美国哈佛大学Ziv M. Williams研究小组揭示单细胞分辨率下语言理解过程中的语义编码。这一研究成果于2024年7月3日在线发表在国际学术期刊《自然》上。

研究人员记录了左侧语言主导的前额叶皮层中的单个细胞，参与者在听取语义多样的句子和自然故事时进行记录。通过跟踪它们在自然语言处理过程中的活动，研究人员发现单个神经元对语义信息有着精细的皮层表示。这些神经元对特定单词的含义有选择性地响应，并可靠地区分单词和非单词。此外，它们的活动非常动态，而不是对单词作为固定的记忆表征进行响应，而是根据特定的句子语境反映单词的含义，独立于它们的语音形式。

总体而言，研究人员展示了这些细胞集合在实时语音中准确预测单词的广泛语义类别，并跟踪它们出现的句子。研究人员还展示了它们如何编码这些含义表征的层次结构，以及这些表征如何映射到细胞群体上。这些发现揭示了人类大脑皮层在神经元尺度上语义表征的精细详细组织，并开始阐明语言理解过程中含义的细胞水平处理。

据了解，从语音声音序列或字母中，人类能够通过语言提取丰富而细致的含义。这种能力对人类的交流至关重要。然而，尽管对支持语言和语义处理的大脑区域有了越来越深入的了解，但在神经组织中单细胞水平上以及动作电位的时间尺度上提取语言含义仍然大多数是未知的。

附：英文原文

Title: Semantic encoding during language comprehension at single-cell resolution

Author: Jamali, Mohsen, Grannan, Benjamin, Cai, Jing, Khanna, Arjun R., Muoz, William, Caprara, Irene, Paulk, Angelique C., Cash, Sydney S., Fedorenko, Evelina, Williams, Ziv M.

Issue&Volume: 2024-07-03

Abstract: From sequences of speech sounds1,2 or letters3, humans can extract rich and nuanced meaning through language. This capacity is essential for human communication. Yet, despite a growing understanding of the brain areas that support linguistic and semantic processing4,5,6,7,8,9,10,11,12, the derivation of linguistic meaning in neural tissue at the cellular level and over the timescale of action potentials remains largely unknown. Here we recorded from single cells in the left language-dominant prefrontal cortex as participants listened to semantically diverse sentences and naturalistic stories. By tracking their activities during natural speech processing, we discover a fine-scale cortical representation of semantic information by individual neurons. These neurons responded selectively to specific word meanings and reliably distinguished words from nonwords. Moreover, rather than responding to the words as fixed memory representations, their activities were highly dynamic, reflecting the words’ meanings based on their specific sentence contexts and independent of their phonetic form. Collectively, we show how these cell ensembles accurately predicted the broad semantic categories of the words as they were heard in real time during speech and how they tracked the sentences in which they appeared. We also show how they encoded the hierarchical structure of these meaning representations and how these representations mapped onto the cell population. Together, these findings reveal a finely detailed cortical organization of semantic representations at the neuron scale in humans and begin to illuminate the cellular-level processing of meaning during language comprehension.

DOI: 10.1038/s41586-024-07643-2

Source: https://www.nature.com/articles/s41586-024-07643-2