Saifuddin, Mashel Fatema et al. (2021) International Worm Meeting "Olfactory memory consolidation requires the TRPV channel OSM-9 in sensory neurons of the circuit."

Miller, Julia, L'Etoile, Noelle, Chandra, Rashmi, Chen, Alec, Benedetti, Kelli, Gallegos, Maria, Dunn, Raymond, Zhang, Bo, Kaye, Julia, Saifuddin, Mashel Fatema, Kato, Saul

[International Worm Meeting, 2021]

Memory is one of the most important abilities of the brain. It is defined as an alteration in behavior as a consequence of an experience. For example, the C. elegans nematode will downregulate its chemotactic response to the innately attractive odor, butanone, if the odor is not paired with food. Through repeated, spaced training with this odor in the absence of food, C. elegans will maintain this memory for a prolonged period of time. Although transient receptor potential (TRP) channels are classically thought of as primary sensory receptors, it was reported that the OSM-9/TRPV5/TRPV6 (TRP vanilloid 5/6) channel is required for single exposure learning. Here we describe a new role for osm-9 in consolidation of memory that is induced by repeated, spaced training. In this paradigm, osm-9 mutant animals learn as well as wild-types, but are unable to consolidate the memory. Though sleep is required for memory consolidation, loss of the TRPV channel OSM-9 does not affect sleep. This indicates that the TRP channel promotes memory in a process that acts outside the sleep pathway. We investigate the endogenous expression pattern of OSM-9 and show that it is not expressed in the butanone-responsive AWC olfactory sensory neuron. Instead, it is expressed in the paired AWA olfactory neuron, the ASH nociceptive neurons, the OLQ and two other unidentified sensory neurons which are most likely ADF and ADL as they express osm-9 mRNA. Because OSM-9 acts in sensory neurons that do not participate in butanone sensation, this indicates that the circuit participates in olfactory memory consolidation.