Modularity in the brain of arthropods: individual neurons that support ?What? but not ?Where? memories. Daniel Tomsic. Dynamics of prey capture and Escape

JULIETA SZTARKER; DANIEL TOMSIC

Washington

Conferencia; Dynamics of prey capture and Escape; 2013

. Janelia Farm Research Campus HHMI

Experiments with insects and crabs have demonstrated their remarkable capacity to learn and memorize complex visual features. Such abilities are thought to require modular brain processing similar to that occurring in vertebrates. Yet, physiological evidence for this type of functioning in the small brains of arthropods is still scarce. In the crab Neohelice granulata (previously called Chasmagnathus granulatus) the learning rate as well as the long-term memory of a visual stimulus has been found to be reflected in the performance of identified lobula giant neurons (LGs). The memory can only be evoked in the training context, indicating that animals store two components of the learned experience, one related to the visual stimulus and one related to the visual context. By performing intracellular recordings in the intact animal, we show that the ability of crabs to generalize the learned stimulus into new space positions and to distinguish it from a similar but unlearned stimulus, two of the main attributes of stimulus-memory, can be completely explained by the performance of the LGs. Conversely, we found that LGs do not support the visual context-memory component. Our results provide physiological evidence that the memory traces regarding ?what? and ?where? are stored separately in the arthropod brain.