The phrase, "I think therefore I am," written by Rene Descartes in 1637, expressed the philosophy at that time in history. According to "Memory: From Mind to Molecules," the statement proved to be incorrect from biological studies in the 20th century. The phrase rested on the belief that mind and body existed as separate entities, but neuroscience showed nerve cells communicate with the rest of the body, and vice versa.
Nerve Cells
The book, "In Search of Memory," indicates that in 1839 anatomists described the cell theory, which holds that all living entities are comprised of the same essential elements called cells. By 1890, the theory expanded to formulate the neuron doctrine that states that all living organisms have nerve cells or neurons that represent the basic signaling components in the brain.
Synapses
According to the University of Washington, Sir Charles Sherrington in 1897 first described a synapse, the space between two nerve cells. A dendrite comprises the top end of a nerve cell that receives chemical information. The dendrite, after receiving the chemical material or neurotransmitter, turns into an electric impulse. The electric impulse stimulates the cell body and the axon or bottom of the neuron to stimulate the release of a neurotransmitter. The process continues to send messages to and from the brain to either sensory endings or motor endings.
Neurotransmitters
"Integrative Psychiatry" describes the main neurotransmitters communicated at the synapses between the neurons. The four neurotransmitters regulating mood include serotonin, norepinephrine, dopamine and gamma amino butyric acid, or GABA. Other common neurotransmitters acting at the synapses consist of histamine, glutamate and acetycholine.
Ionic Theory & Action Potentials
The University of Washington describes ions as chemicals in the body that produce an electric charge. The positive and negative ions used in the nerve system include sodium, potassium, chloride and calcium. These ions move through channels or holes in the neuron cell wall in a process called an action potential. The action potential generates the electric charge.
Diseases Related to Neurotransmitters
According to "In Search of Memory," defects in the ion channel or action potential that arise from mutation in the genes produce some forms of epilepsy. After delineation of the defects in 1990, researchers used the knowledge to focus on precise treatments for the specific epilepsy.
The tranquilizing drugs, like Valium and Xanax, and alcohol bind to the neurotransmitter, GABA, and produce a calming effect when anxiety arises. Anesthetic agents attach to GABA and produce sleep for surgical procedures.
"Integrative Psychiatry" describes an imbalance of the neurotransmitters of serotonin, norepinephrine, dopamine and GABA producing symptoms of depression. The selective serotonin reuptake inhibitors of Celexa, Prozac and Zoloft treat depression with their effect on these mood neurotransmitters.
Reduced levels and imbalances of the neurotransmitters, serotonin and norepinephrine, appear to contribute to the persistent pain in fibromyalgia. The serotonin norepinephrine reuptake inhibitor, Cymbalta, reduces the pain in fibromyalgia.
According to the "National Institute of Neurological Disorders and Stroke," Parkinson's Disease occurs from the loss of the cells producing the neurotransmitter, dopamine. The drug, levodopa, treats Parkinson's Disease by helping to replace the loss of cells.
References
- "Memory: From Mind to Molecules"; Memory and the Biological Basis of Individuality; L. R. Squire, MD & E. R. Kandel, MD; 2009
- "In Search of Memory"; One Cell at a Time; E. R. Kandel, M.D.; 2006
- Integrative Psychiatry: Neurotransmitters
- University of Washington: Neuroscience for Kids
- National Institute of Neurological Disorders and Stroke: Parkinson's Disease
