Effects of V1 feedback on LGN function

V1 反馈对 LGN 功能的影响

• 批准号: 7045997
• 负责人: EHUD KAPLAN
• 金额: $ 41.38万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7045997
• 关键词: Macaca fascicularis; lateral geniculate body; neural information processing; retina; visual cortex; visual feedback; visual pathways; visual phototransduction

DESCRIPTION (provided by applicant): The long range goal of our research is to understand how thalamic neurons integrate their various feedforward and feedback inputs, and what role these inputs play in the flow of information from retina to cortex through the thalamus. Most of the inputs and synapses in the mammalian lateral geniculate nucleus (LGN) are extraretinal, but the way in which these diverse inputs are integrated to control the flow of visual information from retina to cortex is not understood. In particular, the influence of the descending inputs from the cortex and the perigeniculate nucleus (PGN) on the spatio-temporal properties of receptive fields of LGN relay neurons is unknown. To address this gap in our knowledge, we shall study the temporal and spatial aspects of receptive fields in monkey LGN before and during inactivation of the cortical feedback to the LGN. The dynamical properties will be probed with a double m-sequence stimulation paradigm, which will provide new information about both the linear and non-linear dynamics of these neurons, and will expose the effects that the feedback from V1 has on this dynamical behavior. Our hypothesis is that the corticofugal feedback to the LGN has a significant effect on four specific aspects of LGN function: dynamics, receptive field organization, transmission from retina to cortex and response gain. The proposed studies will furnish new information about the effects of the corticofugal pathway on several important dynamical and spatial parameters of the receptive fields of LGN relay cells. These findings will extend and deepen our understanding of the function of this massive yet elusive neural pathway, and pave the way for realistic modeling of the early stages of the visual system. Because such descending pathways are ubiquitous in the brain, the findings are likely to relevant to other reciprocally connected brain regions.

描述(申请人提供)：我们研究的长期目标是了解丘脑神经元如何整合它们的各种前馈和反馈输入，以及这些输入在通过丘脑从视网膜到皮质的信息流中扮演什么角色。哺乳动物外侧膝状核(LGN)中的大部分输入和突触是在视网膜外的，但这些不同的输入是如何整合以控制视觉信息从视网膜到皮质的流动的方式尚不清楚。特别是，皮质和周围核(PGN)的下行输入对LGN中继神经元感受野的时空特性的影响尚不清楚。 为了解决我们知识中的这一差距，我们将研究猴子LGN中感受野的时间和空间方面，在去激活对LGN的皮质反馈之前和期间。动力学特性将用双m序列刺激范式来探索，这将提供关于这些神经元的线性和非线性动力学的新信息，并将揭示来自V1的反馈对这种动力学行为的影响。我们的假设是，对LGN的皮质分离反馈对LGN功能的四个具体方面有显著影响：动力学、感受野组织、从视网膜到皮质的传递和反应获得。 所提出的研究将提供有关皮质分离通路对LGN中继细胞感受野的几个重要动力学和空间参数的影响的新信息。这些发现将扩大和加深我们对这一庞大但难以捉摸的神经通路功能的理解，并为视觉系统早期阶段的逼真建模铺平道路。由于这种下行通路在大脑中普遍存在，这一发现很可能与大脑其他相互连接的区域相关。