• 생물정신의학
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• 제17권1호
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• pp.37-43
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• 2010

Objectives : The $2^{nd}$ to $4^{th}$ digit length ratio(2D : 4D) is a sexually dimorphic trait regardless of ethnicity and shows sex differences. According to previous research, men usually have a relatively shorter $2^{nd}$ digit than $4^{th}$ digit. There is tendency that men with lower 2D : 4D are perceived as being more masculine and tend to perform better in some physical sports. Furthermore, 2D : 4D is negatively associated with trait aggression. In this study, we examine gender difference of 2D : 4D and compare 2D:4D of female Korean national team members to 2D : 4D of control subjects. Besides that, we also compare 2D : 4D of female Korean national team members according to their sports entries. Methods : The sample of this study is 396 people, 67 female Korean national team member, 216 control women and 113 control men. We measured $2^{nd}$ to $4^{th}$ digit length of their right hand. In addition, we collected demographic information of female Korean national team members using a self-report questionnaire. Results : The mean 2D : 4D of female Korean national team members is 0.96(SD=0.04), smaller than control women's 2D : 4D(0.97, SD=0.03) and significantly higher than control men's 2D : 4D(0.95, SD=0.03). We also found differences between control men and women. Non-martial arts related sports athletes have significant difference with control men in 2D : 4D. However, martial arts related sports athletes' 2D : 4D is not significantly different from other groups, including control men. Conclusion : These results are consistent with the findings of previous research that there is a significant difference between men and women in their 2D : 4D. Furthermore, 2D : 4D of martial arts related sports athletes have not shown any difference from the 2D : 4D of control men that 2D : 4D of non-martial arts related athletes have shown. This fact is important in consideration of masculine characteristics. For further research, it is necessary to examine 2D : 4D difference according to sport ability and gender differences.

• 생물정신의학
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• 제18권1호
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• pp.25-35
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• 2011

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.

• 한국산학기술학회논문지
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• 제13권9호
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• pp.3983-3990
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• 2012

과도한 음주와 흡연은 인체에 유해하며, 다양한 영향요인들이 있다. 본 연구의 목적은 생물학적 요인인 손가락 길이비(2D:4D)와 음주 및 흡연과의 관계를 파악하는데 있다. 연구대상자는 대학생 435명(남자 121명, 여자 314명)으로 음주와 흡연 관련 설문에 응답한 후 복사기를 이용하여 손가락길이가 측정되었다. 연구 결과, 대학생들의 손가락 길이비는 남자 0.95, 여자 0.96으로 남녀 간에 유의한 차이가 있었다(p<0.001). 음주여부에 따른 손가락 길이비는 여자에서만 왼손에서 유의한 차이가 있었고(p<0.05), 흡연여부에 따른 손가락 길이비는 남자에서만 왼손에서 유의한 차이가 있었다(p<0.05). 음주 및 흡연과 손가락 길이비 사이의 관계는 왼손의 손가락 길이비가 낮을수록 음주량과 흡연량이 많은 것으로 나타났다(p<0.05). 결론적으로, 모체내 테스토스테론의 영향을 받는 손가락 길이비는 흡연 및 음주 선호와 상관관계가 있으므로, 음주와 흡연 예방프로그램이나 절주와 금연프로그램의 진행시 참여자의 손가락 길이비도 하나의 기초자료로 활용될 수 있을 것으로 사료된다.

• 한국산학기술학회논문지
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• 제14권3호
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• pp.1245-1251
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• 2013

본 연구의 목적은 손잡이 유형에 따른 손가락 길이비(2D:4D)의 특성을 파악하는데 있다. 자료수집은 2010년 10월 4일부터 2012년 4월 30일까지 실시되었다. 연구대상자들은 손잡이 유형 평가 후, 캘리퍼를 사용하여 양손의 집게손가락과 반지손가락의 길이가 측정되었다. 연구 결과, 2D:4D는 왼손잡이는 왼손에서, 오른손잡이는 오른손에서 성차이가 두드러지게 나타났다. 그러나 손잡이 유형에 따라서는 남녀 모두 유의한 차이가 없었다. 남자에서 왼손잡이는 좌우 2D:4D 사이에 차이가 없었으나, 오른손잡이는 오른손이 유의하게 2D:4D가 낮은 것으로 나타났다. 좌우 2D:4D의 상관관계는 남자에서는 오른손잡이의 상관관계가 높았고, 여자에서는 왼손잡이의 상관관계가 높았다. 결론적으로, 2D:4D는 한국인에서 손잡이 유형사이에 차이는 없으나, 성차이와 좌우 2D:4D의 상관관계는 손잡이 유형에 따라 다른 특성을 나타낸다고 할 수 있을 것이다.

