Adaptive Engram Migration as a Trigger for Transient Auditory Hallucinations in the Aging Brain: A Proposed Mechanistic Hypothesis

Age-related neuronal attrition is well-characterized, but its interaction with high-salience autobiographical memory storage remains poorly understood. We propose the Adaptive Engram Migration Hypothesis (AEMH): when neurons constituting a high-salience memory engram approach senescence, the brain initiates a protective redistribution of that memory trace to a more structurally resilient neural substrate. This migration involves a transient lability window during which internally-generated memory signals breach conscious awareness - perceived as vivid, modality-specific sensory hallucinations. The index case is a first-person clinical observation: a cognitively intact 42-year-old male physician experienced a clear, compelling auditory hallucination of his spouse's voice in a sensory-deprived environment. Four convergent lines of evidence support the mechanistic plausibility of AEMH: engram biology, memory reconsolidation theory, the deafferentation model established by Charles Bonnet Syndrome, and predictive coding theory. The AEMH generates five testable predictions and carries direct clinical implications for the reframing of non-distressing auditory hallucinations in healthy aging adults as observable signatures of active memory-preservation rather than aberrant symptoms.