The Ecological Brain

2021 ◽  
pp. 35-50
Author(s):  
Susan D. Healy
Keyword(s):  
Life History ◽  
Selection Pressure ◽  
Brain Size ◽  
Brain Regions ◽  
Range Size ◽  
Overwhelming Evidence ◽  
Sensory Motor ◽  
The Relationship ◽  
Life History Variables

In this chapter, I examine the evidence for a role for the preeminent selection pressure, ecology, in shaping animal brains and in causing changes in brain size within and among species. I describe what ‘ecology’ has meant in comparative analyses, e.g. foraging, range size, and life history variables. I provide evidence for a clear association between ecology and the size of sensory-motor brain regions and go on to use the relationship between space and the hippocampus to show the generality of this relationship beyond food storing. I discuss the strength of the data showing that migration, foraging, and domestication have caused changes in brain size. I conclude that while there is evidence of domestication, in particular, having changed whole brain size, it is at the level of brain regions that there is overwhelming evidence for an effect of ecology on brain size.

Brain size evolution in anurans: a review

2019 ◽  
Vol 69 (3) ◽  
pp. 265-279 ◽  
Author(s):  
Chun Lan Mai ◽  
Wen Bo Liao
Keyword(s):  
Sexual Selection ◽  
Life History ◽  
Life History Traits ◽  
Developmental Stages ◽  
Brain Size ◽  
Ecological Factors ◽  
Brain Regions ◽  
Sperm Length ◽  
Testis Size ◽  
Size Evolution

Abstract Selection pressure is an important force in shaping the evolution of vertebrate brain size among populations within species as well as between species. The evolution of brain size is tightly linked to natural and sexual selection, and life-history traits. In particular, increased environmental stress, intensity of sexual selection, and slower life history usually result in enlarged brains. However, although previous studies have addressed the causes of brain size evolution, no systematic reviews have been conducted to explain brain size in anurans. Here, we review whether brain size evolution supports the cognitive buffer hypothesis (CBH), the expensive tissue hypothesis (ETH), or the developmental cost hypothesis (DCH) by analyzing the intraspecific and/or interspecific patterns in brain size and brain regions (i.e., olfactory nerves, olfactory bulbs, telencephalon, optic tectum, and cerebellum) associated with ecological factors (habitat, diet and predator risk), sexual selection intensity, life-history traits (age at sexual maturity, mean age, longevity, clutch size and egg size, testis size and sperm length), and other energetic organs. Our findings suggest that brain size evolution in anurans supports the CBH, ETH or DCH. We also suggest future directions for studying the relationships between brain size evolution and crypsis (i.e., ordinary mucous glands in the skin), and food alteration in different developmental stages.

Abundance-range size relationships of macrolepidoptera in Britain: the effects of taxonomy and life history variables

1997 ◽  
Vol 22 (4) ◽  
pp. 453-461 ◽  
Author(s):  
RACHEL QUINN ◽  
KEVIN GASTON ◽  
TIM BLACKBURN ◽  
BRIAN EVERSHAM
Keyword(s):  
Life History ◽  
Range Size ◽  
Life History Variables

scholarly journals Brain size predicts problem-solving ability in mammalian carnivores

2016 ◽  
Vol 113 (9) ◽  
pp. 2532-2537 ◽  
Author(s):  
Sarah Benson-Amram ◽  
Ben Dantzer ◽  
Gregory Stricker ◽  
Eli M. Swanson ◽  
Kay E. Holekamp
Keyword(s):  
Body Mass ◽  
Cognitive Abilities ◽  
Brain Size ◽  
Technical Problem ◽  
Behavioral Flexibility ