源是基于氮化铟镓的超亮发光二极管（LED），它可以产生传统的光脉冲以及各种随时间变化的刺激，用于视觉系统的定量研究。特别是，使用该仪器可以产生频率范围从0.05到50Hz的时间正弦调制光刺激，在对比度超过85%时谐波失真小于1%。在超过4.5个对数单位的强度范围内，光源施加的电压与发射的能量之间呈线性关系，直至完全抑制哺乳动物视杆细胞中的光敏感电流。该光源占用空间最小，不会产生明显的辐射热和嗡嗡声，可用于“体外”单细胞研究以及视网膜电图（ERG）的“体内”记录。
