scholarly journals Distribution of vitamin C is tissue specific with early saturation of the brain and adrenal glands following differential oral dose regimens in guinea pigs

2015 ◽  
Vol 113 (10) ◽  
pp. 1539-1549 ◽  
Author(s):  
Stine Hasselholt ◽  
Pernille Tveden-Nyborg ◽  
Jens Lykkesfeldt
Keyword(s):  
Vitamin C ◽  
Guinea Pigs ◽  
Adrenal Glands ◽  
Biological Fluids ◽  
Brain Regions ◽  
Hill Equation ◽  
Distribution Kinetics ◽  
The World ◽  
Dose Concentration ◽  
The Brain

Vitamin C (VitC) deficiency is surprisingly common in humans even in developed parts of the world. The micronutrient has several established functions in the brain; however, the consequences of its deficiency are not well characterised. To elucidate the effects of VitC deficiency on the brain, increased knowledge about the distribution of VitC to the brain and within different brain regions after varying dietary concentrations is needed. In the present study, guinea pigs (like humans lacking the ability to synthesise VitC) were randomly divided into six groups (n 10) that received different concentrations of VitC ranging from 100 to 1500 mg/kg feed for 8 weeks, after which VitC concentrations in biological fluids and tissues were measured using HPLC. The distribution of VitC was found to be dynamic and dependent on dietary availability. Brain saturation was region specific, occurred at low dietary doses, and the dose–concentration relationship could be approximated with a three-parameter Hill equation. The correlation between plasma and brain concentrations of VitC was moderate compared with other organs, and during non-scorbutic VitC deficiency, the brain was able to maintain concentrations from about one-quarter to half of sufficient levels depending on the region, whereas concentrations in other tissues decreased to one-sixth or less. The adrenal glands have similar characteristics to the brain. The observed distribution kinetics with a low dietary dose needed for saturation and exceptional retention ability suggest that the brain and adrenal glands are high priority tissues with regard to the distribution of VitC.

scholarly journals Neural Correlates of Group Bias During Natural Viewing

2018 ◽  
Vol 29 (8) ◽  
pp. 3380-3389
Author(s):  
Timothy J Andrews ◽  
Ryan K Smith ◽  
Richard L Hoggart ◽  
Philip I N Ulrich ◽  
Andre D Gouws
Keyword(s):  
Time Course ◽  
Social Groups ◽  
Sensory Information ◽  
Brain Regions ◽  
Group Differences ◽  
Neural Basis ◽  
Brain Responses ◽  
The World ◽  
High Level ◽  
The Brain

Abstract Individuals from different social groups interpret the world in different ways. This study explores the neural basis of these group differences using a paradigm that simulates natural viewing conditions. Our aim was to determine if group differences could be found in sensory regions involved in the perception of the world or were evident in higher-level regions that are important for the interpretation of sensory information. We measured brain responses from 2 groups of football supporters, while they watched a video of matches between their teams. The time-course of response was then compared between individuals supporting the same (within-group) or the different (between-group) team. We found high intersubject correlations in low-level and high-level regions of the visual brain. However, these regions of the brain did not show any group differences. Regions that showed higher correlations for individuals from the same group were found in a network of frontal and subcortical brain regions. The interplay between these regions suggests a range of cognitive processes from motor control to social cognition and reward are important in the establishment of social groups. These results suggest that group differences are primarily reflected in regions involved in the evaluation and interpretation of the sensory input.

scholarly journals High dietary fat and cholesterol exacerbates chronic vitamin C deficiency in guinea pigs

2010 ◽  
Vol 105 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Henriette Frikke-Schmidt ◽  
Pernille Tveden-Nyborg ◽  
Malene Muusfeldt Birck ◽  
Jens Lykkesfeldt
Keyword(s):  
Vitamin C ◽  
Guinea Pigs ◽  
Cholesterol Content ◽  
Dietary Lipid ◽  
Western World ◽  
High Fat ◽  
Vitamin C Deficiency ◽  
Increased Risk ◽  
Oxidation Ratio ◽  
The Brain

