Neuroscience
Encyclopedia : N : NE : NEU : Neuroscience
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Contents
History
Early views on the function of the brain, regarded it to be a form of “cranial stuffing” of sorts. In Egypt, from the late Middle Kingdom onwards, in preparation for mummification, the brain was regularly removed, for it was the heart that was assumed to be the seat of intelligence. According to Herodotus, during the first step of mummification: ‘The most perfect practice is to extract as much of the brain as possible with an iron hook, and what the hook cannot reach is mixed with drugs.’ Over the next two thousand years, this view came to be reversed; the brain is now known to be seat of intelligence, although colloquial variations of the former remain as in “memorizing something by heart”.
Overview
The biological study of the human brain is an interdisciplinary field that involves many levels of study, from the molecular level through the cellular level (individual neurons), the level of relatively small assemblies of neurons like cortical columns, that of larger subsystems like that which subserves visual perception, up to large systems including the cerebral cortex or the cerebellum, and at the highest level the nervous system as a whole.At this highest level, neuroscientific approaches combine with cognitive science to create cognitive neuroscience, a discipline first populated mostly by cognitive psychologists, currently becoming a dynamic specialty of its own. Some researchers believe that cognitive neuroscience provides a bottom-up approach to understanding the mind and consciousness that is complementary to, or may replace, the top-down approach of psychology.
The concern of neuroscience includes such diverse topics as
- the operation of neurotransmitters at the synapse
- the biological mechanisms that underlie learning (both declarative learning and motor learning)
- how genes contribute to neural development in the embryo and throughout life
- the operation of relatively simpler neural structures of other organisms like marine snails
- and the structure and functioning of complex neural circuits in perceiving, remembering, and speaking.
Neuroanatomy
The human nervous system is divided into the central and peripheral nervous systems. The central nervous system consists of the brain and spinal cord, and plays a key role in controlling behavior.The peripheral nervous system is made up of all the neurons in the body outside of the central nervous system, and is further subdivided into the somatic and autonomic nervous systems. The somatic nervous system is made up of afferent neurons that convey sensory information from the sense organs to the brain and spinal cord, and efferent neurons that carry motor instructions to the muscles.
The autonomic nervous system also has two subdivisions. The sympathetic nervous system is a set of nerves that activate what has been called the "fight-or-flight" response that prepares the body for action. The parasympathetic nervous system instead prepares the body to rest and conserve energy.
Fields within neuroscience
There are many areas of study within neuroscience including:- Neurobiology, which aims to study cells of the nervous system and the organization of these cells into functional circuits that process information and mediate behavior.
- Molecular and cellular neuroscience, which integrate neurobiology with neurochemistry with the goal of understanding the cellular and chemical mechanisms of normal and abnormal brain function.
- Developmental neuroscience, which studies how the ectodermally-derived central nervous system and mesodermally-derived peripheral nervous system develops into adulthood. Developmental neuroscience uses many different animal models, including the fruit fly Drosophila melanogaster , zebrafish Danio rerio, Xenopus laevis tadpoles, and the worm Caenorhabditis elegans.
- Cognitive neuroscience, which aims to understand the mechanisms that underlie "higher level" brain functions, usually in humans. These include language, learning and memory, attention, and emotion.
- Computational and systems neuroscience, which seek to understand how information is processed by the nervous system. The methods of research combine mathematical and computational models with physiological recordings of single cells, neuronal clusters, and entire brain systems.
- Behavioral Neuroscience, which assesses the neural underpinnings of a vast array of behaviors, from primate saccadic eye movements to the complex foraging behavior of bees.
- Sensory Neuroscience, which attempts to understand how sensory areas of the brain represent information from the outside world.
- Neurology, which is the branch of medicine that deals with the nervous system.
- Neurobiology of disease: This field, directly aligned with medical research, is interested in understanding diseases associated with the nervous system.
"Neuroscience" refers to all the fields that study the nervous system. In some sense, psychology is a sub-field of neuroscience, although some mind/body theorists argue that the definition goes the other way. One of the largest related fields which shares many features of both psychology and neuroscience is neuropsychopharmacology. Neurobiology is sometimes used interchangeably with neuroscience, but it refers specifically to the study of the biology of the nervous system.Below is a list of related and overlapping fields: