CORTICAL SUBSTRATES OF VISUAL SHORT TERM MEMORY

本研究的目的是检测其特性和神经功能。 基材的临时存储机构必须确保 主动观察者视觉刺激的连续性。我们用 生理鉴定的心理物理测量和损伤 猕猴选定的纹外皮质区的区域 探索这些皮质区域在存储 视觉刺激的基本特征，其运动方向。 在过去的一年里，我们进行了许多不是 只是对短期感觉的机制提供了新的见解 存储，但也建议和指出新的心理物理工具 积极观察者的短期记忆研究。(1)我们发现 低水平和高水平运动刺激的保持能力随时间下降 对于这两种运动类型是相似的，并且在 存在运动噪声。这一结果表明，这个过程 方向信息的底层临时存储对于 这两种类型的运动。它还指出了 编码和存储网络中的抑制性相互作用 感官信息。(2)使用被噪声掩盖的运动刺激 也让我们发现了MT和MST区域的选择性贡献 到动作处理。MT/MST的病变产生了巨大的、永久性的 仅用运动刺激辨别方向的缺陷 被噪音掩盖了。(3)我们最近发现MT/MST区的病变 严重限制了关于运动方向的信息的保留。 如果得到确认，这一结果将首次证明 暂时性储存中中间视觉皮质区域的参与 视觉信息。这些研究提供了一个重要的联系 在涉及扫视条件下的显示更新的实验之间 (Hayhoe，Pelz和Ballard)和心理物理学研究 脑部病变(Merigan)。特别是，我们计划使用噪音掩蔽， 这让我们发现了许多临时的 储存机制在活动性人类短时记忆研究中的应用 观察者执行视觉记忆任务。此外，发现了 存在方向性噪声时的运动知觉缺陷 并在MT/MST损伤后的短期记忆中提示了一些新的 研究人类大脑皮层损伤影响的任务。

This research is aimed at examining the properties and the neural substrate of the temporary storage mechanism necessary to ensure continuity of visual stimulation of an active observer. We use psychophysical measures and lesions of physiologically identified regions in selected extrastriate cortical areas in macaque monkeys to explore the role of these cortical areas in storing one of the fundamental features of the visual stimulus, its direction of motion. During the past year we performed a number of experiments that not only provide new insights into the mechanisms of short-term sensory storage but also suggest and point to new psychophysical tools for the study of short-term memory of active observers. (1) We found that the decline in retention of low- and high-level motion stimuli with time is similar for the two types of motion and is accelerated in the presence of motion noise. This result suggests that the process underlying temporary storage of direction information may be common to the two types of motion. It also points to the existence of inhibitory interactions within the networks encoding and storing sensory information. (2) The use of motion stimuli masked by noise also allowed us to uncover selective contribution of areas MT and MST to motion processing. Lesions of MT/MST produced a large, permanent deficit in the discrimination of direction only with motion stimuli masked by noise. (3) We recently found that lesions of areas MT/MST severely limit the retention of information about motion direction. If confirmed, this result for the first time demonstrates the involvement of intermediate visual cortical areas in temporary storage of visual information. These studies provide an important link between the experiments involving saccade-contingent display updating (Hayhoe, Pelz and Ballard) and psychophysical studies of patients with brain lesions (Merigan). In particular, we plan to use noise masking, which allowed us to uncover many of the properties of the temporary storage mechanism, in the study of short-term memory of active human observers performing visual memory tasks. Moreover, the finding of the deficit in motion erception in the presence of directional noise and in short-term memory after MT/MST lesions suggests a number of new tasks for the study of the effects of cortical lesions in humans.