Vitamin C deficiency – or hypovitaminosis C defined as a plasma concentration below 23 μm – is estimated to affect hundreds of millions of people in the Western world, in particular subpopulations of low socio-economic status that tend to eat diets of poor nutritional value. Recent studies by us have shown that vitamin C deficiency may result in impaired brain development. Thus, the aim of the present study was to investigate if a poor diet high in fat and cholesterol affects the vitamin C status of guinea pigs kept on either sufficient or deficient levels of dietary ascorbate (Asc) for up to 6 months with particular emphasis on the brain. The present results show that a high-fat and cholesterol diet significantly decreased the vitamin C concentrations in the brain, irrespective of the vitamin C status of the animal (P < 0·001). The brain Asc oxidation ratio only depended on vitamin C status (P < 0·0001) and not on the dietary lipid content. In plasma, the levels of Asc significantly decreased when vitamin C in the diet was low or when the fat/cholesterol content was high (P < 0·0001 for both). The Asc oxidation ratio increased both with low vitamin C and with high fat and cholesterol content (P < 0·0001 for both). We show here for the first time that vitamin C homoeostasis of brain is affected by a diet rich in fat and cholesterol. The present findings suggest that this type of diet increases the turnover of Asc; hence, individuals consuming high-lipid diets may be at increased risk of vitamin C deficiency.

scholarly journals Visual stability

2011 ◽  
Vol 366 (1564) ◽  
pp. 468-475 ◽  
Author(s):  
David Melcher
Keyword(s):  
Cognitive Neuroscience ◽  
State Of The Art ◽  
Brain Regions ◽  
Clinical Neurology ◽  
Visual Stability ◽  
Retinal Motion ◽  
Brain Circuits ◽  
The World ◽  
The Brain

Our vision remains stable even though the movements of our eyes, head and bodies create a motion pattern on the retina. One of the most important, yet basic, feats of the visual system is to correctly determine whether this retinal motion is owing to real movement in the world or rather our own self-movement. This problem has occupied many great thinkers, such as Descartes and Helmholtz, at least since the time of Alhazen. This theme issue brings together leading researchers from animal neurophysiology, clinical neurology, psychophysics and cognitive neuroscience to summarize the state of the art in the study of visual stability. Recently, there has been significant progress in understanding the limits of visual stability in humans and in identifying many of the brain circuits involved in maintaining a stable percept of the world. Clinical studies and new experimental methods, such as transcranial magnetic stimulation, now make it possible to test the causal role of different brain regions in creating visual stability and also allow us to measure the consequences when the mechanisms of visual stability break down.

scholarly journals Vitamin C deficiency in weanling guinea pigs: differential expression of oxidative stress and DNA repair in liver and brain

2007 ◽  
Vol 98 (6) ◽  
pp. 1116-1119 ◽  
Author(s):  
Jens Lykkesfeldt ◽  
Gilberto Perez Trueba ◽  
Henrik E. Poulsen ◽  
Stephan Christen
Keyword(s):  
Oxidative Stress ◽  
Dna Repair ◽  
Vitamin C ◽  
Lipid Oxidation ◽  
Protein Oxidation ◽  
Guinea Pigs ◽  
Vitamin C Deficiency ◽  
Markers Of Oxidative Stress ◽  
Selective Preservation ◽  
The Brain

