Shulman Robert G, Rothman Douglas L
Magnetic Resonance Research Center, Department of Radiology, Yale University School of Medicine, New Haven, CT, United States.
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States.
Front Hum Neurosci. 2019 Mar 11;13:28. doi: 10.3389/fnhum.2019.00028. eCollection 2019.
The dominant model for interpreting brain imaging experiments, which we refer to as the Standard Cognitive Model (SCM), assumes that the brain is organized in support of mental processes that control behavior. However, functional neuroimaging experiments of cognitive tasks have not shown clear anatomic segregation between mental processes originally proposed by this model. This failing has been blamed on limitations in imaging technology and non-linearity in the brain's implementation of these processes. However, the validity of the underlying cognitive models used to describe the brain has rarely been questioned or directly tested against imaging results. We propose an alternative model of brain function, that we term the Non-cognitive Behavioral Model (NBM), which correlates observed human behavior directly with measured brain activity without making assumptions about intervening cognitive processes. Our model derives from behavioral psychology but is extended to include brain activity, in addition to behavior, as observables. A further extension is the role of neuroplasticity, as opposed to innate cognitive processes, in developing the brain's support of cognitive behavior. We present the theoretical basis with which the SCM maps cognitive processes onto functional magnetic resonance and positron emission tomography images and compare and contrast with the NBM. We also describe how the NBM can be used experimentally to study how the brain supports behavior. Two applications are presented that support the usefulness of the NBM. In one, the NBM use of the total functional imaging signal (not just the differences between states) provides a stronger correlation of neural activity with the behavioral state of consciousness than the SCM approach in both anesthesia and coma. The second example reviews studies of facial and object recognition that provide evidence for the NBM proposal that neuroplasticity and experience play key roles in the brain's support of recognition and other behaviors. The conclusions regarding neuroplasticity are then generalized to explain the incomplete functional segregation observed in the application of the SCM to neuroimaging.
用于解释脑成像实验的主流模型，我们称之为标准认知模型（SCM），它假定大脑的组织方式是为了支持控制行为的心理过程。然而，认知任务的功能神经成像实验并未显示出该模型最初提出的心理过程之间存在清晰的解剖学分离。这种失败被归咎于成像技术的局限性以及大脑在执行这些过程时的非线性。然而，用于描述大脑的潜在认知模型的有效性很少受到质疑，也很少直接与成像结果进行对比测试。我们提出了一种脑功能的替代模型，我们称之为非认知行为模型（NBM），该模型将观察到的人类行为直接与测量到的大脑活动相关联，而无需对中间的认知过程做出假设。我们的模型源自行为心理学，但扩展到将大脑活动（除行为外）也作为可观测对象。进一步的扩展是神经可塑性的作用，与先天认知过程相对，它在大脑对认知行为的支持发展过程中发挥作用。我们阐述了SCM将认知过程映射到功能磁共振成像和正电子发射断层扫描图像上的理论基础，并与NBM进行比较和对比。我们还描述了如何通过实验使用NBM来研究大脑如何支持行为。给出了两个应用实例来支持NBM的实用性。在一个实例中，NBM对总功能成像信号的使用（不仅仅是状态之间的差异）在麻醉和昏迷状态下都比SCM方法提供了更强的神经活动与意识行为状态之间的相关性。第二个例子回顾了面部和物体识别研究，这些研究为NBM的观点提供了证据，即神经可塑性和经验在大脑对识别及其他行为的支持中起关键作用。然后将关于神经可塑性的结论进行推广，以解释在将SCM应用于神经成像时观察到的功能分离不完整的现象。
