Multisensory response enhancement

A combined response exceeding a specified unisensory benchmark. For baseline-corrected mean spike counts, $R_{AV}>\max (R_A,R_V)$ defines enhancement over the strongest component. This differs from exceeding the sum, and depends on the response measure, analysis window and statistical comparison.

The tendency for relative multisensory enhancement to be larger when component stimuli evoke weak responses. Absolute gain and percentage gain must be distinguished: $100(R_{AV}-R_{\max })/R_{\max }$ can increase merely because the denominator becomes small. A ratio is undefined at a zero denominator and does not directly measure information or behavioral benefit.

A combined response exceeding the sum of its separately measured component responses under an explicit baseline convention. Consistent subtraction of spontaneous activity prevents counting background twice. Enhancement above the strongest component need not be superadditive.