Pritz, Christian et al. (2021) International Worm Meeting "Principles for coding associative memories in a compact neural network"

Itskovits, Eyal, Menasherof, Mai, Zaslaver, Alon, Nelken, Tal, Pritz, Christian, Ruach, Rotem, Bokman, Eduard, Gritsenko, Vladimir, Azulay, Aharon

[International Worm Meeting, 2021]

A major goal in neuroscience is to elucidate the principles by which memories are stored in a neural network. Here, we have systematically studied how the four types of olfactory associative memories (short- and long-term memories, each as positive and negative associations) are encoded within the compact neural network of C. elegans worms. By combining these robust training paradigms with fast confocal calcium imaging using multi-neuron and whole-brain imaging approaches, we systematically traced experience-dependent activity changes down to the level of individual neurites. Interestingly, short-term, but not long-term, memory broadly altered memory-evoked responses of chemosensory neurons. Modulated activity in three neurons, namely AWA, AWC, and ASE, sufficed to discriminate between the different memory states. This economy in memory-coding neurons increases memory capacity and limits non-innate behavioral responses. In contrast, long-term memory was relegated to deeper layers of the network. Primary interneurons, AIY and AIA, exhibit memory-state-dependent activation signatures, allowing the sensory system to resume innate functionality. In conclusion, olfactory associative memory appears to follow a hierarchical and temporally structured encoding logic.

Gilchrist EJ et al. (1995) International C. elegans Meeting "A C. ELEGANS MYOTONIC DYSTROPHY GENE HOMOLOGUE."

Gilchrist EJ, Baillie DL

[International C. elegans Meeting, 1995]

Myotonic Dystrophy is an inherited, autosomal dominant disease that results in a progressive wasting of the skele- tal muscles (and sometimes heart and smooth muscles) in humans. The gene has been cloned and sequenced (R. Korneluk, personal communication) and encodes a large protein that has been localised to neuromuscular and myotendinous junctions. The N-terminus domain bears similarity to cAMP-dependent serine/threonine protein kinases. Yuji Kohara, in his cDNA sequencing project, identified a C. elegans gene that is 75% similar (if conserved amino acids are considered) to the kinase domain of the human myotonic dystrophy gene. He mapped the cDNA to LG I (personal communication), and, through Southern analysis, we have placed the cDNA on cosmid K06G1. This cosmid was injected into wild-type N2 hermaphrodites by Diana Collins, and we are currently trying to rescue some of the genes in this region with the extrachromosomal array. One candidate gene was unc-57. Animals homozygous for mutations in unc-57 show no obvious structural muscle defects. This is consistent with unc-57 being a muscle, or neuro- muscular kinase. However, the Unc-57 phenotype is not rescued in animals carrying the K06G1 extrachromo- somal array. We are now focusing on some of the lethal mutations in this region that have been isolated in the laboratory of Ann Rose at UBC.