Neuronal mechanisms of cortical processing in early vision

早期视觉皮质处理的神经元机制

• 批准号: 9884766
• 负责人: Jose Manuel Alonso
• 金额: $ 40.5万
• 依托单位: STATE COLLEGE OF OPTOMETRY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-03-01 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9884766
• 关键词: Affect; Amblyopia; Animals; Automobile Driving; Brain; Cells; Chronic; Complex; Dimensions; Disease; Equilibrium; Eye; Felis catus; Frequencies; Goals; Human; Image; Knowledge; Light; Location; Mammals; Measurement; Measures; Mediating; Methods; Myopia; Neurons; Neurosciences; Output; Paper; Pathway interactions; Perception; Phase; Primates; Process; Property; Psychophysics; Research; Sampling; Signal Pathway; Signal Transduction; Spottings; Stimulus; Structure; Testing; Textbooks; Thalamic structure; Time; V1 neuron; Vision; Visual; Visual Acuity; Visual Cortex; Visual Fields; Visual Perception; Visual system structure; Work; area striata; awake; base; brain research; clinical application; design; fly; innovation; lens; luminance; multi-electrode arrays; novel; receptive field; response; temporal measurement; visual information; visual processing

PROJECT SUMMARY Visual information is transferred from the eye to the brain through ON and OFF pathways that signal the presence of light and dark features in visual scenes. ON and OFF pathways are present in all animals with image-forming visual-systems including flies and primates, however, we still have a poor understanding of how they interact in visual processing. While neuroscience textbooks describe ON and OFF pathways as sharing equal cortical space, recent work has demonstrated that the OFF pathway greatly dominates cortical responses. We hypothesize that this cortical OFF dominance originates from a difference in the contrast response function between ON and OFF pathways that we recently discovered. Because contrast saturation is more pronounced within the ON pathway, light stimuli are spatially distorted and less effective at driving cortical responses than dark stimuli, which causes the cortex to be OFF dominated. Because of this greater spatial distortion for lights, we predict that ON/OFF differences in contrast saturation will have major implications not only in cortical function but also in human visual perception and visual disease. Therefore, this proposal uses the differences in ON/OFF contrast saturation as a conceptual framework to predict and investigate how cortical OFF dominance changes under different stimulation conditions and the implications of these changes for the perception of lights and darks. Our conceptual framework predicts that cortical OFF dominance will increase when the image is out of focus either because of normal changes in lens accommodation (e.g. blurred background when fixating a target at close distance) or visual disease (e.g. amblyopia, myopia). In turn, cortical OFF dominance will decrease when seeing high spatial frequencies with high mean luminance, which are common outdoors. To test our predictions and investigate the dynamics of ON and OFF cortical function, we will measure the responses of cortical single neurons to dark and light targets under a large variety of stimulus conditions (e.g. different contrasts, spatial frequency, mean luminance, luminance distribution). We will then use the same stimulus conditions to measure changes in light/dark visual acuity and visual salience in humans. To fully characterize cortical responses of single neurons to multiple stimulus dimensions, we will use an innovative multielectrode array that we have been developing over the past years to record from well-isolated single neurons for prolonged periods of time. This novel technical approach allows us to obtain an unprecedented characterization of the stimulus space that modulates ON/OFF signaling by testing a large combination of stimulus conditions that could not be fully explored with previous methods.

项目摘要 视觉信息通过开关的路径从眼睛转移到大脑，以发出信号 在视觉场景中存在光和黑暗特征。所有动物中都存在和关闭路径 然而，包括苍蝇和灵长类动物在内的图像形成视觉系统，我们仍然对如何如何了解 他们在视觉处理中相互作用。而神经科学教科书则描述了分享道路和关闭路径 相等的皮质空间，最近的工作表明，偏离道路极大地占主导地位 回答。我们假设这种皮质的占主导地位源于对比的差异 我们最近发现的开路和关闭路径之间的响应功能。因为对比度饱和是 在途径中更明显，光刺激在空间上扭曲，驾驶有效性较小 皮质反应比黑暗刺激，这会导致皮质偏离主导。因此更大 灯的空间失真，我们预测对比饱和的开/关差异将具有重大 不仅对皮质功能，而且对人类视觉感知和视觉疾病的影响。因此，这个 建议使用ON/OFF对比度饱和的差异作为预测和的概念框架 调查在不同刺激条件下皮质偏离优势的变化以及 这些变化是灯光和黑暗的感知。我们的概念框架预测了皮质的脱节 当图像不集中时，优势将增加，因为镜头的正常变化 适应性（例如，在固定近距离固定目标时进行模糊的背景）或视觉疾病（例如 弱视，近视）。反过 高平均亮度，这是常见的户外。测试我们的预测并研究 在皮质功能上，我们将测量皮质单神经元对黑暗和光的响应 在各种刺激条件下的目标（例如，不同的对比度，空间频率，平均亮度， 亮度分布）。然后，我们将使用相同的刺激条件来测量光/深色视觉的变化 人类的敏锐度和视觉显着性。充分表征单神经元对多个的皮质反应 刺激尺寸，我们将使用我们一直在开发的创新多电极阵列 过去的几年记录了良好的单个神经元的长时间。这本小说的技术 方法使我们能够获得对开/关的刺激空间的前所未有的表征 通过测试大量的刺激条件组合来传导，这些刺激条件无法完全探索 方法。