A 128-channel Flexible Probe for Stable Neural Recording in the Visual Cortex

High-density neural interfaces are pivotal for advancing visual brain-computer interfaces (BCIs), where decoding complex perceptual information necessitates large-scale and high-fidelity neural recordings. Conventional silicon-based probes, however, provoke chronic neuroinflammation and glial scarring, limiting their utility for longitudinal studies. To overcome these challenges, we design and fabricate a high-density flexible vision probe (HFVP) featuring 128 channels, reliable packaging (compact ball grid array), and ultrathin form factor (≈1.2 µm). The electrode sites are further modified with biocompatible iridium oxide (IrO x ) film to improve the electrochemical performance by an order of magnitude, facilitating high-fidelity neural signal acquisition. In vivo recordings of the mouse's primary visual cortex (V1) have demonstrated HFVP's capacity for large-scale neural recording and revealed that neurons with preferences for visual stimuli exhibit higher spike correlation. Moreover, the stability of the HFVP is assessed for over sixteen weeks without apparent degradation. The HFVP presented in this work provides a stable and effective tool for chronic neural recording in the visual cortex and prospective applications in vision reconstruction.