scholarly journals Primate hippocampus size and organization are predicted by sociality but not diet

2019 ◽  
Author(s):  
Orlin S. Todorov ◽  
Vera Weisbecker ◽  
Emmanuel Gilissen ◽  
Karl Zilles ◽  
Alexandra A. de Sousa
Keyword(s):  
Sex Differences ◽  
Home Range ◽  
Group Size ◽  
Phylogenetic Signal ◽  
Spatial Navigation ◽  
Ecological Factors ◽  
Hippocampal Volume ◽  
The Other ◽  
Sex Dimorphism ◽  
Cornu Ammonis

AbstractThe hippocampus is well known for its roles in spatial navigation and memory, but it is organized into regions that have different connections and functional specializations. Notably, the region CA2 has a role in social and not spatial cognition, as is the case for the regions CA1 and CA3 that surround it. Here we investigated the evolution of the hippocampus in terms of its size and organization in relation to the evolution of social and ecological variables in primates, namely home range, diet and different measures of group size. We found that the volumes within the whole cornu ammonis coevolve with group size, while only the volume of CA1 and subiculum can also be predicted by home range. On the other hand, diet, expressed as a shift from folivory toward frugivory, was shown to not be related to hippocampal volume. Interestingly, CA2 was shown to exhibit phylogenetic signal only against certain measures of group size but not with ecological factors. We also found that sex differences in the hippocampus are related to body size sex dimorphism. This is in line with reports of sex differences in hippocampal volume in non-primates that are related to social structure and sex differences in behaviour. Our findings support the notion that in primates, the hippocampus is a mosaic structure evolving in line with social pressures, where certain subsections evolve in line with spatial ability too.

scholarly journals Primate hippocampus size and organization are predicted by sociality but not diet

2019 ◽  
Vol 286 (1914) ◽  
pp. 20191712 ◽  
Author(s):  
Orlin S. Todorov ◽  
Vera Weisbecker ◽  
Emmanuel Gilissen ◽  
Karl Zilles ◽  
Alexandra A. de Sousa
Keyword(s):  
Sex Differences ◽  
Home Range ◽  
Group Size ◽  
Phylogenetic Signal ◽  
Spatial Navigation ◽  
Ecological Factors ◽  
Hippocampal Volume ◽  
The Other ◽  
Sex Dimorphism ◽  
Cornu Ammonis

The hippocampus is well known for its roles in spatial navigation and memory, but it is organized into regions that have different connections and functional specializations. Notably, the region CA2 has a role in social and not spatial cognition, as is the case for the regions CA1 and CA3 that surround it. Here, we investigated the evolution of the hippocampus in terms of its size and organization in relation to the evolution of social and ecological variables in primates, namely home range, diet and different measures of group size. We found that the volumes within the whole cornu ammonis coevolve with group size, while only the volume of CA1 and subiculum can also be predicted by home range. On the other hand, diet, expressed as a shift from folivory towards frugivory, was shown to not be related to hippocampal volume. Interestingly, CA2 was shown to exhibit phylogenetic signal only against certain measures of group size, but not with ecological factors. We also found that sex differences in the hippocampus are related to body size sex dimorphism. This is in line with reports of sex differences in hippocampal volume in non-primates that are related to social structure and sex differences in behaviour. Our findings support the notion that in primates, the hippocampus is a mosaic structure evolving in line with social pressures, where certain subsections evolve in line with spatial ability too.

SEX DIMORPHISM IN THE ADRENAL OF HAMSTERS

1974 ◽  
Vol 75 (3) ◽  
pp. 550-560 ◽  
Author(s):  
G. Zieger ◽  
B. Lux ◽  
B. Kubatsch
Keyword(s):  
Sex Differences ◽  
Adrenal Glands ◽  
The Other ◽  
Specific Function ◽  
Sex Dimorphism ◽  
Histological Changes ◽  
Zona Reticularis ◽  
Steroid Secretion ◽  
Golden Hamsters ◽  
Syrian Golden Hamsters

ABSTRACT The adrenals of the hamster differ in many respects from those of other mammals that have been studied so far. The higher weight and the higher steroid secretion of the male adrenal are conspicuous features. The adrenals of 144 Syrian golden hamsters between the 1st and 12th week of life were studied histologically and histometrically in order to see whether these sex differences also show up in the morphology of the adrenals. Histologically in both sexes a typical zonation in glomerulosa and fasciculata could be observed from the 2nd week onwards. Both zones consist of compact cells. Already at the end of the 4th week in some sections, sex-specific differences are found. From the 5th week up to the end of our experiment these differences are so pronounced that it is possible with 100% accuracy to determine the sex of the animal from the appearance of the adrenal: the zona reticularis of the female adrenal shows a higher cellularity than in the male adrenal. In males on the other hand, the cells are arranged less densely and development of intracellular vacuoles in the adjacent fasciculata and in the zona reticularis are seen. The histilogical sex differences are significant from the end of the 4th week up to the end of our study. Parallel with the histological changes a difference in the weights of the adrenals begins to appear from the 4th week onwards. The male adrenal glands are heavier than those of females. This weight difference can be confirmed statistically from the 6th week onwards. The studies provided a morphological basis for the reticularis of the adrenals of golden hamsters for the sex-specific function and weight.

