Application of voltage-sensitive dye imaging in VI

电压敏感染料成像在VI中的应用

• 批准号: 6903354
• 负责人: MATTEO CARANDINI
• 金额: $ 25.36万
• 依托单位: SMITH-KETTLEWELL EYE RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6903354
• 关键词: bioimaging /biomedical imaging; cats; electrical potential; electroencephalography; electrophysiology; evoked potentials; fluorescent dye /probe; imaging /visualization /scanning; lateral geniculate body; membrane potentials; nontherapeutic iontophoresis; technology /technique development; visual cortex; visual pathways

DESCRIPTION (provided by applicant): Optical imaging methods based on voltage-sensitive dyes (VSD) allow one to monitor the activity of entire neuronal populations concurrently. Thanks to newly developed dyes and advanced cameras, this technique affords high spatiotemporal resolution and high signal/noise ratios. While current methods of VSD imaging have resulted in substantial advances in our understanding of primary visual cortex (V1), these methods can be further enhanced (Aim 1), and applied to new areas of inquiry (Aim 2). The first aim is to develop methods of stimulation and data analysis that will increase signal/noise ratio and allow a broader range of measurements. In preliminary measurements, we found that the power distribution of the physiological noise in VSD measurements is concentrated at low frequencies. Noise power decreases with frequency. Traditional methods of stimulation in VSD experiments evoke responses at low frequencies - not an optimal choice. Instead, I propose to employ stimuli that evoke responses oscillating at high frequencies, where they are well clear of the noise. We will test whether indeed these methods are more efficient than the traditional ones, and if they afford increased spatiotemporal resolution. Along these lines, I also propose to apply to VSD imaging powerful methods of white-noise analysis originally developed for electrophysiological techniques. In particular, I propose to obtain maps of orientation preference using white noise in the orientation domain and maps of retinotopy using multi-focal m-sequences. These techniques will allow us to measure the evolution of orientation selectivity in time, and the complex interactions between different retinotopic locations. The second aim is to apply VSD imaging to the study of functional connectivity between brain regions. We can achieve this by stimulating or recording electrically in one region, while obtaining event-triggered maps with VSD imaging in the other region. I propose to develop this method and to apply it to the functional connectivity between lateral geniculate nucleus (LGN) and V1. To develop event-triggered VSD imaging, at first we will concentrate on extremely large electrical events: induced interictal events similar to those seen in epilepsy. We will induce these events with focal iontophoresis in V1 of gabazine, a selective GABAA antagonist. Then, we will measure event-triggered maps corresponding to activity in LGN. Activity in LGN can be induced electrically, or through visual stimulation, or can be spontaneous. The resulting spike-triggered maps of VSD signals in V1 will reflect and illuminate the rules of connectivity between LGN and V1. These methods ultimately blur the distinction between anatomy and physiology. If successful, they could in principle be applied to any pair of brain regions, as long as one of them is on the surface of the brain.

描述（由申请人提供）：基于电压敏感染料（VSD）的光学成像方法允许同时监测整个神经元群的活动。得益于新开发的染料和先进的相机，该技术提供了高时空分辨率和高信噪比。虽然当前的 VSD 成像方法已经使我们对初级视觉皮层 (V1) 的理解取得了实质性进展，但这些方法可以进一步增强（目标 1），并应用于新的研究领域（目标 2）。第一个目标是开发刺激和数据分析方法，以提高信号/噪声比并允许更广泛的测量。在初步测量中，我们发现VSD测量中生理噪声的功率分布集中在低频。噪声功率随频率而降低。 VSD 实验中的传统刺激方法会引起低频反应，这不是最佳选择。相反，我建议采用激发高频振荡反应的刺激，这样它们就可以完全消除噪音。我们将测试这些方法是否确实比传统方法更有效，以及它们是否能够提供更高的时空分辨率。沿着这些思路，我还建议将最初为电生理技术开发的强大的白噪声分析方法应用于 VSD 成像。特别是，我建议使用方向域中的白噪声来获取方向偏好图，并使用多焦 m 序列来获取视网膜局部图。这些技术将使我们能够测量方向选择性随时间的演变，以及不同视网膜位置之间的复杂相互作用。第二个目标是将 VSD 成像应用于研究大脑区域之间的功能连接。我们可以通过在一个区域进行电刺激或记录，同时在另一区域通过 VSD 成像获得事件触发图来实现这一点。我建议开发这种方法并将其应用于外侧膝状核 (LGN) 和 V1 之间的功能连接。为了开发事件触发的 VSD 成像，首先我们将专注于极大的电事件：类似于癫痫中所见的诱发间期事件。我们将通过 Gabazine（一种选择性 GABAA 拮抗剂）V1 的局灶离子电渗疗法来诱导这些事件。然后，我们将测量与 LGN 中的活动相对应的事件触发图。 LGN 的活动可以通过电或视觉刺激诱导，也可以是自发的。由此产生的 V1 中 VSD 信号的尖峰触发图将反映并阐明 LGN 和 V1 之间的连接规则。这些方法最终模糊了解剖学和生理学之间的区别。如果成功的话，原则上它们可以应用于任何一对大脑区域，只要其中一个位于大脑表面。