Insulin and Memory in Invertebrates.

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Insulin and insulin-like peptides (ILP) regulate glucose homeostasis, while insulin-like growth factors (IGF) promote cell growth and differentiation.
• Distinguishing ILP from IGF in invertebrates is challenging due to overlapping functions, leading to the unified term Insulin/IGF Signaling (IIS).
• IIS plays a crucial role in cognitive functions, with significant research in mammals focusing on its potential in Alzheimer's disease treatment.

Purpose of the Study:

• To review the role of Insulin/IGF Signaling (IIS) in memory formation across various invertebrate species.
• To highlight the advanced understanding of IIS molecular mechanisms in invertebrates compared to mammals.
• To underscore the potential of invertebrate models for studying insulin, ILPs, and IGFs in cognitive function.

Main Methods:

• Review of existing literature on IIS function in invertebrate memory.
• Comparative analysis of IIS roles in different invertebrate models, including *Drosophila melanogaster*, *Caenorhabditis elegans*, and *Lymnaea stagnalis*.
• Examination of molecular mechanisms at transcriptional and translational levels.

Main Results:

• IIS is implicated in aversive olfactory memory in *Drosophila melanogaster*.
• IIS controls NaCl response in *Caenorhabditis elegans*, varying with starvation duration.
• IIS is critical for conditioned taste aversion in *Lymnaea stagnalis*.

Conclusions:

• Invertebrate models provide advanced insights into the molecular mechanisms of IIS in cognition.
• IIS is a conserved signaling pathway involved in diverse memory processes across phyla.
• Further research in invertebrates can illuminate the broader roles of insulin, ILPs, and IGFs in cognitive function.