Gene therapy for color blindness near 530 nm, and the S cone absorbs near 420 nm. Contrary to popular belief, the peak absorption frequency for L, M, and S cones do not exactly correspond to red, green, and blue wavelength. Rather, the peak frequency for the L cone is orange, yellowish green in M cones, and blue-violet in S cones. These cones transduce the absorbed light into electrical information to be relayed to neurons in the retina such as retinal bipolar cells and retinal ganglion cells, before reaching the brain. The signals from different cones are added or subtracted from each other to process the
Excitable medium Excitable medium An excitable medium is a nonlinear dynamical system which has the capacity to propagate a wave of some description, and which cannot support the passing of another wave until a certain amount of time has passed (known as the refractory time). A forest is an example of an excitable medium: if a wildfire burns through the forest, no fire can return to a burnt spot until the vegetation has gone through its refractory period and regrown. In chemistry, oscillating reactions are excitable media, for example the Belousov–Zhabotinsky reaction and the Briggs–Rauscher reaction. Pathological activities in the heart and