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

项目摘要 内隐空间注意是一种对输入信息进行过滤的选择性过程。考虑到皮质骨的高成本 计算，需要这样的机制来优化资源管理。研究主要集中在 皮层执行外源性（非自愿的;自下而上）和内源性（自愿的;自上而下）注意 通常涉及额叶和顶叶区域的注意力调节，并假设在枕叶区域类似的效果。 尽管少数功能性磁共振成像研究表明，早期视觉区域和内隐注意力之间存在联系，但功能性磁共振成像记录显示， 但并不操纵大脑功能，留下关于因果关系的问题没有答案。此外，本发明还 目前还缺乏关于额叶区域受到外源性、自下而上的调节的研究。行为上，差异 这两种注意力系统之间的联系也有报道。在增加空间分辨率的任务中， 外源性注意损害绩效，但内源性注意总是 提高性能。使用选择性适应，研究表明，与内源性注意力不同， 它灵活地增加或减少空间分辨率，外源性注意总是增加分辨率。 这些结果表明，这两个内隐注意系统可能会改变视觉表征的基本视觉 以不同的方式测量维度（例如空间频率和对比度）。需要更多的实证工作， 描绘了大脑皮层的计算和区域负责注意力的调制性能。 解决这些问题需要一个创新的研究计划， 心理物理学方法，非侵入性脑刺激（TMS）和人体电生理学。我 迄今为止，本论文的工作主要是利用基于模型的心理物理学和经颅磁刺激来检验以下假设：（1） 外源性注意力通过提高目标方位的增益来改变感觉调谐，沿着增加空间方位， 频率大于目标;（2）早期视觉区域的短暂中断（通过TMS）将减少 外生注意力带来的绩效收益和成本。这项工作产生了几个 重要的结果和产生的后续问题，我将在拟议的研究计划中解决。做 因此，我将使用计算建模和反向相关来测试表征水平上的差异 两种内隐注意力系统之间的联系此外，在功能磁共振成像引导的TMS的帮助下，我将测试功能性 枕区和额叶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培训。在 建议博士后培训阶段，我将获得理论和方法的培训，在人类 将时间动力学引入我的研究的电生理学。的这种组合 实验和方法有可能产生非常有影响力的发现和新的研究路线， 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.