Perceptual And Motor Decisions In The Primate Brain

灵长类动物大脑的感知和运动决策

• 批准号: 7734619
• 负责人: Kirk G Thompson
• 金额: $ 141.7万
• 依托单位: NATIONAL EYE INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7734619
• 关键词: Accounting; Address; Affect; Attention; Behavior; Behavioral; Brain; Brain region; Choice Behavior; Cognitive; Cues; Discrimination; Disease; Exhibits; Eye; Eye Movements; Goals; Human; Individual; Knowledge; Lead; Location; Manuals; Measures; Mediating; Memory; Modeling; Monkeys; Motor; Movement; Neurons; Output; Perception; Photic Stimulation; Physiological; Prefrontal Cortex; Primates; Process; Production; Reaction Time; Reporting; Role; Saccades; Sensory; Signal Transduction; Spike Potential; Staging; Stimulus; Synapses; System; Testing; Time; Training; Visual; Visual Perception; Visual attention; Visuospatial; Work; base; cognitive neuroscience; design; experience; frontal eye fields; neurophysiology; oculomotor; relating to nervous system; research study; response; visual information; visual search; visual stimulus

One of the outstanding questions of cognitive neuroscience is how we are able to focus visual attention on specific objects and locations without moving our eyes. To this end, we have been investigating the role of the frontal eye field (FEF) in visual perception. The FEF is located in the prefrontal cortex and participates in the transformation of visual information into commands to move the eyes. Multiple lines of evidence suggest that developing oculomotor commands originating from the FEF mediate visual spatial attention. In ref. 1 we simultaneously recorded local field potentials (LFPs) and spiking activity in the FEF of monkeys performing memory-guided saccade and covert visual search tasks in the absence of eye movements. We compared visual latencies and the time course of spatially selective responses in LFP and spiking activity. Consistent with the view that LFPs represent synaptic input, visual responses appeared first in the LFPs followed by visual responses in the spiking activity. However, spatially selective activity identifying the location of the target in the visual search array appeared in the spikes about 30 ms before it appeared in the LFPs. Because LFPs reflect dendritic input and spikes measure neuronal output in a local brain region, this temporal relationship suggests that spatial selection necessary for attention and eye movements is computed locally in FEF from spatially nonselective inputs. In ref. 2 we addressed the question of how cognitive processes control spatial attention in the absence of visual input. We recorded FEF activity in monkeys trained to perform a difficult discrimination task in which the monkeys attended the locations of the visual stimuli to be discriminated before they actually appeared. We found that most FEF neurons exhibited elevated activity when a cue informed the monkey that a stimulus would appear. This anticipatory attention-related activity in FEF occurred without any visual stimulation and was not related to motor processes. Together, these studies demonstrate that stimulus-driven and cognitively-driven spatial attention signals are present in FEF and are independent of saccade command signals. Therefore, FEF probably serves an important role in controlling visual spatial attention in addition to its well known role in saccade production. In ref. 3 we examined whether the reliability of the neural representation of the salient target location predicted the monkeys accuracy of reporting target location. We found that FEF neurons reliably encoded the location of the target stimulus not only on correct trials, but also on error trials. The representation of target location in FEF persisted until the manual behavioral report but did not increase in magnitude. These results provide physiological evidence that under certain circumstances, accurate perceptual representations do not always lead to accurate behavioral reports and that variability in processes outside of perception must be considered to account for the variability in perceptual choice behavior. In ref 4 we examined how information flows between perceptual and motor processing stages in the brain. Most models assume that response time comprises the time required for successive processing stages, but they disagree about whether information is transmitted continuously or discretely between stages. We tested these alternative hypotheses by measuring when movement-related activity began in the FEF of monkeys performing visual search tasks of varying difficulty. We found that the buildup of saccadic movement-related activity in FEF is delayed in inefficient visual search and variability in the delay of this activity accounted for the variability in reaction time. These findings provide neurophysiological support for the hypothesis that information is transmitted discretely between perceptual and motor stages of processing. These studies have extended our understanding about the frontal eye field far beyond its familiar role in controlling eye movements. With this knowledge we can design experiments to investigate the flow of sensory information through the brain as it is transformed into perception and action. This work helps us understand the mechanisms of how the brain focuses attention to make perceptual decisions and guide behavior, which is necessary to be able to understand and treat attention-related disorders in humans.

认知神经科学的杰出问题之一是，我们能够在不动眼睛的情况下将视觉注意力集中在特定对象和位置上。为此，我们一直在研究额眼场（FEF）在视觉感知中的作用。 FEF位于前额叶皮层中，参与将视觉信息转换为命令以移动眼睛的情况。多种证据表明，开发源自FEF的动眼命令介导了视觉空间的关注。 在参考1我们同时记录了在没有眼动动作的情况下执行记忆引导的扫视和秘密视觉搜索任务的猴子FEF中的局部田间电位（LFP）和尖峰活动。我们比较了视觉潜伏期和LFP和尖峰活动中空间选择性响应的时间过程。 与LFP表示突触输入的观点一致，LFP中首先出现视觉响应，然后在峰值活动中进行视觉响应。 但是，在空间选择性的活动中识别目标在视觉搜索阵列中的位置，出现在尖峰中，然后出现在LFPS中。 由于LFP反映了树突状输入和尖峰测量局部大脑区域中的神经元输出，因此这种时间关系表明，注意力和眼球运动所需的空间选择是通过空间非选择性输入在FEF中本地计算的。 在参考2我们解决了在没有视觉输入的情况下认知过程如何控制空间注意力的问题。我们记录了经过训练的猴子中的FEF活动，以执行一项困难的歧视任务，其中猴子参加了视觉刺激的位置，然后才能真正出现。我们发现，当一个提示告诉猴子会出现刺激时，大多数FEF神经元表现出升高的活性。 FEF中的这种预期注意力相关的活性发生在没有任何视觉刺激的情况下，与运动过程无关。这些研究共同表明，FEF中存在刺激驱动和认知驱动的空间注意力信号，并且独立于扫视命令信号。因此，除了其在扫视生产中的众所周知的作用外，FEF可能在控制视觉空间注意力方面发挥着重要作用。 在参考3我们检查了显着目标位置的神经表示的可靠性是否预测了报告目标位置的准确性。我们发现，FEF神经元不仅在正确试验中，而且在错误试验中可靠地编码了目标刺激的位置。 FEF中目标位置的表示一直持续到手动行为报告，但幅度没有增加。这些结果提供了生理证据，表明在某些情况下，准确的感知表示并不总是会导致准确的行为报告，并且必须考虑考虑感知之外的过程的变异性来说明感知选择行为的可变性。 在参考文献4中，我们研究了大脑感知和运动处理阶段之间的信息如何流动。 大多数模型都认为响应时间包括连续处理阶段所需的时间，但他们不同意信息在阶段之间是否连续还是离散地传输。 我们通过测量与运动相关的活动何时在执行不同难度的视觉搜索任务的FEF中开始测量与运动相关的活动来检验这些替代假设。 我们发现，FEF中与Saccadic运动相关的活动的积累延迟的视觉搜索效率低下和此活动的延迟差异造成了反应时间的可变性。 这些发现提供了神经生理学的支持，即信息在处理的感知阶段和运动阶段之间传递信息。 这些研究扩展了我们对额眼场的理解，远远超出了其在控制眼动运动中熟悉的作用。有了这些知识，我们可以设计实验，以研究感觉信息通过大脑转化为感知和动作的流动。这项工作有助于我们了解大脑如何将注意力集中在做出感知决策和指导行为的机制，这对于能够理解和治疗人类的注意力相关的疾病是必不可少的。