Abstract

Overview

Adult hippocampal neurogenesis and hippocampus-dependent cognition in mice have suffered due to exposure to hypomagnetic fields, concurrent with a decrease in reactive oxygen species in the absence of geomagnetic fields.

Findings

• A past theoretical study proposed that the Radical Pair Mechanism could explain these phenomena. In this mechanism, a flavin-superoxide radical pair, initially in a singlet spin configuration, experiences magnetically dependent spin dynamics altering its recombination as the magnetic field is reduced.
• However, this study identifies two critical weaknesses in the Radical Pair Mechanism:
  1. The assumed initial singlet state does not align with known biological reaction pathways producing such radical pairs.
  2. The mechanism ignores rapid spin relaxation of free superoxide, eliminating magnetic sensitivity under geomagnetic/hypomagnetic conditions.
• In response, this investigation suggests a model based on a radical triad which integrates a secondary radical scavenging reaction to plausibly explain the observed effects without relying on unrealistic assumptions.

  This novel approach offers a coherent framework for understanding hypomagnetic field effects in biological systems, aligning with experimental data while maintaining biologically realistic parameters.

Conclusion

The study introduces a significant advancement in comprehending the impacts of diminished geomagnetic fields on neurogenic processes in mice, proposing an innovative and more biologically plausible model involving radical triads.