Bridging Language Models and Brain Activity
A study connects artificial and biological neurons to enhance language understanding.
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Table of Contents
Linking computer models that understand language with how our brains process language has gained more attention lately. On one side, computer models help us figure out how our brains represent and understand language. On the other side, insights from brain studies can help us assess and enhance these computer models.
The connection between these models and Brain Activity is usually made by comparing the features in the models to brain activity data. Features in computer models are generated by Artificial Neurons, while brain activity is measured through biological neurons. Successful collaboration between these two fields has led to valuable insights in both neuroscience and Language Processing.
However, there are two main challenges that hold back further progress. First, features in the models are usually generalized and do not capture fine details. Most studies use broad features, which fail to examine the inner workings of the models. A better approach would be to analyze the specific components and their functions in order to match them more closely to brain activity. Second, brain activity is often measured in isolated parts of the brain. This approach overlooks the complex connections and interactions that occur in the brain during language processing.
To tackle these issues, we sought to answer a few key questions:
- How can we define finer details in artificial neurons in these computer models?
- Do these neurons carry important language-related information?
- Is there a clear connection between artificial neurons and biological neurons in the brain?
To answer these questions, we lay out a framework that connects the artificial neurons from computer models to biological neurons in our brains. We used a dataset of brain scans while individuals listened to stories in order to test our framework. We employed a computer language model called BERT to analyze the stories' text. Each part of this text model can be treated as a separate artificial neuron.
We calculated how active these artificial neurons were in response to the stories and compared this with the brain data. By measuring the connection between the activity of artificial and biological neurons, we aimed to learn more about how they interact.
Experimental Findings
Our findings revealed a strong connection between the artificial neurons of the language model and the biological neurons in the brain. This connection suggests that artificial neurons can indeed represent meaningful language information, and they do connect with brain activity related to language processing.
We mapped out how often specific artificial neurons lined up with biological neurons, observing that deeper layers of the model produced stronger connections. This means that the more complex aspects of the language model were better aligned with brain functions.
We also discovered which specific brain regions showed the strongest connections with the model. Certain regions, known for language understanding, were particularly prominent. For example, areas known for handling grammar and those involved in memory were heavily linked to certain artificial neurons.
Furthermore, we assigned different language roles to the artificial neurons based on the types of words they interacted with in the language tasks. We saw that certain patterns emerged where some neurons were more related to nouns and verbs while others were tied to punctuation or pronouns. These insights revealed how different parts of the language model captured distinct linguistic elements.
Related Work
Research connecting Language Models and brain activity is not entirely new, but previous efforts often treated entire layers of the model as single neurons. This approach lacked the precision needed to capture the full range of neuron interactions.
Earlier studies focused on the connection between models and brain responses to specific words or phrases. Over time, more advanced models have emerged, improving our ability to predict brain activity based on linguistic structure. These developments have led to better performance in both language tasks and the interpretation of brain responses to language.
Despite these advancements, a gap still existed between the fine details of the model's structure and the complex workings of the brain. By offering a more detailed representation of artificial neurons, we can bridge this gap and enhance our understanding of both systems.
Challenges and Limitations
While our study brought forward valuable insights, it also faced several limitations. First, we relied on a specific language model, and there may be differences between various models and how they relate to brain activity. Future research should explore these variations across different types of models.
Additionally, while we provided strong evidence for the connection between artificial and biological neurons, further tests, such as using brain data from unrelated stimuli, could solidify our findings. We also acknowledged the possibility that the method we used to measure neuron activity might lead to some information loss. Exploring alternative methods could give a more comprehensive picture.
Finally, our understanding of the connection between artificial and biological neurons was limited to a single linguistic framework. Future work should strive to investigate more diverse linguistic connections to draw a broader understanding of how language is processed by both computers and human brains.
Conclusion
In summary, our study showcases a framework that successfully links artificial neurons in language models with biological neurons in the human brain. This connection not only improves our understanding of how language is processed in machines but also sheds light on brain functions during language comprehension.
The outcomes of this research may aid in the development of better language-processing models that are more aligned with the workings of the human brain. By pursuing these connections, we can unlock new pathways for future studies and technological advancements in natural language processing and neuroscience.
Title: Coupling Artificial Neurons in BERT and Biological Neurons in the Human Brain
Abstract: Linking computational natural language processing (NLP) models and neural responses to language in the human brain on the one hand facilitates the effort towards disentangling the neural representations underpinning language perception, on the other hand provides neurolinguistics evidence to evaluate and improve NLP models. Mappings of an NLP model's representations of and the brain activities evoked by linguistic input are typically deployed to reveal this symbiosis. However, two critical problems limit its advancement: 1) The model's representations (artificial neurons, ANs) rely on layer-level embeddings and thus lack fine-granularity; 2) The brain activities (biological neurons, BNs) are limited to neural recordings of isolated cortical unit (i.e., voxel/region) and thus lack integrations and interactions among brain functions. To address those problems, in this study, we 1) define ANs with fine-granularity in transformer-based NLP models (BERT in this study) and measure their temporal activations to input text sequences; 2) define BNs as functional brain networks (FBNs) extracted from functional magnetic resonance imaging (fMRI) data to capture functional interactions in the brain; 3) couple ANs and BNs by maximizing the synchronization of their temporal activations. Our experimental results demonstrate 1) The activations of ANs and BNs are significantly synchronized; 2) the ANs carry meaningful linguistic/semantic information and anchor to their BN signatures; 3) the anchored BNs are interpretable in a neurolinguistic context. Overall, our study introduces a novel, general, and effective framework to link transformer-based NLP models and neural activities in response to language and may provide novel insights for future studies such as brain-inspired evaluation and development of NLP models.
Authors: Xu Liu, Mengyue Zhou, Gaosheng Shi, Yu Du, Lin Zhao, Zihao Wu, David Liu, Tianming Liu, Xintao Hu
Last Update: 2023-03-26 00:00:00
Language: English
Source URL: https://arxiv.org/abs/2303.14871
Source PDF: https://arxiv.org/pdf/2303.14871
Licence: https://creativecommons.org/licenses/by/4.0/
Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.
Thank you to arxiv for use of its open access interoperability.