THE IMMUNE SYSTEM
The immune system is the body’s inbuilt mechanism to protect itself from attack by potentially hazardous foreign invaders.
The brain controls the immune system more directly than it was earlier thought. It also receives feed back from the immune system.
Research has shown that nerve fibers innervate immune system organs like the lymph nodes, bone marrow, and spleen, and also determine the number of lymphocytes that are available to fight.
Neurotransmitters and hormones also influence the ability of the lymphocytes to multiply and their ability to effectively kill invaders.
An underactive immune system leads to infection, whereas an overactive immune system may lead to autoimmune diseases.
Thus maintaining a constant balance is very important.
Immunologist Gerard Renoux suggested that this balance is maintained by the brain.
He found that lesions of the left hemisphere led to drop in the number and efficiency of white blood cells in the spleen of rats.
Lesions to the right hemisphere led to increase in immune activity.
Immunologist Ed Blalock suggested that the immune system sends feedback to the brain about the internal state of the body by secreting hormones.
In the early 1920s, Ader’s experiments with cyclophosphamide, (an immuno-suppressant), and saccharine flavored water showed that the immune system could be classically conditioned.
Thus, the brain-immune system link received more support.
Newer findings suggest that motivational-emotional system and psycho-social factors can influence the immune system functioning both, in a positive as well as a negative manner.