Neuroarchitecture of the crustacean visual system (poster)

JULIETA SZTARKER, NICHOLAS J. STRAUSFELD, DANIEL TOMSIC

Nyborg, Dinamarca

Congreso; 7º International Congress of Neuroethology.; 2004

Society for Neuroethology

The principal interest of our research group is to understand how the visual information is acquired, processed and stored. The escape response of the crab Chasmagnathus granulatus and its changes as a result of learning has been thoroughly studied. By doing intracellular recordings in the optic lobes of the alive crab, we identified a group of neurons, the lobula giant (LG) neurons that responds best to the visual danger stimulus (VDS) used for the behavioral experiments (Berón de Astrada & Tomsic, 2002).  These cells also show short and long-term changes after a visual learning that strikingly correlates with the crab behavior (Tomsic et al., 2003).  The morphology of this neurons was described using intracellular staining.  Nevertheless, to have a better insight to the circuital organization and the possible pathways involved in the acquisition of visual information, it is important to have a detail description of the visual system. For this purpose, we used a reduced silver technique, the Bodian staining witch allow to see the whole network of cells. Using the previously described morphology of the LG neurons we were able to recognize this cell and to separate this cell class in two groups: the monostratified LG (M-LG) and the bistratified LG (B-LG) witch differ in their morphology and orientation within the optic lobes. However, they share one layer in the lobula suggesting a functional relationship between the two groups. Another interesting result is the fact that in each lobula there are only 14  M-LG. These cells are parallel oriented and possess large somas (900 mm2). In these poster we present a thorough description of these two groups along with a general description of the organization of the optic neuropils of this decapod crab.