Increased Brain Activation for Dual Tasking with 70-Days Head-Down Bed Rest

Area of Science:

• Neuroscience
• Space Physiology
• Human Physiology

Background:

• Head-down tilt bed rest (HDBR) simulates microgravity effects on Earth.
• Dual-task performance can be impaired during space missions.
• Understanding HDBR's impact on dual-tasking neural control offers insights into spaceflight efficiency.

Purpose of the Study:

• To evaluate changes in dual-task performance and brain activation during HDBR.
• To investigate the neural efficiency during simulated microgravity.

Main Methods:

• Eighteen healthy males underwent 70 days of 6° HDBR.
• Functional MRI assessed bimanual finger tapping during single and dual tasks at 7 time points.
• A control group (12 males) did not undergo HDBR.

Main Results:

• A widespread brain network (frontal, parietal, cingulate, temporal, occipital cortices) showed increased activation during dual-tasking under HDBR.
• Increased activation differences between dual and single tasks were observed during HDBR compared to pre/post-HDBR.
• A positive correlation was found between changes in dual-task reaction time cost and brain activation cost.

Conclusions:

• HDBR necessitates greater neurocognitive control for dual-task execution.
• Findings suggest HDBR-induced neural changes may predict dual-task processing alterations in spaceflight.
• This research provides valuable insights into sensorimotor and cognitive functions during microgravity exposure.