Why Do We Sometimes Sense Light in the Absence of Light?

Why do the eye's photoreceptors misfire, signaling to the brain that they sense photons—even when no photons (light) are present? MedicalNewsToday
reports that scientists may have the answer. "Reporting in the June 10 issue of Science, neuroscientists at the Johns Hopkins University School of Medicine have discovered that a light-capturing pigment molecule in photoreceptors can be triggered by heat, as well, giving rise to these false alarms."
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