A novel activity associated to the neurons of a SOM, called Residual Activity (RA), is defined in order to enlarge into the temporal domain the capabilities of a Self-Organizing Map for clustering and classifying the input data when it offers a temporal relationship. This novel activity is based on the biological plausible idea of partially retaining the activity of the neurons for future stages, that increases their probability to become the winning neuron for future stimuli. The proposed paper also proposes two quantifiable parameters for evaluating the performances of algorithms that aim to exploit temporal relationship of the input data for classification. Special designed benchmarks with spatio-temporal relationship are presented in which the proposed new algorithm, called TESOM (acronym for Time Enhanced SOM), has demonstrated to improve the temporal index without decreasing the quantization error.