Mice Reach Higher Visual Sensitivity at Night by Using a More Efficient Behavioral Strategy.

Area of Science:

• Neuroscience
• Chronobiology
• Vision Science

Background:

• Circadian clocks regulate physiological adjustments to daily light-dark cycles.
• The retina possesses an intrinsic circadian clock, influencing its physiology.
• The functional impact of retinal diurnal rhythms on visual perception and behavior remains unclear.

Purpose of the Study:

• To investigate the influence of the diurnal rhythm on the sensitivity limits of mouse vision.
• To determine whether observed behavioral changes are due to retinal processing or higher-level strategies.

Main Methods:

• A photon detection task was employed to link retinal output signals to visually guided behavior.
• Electrophysiological recordings were performed on key retinal ganglion cell types (ON sustained, OFF sustained, OFF transient alpha).
• Behavioral strategies were analyzed in relation to the animal's diurnal state and task history.

Main Results:

• Visually guided behavior at its sensitivity limit exhibits strong diurnal control, peaking in sensitivity and stability at night.
• Diurnal variations in visual sensitivity were not localized to the retina.
• Mice demonstrated a more efficient nocturnal visual search strategy, which could be adopted during their subjective day after prior nocturnal experience.

Conclusions:

• The day/night cycle significantly impacts high-level sensory processing and behavioral strategies in vision.
• Behavioral diurnal differences are mediated by adaptive search strategies rather than retinal sensitivity changes.
• Visual psychometric functions are robustly influenced by an animal's diurnal state, search strategy, and task experience.