and about the pathophysiology of neurological disease processes, including cellular mechanisms underlying etiology, course, and outcome. Knowledge about these biological processes can lead to the design of strategies aimed at treating specific symptoms and disorders and evaluating the efficacy and limitations of those treatments. Such understanding also can be important in framing and implementing a rational prevention strategy. The more that is known about etiology, the more possible it becomes to target preventive interventions to intervene in causal chains.
Neuroscience research varies in scope from highly theoretical to practical application, but, in general, the neuroscience research supported by the National Institutes of Health (NIH) takes a more disease-oriented focus, whereas the research supported by the National Science Foundation (NSF) focuses on acquiring basic knowledge about the functioning of the nervous system. The strategic value of having these complementary approaches is well recognized, but merits reaffirmation: knowledge from research in basic science is essential for applied investigations. Using worms or grasshoppers to study how nerve cells grow, differentiate, and reach their targets, and investigating the interaction between genetic and environmental factors in these processes, provides a simpler model system for understanding how more complex systems function.
Neuroscience research has provided important insights into how mental disorders arise. The discovery of chemical neurotransmission more than 70 years ago can be taken as the beginning of the modern neuroscience era. Prior to this discovery, understanding of the brain was limited to knowledge of its anatomy. Now, however, the functional relationship between certain classes of transmitters and specific neurons, the nature of transmitter receptors, and the consequences of receptor activation are being studied. Specific data are being gathered that define conditions in which channels will open or close, calcium will enter the cell or be excluded, and genes will be activated or silenced.
The basic function of nerve cells is to transmit information. Once chemical neurotransmitters are released, they act on neighboring cells to excite or inhibit them. There is a highly precise interaction between the neurotransmitter and a specific receptor protein on the target cell that regulates the latter's response, yet a single neurotransmitter can affect multiple receptors. For example, the neurotransmitter serotonin, which is important in both depression and schizophrenia, acts on at least 11 different specific serotonin receptors, and the neurotransmitter gamma-amino butyric acid (GABA) may act on as many as 100. These receptors differ slightly in their molecular structure and in the target functions