Neurophysiology

This section does not cite any sources. (May 2012)

Antiquity

Neurophysiology has been a subject of study since as early as 4,000 B.C. In the early B.C. years, most studies were of different natural sedatives like alcohol and poppy plants.^{[citation needed]} In 1700 B.C., the Edwin Smith surgical papyrus was written. This papyrus was crucial in understanding how the ancient Egyptians understood the nervous system. This papyrus looked at different case studies about injuries to different parts of the body, most notably the head. The knowledge presents a rational and scientific approach to medicine in ancient Egypt.^[10]^: 58 Beginning around 460 B.C., Hippocrates began to study epilepsy, and theorized that it had its origins in the brain. Hippocrates also theorized that the brain was involved in sensation, and that it was where intelligence was derived from. Hippocrates, as well as most ancient Greeks, believed that relaxation and a stress free environment was crucial in helping treat neurological disorders, that "healthy Mediterranean diet and daily moderate physical activity can prevent disease".^[11] In 280 B.C., Erasistratus of Chios theorized that there were divisions in vestibular processing in the brain, as well as deducing from observation that sensation was located there.^[12]

In 177 Galen theorized that human thought occurred in the brain, as opposed to the heart as Aristotle had theorized.^[13] The optic chiasm, which is crucial to the visual system, was discovered around 100 C.E. by Marinus.

Middle ages

Abū Bakr al-Rāzī (864 or 865–925 or 935 C.E.), also known by his Latin name Rhazes, a Persian physician, philosopher, and alchemist, wrote a book for al-Mansur (Kitāb al-Manṣūrī) of 26 sections on body structures, including nerves, muscles, and organs such as the eyes and heart.^[14]^[15]^[16] It was translated into Latin by Gerard of Cremona around 1180.^[17] c. 1000, Al-Zahrawi, living in Iberia, began to write about different surgical treatments for neurological disorders. He described a surgical procedure for treating such a neurological disease as migraine (in particular, ligation of the temporal artery for migraine),^[18] in his thirty-volume medical encyclopedia, the Kitab al-Tasrif manuscript, completed in the year 1000.^[19] Al-Zahrawi was first to discover the root cause of paralysis.^[20] In Persia, Avicenna (Ibn-Sina) presented detailed knowledge about skull fractures and their surgical treatments.^[21] In 1216, the first anatomy textbook in Europe, which included a description of the brain, was written by Mondino de Luzzi.^[22]^: 64 In 1402, St Mary of Bethlehem Hospital (later known as Bedlam in Britain) was the first hospital used exclusively for the mentally ill.^[23]

16th century

In 1504, Leonardo da Vinci continued his study of the human body with a wax cast of the human ventricle system. In 1536, Nicolo Massa described the effects of different diseases, such as syphilis on the nervous system. He also noticed that the ventricular cavities were filled with cerebrospinal fluid.^[24] In 1542, the term physiology was used for the first time by a French physician named Jean Fernel, to explain bodily function in relation to the brain.^[25]

In 1543, Andreas Vesalius wrote De humani corporis fabrica, which revolutionized the study of anatomy. The book 7 of this corpus described the structure and functions of the brain and its coverings, the eye, the organs of sensation, and the nerves of the limbs. In this book, he described the pineal gland and what he believed the function was, and was able to draw the corpus striatum which is made up of the basal ganglia and the internal capsule. It was closed with a chapter on the correct way to dissect the brain.^[26] In 1549, Jason Pratensis published De Cerebri Morbis. This book was devoted to neurological diseases, and discussed symptoms, as well as ideas from Galen and other Greek, Roman and Arabic authors. It also looked into the anatomy and specific functions of different areas.^[27] In 1550, Andreas Vesalius worked on a case of hydrocephalus, or fluid filling the brain. In the same year, Bartolomeo Eustachi studied the optic nerve, mainly focusing on its origin in the brain. In 1564, Giulio Cesare Aranzio discovered the hippocampus,^[28] naming it such due to its shape resemblance to a sea horse.

17th century

In 1621, Robert Burton published The Anatomy of Melancholy, which looked at the loss of important characters in one's life as leading to depression.^[29] In 1649, René Descartes studied the pineal gland. He mistakenly believed that it was the "soul" of the brain, and believed it was where thoughts formed. In 1658, Johann Jakob Wepfer studied a patient in which he believed that a broken blood vessel had caused apoplexy, or a stroke. The European Stroke Conference has awarded the Wepfer Prize for stroke research annually since 2005.^[30] In 1664, Thomas Willis published his Anatomy of the Brain. He described the brain more clearly, setting forth the circle of Willis, the circle of vessels that enables arterial supply of the brain. He described epilepsy, apoplexy, and paralysis.^[31]

18th century

In 1749, David Hartley published Observations on Man, which focused on frame (neurology), duty (moral psychology) and expectations (spirituality) and how these integrated within one another.^[32] This text was also the first to use the English term psychology. In 1752, the Society of Friends created an asylum in Philadelphia, Pennsylvania. The asylum intended to give not only medical treatment to those mentally ill, but also provide with caretakers and comfortable living conditions.^{[citation needed]} In 1755, Jean-Baptiste Le Roy began using electroconvulsive therapy for the mentally ill, a treatment still used today in specific cases. In 1760, Arne-Charles studied how different lesions in the cerebellum could affect motor movements.^[33] In 1776, Vincenzo Malacarne [it] studied the cerebellum intensely, and published a book solely based on its function and appearance.

