Quanta (July 30) -- Scientists ponder how the intrinsic circuitry of the brain’s visual cortex generates the patterns of activity that underlie the distinct geometric shapes people typically see when under the influence of psychedelics. Physicist Nigel Goldenfeld of the U. of I. has proposed a twist on the original idea of a mathematical mechanism for generating many of the repeating patterns commonly seen in biology, factoring in the complications of the brain’s “noise.”