A color-coded SSVEP-based brain-computer interface.

Ju, Shance; Ming, Gege; Dong, Guoya; Gao, Xiaorong; Wang, Yijun · J Neural Eng · 2026

basic_science · Level V

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Abstract

Steady-state visual evoked potential (SSVEP) based brain-computer interfaces (BCIs) predominantly employ frequency, phase, or spatial coding. This study proposes a color-dimension SSVEP encoding scheme and evaluates its feasibility and elicited response characteristics. Seven isoluminant colors were paired to form 21 combinations, and four stimulation paradigms (sliding checkerboard, reversing checkerboard, flickering checkerboard, and solid-color flicker) were used to investigate the modulatory effects of color on SSVEP. Offline simulations and an online four-target SSVEP-BCI were conducted for validation purposes. Under identical frequencies and initial phases, different color combinations produced separable SSVEP patterns in amplitude, topography, and phase, enabling reliable classification. At 10 Hz, the online four-target system with solid-color flicker achieved an average information transfer rate (ITR) of 80 ± 0 bits per minute (bits/min). The proposed approach introduces an additional encoding dimension for SSVEP-BCI, expanding stimulus design options and supporting broader applications.