I wish I knew the answer! This is a very broad question. The five senses activities are often deemed to be correlated with the brain signals resulted from the activities of cortical neurons of certain regions in the brain. A variety of brain imaging techniques such as EEG, fMRI, etc. collect these signals with difference temporal and spatial resolution. A good number of signal processing, statistic methods and machine learning techniques can be applied on the collected signals to extract the desired insights.

As for cognitive functions of the brain, it is rather hard to say how and where they happen how they correlate to brain sensory inputs. Perhaps psychological systems are examples of 'esoteric systems'.