Molecular maps of neural activity and quiescence

The rapid accumulation of inducible transcription factors (ITFs), such as c -Fos and Zif268, in activated neurons combined with histological methods th at offer detection at the cellular level are key features that have led to their wide use in visualizing activated neurons. There are two major drawba cks of ITFs that limit their use in the CNS - cell-type expression specific ity and stimulus-transcription coupling uncertainty. Recent technical advan ces in the field of molecular activity mapping now permit dual-labeling app roaches that help resolve some of these ambiguities and identify neurons th at are activated by different sensory stimuli. Furthermore, the recent iden tification of the robl/LC7-like gene, which shows immediate-early repressio n after stimulation, may have utility in functional mapping where it can be used to delineate quiescent neurons and serve as a complement to molecular activity markers.