A Closer Look at the Hippocampus and Memory. Issue 8 (August 2017) - Voss, Joel L.
Abstract : Current interpretations of hippocampal memory function are blind to the fact that viewing behaviors are pervasive and complicate the relationships among perception, behavior, memory, and brain activity. For example, hippocampal activity and associative memory demands increase with stimulus complexity. Stimulus complexity also strongly modulates viewing. Associative processing and viewing thus are often confounded, rendering interpretation of hippocampal activity ambiguous. Similar considerations challenge many accounts of hippocampal function. To explain relationships between memory and viewing, we propose that the hippocampus supports the online memory demands necessary to guide visual exploration. The hippocampus thus orchestrates memory-guided exploration that unfolds over time to build coherent memories. This new perspective on hippocampal function harmonizes with the fact that memory formation and exploratory viewing are tightly intertwined. Trends: Memory experiments do not typically measure exploratory viewing behavior, and therefore the observed neural signals can reflect an unknown mixture of processing related to memory, perception, and visual exploration. Experiments that quantify viewing behaviors during memory formation suggest that important memory–viewing interactions have been missed in previous research, warranting re-evaluation of conclusions about memory mechanisms supported by structures such as the hippocampus. The hippocampus contributes to viewing during memory formation by providing online memory representations to guide effective exploration, which results in coherently organized memories. This new theoretical perspective suggests that the hippocampus and viewing are tightly intertwined because hippocampal contributions to memory formation unfold over the timecourse of an episode in synchrony with the timecourse of viewing behavior.