Insulin-mediated synaptic plasticity in the CNS: Anatomical, functional and temporal contexts

Area of Science:

• Neuroscience
• Metabolic disorders
• Endocrinology

Background:

• The brain was historically considered insulin-insensitive, but emerging evidence shows insulin's critical role in CNS functions.
• Insulin impacts brain metabolism, cognition, and motivated behaviors, with region-specific and temporal activities.
• Brain insulin resistance is implicated in neuroplasticity deficits associated with obesity and type 2 diabetes mellitus (T2DM).

Purpose of the Study:

• To review the anatomical, temporal, and functional contexts of insulin activity in the central nervous system (CNS).
• To explore how insulin promotes neuroplasticity from development to adulthood.
• To identify critical time points where insulin's neuroplasticity-enhancing effects may transition to impairment.

Main Methods:

• Review of existing literature on insulin's role in the brain.
• Analysis of insulin's actions in specific brain regions (hippocampus, nucleus accumbens, ventral tegmental area).
• Conceptualization of brain insulin receptor activity as a continuum from development to adulthood.

Main Results:

• Insulin facilitates neuroplasticity, supporting cognitive functions and motivated behaviors.
• Insulin's effects are context-dependent, varying by brain region and developmental stage.
• Impaired brain insulin signaling is linked to neuroplasticity deficits in metabolic diseases.

Conclusions:

• Insulin plays a crucial, multifaceted role in brain function and neuroplasticity across the lifespan.
• Understanding the temporal and anatomical contexts of brain insulin action is key.
• Further research is needed to pinpoint critical transition points in the insulin neuroplasticity continuum, especially concerning T2DM and obesity.