Neonates are particularly susceptible to malnutrition due to their limited reserves of micronutrients and their rapid growth. In the present study, we examined the effect of vitamin C deficiency on markers of oxidative stress in plasma, liver and brain of weanling guinea pigs. Vitamin C deficiency caused rapid and significant depletion of ascorbate (P < 0·001), tocopherols (P < 0·001) and glutathione (P < 0·001), and a decrease in superoxide dismutase activity (P = 0·005) in the liver, while protein oxidation was significantly increased (P = 0·011). No changes in lipid oxidation or oxidatively damaged DNA were observed in this tissue. In the brain, the pattern was markedly different. Of the measured antioxidants, only ascorbate was significantly depleted (P < 0·001), but in contrast to the liver, ascorbate oxidation (P = 0·034), lipid oxidation (P < 0·001), DNA oxidation (P = 0·13) and DNA incision repair (P = 0·014) were all increased, while protein oxidation decreased (P = 0·003). The results show that the selective preservation of brain ascorbate and induction of DNA repair in vitamin C-deficient weanling guinea pigs is not sufficient to prevent oxidative damage. Vitamin C deficiency may therefore be particularly adverse during the neonatal period.

scholarly journals Perception and Deception: Human Beauty and the Brain

2019 ◽  
Vol 9 (4) ◽  
pp. 34 ◽  
Author(s):  
Daniel Yarosh
Keyword(s):  
Natural Selection ◽  
Reproductive Success ◽  
Brain Regions ◽  
Reproductive Fitness ◽  
Body Proportions ◽  
Men And Women ◽  
True Value ◽  
The World ◽  
Costly Signals ◽  
The Brain

Human physical characteristics and their perception by the brain are under pressure by natural selection to optimize reproductive success. Men and women have different strategies to appear attractive and have different interests in identifying beauty in people. Nevertheless, men and women from all cultures agree on who is and who is not attractive, and throughout the world attractive people show greater acquisition of resources and greater reproductive success than others. The brain employs at least three modules, composed of interconnected brain regions, to judge facial attractiveness: one for identification, one for interpretation and one for valuing. Key elements that go into the judgment are age and health, as well as symmetry, averageness, face and body proportions, facial color and texture. These elements are all Costly Signals of reproductive fitness because they are difficult to fake. However, people deceive others using tricks such as coloring hair, cosmetics and clothing styles, while at the same time they also focus on detecting fakes. People may also deceive themselves, especially about their own attractiveness, and use self-signally actions to demonstrate to themselves their own true value. The neuroscience of beauty is best understood by considering the evolutionary pressures to maximize reproductive fitness.

scholarly journals Cortical and subcortical predictive dynamics and learning during perception, cognition, emotion and action

2009 ◽  
Vol 364 (1521) ◽  
pp. 1223-1234 ◽  
Author(s):  
Stephen Grossberg
Keyword(s):  
Brain Regions ◽  
Unified Theory ◽  
Neural Models ◽  
Predictive Dynamics ◽  
Motor Processes ◽  
The World ◽  
Intimate Link ◽  
Current Value ◽  
Brain Processing ◽  
The Brain

An intimate link exists between the predictive and learning processes in the brain. Perceptual/cognitive and spatial/motor processes use complementary predictive mechanisms to learn, recognize, attend and plan about objects in the world, determine their current value, and act upon them. Recent neural models clarify these mechanisms and how they interact in cortical and subcortical brain regions. The present paper reviews and synthesizes data and models of these processes, and outlines a unified theory of predictive brain processing.

scholarly journals Invariant representations of mass in the human brain

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Sarah Schwettmann ◽  
Joshua B Tenenbaum ◽  
Nancy Kanwisher
Keyword(s):  
Action Planning ◽  
Brain Regions ◽  
Motion Energy ◽  
Physics Engine ◽  
The World ◽  
Invariant Representations ◽  
Physical Variables ◽  
Orthogonal Dimension ◽  
The Brain ◽  
Physical Quantities

An intuitive understanding of physical objects and events is critical for successfully interacting with the world. Does the brain achieve this understanding by running simulations in a mental physics engine, which represents variables such as force and mass, or by analyzing patterns of motion without encoding underlying physical quantities? To investigate, we scanned participants with fMRI while they viewed videos of objects interacting in scenarios indicating their mass. Decoding analyses in brain regions previously implicated in intuitive physical inference revealed mass representations that generalized across variations in scenario, material, friction, and motion energy. These invariant representations were found during tasks without action planning, and tasks focusing on an orthogonal dimension (object color). Our results support an account of physical reasoning where abstract physical variables serve as inputs to a forward model of dynamics, akin to a physics engine, in parietal and frontal cortex.

