Acute alcohol often impairs hippocampal function producing what appears to be a selective, temporary lesion of this brain region.  In humans, the hippocampus is critical for declarative memory while in rodents the hippocampus is critical for a variety of cognitive functions including spatial memory.  Specifically, the hippocampus facilitates the learning of salient places in a given environment and this type of cognition often overshadows other types of cognition, such as learning about salient cues. 

 

When animals are tested following the administration of acute alcohol they demonstrate a significant reduction in the use of spatial memory while also demonstrating a significant increase in the use of cue based memory.  This is demonstrated in the data figure that is described in Matthews et al., 1999. 

 

In addition, it has been demonstrated that individual pyramidal neurons in the hippocampus demonstrate spatial specificity when freely behaving rodents navigate an environment.   These neurons, termed place cells, seem to provide place information, termed place fields, for animals when they are behaving.   The discovery of place cells by John O’Keefe was recently cited when he won the Nobel Prize in Physiology.

 

If administration of alcohol impairs the use of spatial memory in rodents then it seems reasonable that similar doses of alcohol will alter the place information provided by place cells when recorded in freely behaving rodents.   This is in fact the case.  As seen in the video, acute alcohol administration, at doses similar to doses that impair spatial memory, degrade the spatial specificity of hippocampal place cells.  Importantly, this degradation is apparent only when the animal is intoxicated and the specificity of the field recovers when the animal is again sober.   These data are discussed in Matthews et al., 1996.