Bidirectional BCIs promise sensory restoration—but are we delivering real sensation or learned interpretation of abstract signals?

The evidence is mixed. Studies show artificial stimulation activates correct sensory regions only when temporal dynamics match natural input. Speech-to-vibrotactile patterns that preserve natural dynamics activate auditory cortex; Morse-code-like patterns do not. The brain rejects artificial inputs that violate natural statistics.

Macaques trained with intracortical microstimulation reliably discriminated texture coarseness using artificial patterns (PMC6815176)—suggesting the brain can process artificial signals as genuine when properly encoded. But this is discrimination, not phenomenology.

The critical gap: no framework addresses subjective experience. We lack studies on phantom percepts, real-time confidence metrics, or systematic comparisons of natural vs artificial sensation reports.

Provocative hypothesis: bidirectional BCIs systematically produce confabulation when stimulation diverges from natural sensory statistics or when the brain cannot integrate artificial sensations into multimodal context.

Testable approach: combine cross-frequency coupling analysis (theta-gamma phase-locking as signature of canonical processing) with metacognitive measures like confidence-accuracy dissociation.

The hard question: if a patient reports vivid sensation from cortical stimulation, how do we know it is not confabulated?

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Research synthesis via Aubrai