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White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system. The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons). This myelin is found in almost all long nerve fibers, and acts as an electrical insulation.
The external capsule is a series of white matter fiber tracts in the brain. These fibers run between the most lateral (toward the side of the head) segment of the lentiform nucleus (more specifically the putamen) and the claustrum. The white matter of the external capsule contains fibers known as corticocortical association fibers.
The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres has an outer layer of grey matter, the cerebral cortex, that is supported by an inner layer of white matter. In eutherian (placental) mammals, the hemispheres are linked by the corpus callosum, a very large bundle of nerve fibers.
The arcuate fasciculus is a white matter pathway in the brain which contains two branches: a ventral branch connecting Wernicke's area with Broca's area and a dorsal branch connecting the posterior temporal region with the middle frontal gyrus. This dorsal branch appears to be particularly important for phonological working memory processes. [183]
Based upon its structure and connectivity, its function is suggested to be related to coordination of different brain functions; i.e. the conductor analogy. Consciousness functionally can be divided into two components: (i) wakefulness, which is arousal and alertness; (ii) content of consciousness, which is the processing of content.
The fundamental function of this part of the ear is to gather sound energy and deliver it to the eardrum. Resonances of the external ear selectively boost sound pressure with frequency in the range 2–5 kHz. [2] The pinna as a result of its asymmetrical structure is able to provide further cues about the elevation from which the sound originated.
Brain fog during menopause could also "be related to changes in the hypothalamus at the base of the brain, which we know occurs from the decreasing levels of estrogen," Minkin says.
In humans, the cerebrum is the largest and best-developed of the five major divisions of the brain. The cerebrum is made up of the two cerebral hemispheres and their cerebral cortices (the outer layers of grey matter), and the underlying regions of white matter. [2] Its subcortical structures include the hippocampus, basal ganglia and olfactory ...