Browsing by Author "Kocijančić, Dušica (37031231300)"

Introduction Lateralization of brain functions such as language and manual dominance (hand preferences and fine motor control) are most likely under genetic control. However, this does not preclude the effect of various environmental factors on functional brain lateralization. A strong association of non-right-handedness (left- and mixed-handedness) with various neurodevelopmental conditions (e.g. schizophrenia, autism, Rett syndrome) implies that in some cases, non-right-handedness may be acquired rather than inherited (i.e., pathologically determined). Objective The aim of the study was: (a) re-investigation of several known risk factors for left-handedness (age of mother and/or father, twin pregnancies, and birth order), and (b) examination of hitherto uninvestigated factors (type of birth, Apgar score, maternal smoking during pregnancy). Methods Putative, causative environmental agents for this shift in manual distributions are explored in a sample of 1031 high school students (404 males and 627 females) from Belgrade. Both pre-existing (age of parents, twin pregnancy, and birth order) and new (Apgar score, maternal smoking, type of birth) putative agents are examined. Results We found that maternal smoking and low Apgar score (2-6) can significantly increase risk for lefthandedness (p=0.046 and p=0.042, respectively). The remaining factors showed no significant association with left-handedness in adolescents. Conclusion Our study clearly demonstrates that left-handedness may be related to maternal smoking during pregnancy and a low Apgar score on birth.

To date, lateralization in living beings is a phenomenon almost mythologically unexplored. Scientists have proved that lateralization is not exclusively a human feature. Investigations in molecular biology, protein structure, mobility of bacteria, and intracellular lateralization in ciliates, shows important and universal nature of lateralization in living systems. Dominant lateralization implies the appearance of a dominant extremity, or a dominant sense during the performance of complex psychomotor activities. Hand dominance is usually defined as a tendency to use one hand rather than another to perform most activities and this is considered to be the most obvious example of cerebral lateralization and exclusive characteristic of humans. However, there are some exceptions in other species. The dominant hand is able to perform more complex and subtle manual tasks than the non-dominant hand, and this behavioral superiority is the absolute result of additional cerebral support. The asymmetry of brain organization was confirmed in rats, chimpanzees, dogs and birds, some fishes and lizards. The relationships between hand dominance with brain structure and function remain far from clear. For a long time, lateralization was considered unique to humans, but recently it has become clear that lateralization is a fundamental characteristic of the organization of brain and behavior in all vertebrates. It has been questioned to what extent lateralization in humans and other vertebrates may be comparable. © 2016. Srpski Arhiv za Celokupno Lekarstvo. All right reserved.