Ex vivo and in vivo imaging of mouse parietal association cortex activity in episodes of cued fear memory formation and retrieval

The parietal cortex in rodents has an integrative function and participates in sensory and spatial processing, movement planning and decision-making. However, much less is known about its functions in associative memory processing. Here using Fos immunohistochemical mapping of neuronal activity and two-photon imaging in Fos-eGFP mice we show an involvement of anterior part of the parietal cortex (PtA) in the formation and retrieval of recent fear memory in mice. Using ex vivo c-fos imaging we demonstrate the specific activation of the PtA during recent memory retrieval. In vivo two-photon c-fos imaging confirms these results as well as establishes the activation of the PtA neurons during fear memory formation. Additionally, we describe a design of Fos-Cre-GCaMP transgenic mice to investigate long-term changes of calcium dynamics in neurons captured with Fos-TRAP technique during fear conditioning training.