Study of conditions to evaluate light hypersensitivity in a light-dark box using a mouse model and a mydriatic

The pathophysiology and treatment of sensory hypersensitivity remain unclear. This study aimed to identify a simple behavioral analysis device and animal model evaluating glare sensitivity and to test the effects of psychotropic drugs using this device.

We recorded the response to light stimulation using a light-dark box (LDB) in male mice in mydriatic-induced glare sensitivity (MiG) and normal control (NC) groups. We also investigated the effects of chronic drug administration (aripiprazole, risperidone, and diazepam). For biological analysis, we measured monoamine levels in the hippocampus, prefrontal cortex, amygdala, hypothalamus, and visual cortex using high-performance liquid chromatography (HPLC).

"Time spent in the light box" under the condition "dark-reared and a light box with 1000 lux illuminance" showed significantly shorter durations in the MiG compared to the NC. Aripiprazole administration in MiG and diazepam administration in NC and MiG caused a significant decrease in amygdalar serotonin (5-HT). The administered drug in this study did not restore the MiG's time spent in the light box to the same level as the NC.

"Time spent in the light box" under the condition "dark-reared and a light box with 1000 lux illuminance" was considered useful as an item for evaluating glare sensitivity. The trends in brain monoamine changes and behavioral analysis suggest that the reduction of 5-HT in the amygdala by aripiprazole and diazepam may be involved in alleviating glare sensitivity and anxiety. However, no significant behavioral change was observed, so aripiprazole/risperidone/diazepam could not be said to function clearly as a treatment for glare sensitivity.