Effects of spaceflight on the EEG alpha power and functional connectivity

Abstract

Electroencephalography (EEG) can detect changes in cerebral activity during spaceflight. This study evaluates the effect of spaceflight on brain networks through analysis of the Default Mode Network (DMN)'s alpha frequency band power and functional connectivity (FC), and the persistence of these changes. Five astronauts' resting state EEGs under three conditions were analyzed (pre-flight, in-flight, and post-flight). DMN’s alpha band power and FC were computed using eLORETA and phase-locking value. Eyes-opened (EO) and eyes-closed (EC) conditions were differentiated. We found a DMN alpha band power reduction during in-flight (EC: p < 0.001; EO: p < 0.05) and post-flight (EC: p < 0.001; EO: p < 0.01) when compared to pre-flight condition. FC strength decreased during in-flight (EC: p < 0.01; EO: p < 0.01) and post-flight (EC: ns; EO: p < 0.01) compared to pre-flight condition. The DMN alpha band power and FC strength reduction persisted until 20 days after landing. Spaceflight caused electrocerebral alterations that persisted after return to earth. Periodic assessment by EEG-derived DMN analysis has the potential to become a neurophysiologic marker of cerebral functional integrity during exploration missions to space.

The Influence of Magnetic Fields, Including the Planetary Magnetic Field, on Complex Life Forms: How Do Biological Systems Function in This Field and in Electromagnetic Fields?

“…While not an "overt injury" to the brain, space flight has led to the detection of cognitionassociated changes [85,[144][145][146]. Some reports have questioned whether the head-down tilt bedrest, a surrogate for spaceflight, captures the true nature of spaceflight-induced cognitive changes [147].…”

The Influence of Magnetic Fields including the Geomagnetic Field of Earth on Complex Life Forms: A Silent “Partner” in Human Health and Disease?

“…MEG can also be used for localizing and characterizing epileptic events [139] and potentially, post-traumatic stress disorders [140]. While not an "overt injury" to the brain, space flight has led to the detection of cognition-associated changes [82,[141][142][143]. The basis for such changes is likely not due to leaving the GMF of Earth completely since life in LEO on the ISS thus far, so may be related mainly to gravity changes, stresses, and living in confined environments.…”