Depth‐Customizable 3D Electrode Array for Recording Functional Connectivity in the Brain

Understanding neural activity across multiple brain regions, especially in three dimensions, is essential for advancing neuroscience research. However, traditional 3D electrode arrays are often restricted to fixed depths, limiting their ability to probe complex brain structures. In this study, a depth‐customizable, flexible 3D multi‐shank electrode array that produces precise neural recordings at various brain depths is developed. Integrating 2D flexible electrode arrays with a modular supporting board allowed the insertion depth to be easily adjusted without re‐fabrication. In vivo experiments produce successful recordings from the motor cortex, somatosensory cortex, and deep structures such as the substantia nigra. Functional connectivity analysis also reveals strong correlations between the substantia nigra and motor cortex, confirming that the developed array can be used to accurately assess neural network dynamics in 3D space. Due to its greater experimental flexibility, the depth‐customizable 3D electrode array developed in this study represents a versatile and cost‐effective tool for assessing functional connectivity across the entire brain.