Rhythmical Photic Stimulation at Alpha Frequencies Produces Antidepressant-Like Effects in a Mouse Model of Depression

<div><p>Current therapies for depression consist primarily of pharmacological agents, including antidepressants, and/or psychiatric counseling, such as psychotherapy. However, light therapy has recently begun to be considered as an effective tool for the treatment of the neuropsychiatric behaviors and symptoms of a variety of brain disorders or diseases, including depression. One methodology employed in light therapy involves flickering photic stimulation within a specific frequency range. The present study investigated whether flickering and flashing photic stimulation with light emitting diodes (LEDs) could improve depression-like behaviors in a corticosterone (CORT)-induced mouse model of depression. Additionally, the effects of the flickering and flashing lights on depressive behavior were compared with those of fluoxetine. Rhythmical flickering photic stimulation at alpha frequencies from 9–11 Hz clearly improved performance on behavioral tasks assessing anxiety, locomotor activity, social interaction, and despair. In contrast, fluoxetine treatment did not strongly improve behavioral performance during the same period compared with flickering photic stimulation. The present findings demonstrated that LED-derived flickering photic stimulation more rapidly improved behavioral outcomes in a CORT-induced mouse model of depression compared with fluoxetine. Thus, the present study suggests that rhythmical photic stimulation at alpha frequencies may aid in the improvement of the quality of life of patients with depression.</p></div

Effects of 8 or 14 days of treatment with photic stimulation and fluoxetine on the forced swim test in the CORT-induced mouse model of depression.

<p>The only-CORT group exhibited more immobility than the control group. Photic stimulation for 14 days but not 8 days resulted in a reduction in the immobility time compared with that of the only-CORT group. The fluoxetine-CORT group that received 14 days of treatment displayed a similar amount of immobility time compared with the only-CORT group. Notably, the co-administration of photic stimulation and fluoxetine for 8 days led to a reduction in immobility time compared with that shown by the only-CORT group. *comparison with control, **<i>p</i> < 0.01; ^#comparison with only-CORT group, ^#<i>p</i> < 0.05, Scheffe’s <i>post hoc</i> test.</p

Effects of 10–12 days of treatment with photic stimulation or fluoxetine in the open-field and social interaction tasks in the CORT-induced mouse model of depression.

<p>(A–B) Open-field task: (A) Total distance moved in the open-field box, and (B) time spent in the center area of the open-field box. The photic-CORT and control groups exhibited similar distances moved and amounts of time in the center, whereas the only-CORT and fluoxetine-CORT groups showed a reduction in total distance moved and time spent in the center area compared with the control group. (C) Social interaction task: the photic-CORT and fluoxetine-CORT groups displayed similar interaction times compared with the control group, but the only-CORT group showed a reduced amount of interaction time compared with the other groups. *comparison with control, *<i>p</i> < 0.05, **<i>p</i> < 0.01; ^#comparison with only-CORT group, ^#<i>p</i> < 0.05, ^##<i>p</i> < 0.01, Scheffe’s <i>post hoc</i> test.</p

Effects of 8 days of treatment with photic stimulation or fluoxetine on the elevated plus maze task in the CORT-induced mouse model of depression.

<p>The only-CORT and fluoxetine-CORT groups spent more and less time in the closed and open arms, respectively, than the control group. However, the photic-CORT group spent a similar amount of time in the open and closed arms as the control group, which indicates that the photic-CORT group had a normal level of anxiety. *comparison with control group, **<i>p</i> < 0.01; ^#comparison with only-CORT group, ^##<i>p</i> < 0.01, Scheffe’s <i>post hoc</i> test.</p