The Dissociation of Sensory Integration and Associative Learning in Caenorhabditis elegans and the Molecular Mechanisms Leading to Memory Acquisition

The study of associative learning in C. elegans takes advantage of a genetically tractable organism with a fully mapped connectome, and with a simple nervous system compared with that of mammals. A learning deficient mutant found in a mutagenesis screen, lrn-2, was characterized and mapped to the scd-2 gene, which expresses a receptor tyrosine kinase. scd-2 plays role in both sensory integration and associative learning, and was used to dissociate these two processes at the genetic, cellular, and behavioural levels. At the genetic level, it interacts differently with fsn-1, which expresses part of a ubiquitination complex in sensory integration and associative learning. Expression of scd-2 was previously known to be required in AIA interneurons during sensory integration, but I found that during associative learning, NSM expression is required. Not only are sensory integration and associative learning dissociated, but they also occur simultaneously as a C. elegans encounters sensory stimuli in its environment. The expression of scd-2 is necessary for the acquisition of associative memories of pathogenic bacteria, but not memory recall. This was discovered by using a drug (designed to target the mammalian ortholog of SCD-2) to block SCD-2 activity selectively during training or testing to pathogenic bacteria. We also found that SCD-2 acts upstream of two insulin-like peptides during associative learning, and thus facilitating the overall understanding of the neuronal circuit involved in associative learning in C. elegans.

Department dc:contributor.department

Medical Science

Year dc:date.issued

2020

Author dc:creator

• Wolfe, Glenn

Advisor dc:contributor.advisor

• van der Kooy, Derek

• Associative Learning
• C.elegans
• Crizotinib
• Memory acquisition
• PA14
• Sensory Integration

Statement dc:rights

• Attribution-NonCommercial-NoDerivatives 4.0 International

Licence dc:rights.uri

• http://creativecommons.org/licenses/by-nc-nd/4.0/

Handle dc:identifier.uri

http://hdl.handle.net/1807/100917

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/100917