Live imaging of second messengers in developing retina

长期目标是描述在发育中的哺乳动物视网膜中自发相关神经活动产生的细胞机制。在大脑发育的早期，在感觉体验成为可能之前，电和化学活动自发地在未成熟的神经系统中产生。越来越多的证据表明，这种早期活动对神经回路的适当发育至关重要。对支配人类神经系统正常发育的组织原理有了详细的了解，就有可能了解神经性先天缺陷的起源。此外，它将为设计策略提供关键的见解，使神经系统能够重新连接正常功能的神经回路，以应对发育异常，如

The long-term objective is to delineate the cellular mechanisms by which spontaneous correlated neural activity is generated in the developing mammalian retina. Very early in brain development, before sensory experience is possible, both electrical and chemical activity is generated spontaneously throughout the immature nervous system. There is growing evidence that this early activity is critical for the appropriate development of neural circuits. Developing a detailed understanding of the organizing principles that govern the normal development of the human nervous system may make it possible to understand the origin of neurological birth defects. In addition, it will provide critical insights into devising strategies that allow the nervous system to rewire normal functioning neural circuits in response to developmental abnormalities such as amblyopia (lazy eye). The cellular basis of spontaneous activity in the retina has been studied primarily by electrophysiology and calcium imaging. Spontaneous retinal activity is characterized by depolarizations that occur with a period on the order of minutes. Indeed, we can reproduce this slow periodicity in dissociated retina neurons, indicating that the pacemaker underlying this periodicity may be cell autonomous. Here we propose to test the hypothesis that this slow periodicity is set by oscillations in the second messenger, cAMP. The goals of this proposal are two fold. First, we propose to implement in retinal neurons the use of two indicators - one sensitive to levels of the second-messenger cAMP levels, and the second sensitive to activity of protein kinase-A. Second, we will then use these indicators to determine whether spontaneous oscillations in cAMP underlie the periodicity observed in both the intact retina as well spontaneously active networks formed by dissociated retinal neurons.