Biology subjects

De Dios, Y. E.

Publications and source records attributed to De Dios, Y. E..

3 recordsLinked to original sources

bioRxiv2022

Artificial Gravity During a Spaceflight Analog Alters Brain Sensory Connectivity

Spaceflight has numerous untoward effects on human physiology. Various countermeasures are under investigation including artificial gravity (AG). Here, we investigated whether AG alters resting-state brain functional connectivity changes during head-down tilt bed rest (HDBR), a spaceflight analog. Participants underwent 60 days of HDBR. Two groups received daily AG administered either continuously (cAG) or intermittently (iAG). A control group received no AG. We assessed resting-state functional connectivity before, during, and after HDBR. We also measured balance and mobility changes from pre-to post-HDBR. We examined how functional connectivity changes throughout HDBR and whether AG is associated with differential effects. We found differential connectivity changes by group between posterior parietal cortex and multiple somatosensory regions. The control group exhibited increased functional connectivity between these regions throughout HDBR whereas the cAG group showed decreased functional connectivity. This finding suggests that AG alters somatosensory reweighting during HDBR. We also observed brain-behavioral correlations that differed significantly by group. Control group participants who showed increased connectivity between the putamen and somatosensory cortex exhibited greater mobility declines post-HDBR. For the cAG group, increased connectivity between these regions was associated with little to no mobility declines post-HDBR. This suggests that when somatosensory stimulation is provided via AG, functional connectivity increases between the putamen and somatosensory cortex are compensatory in nature, resulting in reduced mobility declines. Given these findings, AG may be an effective countermeasure for the reduced somatosensory stimulation that occurs in both microgravity and HDBR.

neuroscience↗

bioRxiv2022

Impacts of Spaceflight Experience on Human Brain Structure

Spaceflight induces widespread changes in human brain morphology. It is unclear if these brain changes differ with varying mission durations or ones history of spaceflight experience (e.g., number of prior missions, time between missions). Here we addressed this issue by quantifying voxelwise post-flight changes in gray matter volume, white matter microstructure, extracellular free water (FW), and ventricular volume in a sample of 28 astronauts. We found that longer missions induced greater ventricular expansion and larger FW displacement at the top of the brain. A greater number of prior missions was associated with white matter microstructure declines in a tract supporting voluntary leg movement. Longer inter-mission intervals were associated with greater ventricle expansion, with compensatory ventricular expansion observed only in those crewmembers with inter-missions intervals of 3 years or longer. Longer missions therefore induce more extensive brain fluid shifts, and the ventricles may require at least 3 years to recover post-flight.

neuroscience↗

bioRxiv2020

Brain Connectivity and Behavioral Changes in aSpaceflight Analog Environment with Elevated CO2

Astronauts are exposed to microgravity and elevated CO2 levels onboard the International Space Station. Little is known about how microgravity and elevated CO2 combine to affect the brain and sensorimotor performance during and after spaceflight. Here we examined changes in resting-state functional connectivity (FC) and sensorimotor behavior associated with a spaceflight analog environment. Participants underwent 30 days of strict 6{degrees} head-down tilt bed rest with elevated ambient CO2 (HDBR+CO2). Resting-state functional magnetic resonance imaging and sensorimotor assessments were collected 13 and 7 days prior to bed rest, on days 7 and 29 of bed rest, and 0, 5, 12, and 13 days following bed rest. We assessed the time course of FC changes from before, during, to after HDBR+CO2. We then compared the observed connectivity changes with those of a HDBR control group, which underwent HDBR in standard ambient air. Moreover, we assessed associations between post-HDBR+CO2 FC changes and alterations in sensorimotor performance. HDBR+CO2 was associated with significant changes in functional connectivity between vestibular, visual, somatosensory and motor brain areas. Several of these sensory and motor regions showed post-HDBR+CO2 FC changes that were significantly associated with alterations in sensorimotor performance. We propose that these FC changes reflect multisensory reweighting associated with adaptation to the HDBR+CO2 microgravity analog environment. This knowledge will further improve HDBR as a model of microgravity exposure and contribute to our knowledge of brain and performance changes during and after spaceflight.

neuroscience↗