Effective tactile noise facilitates visual perception

The fulcrum principle establishes that a subthreshold excitatory signal (entering in one sense) that is synchronous with a facilitation signal (entering in a different sense) can be increased (up to a resonant-like level) and then decreased by the energy and frequency content of the facilitating signal. As a result, the sensation of the signal changes according to the excitatory signal strength. In this context, the sensitivity transitions represent the change from subthreshold activity to a firing activity in multisensory neurons. Initially the energy of their activity (supplied by the weak signals) is not enough to be detected but when the facilitating signal enters the brain, it generates a general activation among multisensory neurons, modifying their original activity. In our opinion, the result is an integrated activation that promotes sensitivity transitions and the signals are then perceived. In other words, the activity created by the interaction of the excitatory signal (e.g., visual) and the facilitating signal (tactile noise) at some specific energy, produces the capability for a central detection of an otherwise weak signal. In this work we investigate the effect of an effective tactile noise on visual perception. Specifically we show that tactile noise is capable of decreasing luminance modulated thresholds.