Moro reflex 1169893 202704922 2008-04-02T02:18:01Z SieBot 4005189 robot Adding: [[nl:Moro-reflex]] The '''Moro reflex''', also known as the ''[[Startle reaction|startle reflex]]'', is one of the [[infantile reflex]]es. It may be observed in incomplete form in [[premature birth]] after the 28th week of [[gestation]], and is usually present in complete form by week 34 ([[third trimester]]). It is normally present in all infants/newborns up to 4 or 5 months of age, and its absence indicates a profound disorder of the motor system. An absent or inadequate Moro response on one side is found in infants with hemiplegia, brachial plexus palsy, or a fractured clavicle. Persistence of the Moro response beyond 4 or 5 months of age is noted only in infants with severe neurological defects. It was discovered and first described by Austrian [[pediatrician]] [[Ernst Moro]] (1874-1951). This [[reflex]] is a response to unexpected loud [[noise]] or when the infant feels like it is falling. It is believed to be the only unlearned [[fear]] in human newborns. The [[little Albert]] study used the startle reflex in the famous [[classical conditioning]] experiment to make him fear white fuzzy things. The primary significance of this [[reflex]] is in evaluating integration of the [[central nervous system]] (CNS), since the reflex involves 4 distinct components: # Startle # spreading out the [[arm]]s ([[Anatomical terms of motion|abduction]]) # unspreading the arms ([[Anatomical terms of motion|adduction]]) # [[Cry]]ing (usually) Absence of any component (except crying) or any [[asymmetry]] in the movements is abnormal, as is persistence of the reflex in older infants, children and [[adult]]s. However, in individuals with cerebral palsy, persistence and exacerbation of this reflex is common. References: 1. <references/>Adams and Victor's Neurology, Chapter 28. Normal Development and Deviations in Development of the Nervous System ==External links== * [http://medlineplus.gov/ Medline Plus]: [http://www.nlm.nih.gov/medlineplus/ency/article/003293.htm Moro reflex] * [http://video.google.com/videoplay?docid=-2508818082092298520&q=moro+reflex Video of the Moro Reflex by University of Nebraska (Google Video)] * [http://www.neurology.org/cgi/content/full/68/6/437/DC1 Pathologic Moro Reflex following acute demyelinating lesion of unknown origin in medulla oblongata (Neurology)] {{Primitive_reflexes}} [[Category:Reflexes]] [[Category:Obstetrics]] [[Category:Pediatrics]] [[da:Mororefleksen]] [[de:Moro-Reflex]] [[es:Reflejo de Moro]] [[fr:Réflexe de Moro]] [[it:Riflesso di Moro]] [[he:רפלקס מורו]] [[nl:Moro-reflex]] [[ja:モロ反射]] [[pl:Odruch Moro]] [[zh:莫罗氏反射]]