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

FRANCISCO JAVIER MAZA; FERNANDO LOCATELLI; JULIETA SZTARKER; A. DELORENZI

Montevideo

Congreso; XII Congress International Society for Neuroethology. Montevideo, Uruguay; 2016

SAN

Abstract Memory-related neuralplasticity in the hemiellipsoid bodies, the crab's "mushroom bodies". 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 CaMKIIimmunoreaction and neurogenesis. Additionally, we found by in vivo calciumimaging that the intrinsic neurons of the crab's HBs respond to both mechanicaland visual stimulation. Remarkably, specific changes to a visual dangerstimulus are induced by a training protocol that generates associative memory. Theseresults provide the first in vivo physiological evidence that supports the ideathat the HBs, the crustaceans' mushroom bodies, are involved in memoryprocesses.