Behavioral scientists have explored the biological roots of love as well as the psychological factors that determine love feelings and behaviors. They have devised useful ways of classifying different types of love. .
Increasingly, neuroscientists have attributed significant roles to chemicals, called neurotransmiters in the brain and nervous system. Neurotransmitters are chemicals that are secreted in high concentrations in the synapse, the space between the nerve ends of one nerve cell and those of the next. Nerve cells are arranged in sequences so that nerve impulses can travel rapidly along nerve pathways. Neurotransmitters help the nerve impulse move from one cell to the next. The action of these chemicals has been linked to major thinking and emotional disorders. Many medications used to treat conditions such as depression or schizophrenia act Synapse xt at the synapse on these chemicals. Although not completely proven, some writers have suggested that the broad actions of specific neurotransmitters are involved in feelings and thoughts of love.
One neurotransmitter is named dopamine. It is said to increase attention, motivation, and goal directed behavior. In excess it can produce feelings of exhilaration, increased energy, hyperactivity, sleeplessness, loss of appetite, symptoms of addiction, anxiety, and fear. To the extent that the feeling of ecstasy in romantic love involves these symptoms, it may be the result of dopamine. Many writers have described love as an addiction. Another neurotransmitter, norepinephrine, can also cause exhilaration, excessive energy, and loss of appetite A third chemical, serotonin, has been associated with depression when levels at the synapse are too low. Some anti-depression medications, such as Prozac, work to increase the level of serotonin at the synapses. Decreased levels of serotonin also have been linked to obsessive-compulsive disorder. Lovers often become obsessed in thinking about their loved one. They cannot turn off their racing thoughts. While chemical action in love presents an appealing hypothesis, it remains unproven.
The anatomy of love rests in nerve centers in the brain. These connect with the limbic system, controlling motivation and emotion. The brain’s pain and pleasure centers are also part of this complex neurological mechanism. These centers are responsible for sexual drive and feelings. Another important role in the love process may be played by endorphins, chemicals produced by the brain, similar to morphine, that increase feelings of pleasure and reduce pain. Other brain chemicals, similar to amphetamines, are thought to control the “high” experience when we are in love and the “crash” when love fails. These processes also occur in animals but there is an important difference. Animals lack the highly developed cerebral cortex of humans. The cortex is the seat of thought processes that exert control over the love process. It is by these processes that personal preferences, learning, and past experience influence whom we judge as attractive and acceptable as a partner in love.
The most telling studies of the role of the brain and of neurotransmitters have used MRIs (magnetic resonance imagery), brain scans which measure the volume of blood flowing in various regions of he brain. When a brain area is active the MRI “lights up” in that region. If that region is also known to be a part of the pathway of specific neurotransmitters, it may be assumed that the neurotransmitter is also active in the love process.