Thalamocortical Architecture of a Visual Cortex Without Orientation Columns

没有方向柱的视觉皮层的丘脑皮质结构

• 批准号: 8803130
• 负责人: HARVEY A SWADLOW
• 金额: $ 38.87万
• 依托单位: UNIVERSITY OF CONNECTICUT STORRS
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-01 至 2017-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8803130
• 关键词: Address; Affect; Architecture; Biological Neural Networks; Cells; Environment; Family Felidae; Felis catus; Goals; Inherited; Interneurons; Knowledge; Light; Measures; Methods; Nature; Neurons; Oryctolagus cuniculus; Pathology; Primates; Property; Retinal; Rodent; Stimulus; Structure; Thalamic structure; V1 neuron; Vision; Vision research; Visual; Visual Cortex; Visual Perception; Work; awake; cell type; orientation columns; orientation selectivity; preference; public health relevance; receptive field; relating to nervous system; research study; visual stimulus

DESCRIPTION (provided by applicant): A major goal of the proposed work is to better understand how thalamocortical inputs to rabbit visual cortical (V1) neurons contribute to the synthesis of the diverse receptive fields properties seen in the input layers of V1. In both layers 4 and 6, these include (a) "simple" cells with highly oriented and directional receptive fields composed of separate parallel ON and/or OFF sub-zones, and (b) putative fast spike inhibitory interneurons (SINs) with overlapping ON-OFF, receptive fields that lack significant orientation/direction selectivity. While considerable work has been done on these questions for simple cells in layer 4 of feline V1, little is known about receptive field synthesis in V1 of rabbts and rodents, and the nature of the thalamocortical contribution to this synthesis. V1 of rabbits and rodents is similar to that of carnivores and primates in having many "simple" cells that are highly selective for the orientation of a visual stimulus. However, unlike carnivores and primates, rabbits and rodents lack orientation columns. Moreover, their visual thalamus (LGN) contains neurons that provide directional and orientation information directly to V1. Whereas in cats and primates, orientation and directional selectivity are thought to be synthesized within V1, in rabbits and rodents these properties could potentially be inherited from the thalamus. The proposed experiments will address this question directly, in both layers 4 and 6. We will record from different cell types in the LGN of awake rabbits, some of which have directional and or orientation selective receptive fields. We will make simultaneous recordings from simple cells and SINs in the input layers (4 and 6), the simple cells being highly tuned for orientation/direction, the SINs being poorly tuned. We will use cross-correlation methods to see which LGN cells make functional contacts with which cortical cells. Our preliminary results suggest that layer 4 simple cells do not inherit their orientation/directional preference from LGN directional selective neurons. Therefore, the orientation preference of layer 4 simple cells may be largely created from the receptive field arrangement of ON and OFF LGN afferents, as in the cat. Alternatively, it may be inherited from LGN inputs with concentric receptive fields that show an orientation bias. By measuring the receptive field properties of the LGN inputs to a L4 cortical simple cell, our experiments will be able to distinguish between these two possible mechanisms.

描述（由申请人提供）：所提议工作的一个主要目标是更好地理解兔视觉皮层（V1）神经元的丘脑皮层输入如何有助于 V1 输入层中看到的不同感受野属性的合成。在两层中 如图4和图6所示，这些包括(a)具有由单独的平行ON和/或OFF子区组成的高度定向和定向感受野的“简单”细胞，以及(b)具有重叠ON-OFF感受野的推定的快速尖峰抑制中间神经元(SIN)，其缺乏显着的定向/方向选择性。虽然针对猫科动物 V1 第 4 层的简单细胞的这些问题已经做了相当多的工作，但对于兔子和啮齿动物 V1 中的感受野合成以及丘脑皮质对这种合成的贡献的性质知之甚少。兔子和啮齿动物的 V1 与食肉动物和灵长类动物的 V1 相似，具有许多“简单”细胞，这些细胞对视觉刺激的方向具有高度选择性。然而，与食肉动物和灵长类动物不同， 兔子和啮齿动物缺乏定向柱。此外，它们的视觉丘脑 (LGN) 包含直接向 V1 提供方向和方位信息的神经元。在猫和灵长类动物中，方向和方向选择性被认为是在 V1 内合成的，而在兔子和啮齿动物中，这些特性可能是从丘脑遗传的。所提出的实验将在第 4 层和第 6 层中直接解决这个问题。我们将记录清醒兔子 LGN 中的不同细胞类型，其中一些细胞具有定向和/或方向选择性感受野。我们将从输入层（4 和 6）中的简单单元和 SIN 进行同步记录，简单单元的方向/方向经过高度调整，而 SIN 的调整较差。我们将使用互相关方法来查看哪些 LGN 细胞与哪些皮质细胞进行功能性接触。我们的初步结果表明，第 4 层简单细胞不会从 LGN 定向选择性神经元继承其方向/方向偏好。因此，第 4 层简单细胞的方向偏好可能很大程度上是由 ON 和 OFF LGN 传入的感受野排列产生的，就像猫一样。或者，它可能继承自具有显示方向偏差的同心感受野的 LGN 输入。通过测量 L4 皮质 LGN 输入的感受野特性 简单的细胞，我们的实验将能够区分这两种可能的机制。