The human temporal lobe is a multimodal association area which plays a key role in various aspects of cognition, particularly in memory formation and spatial navigation. Functional and anatomical connectivity of temporal structures is thus a subject of intense research, yet by far underexplored in humans due to ethical and technical limitations. We assessed intratemporal cortico-cortical interactions in the living human brain by means of single pulse electrical stimulation, an invasive method allowing mapping effective intracortical connectivity with a high spatiotemporal resolution. 18 subjects with normal anterior-mesial temporal MR imaging undergoing intracranial presurgical epilepsy diagnostics with multiple depth electrodes were included. The investigated structures were temporal pole, hippocampus, amygdala and parahippocampal gyrus. Intratemporal cortical connectivity was assessed as a function of amplitude of the early component of the cortico-cortical evoked potentials (CCEP). While the analysis revealed robust interconnectivity between all explored structures, a clear asymmetry in bidirectional connectivity was detected for the hippocampal network and for the connections between the temporal pole and parahippocampal gyrus. The amygdala showed bidirectional asymmetry only to the hippocampus. The provided evidence of asymmetrically weighed intratemporal effective connectivity in humans in vivo is important for understanding of functional interactions within the temporal lobe since asymmetries in the brain connectivity define hierarchies in information processing. The findings are in exact accord with the anatomical tracing studies in non-human primates and open a translational route for interventions employing modulation of temporal lobe function.

中文翻译：

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人体时间网络的体内评估：不对称有效连接的证据

人类颞叶是一个多模态关联区域，在认知的各个方面都起着关键作用，特别是在记忆形成和空间导航方面。因此，时间结构的功能和解剖学连通性是一个深入研究的主题，但由于伦理和技术限制，迄今为止在人类中尚未得到充分探索。我们通过单脉冲电刺激评估了活人大脑中的颞内皮质 - 皮质相互作用，这是一种侵入性方法，允许以高时空分辨率绘制有效的皮质内连接。18 名前近中颞叶 MR 成像正常的受试者接受了具有多个深度电极的颅内术前癫痫诊断。研究的结构是颞极、海马、杏仁核和海马旁回。颞内皮质连接被评估为皮质皮质诱发电位 (CCEP) 早期成分幅度的函数。虽然分析显示所有探索的结构之间具有强大的互连性，但在海马网络以及颞极和海马旁回之间的连接中检测到明显的双向连接不对称。杏仁核仅对海马体表现出双向不对称性。提供的人类体内非对称加权时间内有效连接的证据对于理解颞叶内的功能相互作用很重要，因为大脑连接的不对称定义了信息处理的层次结构。