Brain Changes in Response to Long Antarctic Expeditions

Stahn, Alexander; Gunga, Hanns‐Christian; Kohlberg, Eberhard; Gallinat, Jürgen; Dinges, David F.; Kühn, Simone

doi:10.1056/nejmc1904905

Cited by 69 publications

(58 citation statements)

References 5 publications

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“…Toepper et al (2010) found activation in the right hippocampus when participants engaged in a spatial working memory task (Toepper et al, 2010). A more recent study with polar expeditioners who spent 14 months at the German Neumayer III station in Antarctica-a spaceflight analog model to study the effects of social isolation and environmental deprivation-observed reduced hippocampal volume in several regions following the expedition (Stahn et al, 2019). They also reported that reduced hippocampal volume was not associated with general cognitive performance, but it was correlated with performance on a spatial mental rotation task.…”

Section: Hdbr + Co 2 Vs 70-day Hdbr Group Comparisonsmentioning

confidence: 97%

Neural Working Memory Changes During a Spaceflight Analog With Elevated Carbon Dioxide: A Pilot Study

Salazar

Hupfeld

Lee

et al. 2020

Front. Syst. Neurosci.

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Spaceflight missions to the International Space Station (ISS) expose astronauts to microgravity, radiation, isolation, and elevated carbon dioxide (CO 2), among other factors. Head down tilt bed rest (HDBR) is an Earth-based analog for spaceflight used to study body unloading, fluid shifts, and other factors unrelated to gravitational changes. While in space, astronauts need to use mental rotation strategies to facilitate their adaptation to the ISS environment. Therefore, spatial working memory is essential for crewmember performance. Although the effects of HDBR on spatial working memory have recently been studied, the results are still inconclusive. Here, we expand upon past work and examine the effects of HDBR with elevated CO 2 (HDBR + CO 2) on brain activation patterns during spatial working memory performance. In addition, we compare brain activation between 30 days of HDBR + CO 2 and 70 days of HDBR to test the isolated effect of CO 2. Eleven subjects (6 males, 5 females; mean age = 34 ± 8 years) underwent six functional magnetic resonance imaging (fMRI) sessions pre-, during, and post-HDBR + CO 2. During the HDBR + CO 2 intervention, we observed decreasing activation in the right middle frontal gyrus and left regions of the cerebellum, followed by post-intervention recovery. We detected several correlations between brain and behavioral slopes of change with the HDBR + CO 2 intervention. For example, greater increases in activation in frontal, temporal and parietal regions were associated with larger spatial working memory improvements. Comparing the HDBR + CO 2 group to data from our previous 70-day HDBR study, we found greater decreases in activation in the right hippocampus and left inferior temporal gyrus for the HDBR + CO 2 group over the course of the intervention. Together, these findings increase our understanding of the neural mechanisms of HDBR, elevated levels of CO 2 and spaceflight-related changes in spatial working memory performance.

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Section: Hdbr + Co 2 Vs 70-day Hdbr Group Comparisonsmentioning

confidence: 97%

Neural Working Memory Changes During a Spaceflight Analog With Elevated Carbon Dioxide: A Pilot Study

Salazar

Hupfeld

Lee

et al. 2020

Front. Syst. Neurosci.

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“…Hippocampal volumes have been shown to be particularly plastic to environmental factors over relatively short time periods. For example, in a recent study done on eight expeditioners to a constrained and isolated environment in Antarctica, substantial average decreases in volume of about 7.2% were observed after a 14 month period (54). It is possible that the enrichment from a hippocampally-mediated task could act on hippocampal volumes over the training period and even offset or reverse potential declines from being housed in pens with smaller social units.…”

