Brain connectivity changes in response to cortical electrical stimulation in blind neuroprosthesis users

The success of visual neuroprostheses in long-term blind individuals depends not only on the prosthetic technology but also on the brain's ability to readjust its multimodal sensory processing circuits. This study investigates longitudinal changes in resting-state cortical connectivity in two blind subjects implanted with an intracortical microelectrode array (10 × 10 Utah Electrode Array) in the visual cortex for 6 months. During this period, daily microstimulation sessions elicited phosphene perception, and periodic electroencephalographic recordings in the resting state were conducted. Cortical connectivity was quantified using spectral coherence across 64 electroencephalographic channels. Results revealed significant changes in connectivity patterns pre- and post-implantation, with linear trends observed during the implantation period. These trends varied between subjects: User 1 exhibited changes in the 7 to 13 Hz band, while user 2 showed changes in the 15 to 30 Hz band. This study highlights the brain's adaptive capacity in response to sensory restoration and provides insights into optimizing neuroplasticity for improved outcomes in neuroprosthetic interventions.