Context-dependent memory traces in the crab’s mushroom bodies: Functional support for a common origin of high-order memory centers

MAZA FRANCISCO; SZTARKER JULIETA; SHKEDY AVISAG; LOCATELLI F; DELORENZI ALEJANDRO

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

NATL ACAD SCIENCES

Lugar: Washington DC, USA; Año: 2016

0027-8424

The hypothesis of a common origin for the high-order memorycenters in bilateral animals is based on the evidence that severalkey features, including gene expression and neuronal networkpatterns, are shared across several phyla. Central to this hypothesisis the assumption that the arthropods? higher order neuropilsof the forebrain [the mushroom bodies (MBs) of insects and thehemiellipsoid bodies (HBs) of crustaceans] are homologous structures.However, even though involvement in memory processeshas been repeatedly demonstrated for the MBs, direct proof ofsuch a role in HBs is lacking. Here, through neuroanatomical andimmunohistochemical analysis, we identified, in the crab Neohelicegranulata, HBs that resemble the calyxless MBs found in severalinsects. Using in vivo calcium imaging, we revealed trainingdependentchanges in neuronal responses of vertical and mediallobes of the HBs. These changes were stimulus-specific, and, like inthe hippocampus and MBs, the changes reflected the context attributeof the memory trace, which has been envisioned as anessential feature for the HBs. The present study constitutesQ:12 functional evidence in favor of a role for the HBs in memory processes,and provides key physiological evidence supporting a commonorigin of the arthropods? high-order memory centers.