• 생물정신의학
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• 제17권3호
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• pp.136-144
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• 2010

Objectives : The $2^{nd}$ to $4^{th}$ digit length(2D : 4D) ratio reflects the amount of exposure and sensitivity to the prenatal sex hormone and it is considered to be the most convenient and useful way to understand the influence of sex hormone in the determination of human behavioral traits. This study was carried out to find the correlation between the 2D : 4D ratio and characteristics of temperament and character in Korean university students. We assumed that 2D : 4D ratio would show a strong correlation with temperament which is defined to be an inclination of an automatical emotional response to a stimulus. Methods : Participants were 104 university students who completed 2 self-report measures : Temperament and Character Inventory(TCI), Temperament Test. We examined the 2D : 4D ratio of each subject by measuring the lengths of the $2^{nd}$ and $4^{th}$ fingers using a photocopy measurement. We performed statistical analyses using correlation test and t-test to examine the relationship between 2D : 4D ratio and psychological characteristics. Results : We found out the typical sex difference in 2D : 4D ratio. Women had significantly higher 2D : 4D ratio than men. TCI-Character factor(TCI-C) didn't show any significant correlation with the 2D : 4D ratio. TCI-Tempterament factor(TCI-T) and the item of Temperament Test showed a significant correlation with the 2D : 4D ratio. In correlation analysis of the total group including all women and men, the 2D : 4D ratio showed a significant positive correlation in a subscale(shyness with stranger) of harm avoidance scales in TCI-T. In correlation analysis of women's group, the 2D : 4D ratio showed a significant positive correlation in two subscales( fear of uncertainty) and[shyness to stranger] of harm avoidance scales in TCI-T. In correlation analysis of men's group, the 2D : 4D ratio showed a significant negative correlation with a sanguine temperament item of the Temperament Test. Conclusion : The results suggest that the amount of exposure to sex hormone in the prenatal period seems to have an impact on the determination of temperament and characteristics.

• 생물정신의학
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• 제18권4호
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• pp.260-266
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• 2011

Objectives The second to fourth digit ratio (2D : 4D) is known to reflect testosterone level during intrauterine period. Testosterone is essential for masculinization of brain. Cloninger's type II alcoholism is characterized by early age at onset and largely limited to males. Compared with type I alcoholism, type II alcoholism is thought to be masculine. There is a possibility that the digit ratio of type II alcoholism is low compared with type I. We examined digit length ratio in Cloninger's type I and II alcoholism to understand the effects of intrauterine testosterone on the development of alcoholism. Methods The participants were 87 alcohol dependent patients. We divided two subtypes of patients by Irwin's symptom list, based on Cloninger's concept. We captured the images of both palms by the scanner and measured the lengths of digits by the graphic program. Then we analyzed the digit ratios by independent-sample t-test. Results The mean 2D : 4D of type I was 0.942 (right), 0.952 (left). The mean 2D : 4D of type II was 0.927 (right), 0.940 (left). In both hands, 2D : 4D of type II was significantly lower than type I. Conclusions Type II alcoholism showed masculine type of digit length ratio compared with type I. It suggests the exposure of testosterone during intrauterine period might play an important role in determining the course and feature of alcoholism.

