Visual perception evoked by an intracortical 96-channel microelectrode array inserted into human occipital cortex.

 J ClinInvest. 2021. https: //doi.org/10.1172/JCI151331 

Commentary

The aim of this study was to transfer information directly to the visual cortex of visually impaired people and thereby restore basic vision. However, there are no clinically available cortical visual prostheses yet.

For the experiment, an intracortical microelectrode array consisting of 96 electrodes was implanted into the visual cortex of a 57-year-old person who had been blind for six months. The thresholds and properties of visual perception evoked by the intracortical microstimulation were then measured. The resulting intracortical microelectrode implantation and subsequent external implantation were performed without complications, with a mean stimulation threshold of 66.8 ± 36.5 µA for a single electrode.

Consistently high quality recordings were obtained from visually deprived neurons, stimulation parameters remained stable over time, and simultaneous stimulation via multiple electrodes was associated with a significant reduction in threshold (p < 0.001, ANOVA test), elicited discriminative flash perception and allowed visually impaired subjects to identify some letters and to recognize object boundaries.

Furthermore, we were able to observe a learning process that helped the subjects recognize complex patterns over time. The results demonstrate the safety and efficacy of chronic intracortical microstimulation via a large number of electrodes in the human visual cortex, and indicate that it has a high potential to restore functional vision to the visually impaired.