Neuroscience

Drawing by Santiago Ramón y Cajal (1899) of neurons in the pigeon cerebellum

Neuroscience is the scientific study of the nervous system.^[1] Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics, medicine, genetics, and allied disciplines including philosophy, physics, and psychology. It also exerts influence on other fields, such as neuroeducation^[2] and neurolaw. The term neurobiology is usually used interchangeably with the term neuroscience, although the former refers specifically to the biology of the nervous system, whereas the latter refers to the entire science of the nervous system.

The scope of neuroscience has broadened to include different approaches used to study the molecular, cellular, developmental, structural, functional, evolutionary, computational, and medical aspects of the nervous system. The techniques used by neuroscientists have also expanded enormously, from molecular and cellular studies of individual nerve cells to imaging of sensory and motor tasks in the brain. Recent theoretical advances in neuroscience have also been aided by the study of neural networks.

As a result of the increasing number of scientists who study the nervous system, several prominent neuroscience organizations have been formed to provide a forum to all neuroscientists and educators. For example, the

Neuroscience Affective neuroscience Behavioral epigenetics Behavioral neurology Behavioral genetics Behavioral neuroscience Brain–computer interface Cellular neuroscience Chronobiology Clinical neurophysiology Clinical neuroscience Cognitive neuroscience Computational neuroscience Connectomics Cultural neuroscience Educational neuroscience Evolutionary neuroscience Imaging genetics Integrative neuroscience Molecular cellular cognition Molecular neuroscience Motor or Movement neuroscience Neural development Neural engineering Neural network (artificial) Neural network (biological) Neural signal processing Neural tissue regeneration Neuroanatomy Neuroanthropology Neurobioengineering Neurobiology Neurobiotics Neurocardiology Neurochemistry Neurochip Neurocriminology Neurodegeneration Neurodevelopmental disorders Neurodiversity Neuroeconomics Neuroeducation Neuroembryology Neuroendocrinology Neuroepidemiology Neuroepistemology Neuroesthetics Neuroethics Neuroethology Neurogastroenterology Neurogenetics Neurohistory Neuroimaging Neuroimmunology Neuroinformatics Neurointensive care Neurolaw Neurolinguistics Neurology Neuromanagement Neuromarketing Neurometrics Neuromodulation Neuromorphology Neuromonitoring Neurooncology Neuro-ophthalmology Neuropathology Neuropharmacology Neurophenomenology Neurophilosophy Neurophysics Neurophysiology Neuroplasticity Neuropolitics Neuroprosthetics Neuropsychiatry Neuro-psychoanalysis Neuropsychology Neuroradiology Neurorehabilitation Neurorobotics Neurosociology Neurosurgery Neurotechnology Neurotheology Neurotology Neurotoxin Neurotransmitter Neurovirology Paleoneurology Psychiatry Sensory neuroscience Social neuroscience Systems neuroscience Book Category

• Neuroscience on In Our Time at the BBC. (listen now)
• Neuroscience Information Framework (NIF)
• Neurobiology at DMOZ
• American Society for Neurochemistry
• Neuroscience Online (electronic neuroscience textbook)
• Faculty for Undergraduate Neuroscience (FUN)
• Neuroscience for Kids
• Neuroscience Discussion Group in ResearchGate
• Neuroscience Discussion Forum
• Making Your Mind: Molecules, Motion, and MemoryHHMI Neuroscience lecture series -
• Société des Neurosciences

External links

Further reading

References

• List of neuroscience databases
• List of neuroscience topics
• List of neuroscientists
• List of topics related to brain mapping

See also

Finally, neuroscientists have also collaborated with other education experts to study and refine educational techniques to optimize learning among students, an emerging field called educational neuroscience.^[25] Federal agencies in the United States, such as the National Institute of Health (NIH)^[26] and National Science Foundation (NSF),^[27] have also funded research that pertains to best practices in teaching and learning of neuroscience concepts.

^[24].McMaster University In Canada, the CIHR Canadian National Brain Bee is held annually at ^[23] called Brain Awareness Week to increase public awareness about the progress and benefits of brain research.Dana Foundation and cosponsoring a campaign with the ^[22] collaborating with public school teachers to develop Neuroscience Core Concepts for K-12 teachers and students,[21] In addition to conducting traditional research in laboratory settings, neuroscientists have also been involved in the

Public education and outreach

In 2013, the BRAIN Initiative was announced in the US.

Other major organizations devoted to neuroscience include the British Neuroscience Association, the German Neuroscience Society (Neurowissenschaftliche Gesellschaft), and the French Société des Neurosciences. The first National Honor Society in Neuroscience, Nu Rho Psi, was founded in 2006.

The largest professional neuroscience organization is the Society for Neuroscience (SFN), which is based in the United States but includes many members from other countries. Since its founding in 1969 the SFN has grown steadily: as of 2010 it recorded 40,290 members from 83 different countries.^[19] Annual meetings, held each year in a different American city, draw attendance from researchers, postdoctoral fellows, graduate students, and undergraduates, as well as educational institutions, funding agencies, publishers, and hundreds of businesses that supply products used in research.

