Spaceflight can cause long-term structural changes in the human brain

We know that being in space affects different parts of our body, from the brain to the bones; But scientists still do not know the exact details of this change. In a new study, scientists investigated how long-term space missions and the time between them affect human brain fluid.

According to Science Alert, this cerebrospinal fluid, which is stored in four chambers called ventricles in the brain, acts like a shock absorber and protects this organ by reducing the intensity of the blows to the brain. This liquid is also responsible for washing away cellular waste and supplying nutrients from the bloodstream.

Researchers from the University of Florida, NASA’s Johnson Space Center and other US institutions have discovered how spaceflight affects the size of the ventricles and the volume of cerebrospinal fluid. According to them, this increase depends on certain factors, such as the amount of time astronauts spend in space and the time intervals between their space adventures.

“These findings suggest that spaceflight-induced ventricular expansion continues as mission duration increases,” University of Florida neuroscientist Heather McGregor and her colleagues wrote in their paper. In addition, time intervals of less than three years may not provide the ventricles with enough time to recover compensatory capacity.”

An increase in the size of the ventricles and excess fluid in the brain is something that has also been observed in previous studies. This is associated with the upward movement of the brain inside the skull in microgravity, which in turn helps redistribute the fluid.

After taking magnetic resonance imaging (MRI) of 30 astronauts and citing previous studies, the researchers concluded that the longer the space flight, the greater the increase in the size of the ventricles. According to them, a space trip of 6 months or more is where the rate of change seems to stop.

Swelling of the brain’s ventricles is thought to represent a compensatory mechanism during spaceflight that allows the brain to adapt to changes in spinal fluid. After returning to the ground, the spinal fluid slowly returns to its normal level.

“Although a larger change in this structure seems unlikely for shorter missions, it may reflect an initial, adaptive in-flight structural change that gradually returns to its original state over time,” the researchers say.

Ventricular enlargement was less prominent in astronauts whose missions were less than three years apart. According to the researchers, this means that there is not enough time for the ventricles to shrink and readjust to cope with the increase in cerebrospinal fluid.