Oct, 1, 2023

Vol.30 No.2, pp. 84-88


Review

  • Korean Journal of Biological Psychiatry
  • Volume 18(1); 2011
  • Article

Review

Korean Journal of Biological Psychiatry 2011;18(1):25-35. Published online: Jan, 1, 2011

A Study of the Relationships between the Ratio of 2nd to 4th Digit Length and Cerebral Laterality

  • Ahyoung Kim, MD1;Seongkyun Kim, PhD2;Jinyoung Youn, MD3;Jaeseung Jeong, PhD2;Joo-Ho Lee, MD1;Jeong-Ho Chae, MD, PhD4; and Yu-Sang Lee, MD, PhD1;
    1;Yong-In Mental Hospital, Yongin, 2;Department of Bio and Brain Engineering, KAIST, Daejeon, 3;Gyeonggi Provincial Hospital For The Elderly, Yongin, 4;Department of Psychiatry, The Catholic University of Korea College of Medicine, Seoul, Korea
Abstract

Objectives:Cerebral laterality is thought to be an important marker for neurodevelopment. Prenatal testosterone could influence both cerebral laterality and 2nd to 4th finger length ratio(2D:4D). EEG coherence and 2D:4D were examined to investigate the relationship between prenatal testosterone level and cerebral laterality.

Methods:EEG was recorded in 24 healthy subjects in the eyes closed resting state. Differences in 2D:4D finger ratio were used to discriminate "masculine finger type" and "feminine finger type" groups. The 2D:4D ratio was lower and greater than one for the "masculine finger type" group and "feminine finger type" group, respectively. We used coherence analysis to estimate the cortical functional connectivity. 

Results:There were statistically meaningful relationships among cerebral functional connectivity, sex and finger ratio. Man and masculine finger type group showed higher intra-hemispheric coherence than those of woman and feminine finger type group. Woman and feminine finger type group showed higher inter-hemispheric coherence than those of man and masculine finger type group. 

Conclusions:These results imply that prenatal testosterone might act as important determinants of cerebral laterality. Further examination of the relationship between 2D:4D and EEG coherence in schizophrenia could give some clues for the neurodevelopmental hypothesis of schizophrenia genesis.

Keywords 2<sup>nd</sup> to 4<sup>th</sup> digit ratio(2D:4D);EEG coherences;Cerebral laterality.