New evidence confirms link between IQ, brain cortex
Rate of change in the thickness of the brain's cortex is an important factor associated with a person's change in IQ, according to a collaborative study by scientists in five countries. The cortex is the thin, outermost layer of nerve cell tissue of the brain, typically measuring a few millimeters in thickness. The cortex contains nerve cell bodies and is critical for cognitive functions such as perception, language, memory and consciousness. The cortex begins to thin after the age of five or six as part of the normal aging process. This study is the first to show the association between cortical thickness and development in full scale IQ, and has potentially wide-ranging implications for the pedagogical world and for judicial cases in which the defendant's IQ score could play a role in determining the severity of the sentence.