How does covert attention modulate visual perception? Psychophysics, neurostimulation and neuroimaging

项目摘要 隐蔽的空间注意是一个选择性的过程，它过滤输入的信息。考虑到皮质醇的高昂成本 在计算方面，这种机制对于优化资源管理是必要的。研究的重点是 外源性(非自愿；自下而上)和内源性(自愿；自上而下)注意的皮层执行 通常在注意调节中涉及额叶和顶叶区域，在枕叶区域也有类似的影响。 尽管一些功能磁共振研究表明早期视觉区域和隐蔽注意力之间存在联系，但功能磁共振成像记录 但不能操控大脑功能，留下了关于因果关系的问题没有得到回答。另外， 关于外源性的、自下而上的、对额叶的调节作用的研究还很缺乏。行为上的差异 这两个隐蔽的注意系统之间也有报道。在提高空间分辨率的任务中 不利于表现，外源性注意会损害表现，但内源性注意总是 提高性能。使用选择性适应，研究表明，与内源性注意不同 灵活地增加或降低空间分辨率，外源性注意总是提高分辨率。 这些结果表明，这两种隐蔽注意系统都可能将视觉表征改变为基本视觉 维度(例如，空间频率和对比度)以不同的方式。需要更多的实证性工作来 描述大脑皮质的计算和负责注意调节的区域。 解决这些问题需要一个创新的研究计划，将基于模型的 心理物理方法、无创脑刺激(TMS)和人类电生理学。我的 到目前为止，论文工作使用了基于模型的心理物理学和TMS来检验假设：(1) 外源性注意通过提高目标方位和空间的增益来改变感觉调谐 频率大于目标；(2)早期视觉区域的短暂干扰(通过TMS)将减少 外源性注意对绩效带来的好处和代价。这项工作已经产生了几个 重大成果和产生的后续问题，我将在拟议的研究计划中解决这些问题。去做 因此，我将使用计算建模和反向相关来测试表示层上的差异 两个隐蔽的注意力系统之间。此外，在功能磁共振成像引导下的TMS我将测试功能 枕区和额区在内源性和外源性注意对成绩影响中的作用。这 经验将提供基于模型的心理物理学、神经解剖学和功能磁共振成像引导的TMS的培训。在 拟议的博士后培训阶段，我将接受人类理论和方法方面的培训 电生理学将把时间动力学引入我的研究。这样的组合 实验和方法有可能产生极具影响力的发现和新的研究路线，如 并为涉及注意力相关障碍康复的研究提供信息。

Project Summary Covert spatial attention is a selective process that filters incoming information. Given the high cost of cortical computation, such a mechanism is needed for optimal management of resources. Studies focused on the cortical implementation of exogenous (involuntary; bottom-up) and endogenous (voluntary; top-down) attention often implicate frontal and parietal areas in attentional modulation and assume similar effects in occipital areas. Though a handful of fMRI studies suggest a link between early visual areas and covert attention, fMRI records but does not manipulate brain function, leaving questions regarding causality unanswered. Additionally, research implicating exogenous, bottom-up, modulations to frontal areas is lacking. Behaviorally, differences between both covert attention systems have also been reported. In tasks for which increasing spatial resolution is detrimental to performance, exogenous attention impairs performance, but endogenous attention always improves performance. Using selective adaptation, studies have revealed that unlike endogenous attention which flexibly increases or decreases spatial resolution, exogenous attention always increases resolution. These results suggest that both covert attention systems may alter visual representations to basic visual dimensions (e.g. spatial frequency and contrast) in a differential way. More empirical work is needed to delineate the cortical computations and regions responsible for attentional modulations in performance. Addressing these questions requires an innovative research program that integrates model-based psychophysical approaches, non-invasive brain stimulation (TMS) and human electrophysiology. My dissertation work so far has employed model-based psychophysics and TMS to test the hypotheses that: (1) exogenous attention alters sensory tuning by boosting the gain of the target orientation along with spatial frequencies greater than the target; (2) a brief disruption (via TMS) of early visual areas would diminish benefits and costs on performance brought about by exogenous attention. This work has produced several significant results and generated follow-up questions that I will address in the proposed research plan. To do so, I will use computational modeling and reverse correlation to test differences at the level of representation between both covert attention systems. Additionally, with the help of fMRI guided TMS I will test the functional role of occipital and frontal areas in endogenous and exogenous attention’s effect on performance. This experience will provide training in model-based psychophysics, neuroanatomy, and fMRI guided TMS. In the proposed postdoctoral training phase, I will gain theoretical and methodological training in human electrophysiology which will introduce temporal dynamics into my research. Such a combination of experiments and methods has the potential to generate highly impactful findings and novel lines of research as well as inform studies involved in the rehabilitation of attention related disorders.