scholarly journals Effects of Spaceflight Stressors on Brain Volume, Microstructure and Intracranial Fluid Distribution

2021 ◽  
Author(s):  
Jessica K Lee ◽  
Vincent Koppelmans ◽  
Ofer Pasternak ◽  
Nichole E Beltran ◽  
Igor S Kofman ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Space Station ◽  
Free Water ◽  
Bed Rest ◽  
Fluid Distribution ◽  
Functional Changes ◽  
Brain Changes ◽  
And Performance ◽  
Underlying Mechanisms ◽  
The Brain

Abstract Astronauts are exposed to elevated CO2 levels onboard the International Space Station (ISS). Here, we investigated structural brain changes in 11 participants following 30-days of head-down tilt bed rest (HDBR) combined with 0.5% ambient CO2 (HDBR+CO2) as a spaceflight analog. We contrasted brain changes observed in the HDBR+CO2 group with those of a previous HDBR sample not exposed to elevated CO2. Both groups exhibited a global upward shift of the brain and concomitant intracranial free water (FW) redistribution. Greater gray matter changes were seen in the HDBR+CO2 group in some regions. The HDBR+CO2 group showed significantly greater FW decrements in the posterior cerebellum and the cerebrum than the HDBR group. In comparison to the HDBR group, the HDBR+CO2 group exhibited greater diffusivity increases. In half of the participants, the HDBR+CO2 intervention resulted in signs of Spaceflight Associated Neuro-ocular Syndrome (SANS), a constellation of ocular structural and functional changes seen in astronauts. We therefore conducted an exploratory comparisoncompared between subjects that did and did not develop SANS and found asymmetric lateral ventricle enlargement in the SANS group. These results enhance our understanding of the underlying mechanisms of spaceflight-induced brain changes, which is critical for promoting astronaut health and performance.

scholarly journals Dysregulation of excitatory neural firing replicates physiological and functional changes in aging visual cortex

2020 ◽  
Author(s):  
Seth Talyansky ◽  
Braden A. W. Brinkman
Keyword(s):  
Visual Cortex ◽  
Theoretical Work ◽  
Neural Circuitry ◽  
Neural Firing ◽  
Activity Data ◽  
Functional Changes ◽  
Brain Physiology ◽  
Computational Performance ◽  
And Performance ◽  
Underlying Mechanisms

AbstractThe mammalian visual system has been the focus of countless experimental and theoretical studies designed to elucidate principles of neural computation and sensory coding. Most theoretical work has focused on networks intended to reflect developing or mature neural circuitry, in both health and disease. Few computational studies have attempted to model changes that occur in neural circuitry as an organism ages non-pathologically. In this work we contribute to closing this gap, studying how physiological changes correlated with advanced age impact the computational performance of a spiking network model of primary visual cortex (V1). Our results demonstrate that deterioration of homeostatic regulation of excitatory firing, coupled with long-term synaptic plasticity, is a sufficient mechanism to reproduce features of observed physiological and functional changes in neural activity data, specifically declines in inhibition and in selectivity to oriented stimuli. This suggests a potential causality between dysregulation of neuron firing and age-induced changes in brain physiology and performance. While this does not rule out deeper underlying causes or other mechanisms that could give rise to these changes, our approach opens new avenues for exploring these underlying mechanisms in greater depth and making predictions for future experiments.

scholarly journals Modulation of Synaptic Plasticity by Vibratory Training in Young and Old Mice

2021 ◽  
Vol 11 (1) ◽  
pp. 82
Author(s):  
Ida Cariati ◽  
Roberto Bonanni ◽  
Gabriele Pallone ◽  
Giuseppe Annino ◽  
Virginia Tancredi ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Vibration Frequency ◽  
Hippocampal Slices ◽  
The Body ◽  
Whole Body ◽  
Negative Effects ◽  
Functional Changes ◽  
Underlying Mechanisms ◽  
The Brain

In the past 40 years, scientific research has shown how Whole Body Vibration concept represents a strong stimulus for the whole organism. Low (<30 Hz), medium (30–80 Hz), and high (>80 Hz) frequency vibrations can have both positive and negative effects, depending on the oscillation type and duration of exposure to which the body is subjected. However, very little is known about the effects of vibratory training on the brain. In this regard, we verified whether three vibratory training protocols, differing in terms of vibration frequency and exposure time to vibration, could modulate synaptic plasticity in an experimental mouse model, by extracellular recordings in vitro in hippocampal slices of mice of 4 and 24 months old. Our results showed that vibratory training can modulate synaptic plasticity differently, depending on the protocol used, and that the best effects are related to the training protocol characterized by a low vibration frequency and a longer recovery time. Future studies will aim to understand the brain responses to various types of vibratory training and to explore the underlying mechanisms, also evaluating the presence of any structural and functional changes due to vibratory training.

