I. Introduction and Motivations  
A. The Development of a Human-Centric Metaverse  
B. Towards a Human-Centric Metaverse using BCI  
C. Related Surveys and Our Contributions  
D. Paper Organization  

II. Background  
A. The Metaverse  
B. Brain-Computer Interface: Sensor Technology  
C. Deployment of BCI within the Metaverse  

III. BCI-Enhanced User Immersion  

IV. BCI-Enhanced Metaverse User Interactions  

V. Human Digital Twin  

VI. Challenges, Emerging Applications, and Future Research Directions  
A. Current Challenges  
B. Emerging Applications and Future Research Directions  

VII. Conclusion