• 한국산학기술학회논문지
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• 제13권5호
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• pp.2170-2177
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• 2012

집게손가락과 반지손가락의 길이비(2D:4D)는 모체 내에서 태아의 테스토스테론과 에스트로겐의 영향 수준을 반영한다. 본 연구는 보건의료 대학생의 2D:4D와 성역할 정체감 유형을 파악하고 2D:4D와 성역할 정체감 사이의 관계를 파악하고자 시도되었다. 연구대상자는 보건의료 대학생 266명(남자 120명, 여자 146명)으로 성역할 정체감 설문(KSRI)에 응답한 후 복사기를 이용하여 손가락길이가 측정되었다. 연구 결과, 보건의료 대학생들의 2D:4D는 남자 0.95, 여자 0.96으로 남녀 간에 유의한 차이가 있었으며(p<0.01), 성역할 정체감에 있어서는 남자는 양성성 유형(38.3%)이, 여자는 미분화 유형(35.6%)이 가장 많았다. 남녀사이에 남성성 점수는 유의한 차이가 있었으나(p<0.001), 여성성 점수는 유의한 차이가 없었고, 성역할 정체감 유형에 따라서는 2D:4D에 차이가 없었다. 또한 남성성 여성성 점수에 따른 성역할 정체감과 2D:4D 사이의 상관관계는 남자에서는 왼손의 손가락 길이비가 낮을수록 남성성 점수가 높았으며(r= -0.188, p<0.05), 여자에서는 유의한 상관관계가 없었다. 결론적으로 보건의료 대학생 중에서도 여학생들에게 상황적인 변화에 더 잘 적응할 수 있도록 양성성 유형으로 나아갈 수 있는 중재 프로그램이 더욱 더 필요하다. 또한 본 연구에서는 2D:4D와 성역할 정체감과의 상관관계가 높게 나타나지는 않아 추후 한국인을 대상으로 한 더 많은 연구가 필요할 것으로 사료된다.

• 생물정신의학
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• 제21권4호
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• pp.151-160
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• 2014

Objectives Prenatal testosterone is known to influence both cerebral laterality and 2nd to 4th digit ratio (2D : 4D). Epigenetic changes are thought to play some role in it. We studied sex-related differences between 2D : 4D and cerebral laterality in patients with schizophrenia and controls to examine the effects of prenatal testosterone in the development of schizophrenia. Methods Forty one men (18 schizophrenic patients and 23 controls) and 40 women (17 schizophrenic patients and 23 controls) were recruited from one psychiatric hospital in Korea. The 2D : 4D and electroencephalographic (EEG) coherence in 19 channels (66 pairs of interhemispheric coherence and 54 pairs of intrahemispheric coherence) were measured. The sex-related statistical analyses between 2D : 4D and EEG coherence in controls and patients with schizophrenia were performed using multiple regression. Results In male patients, the relationship between 2D : 4D and right intrahemispheric EEG coherence showed mainly positive correlation in delta and theta frequency bands, while it showed negative correlation in male controls. In female patients, the relationship between 2D : 4D and interhemispheric EEG coherence showed stronger positive correlation in alpha and beta frequency bands, while it showed weaker positive correlation in female controls. Conclusions Low prenatal testosterone may play certain roles in altered correlation between 2D : 4D and cerebral laterality in schizophrenia and the development of schizophrenia by epigenetic mechanism.

• 생물정신의학
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• 제24권3호
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• pp.142-148
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• 2017

Objectives The ratio of second to fourth digit length (2D : 4D) could be a potential epigenetic marker of sexual dimorphism reflecting prenatal testosterone exposure. Testosterone is known to affect the development of the brain through an epigenetic mechanism. The purpose of this study was to investigate the effects of exposure to fetal testosterone on the metabolic syndrome based on 2D : 4D of schizophrenia patients and the relationship with the age of onset of schizophrenia. Methods A total of 214 schizophrenia patients participated in this study. The participant's physical and blood tests were performed according to the American National Cholesterol Education Program's Third Amendment of the Metabolic Syndrome Diagnostic Criteria, and the 2D : 4D was measured by the method designed by McFadden. Data were statistically analyzed by t-test, Pearson's correlation analysis and multiple regression model analysis. Results 2D : 4D was significantly higher in female than male in both hands, and there was a statistically significant negative correlation between 2D : 4D and the age of onset of schizophrenia in male. However, 2D : 4D did not show statistically significant correlation with metabolic factors. Conclusions Fetal testosterone suggests the possibility of affecting the age of onset of schizophrenia through the epigenetic mechanism, but there is no clear relationship with metabolic factors.