Long-term memory and visuospatial navigation

Abstract

Background and Aims

Long-term memory is normally assessed with traditional measures such as the Wechsler memory scale. However, these measures might not fully capture individuals’ daily experiences. Long-term memory system has three separate information components: 1) encoding; 2) storage; and 3)retrieval. These three processes are thought to occur in the hippocampal formation. One of the main functions of the hippocampus is to construct and maintain spatial maps of the environment. In fact, when the hippocampus is selectively lesioned, humans present severe spatial memory deficits. The right hippocampus is involved in allocentric object location memory (objects that are part of the environment) and finding one's way through complex environments. This part of the hippocampus is activated during physical navigation. The left hippocampus is activated during the retrieval of memory of navigation. It seems that the visuospatial model requires the encoding, binding and retrieval of an event and its context. Given these findings, visuospatial navigation tasks likely explore long-term memory. In fact, visuospatial navigation can be considered as a valid surrogate for long-term memory and a good probe to activate the hippocampal formation. Neuroimaging studies have greatly improved the literature by providing confirmatory evidence that the hippocampus, together with the parahippocampal and posterior parietal cortices, are engaged in visuospatial navigation. Further, there is evidence from neuroimaging studies that the hippocampus is involved during complex navigational situations. The usefulness of visuospatial navigation as a measure of long-term memory will be discussed.