scholarly journals The evolution of a placenta is not linked to increased brain size in poeciliid fishes

2020 ◽  
Author(s):  
P. K. Rowiński ◽  
J. Näslund ◽  
W. Sowersby ◽  
S. Eckerström-Liedholm ◽  
B. Rogell
Keyword(s):  
Brain Size ◽  
General Pattern ◽  
Somatic Growth ◽  
Maternal Investment ◽  
Brain Growth ◽  
Non Invasive ◽  
Poeciliid Fish ◽  
Total Brain ◽  
Nutrient Provisioning ◽  
The Brain

ABSTRACTMaternal investment is considered to have a direct influence on the size of energetically costly organs, including the brain. In placental organisms, offspring are supplied with nutrients during pre-natal development, potentially modulating brain size. However, the coevolution of the placenta and brain size remains largely unknown in non-mammalian taxa. Here, using eight poeciliid fish species, we test if species with placental structures invest more resources into offspring brain development than species without placental structures. We predict that matrotrophy may entail higher nutrient provisioning rates to the developing embryo than lecithotrophy, resulting in larger brain sizes in offspring of matrotrophic species, and that a relatively larger part of the total brain growth would occur at younger ages (leading to a shallower ontogenetic brain size allometry). We took non-invasive brain size measurements during the first four weeks of life, and compared these to somatic growth measurements. Contrary to our expectations, we did not find any differences in brain size between the two maternal strategies. Furthermore, we did not find any differences in how relative brain size changed over ontogenetic development, between placental and non-placental species. In contrast to the marsupial/placental transition, the species investigated here only exhibit pre-natal provisioning, which may reduce the potential for maternal investment into brain size. Consequently, our results suggest that coevolution between placental structures and juvenile brain size is not a general pattern.

Early enrichment effects on brain development in hatchery-reared Atlantic salmon (Salmo salar): no evidence for a critical period

2012 ◽  
Vol 69 (9) ◽  
pp. 1481-1490 ◽  
Author(s):  
Joacim Näslund ◽  
Kim Aarestrup ◽  
Søren T. Thomassen ◽  
Jörgen I. Johnsson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Brain Size ◽  
Early Period ◽  
Structural Complexity ◽  
Brain Growth ◽  
Atlantic Salmon Salmo Salar ◽  
Rearing Methods ◽  
External Feeding ◽  
The Brain

In hatcheries, fish are normally reared in barren environments, which have been reported to affect their phenotypic development compared with wild conspecifics. In this study, Atlantic salmon ( Salmo salar ) alevins were reared in conventional barren hatchery trays or in either of two types of structurally enriched trays. We show that increased structural complexity during early rearing increased brain size in all investigated brain substructures. However, these effects disappeared over time after transfer to barren tanks for external feeding. Parallel to the hatchery study, a group of salmon parr was released into nature and recaptured at smoltification. These stream-reared smolts developed smaller brains than the hatchery reared smolts, irrespective of initial enrichment treatment. These novel findings do not support the hypothesis that there is a critical early period determining the brain growth trajectory. In contrast, our results indicate that brain growth is plastic in relation to environment. In addition, we show allometric growth in brain substructures over juvenile development, which suggests that comparisons between groups of different body size should be made with caution. These results can aid the development of ecologically sound rearing methods for conservational fish-stocking programs.

MODIFICATION OF THE SCHEDULE OF MYELINATION IN THE RAT BY EARLY NUTRITIONAL DEPRIVATION

PEDIATRICS ◽  
1966 ◽  
Vol 38 (5) ◽  
pp. 801-807
Author(s):  
John W. Benton ◽  
Hugo W. Moser ◽  
Philip R. Dodge ◽  
Sheila Carr
Keyword(s):  
Somatic Growth ◽  
The Body ◽  
Brain Weight ◽  
Newborn Rats ◽  
Brain Lipids ◽  
Nutritional Deprivation ◽  
Control Brain ◽  
Total Brain ◽  
Unlimited Supply ◽  
The Brain

