Implicit aversive memory under anaesthesia in animal models: a narrative review

Area of Science:

• Neuroscience
• Anesthesiology
• Cognitive Psychology

Background:

• Explicit memory deficits after anesthesia are well-studied.
• Implicit memory, less understood, significantly impacts postoperative outcomes.
• Animal models of fear conditioning offer insights into implicit learning under anesthesia.

Purpose of the Study:

• To review animal studies on aversive conditioning during anesthesia.
• To discuss the complex effects of anesthetics on implicit memory.
• To identify knowledge gaps and translational relevance.

Main Methods:

• Review of animal studies on fear conditioning under anesthesia.
• Analysis of neurobiological mechanisms involving amygdala, hippocampus, and neocortex.
• Examination of neurotransmitter system involvement.

Main Results:

• Fear conditioning is demonstrably possible under anesthesia in animal models.
• Anesthetic effects on memory are complex, drug- and dose-dependent.
• Low anesthetic doses can sometimes yield paradoxical effects on learning.

Conclusions:

• Implicit memory formation under anesthesia is a critical area requiring further research.
• Understanding these mechanisms is vital for improving patient recovery and long-term well-being.
• Animal models provide a valuable framework for investigating anesthesia's impact on memory.