The Effects of Vitamin C Administration, Acute Food Deprivation, and Acute Food Intake on Vitamin C Levels in Different Brain Areas of Guinea Pigs

2010 ◽  
Vol 80 (3) ◽  
pp. 197-204 ◽  
Author(s):  
Birsen Kaplan ◽  
Ferihan Çetin ◽  
Sehri Elbeg
Keyword(s):  
Food Intake ◽  
Vitamin C ◽  
Brain Stem ◽  
Food Deprivation ◽  
Guinea Pigs ◽  
Occipital Lobe ◽  
Brain Areas ◽  
Parietal Lobes ◽  
Intraperitoneal Dose ◽  
The Brain

Vitamin C is crucial for the brain. We aimed to investigate the effects of vitamin C administration following 24 hours of acute food deprivation and 24 hours of acute food intake on changes in vitamin C levels in different brain areas of guinea pigs. Vitamin C was administered as a single intraperitoneal dose (500 mg kg-1 body weight) both before acute food deprivation and before acute food intake. At the end of our study, we measured the vitamin C levels in cerebral cortex lobes, brain stem structures, hypophysis, hypothalamus, cerebellum, hippocampus, and amygdala. Vitamin C levels in the frontal and parietal lobes were found to be significantly higher in animals pretreated with vitamin C prior to 24 hours of food deprivation (p < 0.05). Temporal lobe vitamin C level was significantly lower in animals that were subjected to 24 hours of acute food intake following 24 hours of food deprivation (p < 0.05). Increased vitamin C levels were observed in the occipital lobe of all animals that received vitamin C administration (p < 0.05). Vitamin C levels in the brain stem structures such as mesencephalon and pons were significantly decreased in animals pretreated with vitamin C before normal feeding (p < 0.05). Vitamin C level in the hypothalamus was significantly increased after 24 hours of food deprivation (p < 0.05). In conclusion, different areas of the brain may differ in terms of vitamin C content during nutritional changes with or without vitamin C pretreatment, such as 24 hours of food deprivation or 24 hours of food intake following 24 hours of food deprivation. These differences may be attributed to several functions of vitamin C which may occur under these circumstances.

scholarly journals How Can We Trick the Brain Into Seeing Rainbows and Faces?

2019 ◽  
Vol 7 ◽  
Author(s):  
Christoph Guger ◽  
Christoph Kapeller ◽  
Hiroshi Ogawa ◽  
Satoru Hiroshima ◽  
Kyousuke Kamada
Keyword(s):  
Brain Regions ◽  
Brain Surgery ◽  
Patient Reported ◽  
The World ◽  
Scientists And Engineers ◽  
The Brain ◽  
Different Parts

How do different parts of the brain work together to help us see, move, understand, and do other things? For many years, we have known that different brain regions perform different tasks that are important for vision. Some brain regions are responsible for seeing faces, colors, lines, movement, or other parts of the world. But mapping different brain regions in detail is very challenging, especially because everyone’s brain is slightly different. Sometimes, brain surgeons must place electrodes inside a patient’s skull—on the surface of the brain—to get a more detailed map. This article describes a study done by a group of brain surgeons, scientists, and engineers. We studied the activity of a patient’s brain while he looked at different objects. We identified two brain regions that were active when the patient processed faces or colors. If we stimulated these areas, the patient reported seeing faces or colors, even if he was looking at something else! The results of this study help show how different parts of the brain perform different tasks, and could lead to safer, more precise brain surgery.

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