Neuroscience

Definition: The scientific study of the nervous system and associated behaviors.

Science and Profession

Neuroscience is a broad, interdisciplinary field that spans many disciplines, including medicine, psychology, biology, chemistry, physics, computer science, and mathematics. The term neuroscience replaced several earlier labels for the field, including psychobiology, biopsychology, and biological psychology. Neuroscience is closely related to neurology and neurobiology, although the former focuses on clinical and medical phenomena and the latter is concerned more with biology than behavior. Most neuroscientists have earned PhDs, though some will also hold MDs (to contrast, all neurologists are physicians).

There are many subdisciplines within neuroscience, such as behavioral neuroscience (which examines the relationship between the brain and behavior using animal models), cellular and molecular neuroscience (explores chemical and electrical events at the cellular level), cognitive neuroscience (uses neuroimaging to study the brain’s role in thinking, feeling, and behaving in humans), computational neuroscience (uses computer modeling to understand how neurons and neuronal networks work), and developmental neuroscience (examines how the nervous system changes over the course of a lifetime).

Historical Overview

Though the heart was seen as the seat of intellect in the ancient world, the Greek Hippocrates and later the Roman Galen theorized that it may be the brain that is responsible for complex behaviors. Despite the accuracy of these early thinkers, it would be hundreds of years before neuroscience advanced beyond the gross anatomical studies that existed during the Middle Ages and early Renaissance. It was only after several notable discoveries about the physics of electrical conduction that neuroscientific progress resumed, this time with advances in electrophysiology.

Around the turn of the twentieth century, the two pioneering neuroanatomists, Camillo Golgi and Santiago Ramon y Cajal debated whether the structure of the nervous system was a “reticulum” (Golgi) or a discontinuous series of “connections” between neurons (Cajal). Though neither anatomist possessed a microscope powerful enough to determine who was correct at the time, over fifty years later George Palade and Sanford Palay used electron microscopy to verify the existence of synapses and show that it was Cajal who was correct. This demonstration, along with the work of Nobel laureates John Eccles and Bernard Katz, among others, solidified a modern understanding of the typical structure and workings of the nervous system: namely that though communication within individual neurons is electrical in nature, communication between neurons is chemical and occurs through the release of a neurotransmitter from an axon into the synapse. Once in the synapse, the neurotransmitter then binds to the dendrite of a different neuron, thus creating a change in the electrical potential within that neuron.

While neuroanatomists and neurophysiologists were unraveling where and how messages are sent in the nervous system, Canadian psychologist Donald Hebb theorized about how information could be retained. In his 1949 book On the Organization of Behavior, Hebb outlined the parameters via which the nervous system could be modified in response to activity, the phenomenon now known as plasticity. This work proved to be one of the most influential texts in neuroscience history, laying the foundation for further studies into everything from the development of the visual system to learning and memory.

Before the 1950s, most neuroscientific research was conducted using animal models. However, the advent of modern neuroimaging techniques, such as functional magnetic resonance imaging, or fMRI, revolutionized the study of the brain and behavior in humans. Unlike brain wave recordings collected using an electroencephalograph (EEG), which had been used for decades, fMRI allowed neuroscientists to see exactly where within the brain activity was taking place when a human was thinking or behaving.

Continuing advances in technology have allowed neuroscientists to peer into the brain with ever greater resolution and detail. The enhanced ability to see what happens within the brain when a human engages in complex reasoning has facilitated the integration of neuroscience with seemingly unrelated fields such as economics and education. Neuroscience has also greatly informed computer science and systems engineering, with researchers developing innovative technologies based on nervous system processes. Notably, biological neural networks provided the model for artificial neural networks, which became an important driver of breakthroughs in artificial intelligence (AI) in the early twenty-first century.

Key Terms

axon: the part of a neuron responsible for sending information to other neurons

dendrite: the part of a neuron responsible for receiving information from other neurons through the binding of neurotransmitters

electroencephalograph: a physiological instrument used to record electrical activity from the scalp

electrophysiology: the study of the electrical properties of cells

excitation: one consequence of the binding of neurotransmitters to the dendrite of a neuron; when the neuron receives enough excitation in its dendrite, the cell will release the neurotransmitter from its axon onto other cells

neuron: the basic cell of the nervous system; commonly referred to as a brain cell

neurotransmitter: any of a number of chemicals that facilitate communication between neurons

plasticity: a characteristic of brain cells that allows them to change as a result of stimulation and/or changes in activity

synapse: the space between the axon of one neuron and the dendrite of another where communication between cells takes place

Bibliography

"About Neuroscience." Eunice Kennedy Shriver National Institute of Child Health and Human Development, US National Institutes of Health, www.nichd.nih.gov/health/topics/neuro/conditioninfo. Accessed 12 Sept. 2024.

Carter, Rita. Mapping the Mind. University of California Press, 2010.

Gazzaniga, Michael S., et al. Cognitive Neuroscience: The Biology of the Mind. 5th ed. W. W. Norton, 2019.

Glickstein, Mitchell. Neuroscience: A Historical Introduction. MIT Press, 2014. Digital file.

Gross, Charles G. A Hole in the Head: More Tales in the History of Neuroscience. MIT Press, 2012.

Hebb, Donald O. The Organization of Behavior: A Neuropsychological Theory. Wiley, 1949.

Kalat, James W. Biological Psychology. 11th ed. Wadsworth, 2013.

Kandel, Eric, et al. Principles of Neural Science. 6th ed. McGraw Hill, 2021.

Satel, Sally, and Scott O. Lilienfield. Brainwashed: The Seductive Appeal of Mindless Neuroscience. Basic Books, 2013.

BrainFacts.org, Society for Neuroscience, . Accessed 12 Sept. 2024.

Villalba, Eugenio, and Andres Costa. Horizons in Neuroscience Research. Nova, 2015.