Related Experiment Video
Updated: Jun 1, 2026
08:38
Habituation and Prepulse Inhibition of Acoustic Startle in Rodents
Published on: September 1, 2011
Effects of simulated microgravity on brain plasticity: a startle reflex habituation study
Simone Messerotti Benvenuti1, Marta Bianchin, Alessandro Angrilli
1Department of General Psychology, University of Padova, 35131 Padova, Italy.
Physiology & Behavior
|June 2, 2011
Summary
Simulated microgravity impairs learning and brain plasticity in humans. Astronauts in head-down bed rest showed no habituation to startle reflexes, unlike controls, indicating a potential learning deficit for space missions.
Area of Science:
- Neuroscience
- Space Medicine
- Human Physiology
Background:
- Spaceflight poses risks to astronaut health, including potential impacts on cognitive functions.
- Previous research suggests the space environment may alter cerebral neurotransmitters and cognitive performance.
Purpose of the Study:
- To investigate the effects of simulated microgravity on learning and brain plasticity.
- To assess if head-down bed rest affects the habituation of the startle reflex.
Main Methods:
- 22 male subjects were divided into Head-Down Bed Rest (HDBR) and Sitting Control groups.
- Subjects underwent a picture viewing task with acoustic startle probes.
- Startle reflex amplitude was measured using EMG of the orbicularis oculi muscle.
Main Results:
- Sitting control subjects exhibited normal habituation of the startle reflex across blocks.
- Head-down bed rest subjects demonstrated a lack of startle reflex habituation.
- This suggests a deficit in learning and neural plasticity under simulated microgravity.
Conclusions:
- Simulated microgravity induces a lack of plasticity in the startle reflex.
- This learning deficit may have implications for the success of long-duration space missions.
- Further research is needed to understand and mitigate these effects on astronauts.
