 Ripplets are a unique type of cortical oscillation that occurs when thalamocortical axons are activated by light. These oscillations are characterized by a series of negative transients that are similar to hippocampal ripples, but faster and more intense. The firing patterns of both fast spiking and regular spiking neurons are altered depending on whether they are entrained to the ripple or not. Additionally, these ripples can be used as a model system to study the mechanisms behind fast and ultra-fast cortical and hippocampal oscillations. This article was authored by Hang Hu, Rachel E. Hostetler, and Ariel Ackman.