Novel and familiar taste learning elicit different network: The 21st Annual Meeting of the Israel Society for Neuroscience & The First Binational Australian-Israeli Meeting in Neuroscience

Learning of novel taste and its value is rapid, robust and ethologically important to survival of the animal. The gustatory cortex (GC) is critically involved in taste memory formation, consolidation and retrieval. In rodents, novel taste learning is associated with biochemical changes in the GC, however, very little is known about the expression of immediate early genes (IEGs) as network activity markers in correlation with novel taste learning.

Here, we used the expression of Activity Regulated Cytoskeleton Protein (Arc) as a marker of neural activation in the GC following incidental taste learning. We found that novel taste did not modulate Arc expression in the GC when sampling both hemispheres, however novel and familiar taste groups have different expression pattern when comparing left and right GC one hour following learning; whereas the novel taste group exhibit clear lateralized pattern of Arc expression, the familiar taste group exhibits no lateralization of Arc expression. Moreover, continuous familiarization with taste reduced the lateralization. For causal experiment we injected the protein synthesis inhibitor anisomycin into the left or right GC and found a pattern of bimodal distribution of animals performing the memory test- one group of animals with clear impaired memory for the aversive taste, and one group of animals with no memory deficit, indicating that one hemisphere predominantly participates in memory consolidation. We found that separate networks for processing of novel or familiar taste exists in the GC and manifested by symmetrical IEG activation for familiar taste and asymmetrical for novel taste learning.