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In recent decades, a growing number of evidence has challenged the “traditional” view that memory functions performed in the medial temporal lobe (MTL) are divided into different systems (declarative vs non-declarative, episodic vs semantic) and processes (recollection vs familiarity). From this research, a so-called representational approach has emerged, according to which the sub-regions of the MTL are specialized in processing different types of representations, irrespective of the cognitive process engaged. This model predicts that MTL lesions will not only affect memory, but any cognitive process involving the level of representation supported by the region damaged. In this article, we first present the experimental results that led to the emergence of this approach, as well as the principles of functional organization it proposes. We then summarize the functions associated with the hippocampus in representational models (i.e., the construction of spatial scenes and the association of high-resolution features) and explain how this structure can underpin different mechanisms through its internal organization. Finally, we present three possible applications of this approach in the context of neuropsychological evaluations. First, assessing memory functioning involves careful consideration of the representations elicited by a given test. Second, assessing hippocampal integrity without recourse to memory tests can be achieved by evaluating a patient’s ability to construct a spatial scene. Finally, to detect the early cognitive changes associated with Alzheimer’s disease, it is necessary to target the level of representations that rely on the transentorhinal cortex.