title: Lateralization of the grasp reflex in male and female human newborns.
abstract: The lateralization of the grasp reflex was studied in male and female newborns. The mean grasp-reflex strength of the right hand was found to be higher than that of the left hand in males, but the difference was not significant. The mean grasp-reflex strength of the right hand was found to be significantly higher than that of the left hand in females. There was no significant difference between the mean grasp-reflex strengths of the right hand in the male and female subjects. The mean reflex strength of the left hand was found to be higher in males than females; the difference was only marginally significant. The right minus left (R - L) reflex strength showed a significant positive linear relation to the right-and left-reflex strengths in both sexes. This was, however, much more pronounced for the right-reflex than the left-reflex. There was a significantly positive linear correlation between the reflex strengths of the right and left hands and the body weight in males. The females did not show such a relationship between reflex strength and body weight. These sex-related differences in the grasp reflex in newborns were discussed in light of cerebral lateralization and its hormonal modulation.
authors.affiliation: Department of Physiology, Medical Faculty, Atatürk University, Erzurum, Turkey.
authors.forename: U
authors.initials: U
authors.lastname: Tan
authors.forename: R
authors.initials: R
authors.lastname: Ors
authors.forename: M
authors.initials: M
authors.lastname: Kürkçüoglu
authors.forename: N
authors.initials: N
authors.lastname: Kutlu
authors.forename: A
authors.initials: A
authors.lastname: Cankaya
mesh_terms: D001835:Body Weight; D001921:Brain / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D012739:Gonadal Steroid Hormones / Q000502:physiology; D006225:Hand / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction; D012018:Reflex / Q000502:physiology*; D012737:Sex Factors; D013739:Testosterone / Q000502:physiology
chemical_list: D012739:Gonadal Steroid Hormones; D013739:Testosterone