Pulsed infrared light alters neural activity in rat somatosensory cortex in vivo

► Pulsed IR light on cortex induces intrinsic optical signal. ► IR light induced IOS is similar in magnitude and time course to IOS of tactile stimulation. ► INS evokes changes in neural activity without loss of cortical functionality. ► Introduces a new stimulation method for studying cortical circuitry and function.