The Power of Thought
Complex thinking linked to improved immune system function

January 10, 2002

You may have heard that staying active mentally can ward off illness and help you live longer. Now there is evidence from the University of California (Berkeley) to support these observations. A research team led by Dr. Marian C. Diamond (the same neuroscientist who studied Albert Einstein's Brain) has found a link between complex thinking and immune system function.

The immune system helps protect an organism by producing special cells (lymphocytes) that attack and kill organisms and toxins that enter the body. One type of lymphocyte, the CD4 T cell, helps other cells fight off infection. The researchers at Berkeley knew that the brain could influence the immune system. Previous experiments had shown that animals with damage to part of the cerebral cortex (dorsolateral frontal area) had decreased T cell levels. The dorsolateral frontal cortex is important for many complex cognitive tasks such as memory, judgement and planning. The scientists did not know what would happen if they stimulated the dorsolateral frontal cortex in people. Would T cell levels go up? Would the immune system be boosted?

The researchers decided that the card game of contract bridge would be a good way to stimulate the dorsolateral cortex. Bridge is a game that requires memory, judgement and planning...the same functions attributed to the dorsolateral cortex. T cell levels in blood samples from female bridge players (ages 70-80 years old) were compared before and after a 1.5 hour bridge game.

Dr. Diamond and her colleagues found that the card players' CD4 T cell levels were significantly higher after the bridge game than the CD4 T cell levels taken before the game. There were no changes in CD4 T cell levels in women who sat quietly and listened to music while the card game was being played. There were also no changes in the levels of other types of T cells in the card players.

These data indicate that playing bridge provides a boost to the immune system by raising the level of CD4 T cell levels in the blood. It is not known how long T cell levels remain elevated. It is also unknown if these increases in T cell levels are large enough to affect a person's health. Further experiments are needed to discover how complex thought affects health. However, there is certainly no harm in playing games that require planning and memory...chess, checkers, or backgammon anyone?


  1. Diamond, M.C., Weidner, J., Schow, P., Grell, S. and Everett, M. Mental stimulation increases circulating CD4-positive T lymphocytes: a preliminary study. Cognitive Brain Research, 12:329-331, 2001.
  2. White Blood Cells

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