A possible role for protein synthesis, extracellular signal-regulated kinase, and brain-derived neurotrophic factor in long-term spatial memory retention in the water maze.

Hippocampal protein synthesis is dependent upon a number of different molecular and cellular mechanisms that act together to make previously labile memories more stable and resistant to disruption. Both brain-derived neurotrophic factor (BDNF) and extracellular signal-regulated kinase (ERK) are known to play an important role in protein synthesis-dependent memory consolidation, via the mitogen-activated protein-kinase (MAP-K) signaling pathway during the transcription phase of protein synthesis. The current study investigates the influence of protein synthesis inhibition (PSI) by cycloheximide on spatial learning and memory.

Protein degradation, as with protein synthesis, is required during not only long-term spatial memory consolidation but also reconsolidation.

The formation of long-term memory requires protein synthesis, particularly during initial memory consolidation. This process also seems to be dependant upon protein degradation, particularly degradation by the ubiquitin-proteasome system. The aim of this study was to investigate the temporal requirement of protein synthesis and degradation during the initial consolidation of allocentric spatial learning.

Emergence of an egocentric cue guiding and allocentric inferring strategy that mirrors hippocampal brain-derived neurotrophic factor (BDNF) expression in the Morris water maze.

From insects to humans, successful navigation relies on retained representations of spatial relations. These representations are thought to depend on the hippocampal formation, particularly those that are independent of the navigator (allocentric representations). The Morris water maze is a simple and popular task often used to assess spatial navigation.

Vestibular influence on water maze retention: transient whole body rotations improve the accuracy of the cue-based retention strategy.

Spatial learning in the water maze is thought to rely both on distal cues and vestibular information [Aggleton JP, Vann SD, Oswald CJP, Good M. Identifying cortical inputs to the rat hippocampus that subserves allocentric spatial processes: a simple problem with a complex answer. Hippocampus 2000;10:466-74; Pearce JM.

Retention of cue-based associations in the water maze is time-dependent and sensitive to disruption by rotating the starting position.

Research has focused mainly on the acquisition phase of spatial tasks, while retention has been relatively ignored. In three experiments, we determine the type of information that is retained in spatial memory using the water maze task. In experiment 1, we demonstrate that by rotating the distal cues 180 degrees post-acquisition Wistar rats search in the opposite area to where the platform should be.