Corpus Callosum:
Broad plate of dense myelinated fibers that reciprocally interconnect regions of the cortex in all lobes with corresponding regions of the opposite hemisphere. The corpus callosum is located deep in the longitudinal fissure.

The study of how damage to the brain affects cognitive functioning has historically been one of the most important tools for cognitive neuroscience. While the brain is one of the most well protected parts of the body, there are many events that can affect the functioning of the brain. Vascular issues, tumors, degenerative diseases, infections, blunt force traumas, and neurosurgery are just some of the underlying causes of brain damage, all of which may produce different patterns of tissue damage that affect brain functioning in different ways.
The history of neuropsychology is marked by several well-known cases that led to advances in the understanding of the brain. For instance, in 1861 Paul Broca observed how damage to the left frontal lobe resulted in aphasia, an acquired language disorder. As another example, a great deal about memory has been learned from patients with amnesia, such as the famous case of Henry Molaison, known for many years in the neuropsychology literature as "H.M.," whose temporal lobe surgery led to a profound deficit in forming certain kinds of new memories.
While the observation and testing of patients with focal brain damage has provi…

Traditional brain imaging techniques using MRI are very good at visualizing the gross structures of the brain. A structural brain image made with MRI provides high contrast of the borders between gray and white matter, and information about the size and shape of brain structures. However, these images do not detail the underlying structure and integrity of white matter networks in the brain, which consist of axon bundles that interconnect local and distant brain regions.
Diffusion MRI uses pulse sequences that are sensitive to the diffusion of water molecules. By measuring the direction of diffusion, it is possible to make inferences about the structure of white matter networks in the brain. Water molecules within an axon are constrained in their movements by the cell membrane; instead of randomly moving in every direction with equal probability (isotropic movement), they are more likely to move in certain directions, in parallel with the axon (anisotropic movement; Figure 1). Therefore, measures of diffusion anisotropy are thought to reflect properties of the white matter such as fiber density, axon thickness, and degree of myelination. One common measure is fractional anisotropy…

1Physical Medicine and Rehabilitation, University of Alabama at Birmingham, 2Department of Pathology, University of Alabama at Birmingham, 3Department of Neurobiology, University of Alabama at Birmingham, 4Center for Glial Biology and Medicine, University of Alabama at Birmingham

1Department of Pathology and Laboratory Medicine, University of North Carolina School of Medicine, 2Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, 3Division of Neuropathology, Department of Pathology and Laboratory Medicine, University of North Carolina School of Medicine, 4Curriculum in Genetics and Molecular Biology, University of North Carolina School of Medicine, 5Biological and Biomedical Sciences Program, University of North Carolina School of Medicine, 6Department of Radiation Oncology, Emory University School of Medicine, 7Department of Neurology, Neurosciences Center, University of North Carolina School of Medicine

1Elemental Bio-imaging Facility, University of Technology Sydney, 2Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 3Department of Pathology, The University of Melbourne, 4School of Earth Sciences, The University of Melbourne, 5Research School, Ruhr University, 6Department of Physiology, Monash University, 7ESI Ltd., Bozeman, 8Agilent Technologies, Mulgrave

1Department of Rehabilitation Medicine, Inje University of Medicine, Haeundae Paik Hospital, 2Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital

1Department of Life Science and Medical Bioscience, Faculty of Science and Engineering, Waseda University, 2Department of Anatomy and Cell Biology, Interdisciplinary Graduate School of Medicine & Engineering, University of Yamanashi