Neuroscience organizations

Modern neuroscience education and research activities can be very roughly categorized into the following major branches, based on the subject and scale of the system in examination as well as distinct experimental or curricular approaches. Individual neuroscientists, however, often work on questions that span several distinct subfields.

Major branches

Integrative neuroscience makes connections across these specialized areas of focus.

Neurology, psychiatry, neurosurgery, psychosurgery, anesthesiology and pain medicine, neuropathology, neuroradiology, ophthalmology, otolaryngology, clinical neurophysiology, addiction medicine, and sleep medicine are some medical specialties that specifically address the diseases of the nervous system. These terms also refer to clinical disciplines involving diagnosis and treatment of these diseases. Neurology works with diseases of the central and peripheral nervous systems, such as amyotrophic lateral sclerosis (ALS) and stroke, and their medical treatment. Psychiatry focuses on affective, behavioral, cognitive, and perceptual disorders. Anesthesiology focuses on perception of pain, and pharmacologic alteration of consciousness. Neuropathology focuses upon the classification and underlying pathogenic mechanisms of central and peripheral nervous system and muscle diseases, with an emphasis on morphologic, microscopic, and chemically observable alterations. Neurosurgery and psychosurgery work primarily with surgical treatment of diseases of the central and peripheral nervous systems. The boundaries between these specialties have been blurring recently as they are all influenced by basic research in neuroscience. Brain imaging also enables objective, biological insights into mental illness, which can lead to faster diagnosis, more accurate prognosis, and help assess patient progress over time.^[16]

Parasagittal MRI of the head of a patient with benign familial macrocephaly

Translational research and medicine

Ultimately neuroscientists would like to understand every aspect of the nervous system, including how it works, how it develops, how it malfunctions, and how it can be altered or repaired. The specific topics that form the main foci of research change over time, driven by an ever-expanding base of knowledge and the availability of increasingly sophisticated technical methods. Over the long term, improvements in technology have been the primary drivers of progress. Developments in electron microscopy, computers, electronics, functional brain imaging, and most recently genetics and genomics, have all been major drivers of progress.

Neuroscience is also allied with the social and behavioral sciences as well as nascent interdisciplinary fields such as neuroeconomics, decision theory, and social neuroscience to address complex questions about interactions of the brain with its environment.

At the cognitive level, cognitive neuroscience addresses the questions of how psychological functions are produced by neural circuitry. The emergence of powerful new measurement techniques such as neuroimaging (e.g., fMRI, PET, SPECT), electrophysiology, and human genetic analysis combined with sophisticated experimental techniques from cognitive psychology allows neuroscientists and psychologists to address abstract questions such as how human cognition and emotion are mapped to specific neural substrates.

Cognitive and behavioral neuroscience

At the systems level, the questions addressed in systems neuroscience include how neural circuits are formed and used anatomically and physiologically to produce functions such as reflexes, multisensory integration, motor coordination, circadian rhythms, emotional responses, learning, and memory. In other words, they address how these neural circuits function and the mechanisms through which behaviors are generated. For example, systems level analysis addresses questions concerning specific sensory and motor modalities: how does vision work? How do songbirds learn new songs and bats localize with ultrasound? How does the somatosensory system process tactile information? The related fields of neuroethology and neuropsychology address the question of how neural substrates underlie specific animal and human behaviors. Neuroendocrinology and psychoneuroimmunology examine interactions between the nervous system and the endocrine and immune systems, respectively. Despite many advancements, the way networks of neurons produce complex cognitions and behaviors is still poorly understood.

Neural circuits and systems

The fundamental questions addressed in cellular neuroscience include the mechanisms of how neurons process signals physiologically and electrochemically. These questions include how signals are processed by neurites – thin extensions from a neuronal cell body, consisting of dendrites (specialized to receive synaptic inputs from other neurons) and axons (specialized to conduct nerve impulses called action potentials) – and somas (the cell bodies of the neurons containing the nucleus), and how neurotransmitters and electrical signals are used to process information in a neuron. Another major area of neuroscience is directed at investigations of the development of the nervous system. These questions include the patterning and regionalization of the nervous system, neural stem cells, differentiation of neurons and glia, neuronal migration, axonal and dendritic development, trophic interactions, and synapse formation.

The study of the nervous system can be done at multiple levels, ranging from the molecular and cellular levels to the systems and cognitive levels. At the molecular level, the basic questions addressed in molecular neuroscience include the mechanisms by which neurons express and respond to molecular signals and how axons form complex connectivity patterns. At this level, tools from molecular biology and genetics are used to understand how neurons develop and how genetic changes affect biological functions. The morphology, molecular identity, and physiological characteristics of neurons and how they relate to different types of behavior are also of considerable interest.

