(a) Sensitivity profiles of mouse S- and M-opsin (dotted black lines) and spectra of UV (magenta) and green LED/filter combinations used in the mouse stimulator. (b) Sensitivity profiles of mouse S- and M-opsin (dotted black line) and spectra of blue, green and red LED present in a standard TFT monitor. (c) Sensitivity profiles of zebrafish opsins (dotted black lines) and spectra of UV, blue, green and red LEDs used in the zebrafish stimulator. (d) Spectra (in nW) of UV and green LED obtained from measurements using increasing brightness levels; shown are spectra for 0, 9, 19, 29, 39, 49, 59, 68, 78, 88, and 98% brightness. (e) Non-linearised intensity curve (‘raw’) with sigmoidal fit (black), estimated gamma correction curve (black dotted line; ‘Look-up table’) and linearized intensity curve (‘corrected’) for green LED. (f) Photoisomerisation rates for maximal brightness of UV (19.2 and 3.8 photoisomerisations ·103 P*/second/cone for S- and M-opsin, respectively) and green LED (0 and 19.5 ·103 P*/second/cone for S- and M-opsin, respectively). Note that the UV LED also activates M-opsin due to its increased sensitivity in the short wavelength range (β-band, Discussion).