Research Applications of Functional Magnetic Resonance Imaging (fMRI) in Neuroscience

The human brain, which contains approximately 100 billion neurons and more than 100 trillion synapses, is the most complex system in the human body. With the rapid advancement of related disciplines and technologies, a number of new concepts, techniques, and methods have emerged, significantly contributing to the substantial growth in the neurosciences. Contemporary research in neuroscience is mainly characterized by two basic features. The first is that neuroscience research has shifted from the macroscopic to the microscopic level, integrating functional and structural research at the cellular and molecular levels, while also investigating the activity of neurons, synapses, and neural networks. The second is that neuroscience research no longer focuses solely on the control of general physiological (sensory and motor) functions, but has now incorporated complex and advanced mental functions and consciousness under its purview, to explore the relationships between the brain, behavior, and thinking. In neuroscience research, therefore, issues regarding the overall function of the brain must be assessed using in-depth localized knowledge. Numerous methods are available for researching brain function, and functional neuroimaging techniques can be divided into three major categories: (1) Techniques for measuring compounds within the brain, including single-photon emission computed tomography (SPECT), positron emission tomography (PET), and magnetic resonance spectroscopy (MRS); (2) Techniques for measuring local metabolic and blood oxygen changes-an increase in the neuronal activity leads to corresponding changes in local blood flow, oxygen metabolism, and glucose metabolism, thus enabling the study of the neuronal activity of a given brain region by measuring the associated secondary reactions, such as blood flow and metabolism. The primary methods for measuring secondary reactions include PET, fMRI, and optical imaging, techniques which have been utilized most extensively in cognitive science, and are primarily used in research regarding functional localization and the characterization of local brain responses; and (3) Techniques for measuring neuronal activity within the brain-these techniques directly measure the neuronal activity of human brains-including electroencephalography (EEG), magnetoencephalography (MEG), and event-related potential (ERP), which was developed based on EEG and MEG.