| Anecdotally, I participated, as a non-blind control, to a study assessing cross-modal perception in blind folks (how they use their visual cortex to analyze haptic stimuli). The meat of the experience was evaluating the performance of pattern recognition on an array of electrode placed on the tongue. Before and after training, all subjects underwent evoked potential recordings of their tongue (recodring the EEG following electric stimuly on the tongue). Being aware of the protocol in advance, during the "before" evoked potential session, I concentrated on my mouth, visualizing it as a place I was sitting in. I ended up experiencing blue phosphenes (light flashes) sinc'ed with the electric pulses, and my visual cortex was lighting up along with my sensory cortex. That was my first and only proper synesthetic experience (I used to associate vowels and colors as a kid, each vowel clearly mapped to a color, but it was conceptual, not perceptual). Since I was an outlier (similar evoked potentials were only seen in blind subjects after training), I was excluded from the rest of the study, so I could not experience the complex patterns on the "tongue display unit". https://www.sciencesquared.eu/sites/default/files/toungue_di... |
