title: PHOTO-NEURO-ENDOCRINE EFFECTS IN CIRCADIAN SYSTEMS, WITH PARTICULAR  REFERENCE TO THE EYE. OPENING REMARKS.
mesh_terms: D000818:Animals; D001717:Birds; D002940:Circadian Rhythm; D005123:Eye; D005246:Feedback; D007030:Hypothalamo-Hypophyseal System; D008027:Light; D010507:Periodicity; D010827:Physiology
keywords: BIRDS; CIRCADIAN RHYTHM; EYE; FEEDBACK; HYPOTHALAMO-HYPOPHYSEAL SYSTEM; LIGHT; PERIODICITY; PHYSIOLOGY