Neuroscience is often referred to in the plural, as neurosciences.
Neuroscience has traditionally been classed as a subdivision of biology. These days, it is an interdisciplinary science which liaises closely with other disciplines, such as mathematics, linguistics, engineering, computer science, chemistry, philosophy, psychology, and medicine.
Many researchers say that neuroscience means the same as neurobiology. However, neurobiology looks at the biology of the nervous system, while neuroscience refers to anything to do with the nervous system.
Neuroscientists are involved in a much wider scope of fields today than before. They study the cellular, functional, evolutionary, computational, molecular, cellular and medical aspects of the nervous system.
The history of neuroscienceThe Ancient Egyptians thought the seat of intelligence was in the heart. During the mummification process, they would remove the brain, but leave the heart in the body.
Herodotus (circa.484-425 BC), an ancient Greek historian, said:
"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."
The earliest writings on the brain were found in the 1,700 BC Edwin Smith Surgical Papyrus. The word "brain" is mentioned eight times, when the writers were describing the symptoms, diagnosis, and likely outcomes of two people who had head wounds; compound fractures of the skull. Papyrus is an Ancient Egyptian form of paper, made from the papyrus plant. The plant grows wild in marches next to the Nile river - it was cultivated for making paper. Edwin Smith (1822-1906) was an American antique dealer and collector. He gave his name to this particular papyrus.
Hieroglyphics of the word "brain" in the Edwin Smith Surgical Papyrus, 1,700 BC
At around 500 B.C., varying views on the brain began to emerge in Ancient Greece. Alcmaeon, believed to be a student of Pythagoras, wrote that the brain is where the mind is; he was probably the first person in history to express the idea in writing. Hippocrates soon followed, saying the brain is the seat of intelligence.
Later, Aristotle (384-322 BC), a Greek philosopher and polymath, went slightly off the mark by saying that the brain is a blood cooling mechanism and that the heart is the seat of intelligence. He argued that the humans behave more rationally than animals because our larger brains cool down hot blood, thus preventing hot-bloodedness.
Herophilus of Calcedonia (circa.330-250 BC), a Greek physician, and Erasistratus of Ceos (circa. 300-240 BC), a Greek anatomist and royal physician, are known to have made considerable useful contributions to brain and nervous system anatomy. Unfortunately, their writings were lost - we only know about their contributions through secondary sources.
Galen of Pergamon (129-circa. 200), a Greek anatomist who worked in Rome, said that the cerebrum was where the senses were processed because it is soft, while the cerebellum controls muscles because it is denser than the brain.
The microscope - which was probably invented in the Netherlands in 1590 allowed for a much deeper understanding of the brain.
During the late 1980s, Gamillo Golgi (1843-1926) an Italian physician, pathologist, and scientist, used silver chromate salt to show what single neurons looked like. Santiago Ramón y Cajal (1852-1934),a Spanish pathologist, histologist, and neuroscientist, took Golgi's work further and formed the neuron doctrine - a hypothesis that the neuron is the functional unit of the brain. In 1906, Golgi and Cajal were jointly awarded the Nobel Prize in Physiology or Medicine for their extensive works and categorizations of neurons in the brain.
Towards the end of the 19th century, Hermann von Hemholtz, (1821-1894) a German physician and physicist, Hohannes Peter Müller, (1801-1858), a German physiologist, comparative anatomist, ichthyologist, and herpetologist, and Emil du Bois-Reymond, (1818-1896) a German physician and physiologist, demonstrated the electrical excitability of neurons, and how the electrical state of adjacent neurons predictably were affected by an electrically excited neuron.
At the same time, Pierre Paul Broca (1824-1880) a French physician, surgeon, anatomist, and anthropologist, worked on patients who had brain damage. He came to the conclusion that different regions in the brain were involved in specific functions.
John Hughlings Jackson (1835-1911), an English neurologist, through observations of patients with epilepsy, worked out how the motor cortex was organized while watching seizure progression through the body.
Carl Wernicke (1848-1905), a German physician, anatomist, psychiatrist and neuropathologist, believed that certain parts of the brain were responsible for understanding and uttering language.
