TWO CEREBRAL HEMISPHERES, ONE FOCUS OF ATTENTION

大量的证据，来自神经病理学，研究“分裂-- “大脑”患者，在正常受试者的“分割视野”研究中， 而现在从神经成像来看，都一致地表明了这一点- 给予个体初级神经元处理言语材料的能力 发生在左半球，而对视觉形式的分析通常 最初在右半球进行这种情况 “半球专业化”最有可能产生于 两个半球之间的交流受到非常有限的 前脑连合中的大多数神经纤维都很小， 使其更快地在半球内处理信息 而不是在两个半球之间来回穿梭。集中精力 在一个半球进行处理也一定意味着神经元 注意的促进作用在相关的大脑半球和 正如众所周知的那样，关注视觉空间，脱离这个 将注意力从一个轨迹集中到另一个轨迹上 相当长的时间。令人惊讶的是，这一时间成本 在大脑两个半球之间切换注意力从来没有过 有分寸，而且这项提议的目的是这样做。我们将使用 单词和非客观彩色图像的记忆，以点击每个 半球的分析性和因此专注性偏好，已经有了 在记忆过程中表现出高度的相似性 这两种不同类型的材料。反应时间的任何增加 作为将存储器需求从一个切换到另一个的结果 可以检测到材料的类型。这将使用分割的 文字或图像所指向的视场范式 最初到一个半球或另一个半球，并且“切换时间”可以 从而从半球间的其他方面解脱出来 沟通。知道这个切换时间及其属性应该 极大地促进了对认知事件的理解 共同要求两个半球的专业技能；而且它 似乎有可能定义这个时间的能力会很大 应用于评估各种认知障碍，包括 精神分裂症和阅读障碍。

A massive body of evidence, from neuropathology, studies of "split- brain" patients, of "divided visual field" studies in normal subjects, and now from neuroimaging, is all consistent in showing that in right- handed individuals the primary neuronal processing of verbal material takes place in the left hemisphere, while analysis of visual form often proceeds initially in the right hemisphere This situation of "hemispheric specialization" most likely accrues from the Act that communication between the hemispheres is constrained by the very small size of most of the nerve fibers in the forebrain commissures, making it much quicker to process information intrahemispherically than to shuttle back and forth between the hemispheres. Concentrating processing in one hemisphere must also mean that the neuronal facilitation of attention is "focussed" in the relevant hemisphere and that, as is well-known for attending to visual space, disengaging this attentive focus from one locus and concentrating it on another takes a measurable amount of time. Surprisingly, this temporal cost of switching attention between the cerebral hemispheres has never been measured, and it is the intent of this proposal to do so. We will use memory for words and for nonobjective colored images to tap each hemisphere's analytic and hence attentive predilection, already having shown the high degree of similarity in the mnemonic processing of these two disparate types of material. Any increment in reaction time consequent to switching the demands of memory from one to the other type of material can be detected. This will be done using a divided visual field paradigm in which the words or images are directed initially to one or the other hemisphere, and the "switching time" can thus be disentangled from other aspects of interhemispheric communication. Knowing this switching time and its properties should greatly advance understanding of cognitive events that draw upon or demand jointly the specialized skills of the two hemispheres; and it seems likely that the ability to define this time would have wide application in evaluating a variety of cognitive disturbances, including schizophrenia and dyslexia.