Memory-related neural plasticity in the hemiellipsoid bodies, the crab's "mushroom bodies

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

Montevideo

Conferencia; International Conference for Neuroethology; 2016

Internationa Society for Neuroethology

Memory-relatedneural plasticity in the hemiellipsoid bodies, the crab's "mushroombodies". Francisco JavierMaza, Fernando Locatelli,Avishag Shkedy, Julieta Sztarker, Alejandro Delorenzi Laboratorio deNeurobiología de la Memoria, DFBMC, FCEN, Universidad de Buenos Aires. IFIBYNE-CONICET,Argentina. The corpora pedunculata (or mushroom bodies)are complex paired structures in the brain of invertebrate species vastlystudied in insects. Since their description in the mid-1850, the corporapedunculata have been considered to be higher-order brain centers involved in multimodalsensory integration and memory. Although morphologically diverse, a corporapedunculata common ground plan was described across different invertebrates.Moreover, it has been proposed that the mushroom bodies and the vertebratepallium evolved from the same structure in a common ancestor circa 600 millionyears ago. In crustaceans, neuropils sharing a similar pattern with the corporapedunculata are the hemiellipsoid bodies (HBs), which have been proposed tohave an evolutionary common origin. Here, we show in the crab Neohelicegranulata morphological and immunohistochemical studies that parallel theresults of well described HBs in other crustaceans. Golgi impregnation showsthat, like the MBs in insects, the HB globuli cells project to a tract that issubdivide into lobes and claw cells were present. HBs present CaMKII immunoreactionand neurogenesis. Additionally, we found by in vivo calcium imaging that theintrinsic neurons of the crab's HBs respond to both mechanical and visualstimulation. Remarkably, specific changes to a visual danger stimulus areinduced by a training protocol that generates associative memory. These resultsprovide the first in vivo physiological evidence that supports the idea thatthe HBs, the crustaceans' mushroom bodies, are involved in memory processes.