Neuroscience during the twentieth century and todayFrom the 1950s onwards, the scientific study of the nervous system made huge advances, mainly because of the progress achieved in other and related fields, such as computational neuroscience, electrophysiology, and molecular biology. Neuroscientists were able to study the nervous system's structure, functions, development, abnormalities, and ways it can be altered.
The major branches of modern neuroscienceThe following branches of neuroscience, based on research areas and subjects of study can be broadly categorized in the following disciplines (neuroscientists usually cover several branches at the same time):
- Affective neuroscience - in most cases, research is carried out on laboratory animals and looks at how neurons behave in relation to emotions.
- Behavioral neuroscience - the study of the biological bases of behavior. Looking at how the brain affects behavior.
- Cellular neuroscience - the study of neurons, including their form and physiological properties at cellular level.
- Clinical neuroscience - looks at the disorders of the nervous system, while psychiatry, for example, looks at the disorders of the mind.
- Cognitive neuroscience - the study of higher cognitive functions that exist in humans, and their underlying neural bases. Cognitive neuroscience draws from linguistics, neuroscience, psychology and cognitive science. Cognitive neuroscientists can take two broad directions; behavioral/experimental or computational/modeling, the aim being to understand the nature of cognition from a neural point of view.
- Computational neuroscience - attempting to understand how brains compute, using computers to simulate and model brain functions, and applying techniques from mathematics, physics and other computational fields to study brain function.
- Cultural neuroscience - looks at how beliefs, practices and cultural values are shaped by and shape the brain, minds and genes over different periods.
- Developmental neuroscience - looks at how the nervous system develops on a cellular basis; what underlying mechanisms exist in neural development.
- Molecular neuroscience - the study of the role of individual molecules in the nervous system.
- Neuroengineering - using engineering techniques to better understand, replace, repair, or improve neural systems.
- Neuroimaging - a branch of medical imaging that concentrates on the brain. Neuroimaging is used to diagnose disease and assess the health of the brain. It can also be useful in the study of the brain, how it works, and how different activities affect the brain.
- Neuroinformatics - integrates data across all areas of neuroscience, to help understand the brain and treat diseases. Neuroinformatics involves acquiring data, sharing, publishing and storing information, analysis, modeling, and simulation.
- Neurolinguistics - studying what neural mechanisms in the brain control the acquisition, comprehension and utterance of language.
- Neurophysiology- looks at the relationship of the brain and its functions, and the sum of the body's parts and how they interrelate. The study of how the nervous system functions, typically using physiological techniques, such as stimulation with electrodes, light-sensitive channels, or ion- or voltage-sensitive dyes.
- Paleoneurology - the study of the brain using fossils.
- Social neuroscience - this is an interdisciplinary field dedicated to understanding how biological systems implement social processes and behavior. Social neuroscience gathers biological concepts and methods to inform and refine theories of social behavior. It uses social and behavioral concepts and data to refine neural organization and function theories.
- Systems neuroscience - follows the pathways of data flow within the CNS (central nervous system) and tries to define the kinds of processing going on there. It uses that information to explain behavioral functions.
Latest research in neuroscienceRegenerating the spine with a special cell - scientists from the Welcome Trust-MRC Cambridge Stem Cell Institute, University of Cambridge, managed to get dogs with spinal injuries to walk again unaided. They reported in the journal Brain that all the 34 dogs suffered critical spinal cord injuries. None of them could use their back legs and had no feelings (could not feel pain) in their hind legs and surrounding areas.
Many of the dogs were dachshunds, a breed which is particularly prone to spinal cord injuries. When dogs get a slipped disc, unlike humans, there are likely to suffer SCIs (spinal cord injuries).
The dogs were split into two groups. Those in one group were injected with olfactory unsheathing cells from the lining of their own nose, while the others were injected with the liquid which carried the cells (placebo).
The dogs which were injected with olfactory unsheathing cells managed to use their hind legs and coordinate them with their front legs, unlike those in the other group.