scholarly journals Opposite response of blood vessels in the retina to 6° head-down tilt and long-duration microgravity

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Giovanni Taibbi ◽  
Millennia Young ◽  
Ruchi J. Vyas ◽  
Matthew C. Murray ◽  
Shiyin Lim ◽  
...  
Keyword(s):  
Space Station ◽  
Bed Rest ◽  
Vascular Density ◽  
Vascular Response ◽  
Mixed Effects Modeling ◽  
Long Duration ◽  
Fluid Shifts ◽  
Before And After ◽  
And Performance ◽  
The One

AbstractThe Spaceflight Associated Neuro-ocular Syndrome (SANS), associated with the headward fluid shifts incurred in microgravity during long-duration missions, remains a high-priority health and performance risk for human space exploration. To help characterize the pathophysiology of SANS, NASA’s VESsel GENeration Analysis (VESGEN) software was used to map and quantify vascular adaptations in the retina before and after 70 days of bed rest at 6-degree Head-Down Tilt (HDT), a well-studied microgravity analog. Results were compared to the retinal vascular response of astronauts following 6-month missions to the International Space Station (ISS). By mixed effects modeling, the trends of vascular response were opposite. Vascular density decreased significantly in the 16 retinas of eight astronauts and in contrast, increased slightly in the ten retinas of five subjects after HDT (although with limited significance). The one astronaut retina diagnosed with SANS displayed the greatest vascular loss. Results suggest that microgravity is a major variable in the retinal mediation of fluid shifts that is not reproduced in this HDT bed rest model.

scholarly journals A review of alterations to the brain during spaceflight and the potential relevance to crew in long-duration space exploration

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Meaghan Roy-O’Reilly ◽  
Ajitkumar Mulavara ◽  
Thomas Williams
Keyword(s):  
Current Knowledge ◽  
Space Exploration ◽  
Environmental Stressors ◽  
Cumulative Exposure ◽  
Fluid Distribution ◽  
Tissue Microstructure ◽  
Mission Duration ◽  
Long Duration ◽  
And Performance ◽  
The Brain

AbstractDuring spaceflight, the central nervous system (CNS) is exposed to a complex array of environmental stressors. However, the effects of long-duration spaceflight on the CNS and the resulting impact to crew health and operational performance remain largely unknown. In this review, we summarize the current knowledge regarding spaceflight-associated changes to the brain as measured by magnetic resonance imaging, particularly as they relate to mission duration. Numerous studies have reported macrostructural changes to the brain after spaceflight, including alterations in brain position, tissue volumes and cerebrospinal fluid distribution and dynamics. Changes in brain tissue microstructure and connectivity were also described, involving regions related to vestibular, cerebellar, visual, motor, somatosensory and cognitive function. Several alterations were also associated with exposure to analogs of spaceflight, providing evidence that brain changes likely result from cumulative exposure to multiple independent environmental stressors. Whereas several studies noted that changes to the brain become more pronounced with increasing mission duration, it remains unclear if these changes represent compensatory phenomena or maladaptive dysregulations. Future work is needed to understand how spaceflight-associated changes to the brain affect crew health and performance, with the goal of developing comprehensive monitoring and countermeasure strategies for future long-duration space exploration.

scholarly journals Visuomotor Adaptation Brain Changes During a Spaceflight Analog With Elevated Carbon Dioxide (CO2): A Pilot Study

2021 ◽  
Vol 15 ◽  
Author(s):  
Ana Paula Salazar ◽  
Kathleen E. Hupfeld ◽  
Jessica K. Lee ◽  
Lauren A. Banker ◽  
Grant D. Tays ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Brain Activity ◽  
Space Station ◽  
Bed Rest ◽  
Elevated Carbon Dioxide ◽  
Visuomotor Adaptation ◽  
Brain Regions ◽  
Brain Changes ◽  
Carbon Dioxide Co2 ◽  
Adaptation Task

