“左撇子”有時(shí)是遺傳缺陷的表達(dá)或是早期的發(fā)育遲緩。在這一期的Deutsches Ärzteblatt International上,，Stefan Gutwinski與合著者對(duì)左撇子和右撇子提出當(dāng)前的科學(xué)理解,。
在所有族群中都能發(fā)現(xiàn)左撇子,。它出現(xiàn)在人類(lèi)進(jìn)化過(guò)程中的早期，在更高認(rèn)知功能的發(fā)展中起關(guān)鍵作用,。例如,，人類(lèi)語(yǔ)言被認(rèn)為是與通過(guò)手勢(shì)的手動(dòng)交流的單側(cè)大腦控制的發(fā)展一起出現(xiàn)的。而且,，它就在左右手習(xí)慣形成后出現(xiàn),，其中左右手習(xí)慣是所能發(fā)展的人類(lèi)手的非常精細(xì)的運(yùn)動(dòng)功能。
大部分時(shí)間里,，左撇子只是自然出現(xiàn),，正常變異。但是,，在一些病例中,，它是一種不便，可能正好反映出遺傳缺陷或早期發(fā)育障礙,。然而,，左撇子和右撇子在患特定疾病的人中似乎更常見(jiàn)。
例如,，在癲癇,、精粹分裂癥和孤獨(dú)癥中可觀察到這種現(xiàn)象。而且,，當(dāng)前研究顯示,，相對(duì)于右大腦半球而言，左大腦半球活動(dòng)減少可能導(dǎo)致抑郁和躁狂癥的相對(duì)失調(diào),。（生物谷bioon.com)
doi:10.3238/arztebl.2011.0849
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Understanding Left-Handedness
Gutwinski, S; Löscher, A; Mahler, L; Kalbitzer, J; Heinz, A; Bermpohl, F
Background: The human cerebrum is asymmetrical, consisting of two hemispheres with differing functions. Recent epidemiological and neurobiological research has shed new light on the development of the cerebral lateralization of motor processes, including handedness. In this article, we present these findings from a medical perspective. Method: We selectively searched the PubMed online database for articles including the terms "handedness," "left handedness," "right handedness," and "cerebral lateralization." Highly ranked and commonly cited articles were included in our analysis. Results: The emergence of handedness has been explained by physiological and pathological models. Handedness arose early in evolution and has probably been constitutive for the development of higher cognitive functions. For instance, handedness may have provided the basis for the development of speech and fine motor skills, both of which have played a critical role in the evolution of mankind. The disadvantages of certain types of handedness are discussed, as some cases seem to be associated with disease. Conclusion: The consideration of handedness from the epidemiological, neurobiological, and medical points of view provides insight into cerebral lateralization.
