Given that plants lack a central nervous system, the means by which they send and store information is not obvious. There are two hypotheses for memory in "Mimosa," neither of which has yet been generally accepted. The first is when the plant is stimulated it releases a surge of calcium ions that are sensed by the protein calmodulin. The relationship between the ions and proteins are thought to stimulate voltage gated ion channels which cause electrical signals, which could be the base of plant long term memory. The other hypothesis is that plant cells act similarly to neural cells by creating electrical gradients by opening and closing ion channels and passing it along cell junctions. The information passed along can control which genes are turned on and which genes are turned off, which could be a mode for long term memory.