William M. DeBello and Eric I. Knudsen
The barn owl, given a reason, can reorganize its auditory map to match its perception of visual space. This plasticity was thought to center on only one brain area--the inferior colliculus (ICX), the initial site in which the map is formed. Now DeBello and Knudsen identify a second site of plasticity: the superficial layers of the optic tectum (OT), an area that corresponds to the superior colliculus in mammals. While the potential for plasticity declines in the ICX beyond the age of 80 days, the higher-level OT retained the ability to adjust for 200 days. That's bad news for the barn mouse.
2. Putting fear in its place: remapping of hippocampal place cells during fear conditioning
Marta A. P. Moita, Svetlana Rosis, Yu Zhou, Joseph E. LeDoux, and Hugh T. Blair
Hippocampal space cells encode information about the spatial environment, creating a map that tends to remain stable on reentering that space. However, even within a single environment, place cells can change their preferred firing locations, presumably to convey contextual details. This week, Moita et al. show that fear conditioning can induce such a re-mapping process. The remapping was more pronounced in rats that received contextual training. The authors suggest that place cells can convey not only the geometric details of an environment, but motivational and behavioral cues as well.
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