Astronauts on board the International Space Station (ISS) must adapt to several environmental challenges including microgravity, elevated carbon dioxide (CO2), and isolation while performing highly controlled movements with complex equipment. Head down tilt bed rest (HDBR) is an analog used to study spaceflight factors including body unloading and headward fluid shifts. We recently reported how HDBR with elevated CO2 (HDBR+CO2) affects visuomotor adaptation. Here we expand upon this work and examine the effects of HDBR+CO2 on brain activity during visuomotor adaptation. Eleven participants (34 ± 8 years) completed six functional MRI (fMRI) sessions pre-, during, and post-HDBR+CO2. During fMRI, participants completed a visuomotor adaptation task, divided into baseline, early, late and de-adaptation. Additionally, we compare brain activity between this NASA campaign (30-day HDBR+CO2) and a different campaign with a separate set of participants (60-day HDBR with normal atmospheric CO2 levels, n = 8; 34.25 ± 7.9 years) to characterize the specific effects of CO2. Participants were included by convenience. During early adaptation across the HDBR+CO2 intervention, participants showed decreasing activation in temporal and subcortical brain regions, followed by post- HDBR+CO2 recovery. During late adaptation, participants showed increasing activation in the right fusiform gyrus and right caudate nucleus during HDBR+CO2; this activation normalized to baseline levels after bed rest. There were no correlations between brain changes and adaptation performance changes from pre- to post HDBR+CO2. Also, there were no statistically significant differences between the HDBR+CO2 group and the HDBR controls, suggesting that changes in brain activity were due primarily to bed rest rather than elevated CO2. Five HDBR+CO2 participants presented with optic disc edema, a sign of Spaceflight Associated Neuro-ocular Syndrome (SANS). An exploratory analysis of HDBR+CO2 participants with and without signs of SANS revealed no group differences in brain activity during any phase of the adaptation task. Overall, these findings have implications for spaceflight missions and training, as ISS missions require individuals to adapt to altered sensory inputs over long periods in space. Further, this is the first study to verify the HDBR and elevated CO2 effects on the neural correlates of visuomotor adaptation.

scholarly journals Role of Exosomes in Cancer-Related Cognitive Impairment

2020 ◽  
Vol 21 (8) ◽  
pp. 2755 ◽  
Author(s):  
Yong Qin Koh ◽  
Chia Jie Tan ◽  
Yi Long Toh ◽  
Siu Kwan Sze ◽  
Han Kiat Ho ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Cognitive Functioning ◽  
Cell Communication ◽  
Clear Understanding ◽  
Functional Changes ◽  
Patients With Cancer ◽  
Neurological Processes ◽  
Underlying Mechanisms ◽  
Exocytic Pathway ◽  
The Brain

A decline in cognitive function following cancer treatment is one of the most commonly reported post-treatment symptoms among patients with cancer and those in remission, and include memory, processing speed, and executive function. A clear understanding of cognitive impairment as a result of cancer and its therapy can be obtained by delineating structural and functional changes using brain imaging studies and neurocognitive assessments. There is also a need to determine the underlying mechanisms and pathways that impact the brain and affect cognitive functioning in cancer survivors. Exosomes are small cell-derived vesicles formed by the inward budding of multivesicular bodies, and are released into the extracellular environment via an exocytic pathway. Growing evidence suggests that exosomes contribute to various physiological and pathological conditions, including neurological processes such as synaptic plasticity, neuronal stress response, cell-to-cell communication, and neurogenesis. In this review, we summarize the relationship between exosomes and cancer-related cognitive impairment. Unraveling exosomes’ actions and effects on the microenvironment of the brain, which impacts cognitive functioning, is critical for the development of exosome-based therapeutics for cancer-related cognitive impairment.

Morphological Changes in the Brain of Acutely Ill and Weight-Recovered Patients with Anorexia Nervosa

2014 ◽  
Vol 42 (1) ◽  
pp. 7-18 ◽  
Author(s):  
Jochen Seitz ◽  
Katharina Bühren ◽  
Georg G. von Polier ◽  
Nicole Heussen ◽  
Beate Herpertz-Dahlmann ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Cognitive Deficits ◽  
Time Course ◽  
Morphological Changes ◽  
Meta Analysis ◽  
Short Term ◽  
Clinical Prognosis ◽  
Qualitative Review ◽  
Brain Changes ◽  
The Brain

Objective: Acute anorexia nervosa (AN) leads to reduced gray (GM) and white matter (WM) volume in the brain, which however improves again upon restoration of weight. Yet little is known about the extent and clinical correlates of these brain changes, nor do we know much about the time-course and completeness of their recovery. Methods: We conducted a meta-analysis and a qualitative review of all magnetic resonance imaging studies involving volume analyses of the brain in both acute and recovered AN. Results: We identified structural neuroimaging studies with a total of 214 acute AN patients and 177 weight-recovered AN patients. In acute AN, GM was reduced by 5.6% and WM by 3.8% compared to healthy controls (HC). Short-term weight recovery 2–5 months after admission resulted in restitution of about half of the GM aberrations and almost full WM recovery. After 2–8 years of remission GM and WM were nearly normalized, and differences to HC (GM: –1.0%, WM: –0.7%) were no longer significant, although small residual changes could not be ruled out. In the qualitative review some studies found GM volume loss to be associated with cognitive deficits and clinical prognosis. Conclusions: GM and WM were strongly reduced in acute AN. The completeness of brain volume rehabilitation remained equivocal.

