UNVEILING UNEXPRESSSED MEMORIES: THE NATURE OF MEMORY MODULATION THROUGH THE GLASSES OF NEOHELICE

ALEJANDRO DELORENZI; FERNANDEZ LARROSA, NICOLAS; FRANCISCO JAVIER MAZA; GONZALEZ, HEIDI

Neohelice granulata, a Model Species for Studies on Crustaceans,

Cambridge Scholars Publishing

Lugar: Lady Stephenson Library, Newcastle upon Tyne, United Kingdom; Año: 2020; p. 120 - 137

Not all experiences are remembered. Why some experiences form memories that stay for a lifetime, but others vanish in a few hours or even minutes? Research in memory modulation encompasses the studies concerning the neurobiological bases that underlie such variations. The central hypothesis that has been guiding this research proposed that ?the slow consolidation of memories serves an adaptive function by enabling endogenous processes activated by an experience to modulate memory strength? (McGaugh 2000). Today, considerable evidence supporting this vision has been accumulated in evolutionarily distant species: hormones and neuromodulators triggered by arousal or challenging experiences have essential functions in the modulation of the strength of newly acquired memories during consolidation. Although learning skills vary across species depending upon specific adaptations to environmental particularities (Menzel 2007), the molecular machinery and the dynamics of the memory processes are conserved throughout evolution (Menzel 1999, Glanzman 2010) and the modulatory systems that influence memory processes are not the exception. There is a long tradition of studies on neurobiology of learning, memory processes, and physiological adaptive systems on the habitat of Neohelice granulata. Thus, this crab appeared as an exceptional species for the study of how environmental challenges trigger adaptive functions, enabling endogenous processes activated by experiences that modulate the strength of memories.  The distribution of crustaceans from freshwater to marine water, and from salt marshes to terrestrial areas, gives an idea about the adaptations of these animals to cope with salinity changes (Thabet et al. 2017). N. granulata is a remarkable example of this feature, being able to inhabit salt marshes of narrow coastal inlets, estuaries, and lagoons in the Atlantic coast of South America. Since these environments present marked salinity changes, N. granulata shows remarkable physiological adaptations to cope with these fluctuations (Genovese et al. 2006, Onken et al. 2003, Schmitt and Santos 1993). Such adaptations typify N. granulata as a euryhaline species since this crab tolerates salinities ranging from diluted to concentrated seawater. The present review focuses on the studies regarding the interaction between physiological mechanisms to cope with salinity stress, and the neurobiological bases that underlie memory processes, and how these studies have allowed us to propose a different vision than the one currently accepted about the modulation of memory, which states that modulation relies on the modification of the ?strength? of memories.