The Melanopic Sensitivity Function Accounts for Melanopsin-Driven Responses in Mice under Diverse Lighting Conditions
Figure 5
The melanopic sensitivity function accounts for the spectral sensitivity of tonic LGN firing activity in mice with functional rods/cones.
(A) Example response of an Opn1mwR ‘sustained’ LGN neuron to the three test stimuli depicted in Fig. 1A at a range of irradiances (numbers above traces indicate log light intensity relative to the maximum achievable-3.4 log m-lux). (B) Mean ± SEM response to the three stimuli (and below in overlay) at maximum irradiance (n = 46 cells; each unit's response normalised to the largest change in firing rate across all stimuli). (C–E) Irradiance response relationship for Opn1mwR LGN sustained firing responses (20–30 s after stimulus onset) to the three stimuli. Sensitivity could be explained by a single linear function (F-test) when irradiances were expressed in melanopic lux (C; 0.432), but not in effective photon flux for L- or S-cones (D & E; P = 0.001 & 0.022 respectively).