Space station on-orbit identification and performance monitor

1985 ◽  
Author(s):  
E. METTLER ◽  
M. MILMAN ◽  
G. RODRIGUEZ ◽  
A. TOLIVAR
Keyword(s):  
Space Station ◽  
Performance Monitor ◽  
And Performance

Minocycline inhibits mTOR signaling activation and alleviates behavioral deficits in the Wistar rats with acute ischemia stroke

2020 ◽  
Vol 19 ◽  
Author(s):  
Shengyuan Wang ◽  
Chuanling Wang ◽  
Lihua Wang ◽  
Zhiyou Cai
Keyword(s):  
Cerebral Ischemia ◽  
Ischemia Reperfusion ◽  
Mammalian Target Of Rapamycin ◽  
Mtor Signaling ◽  
Acute Ischemia ◽  
Intragastric Administration ◽  
Underlying Mechanisms ◽  
Signaling Activation ◽  
The Brain ◽  
Minocycline Therapy

Background: Mammalian target of rapamycin (mTOR) has been evidenced as a multimodal therapy in the path-ophysiological process of acute ischemic stroke (AIS). However, the pathway that minocycline targets mTOR signaling is not fully defined in the AIS pathogenesis. This study is to aim at the effects of minocycline on the mTOR signaling in the AIS process and further discover the underlying mechanisms of minocycline involved in the following change of mTOR signaling-autophagy. Methods: Cerebral ischemia/reperfusion (CIR) rat animal models were established with the transient suture occlusion into middle cerebral artery. Minocycline (50mg/kg) was given by intragastric administration. The Morris water maze was used to test the cognitive function of animals. Immunohistochemistry and immunofluorescence were introduced for testing the lev-els of synaptophysin and PSD-95. Western blot was conducted for investigating the levels of mTOR, p-mTOR (Ser2448), p70S6, p-p70S6 (Thr389), eEF2k, p-eEF2k (Ser366), p-eIF4B (Ser406), LC3, p62, synaptophysin and PSD-95. Results: Minocycline prevents cognitive decline of the MCAO stroke rats. Minocycline limits the expression of p-mTOR (Ser2448) and the downstream targets of mTOR [p70S6, p-p70S6 (Thr389), eEF2k, p-eEF2k (Ser366) and p-eIF4B (Ser406)] (P<0.01), while minocycline has no influence on mTOR. LC3-II abundance and the LC3-II/I ratio were upregu-lated in the hippocampus of the MCAO stroke rats by the minocycline therapy (P<0.01). p62 was downregulated in the hippocampus from the MCAO stroke rats administrated with minocycline therapy(P<0.01). The levels of SYP and PSD-95 were up-regulated in the brain of the MCAO stroke rats administrated with minocycline therapy. Conclusion: Minocycline prevents cognitive deficits via inhibiting mTOR signaling and enhancing autophagy process, and promoting the expression of pre-and postsynaptic proteins (synaptophysin and PSD-95) in the brain of the MCAO stroke rats. The potential neuroprotective role of minocycline in the process of cerebral ischemia may be related to mitigating is-chemia-induced synapse injury via inhibiting activation of mTOR signaling.

Musical training improves memory for instrumental music, but not vocal music or words

2018 ◽  
Vol 48 (1) ◽  
pp. 150-159
Author(s):  
Jonathan M. P. Wilbiks ◽  
Sean Hutchins
Keyword(s):  
Instrumental Music ◽  
Musical Training ◽  
Vocal Music ◽  
Verbal Material ◽  
The Other ◽  
Musical Experience ◽  
Facilitative Effect ◽  
Musical Excerpts ◽  
And Performance ◽  
The Brain

In previous research, there exists some debate about the effects of musical training on memory for verbal material. The current research examines this relationship, while also considering musical training effects on memory for musical excerpts. Twenty individuals with musical training were tested and their results were compared to 20 age-matched individuals with no musical experience. Musically trained individuals demonstrated a higher level of memory for classical musical excerpts, with no significant differences for popular musical excerpts or for words. These findings are in support of previous research showing that while music and words overlap in terms of their processing in the brain, there is not necessarily a facilitative effect between training in one domain and performance in the other.

Sign in / Sign up

Export Citation Format

Share Document