scholarly journals Sex differences in the association between prenatal exposure to maternal obesity and hippocampal volume in children

2020 ◽  
Vol 10 (2) ◽  
Author(s):  
Jasmin M. Alves ◽  
Shan Luo ◽  
Ting Chow ◽  
Megan Herting ◽  
Anny H. Xiang ◽  
...  
Keyword(s):  
Sex Differences ◽  
Prenatal Exposure ◽  
Maternal Obesity ◽  
Hippocampal Volume

scholarly journals Phylogenetic paleoecology: macroecology within an evolutionary framework

Paleobiology ◽  
2021 ◽  
Vol 47 (2) ◽  
pp. 171-177
Author(s):  
James C. Lamsdell ◽  
Curtis R. Congreve
Keyword(s):  
Species Diversity ◽  
Spatial Variation ◽  
Geographic Distribution ◽  
Evolutionary Biology ◽  
Phylogenetic Signal ◽  
Evolutionary Rates ◽  
The Other ◽  
Ecological Data ◽  
Temporal And Spatial Variation ◽  
Temporal And Spatial

The burgeoning field of phylogenetic paleoecology (Lamsdell et al. 2017) represents a synthesis of the related but differently focused fields of macroecology (Brown 1995) and macroevolution (Stanley 1975). Through a combination of the data and methods of both disciplines, phylogenetic paleoecology leverages phylogenetic theory and quantitative paleoecology to explain the temporal and spatial variation in species diversity, distribution, and disparity. Phylogenetic paleoecology is ideally situated to elucidate many fundamental issues in evolutionary biology, including the generation of new phenotypes and occupation of previously unexploited environments; the nature of relationships among character change, ecology, and evolutionary rates; determinants of the geographic distribution of species and clades; and the underlying phylogenetic signal of ecological selectivity in extinctions and radiations. This is because phylogenetic paleoecology explicitly recognizes and incorporates the quasi-independent nature of evolutionary and ecological data as expressed in the dual biological hierarchies (Eldredge and Salthe 1984; Congreve et al. 2018; Fig. 1), incorporating both as covarying factors rather than focusing on one and treating the other as error within the dataset.

scholarly journals Association between Hippocampal Volume and Working Memory in 10,000+ 9–10-Year-Old Children: Sex Differences

Children ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 411
Author(s):  
Shervin Assari ◽  
Shanika Boyce ◽  
Tanja Jovanovic
Keyword(s):  
Working Memory ◽  
Sex Differences ◽  
Parental Education ◽  
Predictor Variable ◽  
National Sample ◽  
Hippocampal Volume ◽  
Study Data ◽  
Cross Sectional ◽  
The Right

Aim: This study tested sex differences in the association between hippocampal volume and working memory of a national sample of 9–10-year-old children in the US. As the hippocampus is functionally lateralized (especially in task-related activities), we explored the results for the right and the left hippocampus. Methods: This is a cross-sectional study using the Adolescent Brain Cognitive Development (ABCD) Study data. This analysis included baseline ABCD data (n = 10,093) of children between ages 9 and 10 years. The predictor variable was right and left hippocampal volume measured by structural magnetic resonance imaging (sMRI). The primary outcome, list sorting working memory, was measured using the NIH toolbox measure. Sex was the moderator. Age, race, ethnicity, household income, parental education, and family structure were the covariates. Results: In the overall sample, larger right (b = 0.0013; p < 0.001) and left (b = 0.0013; p < 0.001) hippocampal volumes were associated with higher children’s working memory. Sex had statistically significant interactions with the right (b = −0.0018; p = 0.001) and left (b = −0.0012; p = 0.022) hippocampal volumes on children’s working memory. These interactions indicated stronger positive associations between right and left hippocampal volume and working memory for females compared to males. Conclusion: While right and left hippocampal volumes are determinants of children’s list sorting working memory, these effects seem to be more salient for female than male children. Research is needed on the role of socialization, sex hormones, and brain functional connectivity as potential mechanisms that may explain the observed sex differences in the role of hippocampal volume as a correlate of working memory.

scholarly journals Group size and aquatic vegetation modulates male preferences for female shoals in wild zebrafish, Danio rerio

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aditya Ghoshal ◽  
Anuradha Bhat
Keyword(s):  
Group Size ◽  
Aquatic Vegetation ◽  
Natural Habitat ◽  
Ecological Factors ◽  
Choice Test ◽  
Female Group ◽  
Aquatic Flora ◽  
In The Wild ◽  
The Individual