Section: Discussionmentioning

confidence: 99%

Longitudinal Effects of Immediate and Delayed Estradiol on Cognitive Performance in a Spatial Maze and Hippocampal Volume in Menopausal Macaques Under an Obesogenic Diet

et al. 2020

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The consumption of a diet high in fat and refined sugars has several health risks, including the development of cognitive decline and neurodegeneration. For women, menopause carries additional health risks that may interact with a high-fat diet in negative ways. Some symptoms of menopause, including cognitive impairments, can be modulated by hormone replacement therapy (HRT), but the hormonal formulation and the timing of the treatment relative to the onset of menopause are critical factors determining its efficacy. Little is known about how obesogenic, high-fat, high-sugar diets interact with HRT in menopause to affect cognition and neurodegeneration. Given the high prevalence of the consumption of an obesogenic Western-style diet, understanding how the effects of HRT are modulated by an obesogenic diet is critical for developing optimized therapeutic strategies for peri-and post-menopausal women. In this study, we investigated by magnetic resonance imaging (MRI) the effects of either immediate or delayed estradiol hormone therapy on cognition and neuroanatomy following ovo-hysterectomy (OvH) of aged, female rhesus macaques on an obesogenic diet. The macaques were followed for 2.5 years after ovo-hysterectomy, with four time points at which anatomical MRIs were acquired. Analysis of hippocampal volumes revealed an interaction between time point and treatment; hippocampal volumes in the delayed estrogen group, but not the immediate estrogen group, increased over time compared to those in untreated controls. Performance on a hippocampal-dependent spatial maze task showed improved performance in estrogen treated animals compared to OvH macaques given placebo. These results indicate that HRT may contribute to beneficial cognitive outcomes after menopause under an obesogenic diet.

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“…The dentate gyrus (DG) of the hippocampus is likely to play a key role in defining the impact of stress on hippocampal functioning. We recently published data on neuroendocrine and brain changes in response to Antarctic expeditions at the German Neumayer III station characterized by multiple stressors including environmental deprivation and prolonged physical and social isolation 31 . Our data demonstrated considerable decreases in dentate gyrus volume that were associated with changes in key neurotrophins such as brain-derived neurotrophic factor (BDNF).…”

Section: Vulnerability Of the Brain And The Immune System During Isolmentioning

confidence: 99%

“…The distinct changes of the dentate gyrus to environmental deprivation in comparison to other hippocampal subfields is similar to findings from animal models, suggesting a possible link between hippocampal neurogenesis, stress-induced behavioral changes, and environmental deprivation [33][34][35] . Furthermore, whole-brain analysis using voxel-based morphometry revealed significant decreases in gray matter volume of the right dorsolateral prefrontal cortex (DLPFC), and left orbitofrontal cortex (OFC) after the 14-month expedition 31 . THE DLPFC and the OFC are pivotal for executive control such as response inhibition, working memory and cognitive flexibility 36 , but also the generation of and regulation of emotion 37 .…”

Section: Vulnerability Of the Brain And The Immune System During Isolmentioning

confidence: 99%

COVID-19—The largest isolation study in history: the value of shared learnings from spaceflight analogs

Choukèr

Stahn

2020

npj Microgravity

Self Cite

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The world is currently experiencing the largest isolation experiment in history. In an attempt to slow down the spread of the COVID-19 pandemic numerous countries across the world have been shutting down economies, education, and public life. Governments have mandated strict regulations of quarantine and social distancing in an unprecedented manner. The effects of these measures on brain, behavior, neuro-humoral and immunological responses in humans are largely unknown. Life science research for space exploration has a long history in using high-fidelity spaceflight analogs to better understand the effect of prolonged isolation and confinement on genes, molecules, cells, neural circuits, and physiological systems to behavior. We here propose to leverage the extensive experience and data from these studies and build a bridge between spaceflight research and clinical settings to foster transdisciplinary approaches to characterize the neurobehavioral effects on the immune system and vice versa. These approaches are expected to develop innovative and efficient health screening tools, diagnostic systems, and treatments to mitigate health risks associated with isolation and confinement on Earth and during future exploratory spaceflight missions.

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Brain Changes in Response to Long Antarctic Expeditions

Cited by 69 publications

References 5 publications

Neural Working Memory Changes During a Spaceflight Analog With Elevated Carbon Dioxide: A Pilot Study

Neural Working Memory Changes During a Spaceflight Analog With Elevated Carbon Dioxide: A Pilot Study

Longitudinal Effects of Immediate and Delayed Estradiol on Cognitive Performance in a Spatial Maze and Hippocampal Volume in Menopausal Macaques Under an Obesogenic Diet

COVID-19—The largest isolation study in history: the value of shared learnings from spaceflight analogs

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