Photograph of a stained neuron in a chicken embryo

Molecular and cellular neuroscience

In vertebrates, the nervous system can be split into two parts, the human brain alone contains around one hundred billion neurons and one hundred trillion synapses; it consists of thousands of distinguishable substructures, connected to each other in synaptic networks whose intricacies have only begun to be unraveled. The majority of the approximately 20–25,000 genes belonging to the human genome are expressed specifically in the brain. Due to the plasticity of the human brain, the structure of its synapses and their resulting functions change throughout life.^[15] Thus the challenge of making sense of all this complexity is formidable.

The scientific study of the nervous system has increased significantly during the second half of the twentieth century, principally due to advances in molecular biology, electrophysiology, and computational neuroscience. This has allowed neuroscientists to study the nervous system in all its aspects: how it is structured, how it works, how it develops, how it malfunctions, and how it can be changed. For example, it has become possible to understand, in much detail, the complex processes occurring within a single neuron. Neurons are cells specialized for communication. They are able to communicate with neurons and other cell types through specialized junctions called synapses, at which electrical or electrochemical signals can be transmitted from one cell to another. Many neurons extrude long thin filaments of protoplasm called axons, which may extend to distant parts of the body and are capable of rapidly carrying electrical signals, influencing the activity of other neurons, muscles, or glands at their termination points. A nervous system emerges from the assemblage of neurons that are connected to each other.

Human nervous system

Modern neuroscience

In 1952, Alan Lloyd Hodgkin and Andrew Huxley presented a mathematical model for transmission of electrical signals in neurons of the giant axon of a squid, action potentials, and how they are initiated and propagated, known as the Hodgkin–Huxley model. In 1961–2, Richard FitzHugh and J. Nagumo simplified Hodgkin–Huxley, in what is called the FitzHugh–Nagumo model. In 1962, Bernard Katz modeled neurotransmission across the space between neurons known as synapses. Beginning in 1966, Eric Kandel and collaborators examined biochemical changes in neurons associated with learning and memory storage. In 1981 Catherine Morris and Harold Lecar combined these models in the Morris–Lecar model. In 1984, J. L. Hindmarsh and R.M. Rose further modeled neurotransmission.

In parallel with this research, work with brain-damaged patients by cell structure) anatomical definitions from this era in continuing to show that distinct areas of the cortex are activated in the execution of specific tasks.^[14]

Studies of the brain became more sophisticated after the invention of the microscope and the development of a staining procedure by Camillo Golgi during the late 1890s. The procedure used a silver chromate salt to reveal the intricate structures of individual neurons. His technique was used by Santiago Ramón y Cajal and led to the formation of the neuron doctrine, the hypothesis that the functional unit of the brain is the neuron.^[11] Golgi and Ramón y Cajal shared the Nobel Prize in Physiology or Medicine in 1906 for their extensive observations, descriptions, and categorizations of neurons throughout the brain. While Luigi Galvani's pioneering work in the late 1700s had set the stage for studying the electrical excitability of muscles and neurons, it was in the late 19th century that Emil du Bois-Reymond, Johannes Peter Müller, and Hermann von Helmholtz demonstrated that the electrical excitation of neurons predictably affected the electrical states of adjacent neurons, and Richard Caton found electrical phenomena in the cerebral hemispheres of rabbits and monkeys.

The Golgi stain first allowed for the visualization of individual neurons.

Abulcasis, Averroes, Avenzoar, and Maimonides, active in the Medieval Muslim world, described a number of medical problems related to the brain. In Renaissance Europe, Vesalius (1514–1564), René Descartes (1596–1650), and Thomas Willis (1621–1675) also made several contributions to neuroscience.

The view that the heart was the source of consciousness was not challenged until the time of the Plato also speculated that the brain was the seat of the rational part of the soul.^[9] Aristotle, however, believed the heart was the center of intelligence and that the brain regulated the amount of heat from the heart.^[10] This view was generally accepted until the Roman physician Galen, a follower of Hippocrates and physician to Roman gladiators, observed that his patients lost their mental faculties when they had sustained damage to their brains.

Early views on the function of the brain regarded it to be a "cranial stuffing" of sorts. In Egypt, from the late Middle Kingdom onwards, the brain was regularly removed in preparation for mummification. It was believed at the time that the heart was the seat of intelligence. According to Herodotus, the first step of mummification was to "take a crooked piece of iron, and with it draw out the brain through the nostrils, thus getting rid of a portion, while the skull is cleared of the rest by rinsing with drugs."^[8]

The study of the nervous system dates back to ancient Egypt. Evidence of trepanation, the surgical practice of either drilling or scraping a hole into the skull with the purpose of curing headaches or mental disorders or relieving cranial pressure, being performed on patients dates back to Neolithic times and has been found in various cultures throughout the world. Manuscripts dating back to 1700 BC indicated that the Egyptians had some knowledge about symptoms of brain damage.^[7]

Illustration from Gray's Anatomy (1918) of a lateral view of the human brain, featuring the hippocampus among other neuroanatomical features

History

^[6] in 1969.Society for Neuroscience and the ^[5] in 1968,European Brain and Behaviour Society the ^[4] in 1963,International Society for Neurochemistry the [3]