Relative nutritional deprivation was produced in groups of 16 to 21 newborn rats who were all nursed by one dam (deprived group) and compared with control litters containing 10 or less animals. Both groups were weaned at 21 days and thereafter allowed an unlimited supply of food. There was diminished somatic growth in all of the deprived group and, at 2 and 3 weeks, the weight of many of the deprived animals was approximately one-half that of the controls. Brain weight, total brain lipids, cholesterol, and phospholipids were reduced to approximately 80% of the control. Brain cerebrosides were affected to a greater extent than the other lipids, being only 50% of the control values. Histological sections showed less myelin. At 6 weeks, following 3 weeks of ad lib. food intake, the body weight, brain weight, and concentrations of the brain lipids of the initially deprived animals were essentially equal to those in the control animals.

scholarly journals Small within the largest: brain size and anatomy of the extinct Neoepiblema acreensis , a giant rodent from the Neotropics

2020 ◽  
Vol 16 (2) ◽  
pp. 20190914 ◽  
Author(s):  
José D. Ferreira ◽  
Francisco R. Negri ◽  
Marcelo R. Sánchez-Villagra ◽  
Leonardo Kerber
Keyword(s):  
Brain Size ◽  
Imaging Techniques ◽  
Cranial Nerves ◽  
Ecological Factors ◽  
Energetic Cost ◽  
Brain Anatomy ◽  
Non Invasive ◽  
Adaptive Value ◽  
Caviomorph Rodents ◽  
The Brain

The ecomorphological diversity of caviomorph rodents in South America included giant forms, such as the chinchilloid Neoepiblema acreensis from the Upper Miocene of Brazil. The evolution of the brain anatomy and size of these animals can be now studied with non-invasive imaging techniques and exceptional fossils. Caviomorphs show diversity in the traits of the olfactory bulbs, cerebrum, cerebellum, cranial nerves, and blood vessels. Neoepiblema acreensis had a gyrencephalic brain, with an expansion of the frontal lobe, lacking an evident paraflocculus. Compared to the predictions based on extant taxa, even when considering taphonomical effects, N. acreensis , a rodent that weighted almost 80 kg, had a very low encephalization quotient compared to other rodents. The adaptive value of a low energetic cost and other ecological factors could explain the presence of a small brain in this giant rodent––a pattern we also hypothesize for other Neogene giant rodents.

NON-INVASIVE BCI METHOD: EEG - ELECTROENCEPHALOGRAPHY

2019 ◽  
pp. 139-145
Author(s):  
Selma Büyükgöze
Keyword(s):  
Brain Computer Interface ◽  
Computer Interface ◽  
Electrode Placement ◽  
Eeg Signals ◽  
Non Invasive ◽  
Brain Signals ◽  
Brain States ◽  
The Brain

Brain Computer Interface consists of hardware and software that convert brain signals into action. It changes the nerves, muscles, and movements they produce with electro-physiological signs. The BCI cannot read the brain and decipher the thought in general. The BCI can only identify and classify specific patterns of activity in ongoing brain signals associated with specific tasks or events. EEG is the most commonly used non-invasive BCI method as it can be obtained easily compared to other methods. In this study; It will be given how EEG signals are obtained from the scalp, with which waves these frequencies are named and in which brain states these waves occur. 10-20 electrode placement plan for EEG to be placed on the scalp will be shown.

scholarly journals Molecular evolutionary analysis of human primary microcephaly genes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nashaiman Pervaiz ◽  
Hongen Kang ◽  
Yiming Bao ◽  
Amir Ali Abbasi
Keyword(s):  
Evolutionary History ◽  
Genetic Basis ◽  
Brain Size ◽  
Primate Species ◽  
Evolutionary Analysis ◽  
Australopithecus Afarensis ◽  
Primary Microcephaly ◽  
Modern Humans ◽  
History Of ◽  
The Brain

