The ability to acquire and utilize spatial memory representations in the brain is key for successful navigation through novel and familiar environments. This ability is critically dependent on cellular, synaptic and systems mechanisms within medial temporal lobe structures of the mammalian brain. One such structure, the hippocampus, appears to play an important role in integrating relationships amongst stimuli in the environment, forming neural representations of those relationships and utilizing that information to navigate seamlessly through a variety of surroundings. For efficient navigation, synaptic responses within the hippocampus should show potentiated responses when presented with either novel or familiar spatial cues. A key feature underlying this ability, and an important cellular mechanism of memory and spatial memory specifically, is long-term potentiation (LTP). LTP describes a process whereby increases in the strength of synapses lead to highly efficient signal transmission between neurons and through neural networks. The induction of LTP nominally requires the interplay between N-methyl-D-aspartate receptors (NMDAr) and a-amino-3-hydroxy-5- methylisoxazole-4-propionic acid receptors (AMPAr) while the expression of LTP appears to be largely dependent on changes in AMPAr composition. The current chapter examines the importance of the AMPAr and its specific subunits (GluR1 - GluR4) in LTP processes as well as the formation and utilization of spatial memory representations. A summary of in vitro work will be provided to examine how different subunit compositions of the AMPAr contribute to the induction and expression of LTP. This will be compared and contrasted with work examining in vivo hippocampal AMPAr subunit manipulations and outcomes on spatial behavioral processes.

Department of Neuroscience

Tzakis, N. (Niko), & Holahan, M.R. (2016). AMPA receptor subunit contribution to hippocampal-mediated spatial memory. In Spatial, Long-and Short-Term Memory: Functions, Differences and Effects of Injury (pp. 31–46).