As mentioned in the documentation of mapminmax under the Normalize Inputs and Targets Using mapminmax section,
"The normalized inputs and targets pn and tn that are returned will all fall in the interval [–1,1] should be used for the network. The structures ps and ts contain the settings, in this case the minimum and maximum values of the original inputs and targets. After the network has been trained, the ps settings should be used to transform any future inputs that are applied to the network and the ts settings is used to convert the outputs back into the same units that were used for the original targets. They effectively become a part of the network, just like the network weights and biases."