AbstractShoaling decisions in the wild are determined by a combination of innate preferences of the individual along with the interplay of multiple ecological factors. In their natural habitat as well as in the laboratory, zebrafish is a shoaling fish. Here, we investigate the role of group size and associated vegetation in shaping shoaling preferences of wild male zebrafish. We studied the association preference of males to groups of female shoals in a multi-choice test design. We found that males made greater proportion of visits to an 8-female group compared to 2 and 4-female groups. However, males spent similar proportions of time across the three female-containing groups. When artificial vegetation was incorporated along with female number as an additional factor, we found that males prefer high and moderately vegetated patches compared to low or no-vegetation groups, irrespective of the number of females in these patches. Based on experiments using a novel multi-choice design, our results show that preference for group size can change due to interaction of two separate factors. This work is a first attempt to understand the role of aquatic flora in determining shoaling preferences in zebrafish, using an experimental paradigm consisting of a gradation in female and vegetation densities.

Toward Understanding the Contributions of Sex and Situation to Behavior in a College Setting

1987 ◽  
Vol 60 (3) ◽  
pp. 875-883
Author(s):  
Nancy Lipsitt ◽  
Rose R. Olver
Keyword(s):  
Sex Differences ◽  
The Other ◽  
Men And Women ◽  
Male And Female ◽  
Relative Contribution ◽  
College Setting ◽  
Female Subjects

The relative contribution of sex and situation has become a contested issue in the understanding of sex differences in behavior. In the present study, 20 male and 20 female undergraduates were asked to describe their behavior and thoughts in six everyday college situations. Three of the situations were constructed to be typically male and three typically female in content. The results indicate that men and women demonstrate sex-specific characteristics in their responses regardless of the type of situation presented. Men exhibited concern with separateness from others, while women exhibited concern with sustaining connection to others, even when faced with situations described to present demand properties that might be expected specifically to elicit the concern characteristic of the other sex. However, for these students the situation also made a difference: female-defined situations elicited the most masculine responses for both male and female subjects.

Sex Differences in Reward Allocation

1988 ◽  
Vol 67 (3) ◽  
pp. 981-982
Author(s):  
Kerry C. Martin ◽  
Jay Hewitt
Keyword(s):  
Sex Differences ◽  
Work Groups ◽  
The Self ◽  
The Other ◽  
Men And Women ◽  
High Productivity ◽  
Self Interest ◽  
Reward Allocation

Men and women were presented descriptions of two dyadic work groups. In both groups, one member of the dyad did approximately two-thirds of the work. For one of the groups, subjects were asked to imagine that they were the worker of high productivity while for the other group subjects were asked to imagine that they were impartial observers. Subjects were asked to divide the rewards among the two workers for both groups. Men and women did not differ in allocation of reward when acting as impartial observers. When subjects imagined themselves as the worker of high productivity, men gave themselves a greater share of the reward than did women. It was concluded that the results were consistent with the self-interest explanation of sex differences in allocation of reward.

scholarly journals Sex differences in spatial navigation and perception in human adolescents and emerging adults

2015 ◽  
Vol 111 ◽  
pp. 42-50 ◽  
Author(s):  
Jennifer T. Sneider ◽  
Derek A. Hamilton ◽  
Julia E. Cohen-Gilbert ◽  
David J. Crowley ◽  
Isabelle M. Rosso ◽  
...  
Keyword(s):  
Sex Differences ◽  
Emerging Adults ◽  
Spatial Navigation

scholarly journals Sex differences in the behavioral responses of dogs exposed to human chemosignals of fear and happiness

2021 ◽  
Author(s):  
Biagio D’Aniello ◽  
Barbara Fierro ◽  
Anna Scandurra ◽  
Claudia Pinelli ◽  
Massimo Aria ◽  
...  
Keyword(s):  
Sex Differences ◽  
Behavioral Responses ◽  
The Other ◽  
Behavioral Patterns ◽  
Stress Signals ◽  
Stress Behaviors ◽  
The Stranger

AbstractThis research focuses on sex differences in the behavioral patterns of dogs when they are exposed to human chemosignals (sweat) produced in happy and fear contexts. No age, breed or apparatus-directed behavior differences were found. However, when exposed to fear chemosignals, dogs’ behavior towards their owners, and their stress signals lasted longer when compared to being exposed to happiness as well as control chemosignals. In the happy odor condition, females, in contrast to males, displayed a significantly higher interest to the stranger compared to their owner. In the fear condition, dogs spent more time with their owner compared to the stranger. Behaviors directed towards the door, indicative of exit interest, had a longer duration in the fear condition than the other two conditions. Female dogs revealed a significantly longer door-directed behavior in the fear condition compared to the control condition. Overall the data shows that the effect of exposure to human emotional chemosignals is not sex dependent for behaviors related to the apparatus, the owner or the stress behaviors; however, in the happiness condition, females showed a stronger tendency to interact with the stranger.

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