Brain Circuits and Molecules for Consolidated Memory in Drosophila

One central goal in the neuroscience field is to understand how the memory information processed and stored within a complete brain. Here, we use Drosophila melanogaster as an ideal model to understand this issue in terms of gene-gene interactions and neuron-neuron activities to memory. Memory can be defined as a sequentially tripartite process: registration, storage and retrieval. Drosophila mushroom body (MB) comprising aP, a'P' and y neurons is a paired neuropil structure crucial for olfactory memory. Aversive olfactory memory is first registered in the MB y neurons and evolves into labile anesthesia-sensitive memory and consolidated anesthesia-resistant memory (ARM) that equally contribute to 3-hour memory retrieval. Here, we identified the INX5, a gap junction protein in MB neurons is required specifically for ARM formation. To pinpoint the brain region for the storage of ARM and the neural circuits retrieving ARM, we here adopted comprehensively MB-subset GAL4 lines to block the output of synaptic neurotransmission during retrieval. We showed that the outputs of MB aP and a'P' neurons are both required for ARM retrieval. Moreover, we functionally divided a'P' neurons into the afm neurons subset required for ARM during retrieval and the afap neurons subset required during consolidation. Finally, two pairs of MB output neurons the MB-M4 and MB-M10 have been identified to retrieve ARM information from MB a'P' and aP neurons during memory retrieval. We will further investigate: (1) To reveal INX5 in which MB neuron subsets are required for ARM formation. (2) To test if the ARM disruption is caused by acutely silencing the INX5 in MB neurons. (3) To reveal whether the INX5 gap-junctional communication is between MB neurons or between MB and their extrinsic neurons. (4) To reveal the molecule mechanism in MB aP and af neurons during ARM storage. (5) Monitor the neuronal activity with GCaMP6 in MB aP and af neurons after olfactory conditioning. (6) Silencing or overexpressing inx5 gene in MB neurons and monitor neuronal activity with GCaMP6 in MB neurons after olfactory conditioning (7) To identify which neurotransmitters are essential in MB-M4 and MB-M10 neurons for ARM (8) Monitor the neuronal activity with GCaMP6 in MB-M4 and MB-M10 neurons after olfactory conditioning. (9) Searching the other possible MB aP and a'P' extrinsic neurons contribute to ARM formation. We believe through our systematic analysis in the current study will reveal a comprehensive brain circuits and molecule mechanism regarding the consolidated memory.

Project ID:PA10408-0734
External Project ID:MOST104-2311-B182-002