Abstract Background There has been a rapid increase in the brain size relative to body size during mammalian evolutionary history. In particular, the enlarged and globular brain is the most distinctive anatomical feature of modern humans that set us apart from other extinct and extant primate species. Genetic basis of large brain size in modern humans has largely remained enigmatic. Genes associated with the pathological reduction of brain size (primary microcephaly-MCPH) have the characteristics and functions to be considered ideal candidates to unravel the genetic basis of evolutionary enlargement of human brain size. For instance, the brain size of microcephaly patients is similar to the brain size of Pan troglodyte and the very early hominids like the Sahelanthropus tchadensis and Australopithecus afarensis. Results The present study investigates the molecular evolutionary history of subset of autosomal recessive primary microcephaly (MCPH) genes; CEP135, ZNF335, PHC1, SASS6, CDK6, MFSD2A, CIT, and KIF14 across 48 mammalian species. Codon based substitutions site analysis indicated that ZNF335, SASS6, CIT, and KIF14 have experienced positive selection in eutherian evolutionary history. Estimation of divergent selection pressure revealed that almost all of the MCPH genes analyzed in the present study have maintained their functions throughout the history of placental mammals. Contrary to our expectations, human-specific adoptive evolution was not detected for any of the MCPH genes analyzed in the present study. Conclusion Based on these data it can be inferred that protein-coding sequence of MCPH genes might not be the sole determinant of increase in relative brain size during primate evolutionary history.

scholarly journals Effects of Brain Size on Adult Neurogenesis in Shrews

2021 ◽  
Vol 22 (14) ◽  
pp. 7664
Author(s):  
Katarzyna Bartkowska ◽  
Krzysztof Turlejski ◽  
Beata Tepper ◽  
Leszek Rychlik ◽  
Peter Vogel ◽  
...  
Keyword(s):  
Adult Neurogenesis ◽  
Subventricular Zone ◽  
Molecular Mechanisms ◽  
Brain Size ◽  
Hippocampal Formation ◽  
Small Animals ◽  
Suncus Murinus ◽  
The Brain ◽  
Neomys Fodiens ◽  
Migratory Stream

Shrews are small animals found in many different habitats. Like other mammals, adult neurogenesis occurs in the subventricular zone of the lateral ventricle (SVZ) and the dentate gyrus (DG) of the hippocampal formation. We asked whether the number of new generated cells in shrews depends on their brain size. We examined Crocidura russula and Neomys fodiens, weighing 10–22 g, and Crocidura olivieri and Suncus murinus that weigh three times more. We found that the density of proliferated cells in the SVZ was approximately at the same level in all species. These cells migrated from the SVZ through the rostral migratory stream to the olfactory bulb (OB). In this pathway, a low level of neurogenesis occurred in C. olivieri compared to three other species of shrews. In the DG, the rate of adult neurogenesis was regulated differently. Specifically, the lowest density of newly generated neurons was observed in C. russula, which had a substantial number of new neurons in the OB compared with C. olivieri. We suggest that the number of newly generated neurons in an adult shrew’s brain is independent of the brain size, and molecular mechanisms of neurogenesis appeared to be different in two neurogenic structures.

In vivo exploration of brain phosphorus 31 metabolism in patients with senile dementia of Alzheimer type

1994 ◽  
Vol 9 (2) ◽  
pp. 105-109
Author(s):  
G Mecheri ◽  
Y Bissuel ◽  
J Dalery ◽  
JL Terra ◽  
G Balvay ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Senile Dementia ◽  
Phospholipid Metabolism ◽  
Alzheimer Type ◽  
Dementia Of Alzheimer Type ◽  
Non Invasive ◽  
Significant Difference ◽  
The Brain

SummaryIn vivo NMR 31p spectroscopy is a non invasive, non ionizing method of exploration of energy and phospholipid metabolism in the brain. This study consisted of comparing 31p spectra in five patients with Senile Dementia of Alzheimer Type (SDAT) with those of four controls of similar ages. Abnormal phosphonionocsters (PME) concentrations, either high or low, were found in the patients, but statistical analysis did not elicit any significant difference relative to controls.

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