Knowledge Vault 3/43 - G.TEC BCI & Neurotechnology Spring School 2024 - Day 4
Neuroimaging findings of human brain changes following long-duration spaceflight
to the International Space Station and during zero-g flights
Steven Jillings, University of Antwerp (BE)
<Resume Image >

Concept Graph & Resume using Claude 3 Opus | Chat GPT4 | Llama 3:

graph LR classDef brain fill:#f9d4d4, font-weight:bold, font-size:14px; classDef microgravity fill:#d4f9d4, font-weight:bold, font-size:14px; classDef mri fill:#d4d4f9, font-weight:bold, font-size:14px; classDef changes fill:#f9f9d4, font-weight:bold, font-size:14px; classDef future fill:#f9d4f9, font-weight:bold, font-size:14px; A[Steven Jillings] --> B[astronaut brain changes
from microgravity via MRI. 1] A --> C[Body evolved under gravity,
affected by microgravity. 2] C --> D[Monitor brain changes from
harsh space conditions. 3] A --> E[Vestibular system senses gravity,
head movements. 4] A --> F[Brain neuroplasticity: changes from
spaceflight. 5] A --> G[Longitudinal MRI study: pre,
post, 6mo scans. 6] G --> H[Gray matter volume decreased
in temporal, parietal, frontal lobes. 7] G --> I[CSF shifts suggest upward
brain position change. 8] I --> J[Gray matter changes not
atrophy, but fluid shift. 9] I --> K[Other studies corroborate brain
crowding, sulci narrowing. 10] I --> L[Ventricles enlarged >12% post-flight,
>5% at 6mo. 11] G --> M[Diffusion MRI: gray matter
crowding, no tissue loss. 12] I --> N[CSF drives brain position
changes. 13] I --> O[Brain shifts partially resolve
by 6mo post-flight. 14] G --> P[Perivascular spaces enlarged post-flight,
higher in SANS. 15] P --> Q[Ventricular expansion may buffer
intracranial fluid, affect SANS. 16] P --> R[Countermeasure differences: resistance exercise
vs. lower body pressure. 17] F --> S[Brain shift may enhance
transcranial magnetic stimulation. 18] B --> T[Major effects: gray matter
loss, CSF redistribution, ventricular
expansion, perivascular increases. 19] G --> U[Diffusion MRI: neuroplasticity signs
in white, gray matter. 20] U --> V[Tractography: changes in cerebellar,
motor, cognitive tracts. 21] U --> W[Fiber metrics confirm cerebellar
tissue increases. 22] G --> X[fMRI: altered connectivity in
cognitive, vestibular regions. 23] X --> Y[Angular gyrus changes: spaceflight,
parabolic flights, pilots. 24] Y --> Z[Angular gyrus linked to
memory, vestibular function. 25] Y --> AA[Parabolic EEG to study
angular gyrus spatial role. 26] B --> AB[Spaceflight: fluid shifts, neuroplasticity,
key angular gyrus changes. 27] AB --> AC[Some brain changes persist
6mo, need long-term study. 28] A --> AD[Future work: mission duration,
performance, recovery, cumulative effects. 29] A --> AE[Brain health biomarkers, countermeasures
crucial for long missions. 30] class B,D,F,S,AB,AC,AD,AE brain; class C microgravity; class E,G,H,I,J,K,L,M,N,O,P,Q,R,T,U,V,W,X,Y,Z,AA mri; class F,H,I,J,K,L,M,N,O,P,Q,R,U,V,W,X,Y,Z,AA,AB changes; class AD,AE future;


1.- Steven Jillings from University of Antwerp studies changes in astronauts' brains due to microgravity using MRI scans before and after spaceflight.

2.- The human body, including the vestibular system and brain, has evolved under constant 1G gravity and is affected by microgravity.

3.- Studying astronaut brains helps monitor changes from the hostile space environment, including radiation, microgravity, isolation, and high workload.

4.- The vestibular system, which includes otoliths in the inner ear, senses gravity and head movements. It integrates with visual and proprioceptive systems.

5.- Neuroplasticity is the brain's ability to change structure and function in response to development, learning, environment, and spaceflight.

6.- Their longitudinal MRI study scans astronauts before spaceflight, immediately after return, and 6 months later, using anatomical, diffusion, and functional MRI.

7.- Initial anatomical MRI analysis using voxel-based morphometry showed large decreases in gray matter volume in the temporal, parietal and frontal lobes post-flight.

8.- CSF volume decreased at the top of the brain and increased at the bottom and in ventricles, suggesting an upward brain shift.

9.- Gray matter volume changes were less extensive 6 months post-flight, indicating they are not atrophy but rather fluid shift related.

10.- Other research groups found similar evidence of brain tissue crowding at the top and narrowing of sulci, corroborating the upward brain shift.

11.- Ventricular volume increased over 12% immediately post-flight and remained 5% larger 6 months later, an effect size much larger than typical aging.

12.- Diffusion MRI analysis showed gray matter crowding at the top matched the volumetric findings, with no net gray matter tissue loss.

13.- CSF redistribution drives the brain position changes, with CSF decreasing at the top and increasing at the bottom of the brain.

14.- The brain shift effects partially resolve from immediate post-flight to 6 months later but some changes persist compared to pre-flight.

15.- Perivascular space volumes increased post-flight, were higher in astronauts with spaceflight-associated neuro-ocular syndrome (SANS), and differed between NASA and Roscosmos crews.

16.- Ventricular expansion may act as a buffer for intracranial fluid increases and was lower in SANS, suggesting a role in its pathophysiology.

17.- Differences between NASA and Roscosmos crews may relate to use of resistive exercise vs. lower body negative pressure as countermeasures, respectively.

18.- Brain shift modeling suggests it would enhance the effects of transcranial magnetic stimulation by reducing CSF space between the brain and stimulation site.

19.- In summary, the major fluid shift effects include gray matter volume decreases (but not atrophy), CSF redistribution, ventricular expansion, and perivascular space increases.

20.- Diffusion MRI also found signs of neuroplasticity, with localized white and gray matter tissue increases in the basal ganglia, cerebellum and motor cortex.

21.- Tractography analysis revealed changes in cerebellar, corticospinal, corticostriatal, callosal and arcuate fasciculus tracts, some related to motor function and others possibly to deformation.

22.- Fiber density and cross-section metrics confirm net tissue increases in the cerebellum's middle and superior peduncles, the clearest evidence of neuroplasticity.

23.- Functional MRI found altered connectivity in the posterior cingulate, thalamus, angular gyrus and insula, regions involved in environmental monitoring, cognition, and vestibular processing.

24.- The angular gyrus shows decreased connectivity after both spaceflight and parabolic flight and increased connectivity in fighter pilots, suggesting gravity-dependent neuroplasticity.

25.- Angular gyrus connectivity changes also correlate with working memory performance and vestibular function measures, further indicating its role in gravity adaptation.

26.- Planned parabolic flight studies will examine angular gyrus activity during a vertical oddball task using EEG to clarify its link to spatial perception.

27.- In conclusion, spaceflight induces fluid shifts and brain position changes as well as sensorimotor and vestibular neuroplasticity, with the angular gyrus as a key region.

28.- Some spaceflight-induced brain changes persist 6 months post-flight, so complete recovery remains unknown and long-term effects require further study.

29.- Future work aims to assess impacts of mission duration, correlations with performance and clinical outcomes, early recovery, and long-term cumulative effects.

30.- Defining biomarkers and effective countermeasures is crucial to monitor brain health during future long-duration missions, such as to Mars.

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