MentalHealthDaily

Alzheimer’s Smell Loss Linked to Early Locus Coeruleus Axon Damage

by GLOOM

MHD featured image for early locus coeruleus axon loss and Alzheimer's smell dysfunction.

A 2025 Nature Communications study found that Alzheimer’s-like mice lost locus coeruleus noradrenergic axons in the olfactory bulb early: 14% loss by 2 months, 27% by 3 months, and 33% by 6 months, before broader forebrain axon degeneration appeared.1 Early smell loss may reflect a specific brainstem-to-olfactory circuit injury, while smell testing still needs biomarker …

tVNS Alters Effort and Reward Decisions in Severe Depression

by GLOOM

Photoreal illustration of an ear-clip vagus nerve stimulation electrode, with neural pathway motifs representing reward-effort circuits.

An ear-clip that modulates mood by stimulating the vagus nerve has obvious appeal — but the evidence base for non-invasive tVNS in depression has been mixed for a decade. A 2026 cross-over RCT by Forbes et al. sharpens what specifically tVNS does well.1 Research Highlights Transcutaneous vagus nerve stimulation (tVNS) is a non-invasive ear-electrode version …