Mercadante Marcos Tomanik, Cysneiros Roberta Monterazzo, Schwartzman José Salomão, Arida Ricardo Mario, Cavalheiro Esper Abrão, Scorza Fulvio Alexandre
Department of Psychiatry, Universidade Federal de São Paulo/Escola Paulista de Medicina, São Paulo, Brazil.
Med Hypotheses. 2008;70(2):352-7. doi: 10.1016/j.mehy.2007.05.018. Epub 2007 Jun 29.
Neurogenesis studies had an increased development after BrdU (5-bromo-3'-deoxyuridine), a marker of cell proliferation. Today, several studies have showed the relevance of neurogenesis in the hippocampal formation. Notwithstanding, other brains areas have been described presenting neurogenesis, including the amygdala. This key structure is a complex cerebral region which has been associated with social behaviors and the emotional significance of the daily experiences. Several studies have associated the amygdala to the autism, a severe neurodevelopmental disorder. In this paper, we discuss the hypothesis of neurogenesis in the amygdala as a contributing cause of autism. The social skills require competent new neuronal connections, including efficient plasticity synaptic rearranging. Interestingly, emotional context cannot be imprinting in mature neurons in the presence of GABA, a neurotransmitter release during new environments experiences. However, it is known that new neurons are not well responsive to GABA stimulation, allowing the long-term potentiation necessary for the learning process. Based on these evidence it is tantalizing to hypothesize that the sociability impairment seen in some individuals with autism may partly be assigned to impaired regulation of the GABAergic system and to the impact of this impairment on the adequate functioning of the amygdala and on its capacity to store new experiences and to modulate the plasticity of the corticostriatal connections.
在细胞增殖标志物5-溴脱氧尿苷（BrdU）出现后，神经发生研究有了进一步发展。如今，多项研究表明神经发生在海马结构中具有重要意义。尽管如此，其他脑区也被描述存在神经发生现象，包括杏仁核。这个关键结构是一个复杂的脑区，与社交行为以及日常经历的情感意义相关。多项研究将杏仁核与自闭症（一种严重的神经发育障碍）联系起来。在本文中，我们探讨杏仁核中的神经发生作为自闭症一个促成原因的假说。社交技能需要有功能正常的新神经元连接，包括有效的可塑性突触重排。有趣的是，在新环境体验中释放的神经递质γ-氨基丁酸（GABA）存在的情况下，情感背景无法在成熟神经元中留下印记。然而，已知新神经元对GABA刺激反应不佳，这使得学习过程所需的长时程增强得以发生。基于这些证据，很诱人地推测，一些自闭症个体中出现的社交能力受损可能部分归因于GABA能系统调节受损，以及这种损伤对杏仁核正常功能、对其存储新体验以及调节皮质纹状体连接可塑性能力的影响。