In 1784, Félix Vicq-d'Azyr, discovered a black colored structure in the midbrain.^[34] In 1791 Samuel Thomas von Sömmerring alluded to this structure, calling it the substantia nigra.^[35] In the same year, Luigi Galvani described the role of electricity in nerves of dissected frogs.^[36]

19th century

In 1808, Franz Joseph Gall studied and published work on phrenology. Phrenology was the faulty science of looking at head shape to determine different aspects of personality and brain function.^[37]^: 10–11 In 1811, Julien Jean César Legallois studied respiration in animal dissection and lesions and found the center of respiration in the medulla oblongata.^[38] In the same year, Charles Bell finished work on what would later become known as the Bell–Magendie law, which compared functional differences between dorsal and ventral roots of the spinal cord. He was the first to distinguish between motor and sensory nerves and proposed the concept of a “muscle sense”.^[39] In 1822, Karl Friedrich Burdach distinguished between the lateral and medial geniculate bodies, as well as named the cingulate gyrus. The column of Burdach or fasciculus cuneatus, the lateral portion of the dorsal funiculus of the spinal cord is named for him.^[40] In 1824, F. Magendie studied and produced the first evidence of the cerebellum's role in equilibration to complete the Bell–Magendie law. In 1838, Theodor Schwann began studying white and grey matter in the brain, and discovered the myelin sheath. These cells, which cover the axons of the neurons in the brain, are named Schwann cells after him.^[41] In 1843 Carlo Matteucci and Emil du Bois-Reymond demonstrated that nerves transmit signals electrically.^[42]

In 1848, Phineas Gage, the classical neurophysiology patient, had his brain pierced by an iron tamping rod in a blasting accident. He became an excellent case study in the connection between the prefrontal cortex and behavior, decision making and consequences.^[43]^: 19 In 1849, Hermann von Helmholtz studied the speed of frog nerve impulses while studying electricity in the body.^[44]

In 1861, French neurologist Paul Broca discovered that a damaged area of the posterior inferior frontal gyrus also known as Broca's area) in patients caused an inability to speak.^[45]

Italian neuroanatomist professor Camillo Golgi discovered in the 1870s that all the nerve cells in the nervous system are a continuous, interconnected network.^[46]

Regionally specific features of the central brain region were described by Prof. Betz in 1874, making one of the first steps toward the microstructural, cytoarchitectonic parcellation of the entire human cerebral cortex.^[47]^[48]

In 1875, Prof. Richard Caton reported to the British Medical Association that he had observed electrical impulses from the surfaces of living brains in animals.^[49]

In 1894, neurologist and psychiatrist Edward Flatau published a human brain atlas “Atlas of the Human Brain and the Course of the Nerve-Fibres”.^[50]

In 1896, Prof. d'Arsonval conducted the first documented study of the effects of a time-variable magnetic field on the brain, producing physiological changes: a volunteer reported phosphenes and vertigo when a coil stimulated his head at 42 Hz.^[51]

20th century

In 1902, Prof. Julius Bernstein contributed to the physiology of nerve impulses by proposing that the action potential results from a change in the permeability of the axonal membrane to ions, thereby providing knowledge of the origin of the "resting potential" and the "action potential" in the nerve. The "membrane hypothesis" explained the resting potential of nerve and muscle as a diffusion potential set up by the tendency of positively charged ions to diffuse from their high concentration in cytoplasm to their low concentration in the extracellular solution, while other ions are held back. Bernstein was also the first to introduce the Nernst equation for resting potential across the membrane.^[52]

In 1907, Prof. Louis Lapicque proposed that the action potential occurs at threshold crossing[39] (later better shown to be a product of dynamic ionic conduction systems).^[53]

In 1909, German anatomist Korbinian Brodmann published his original research on brain mapping, defining 52 distinct regions of the cerebral cortex, known as Brodmann areas now.^[54]

In 1924, German physiologist and psychiatrist Hans Berger (1873–1941) discovered the electrical activity of the brain (called brain waves) and, in particular, the alpha wave rhythm, which is a type of brain wave.^[55]^[56]

A great deal of study on sensory organs and the function of nerve cells was conducted by British physiologist Edgar Adrian. In 1928, he observed nerve fibers in action during his experiments on frogs, and was able to record the electrical discharge of single nerve fibres under physical stimulus.^[57] He concluded that the excitation of the skin under constant stimulus is initially strong but gradually decreases over time, whereas the sensory impulses passing along the nerves from the point of contact are constant in strength, yet are reduced in frequency over time, and the sensation in the brain diminishes as a result.^[57] Extending these results to the study of pain causes by the stimulus of the nervous system, he made discoveries about the reception of such signals in the brain and spatial distribution of the sensory areas of the cerebral cortex in different animals. These conclusions lead to the idea of a sensory map, called the homunculus, in the somatosensory system. This distorted view of the human body was based on the neurological "map" of the regions and parts of the human brain response.^[57]

In 1944, Prof. Josef Erlanger and Herbert Gasser were awarded the Nobel Prize in Physiology or Medicine "for their discoveries relating to the highly differentiated functions of single nerve fibres."^[58] They discovered action potentials of two phases: spike and postspike; and they revealed nerves in many forms, each with its own excitability potential. They also found a proportion between nerve fiber diameter and action potential velocity. ^[59]

In 1950, Prof. Wilder Penfield published a book called The Cerebral Cortex of Man with maps of the location of various functions (motor, sensory, memory, vision) in the brain, that he defined during the process of treating epilepsy.^[60] Prof. Wilder Penfield and his colleagues Edwin Baldry and Theodore Rasmussen are considered the creators of the cortical homunculus.^[61]

History

Antiquity

Middle ages

16th century

17th century

18th century

19th century

20th century

See also

References

Sources

Wikiwand - on