Word: cortex
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...meter, and it can take about two seconds for the message to arrive. From there, it is relayed in a bewildering flurry of chemical messages to the brain, first to the thalamus, where sensations like heat, cold, pain and touch first become conscious. Then on to the cerebral cortex, where the intensity and location of pain are recognized. This final stretch of the pathway is the great terra incognita in pain research. Says Fields...
...electrode into the consciousness." In any case, it is the cortex that coordinates such highly sophisticated responses to pain as screaming "Ouch!" and rubbing the sore...
Most experts now think a baby is born with a number of reflexes that are gradually replaced by the "cortical behavior" dictated from the cortex of its rapidly developing brain. Brown's Lipsitt believes that a period of "disarray" during the course of this transition may be an important element in the "crib deaths" that can mysteriously strike during the first year. The struggle to escape from accidental smothering in bedclothes, known as the "respiratory occlusion reflex," is automatic at birth but then needs to be learned. Says Lipsitt: "The peak of 'disarray' is right...
...work of Dr. Donald Stein and three colleagues at Clark University in Worcester, Mass. As reported in last week's issue of Science, the group attempted to restore mental functioning in 21 rats whose brains had been damaged by removal of large sections of the frontal cortex. This section of the brain is involved in the learning of complex spatial relationships. Typically, rats sustaining such a severe injury would take 18 days or more to master a maze that required them to alternate right and left turns in the correct order to get a drink of water...
Before attempting to repair the brain damage, Stein's team waited a week to allow for the natural accumulation of healing proteins called nerve growth factors. Then they implanted a pinhead-size lump of tissue that had been taken from the frontal cortex of normal rat embryos. The researchers used fetal cells because they are rich in growth factors and adapt easily to a new environment. Result of the operation: the brain-damaged rats were able to learn the maze in just 8½ days. While this is still slower than normal, says Stein, "the transplant was clearly producing...