Prusky et al., 2000 Prusky G.T.

West P.W.R.

Douglas R.M. Behavioral assessment of visual acuity in mice and rats.

Y-shaped water maze experiments were performed in either scotopic (dark) or photopic (light) condition (). During adaptation periods, mice were released in the water close to stimulating light boxes for discovering the hidden platform. During adaptation period, the released place became further from the light boxes with time and ultimately mice were released at the release chute. The adaptation lasted for 2 days with one section (12 trials per section) per day. After adaptation mice were trained to find a hidden platform associated to the task stimuli. Trainings usually lasted for 7 days: one section per day and 12 trials per section. The platform and the associated stimuli were placed right or left randomly across trials in each section, such as LRLRLLRRLRRL. Upon completion of the trainings, the test sections were conducted in two separated days. In Task #1 animals were trained with visible light horizontal and vertical light gratings (0.8 circles per degree, c/d, 7.26 × 10photons·μm·sat the release chute) and then tested to discriminate visible (7.26 × 10photons·μm·sat the release chute) and NIR (8.01 × 10photons·μm·sat the release chute) horizontal/vertical light gratings in the dark background. For the visual acuity test in the dark background, 0.054 c/d, 0.08 c/d, 0.107 c/d, 0.134 c/d, 0.161 c/d, 0.214 c/d, 0.268 c/d, 0.322 c/d, 0.35 c/d, 0.38 c/d, 0.435 c/d gratings were tested for 980-nm light stimuli (8.01 × 10photons·μm·sat the release chute) and 535-nm light stimuli (7.26 × 10photons·μm·sat the release chute). In Task #2 animals were trained and tested to discriminate NIR light gratings made of LEDs arrays under the background visible room light (background light intensity equivalent to 535-nm light was 4.31 × 10photons·μm·s). Two lines of 535-nm LEDs and two lines of 980-nm LEDS were placed perpendicular to each other. Each line was made of 18 LEDs. The left pattern was 90 degrees rotated compared to the right pattern. The training lasted for 9 days with one section per day and 12 trials per section with 980-nm LEDs on only. In Task #2, the intensity of 980-nm light pattern measured at the release chute was 8.01 × 10photons·μm·sand 535-nm light pattern was 7.26 × 10photons·μm·s. In Task #3 animals were trained with visible light triangle and circle patterns and tested to discriminate visible and NIR light triangle/circle patterns under the dark background. In Task #4 animals were tested to discriminate visible light triangle/circle patterns under the visible light background (7.26 × 10photons·μm·s) or NIR light background (8.01 × 10photons·μm·s). In Task #3 and #4, the intensity of 980-nm light pattern measured at the release chute was 8.01 × 10photons·μm·sand 535-nm light pattern was 7.26 × 10photons·μm·s. In Task #5 animals were tested to discriminate patterns in the mixture of visible and NIR light patterns. The hidden platform was associated with the triangle pattern and four different stimuli were presented randomly (see Figure 6 I). In Task #5, the intensity of 980-nm light pattern measured at the release chute was 2.32 × 10photons·μm·sand 535-nm light pattern was 1.57 × 10photons·μm·s. All videos were acquired by infrared camera and analyzed by Corel Screen Cap X6 and Origin 8.0. Y shaped water maze experiments were implemented 3-8 weeks after pbUCNP-injection. The spectrum of 980-nm LEDs was measured using spectrometer (Avantes USB2.0) to confirm there is no detectable visible light emission.