Sensory and Motor Systems
Author: Julieta Sztarker | Email: sztarker@fbmc.fcen.uba.ar
Julieta Sztarker1°2°, Yair Barnatan1°, Claire Rind3°, , , , , , ,
1° IFIBYNE (CONICET-UBA)
2° Depto FBMC, FCEN, UBA
3° NUBI, Newcastle University
Arthropods are diverse, abundant, successful animals that exploit all ecological niches. They sense the environment, move, interact with prey/predators/conspecifics, learn, etc. using small brains with 5 orders of magnitude less neurons than mammals. Hence, these microbrains need to be highly efficient in information processing. One distinct aspect is the presence of large, easily identifiable single neurons that act as functional units for information processing integrating a high volume of information to guide behavior. To understand the synaptic organization behind these high integration nodes research on suitable neurons is needed. The lobula giant neurons (LG) found in the third optic neuropil, the lobula, of crabs, respond to moving stimuli, integrate information from both eyes, show short- and long- term plasticity and are thought to be key elements in the visuomotor transformation guiding escape responses to approaching objects. One subgroup, the MLG1 (Monostratified Lobula Giants type 1) possesses wide main branches and a regular arrangement in a layer of the lobula that allows their identification even in unstained preparations. Here, we describe the types and abundance of synaptic contacts involving MLG1 profiles using transmission electron microscopy (TEM). We found an unexpected diversity of synaptic motifs and an apparent compartmentalization of the dendritic arbor in two domains where MLG1s act predominantly as presynaptic or postsynaptic, respectively.