Neuroscience in Space

Astronaut Anne McClain performing the European Space Agency's Neuroscience experiment, "Time Perception in Microgravity" (Source: NASA). In this experiment, the crewmembers wear a virtual-reality headset and perform a series of activities that indicate their "feeling" of how much time passes in different scenarios. You can see that Anne is freefloating - this is because we want these perceptions to be removed from any physical inputs.

This book arrived in the mail last night - I ordered it weeks ago but this isn't considered an "essential item" (I beg to differ!!) so it was only shipped out recently.

The book is Neuroscience in Space by Gilles Clément and Millard F Reschke.  Published in 2008 (the same year that the Columbus Module was flown on on the Atlantis Shuttle with mission STS-122 and attached to the ISS), these scientists reviewed all the neuroscience research from the Shuttle program and from the Russian MIR station. The book is a technical description of the state of the art - what was known in 2008. I've been curious about the brains of astronauts for a long time so this will be my new bedtime reading. I'm sure that space-medicine folks have all read this text, but I'm a physicist so I'm a bit late to the game. 

The authors of this text, Gilles Clément  and Millard Reschke are both active in the field of Space Neuroscience. Gilles Clément has worked as the director of the French Centre national de la recherche scientifique (CNRS), and is a researcher at the Lyon Neuroscience Research Center in France. We are familiar with Gilles Clément at ESA because he has research payloads on the ISS right now. In fact, here is a list of the ISS Neurology Payloads he's been a part of: 

• 3D Space - Mental Representation of Spatial Cues During Space Flight This experiment started in 2008 and finished in 2011. The purpose of the Mental Representation of Spatial Cues During Space Flight (3D-Space) experiment was to investigate how astronauts perceived two-dimensional depictions of three-dimensional images (for example, a line-drawing of a box) - and how this changed in microgravity and after spaceflight. 

• BRAIN-DTI - Spaceflight induced neuroplasticity studied with advanced magnetic resonance imaging methods This experiment started in 2014 (Increment 39) and is ongoing. The overall objective of this research is to determine whether biomarkers of neuroplasticity in vestibular signal processing can be found using the model of microgravity. In other words: how does the brain communicate with itself and how does this change in microgravity? 

• PATTERNS - Patterns of Acceleration and Navigation on board the ISS . This research looks at the normal patterns of head and body accelerations experienced by astronauts during adaptation to microgravity. Also, it looks at the strategies adopted by astronauts in order to navigate around the ISS. 

• PERSPECTIVES This was a technology demonstration - the commissioning and testing of a Virtual Reality headset -  developed by the French Space Agency (CNES) for the 2016/2017 Proxima mission of ESA Astronaut Thomas Pesquet. This VR headset was then used in the experiments GRASP and Time Perception in Microgravity (both commissioned by Thomas Pesquet). 

• REVERSIBLE FIGURES - Perspective Reversible Figures in Microgravity This experiment ran from 2012 (Inc 31) to 2014 (Inc 40). The objective of this experiment was to identify, for a series of ten ambiguous figures, how long it took for the crewmembers to mentally reverse the image - and how many reversals the crewmembers experienced in a given period of time. Researchers found that, after adaptation to microgravity, ISS crewmembers developed larger depth perception instability, manifested by an equal probability for seeing each 3D interpretation after three months in space. 

• SPIN - Validation of Centrifugation as a Countermeasure for Otolith Deconditioning During Spaceflight This experiment started on the ISS in 2007 (Increment 16) and finished in 2012 (Increment 32). This research looked at how gravity sensing reflexes between the inner ear vestibular system and the visual system is affected in microgravity. Particularly, this investigation focused on these otolith-ocular reflexes and the correlation with the development of symptoms during upright standing such as changes in heart rate, blood pressure, and cerebral blood flow that can be relieved by sitting down.

• Straight-Ahead in Microgravity  How we perceive the direction of "straight-ahead" along the horizontal and vertical meridian is largely determined by both otolith (the structure in the inner-ear which is part of the vestibular system) and somatosensory inputs (a collection of sensory inputs in the central nervous system). These are both altered in microgravity. During spaceflight, adaptive processes are take place within the central nervous system to take into account the new environment, and compute new spatial egocentric and world-centered representations or frames of reference. The Straight Ahead in Microgravity investigation measured and monitored how these frames changed over time by investigating eye movements and crewmember's reporting of their own perception.

• TIME Perception in Microgravity This experiment started in 2017 and continues through today. ESA Crewmembers Alexander Gerst and Luca Parmitano have participated in this research. This experiment looks at how someone's sense of time is changed in microgravity. For example, if I were to ask you to estimate how long a minute is, what would you say? (incidentally,  my own perception of time is always wildly off. I can NEVER estimate how much time has passed and I'm perpetually late to things!)

I've only had a chance to scan the chapters of this book so I see that there's a lot about perception of the body in space, body posture, and adaptation. I gotta be honest, when I started reading about space motion sickness, I started feeling a little ill myself. The authors write, "After long-duration spaceflight, full recovery of balance, as measured by a posture platform, takes up to four weeks. However, some crewmembers felt like they did not return to baseline until between ten weeks and five months later."

Wow. Five months. That's a long time to feel unbalanced! I was immediately reminded of the first time I lived/worked on a U.S. Navy ship. Because the ship is constantly rocking, it's hard to maintain your balance while you stand and talk to a shipmate, while you walk down the passageways, or while you stand in front of the sink to brush your teeth. I got into the habit of bracing myself while I brushed, leaning forward and resting my hips on the sink. For days after returning to solid-ground, I would often feel like the ground was rocking, and I continued to brace myself when I brushed my teeth!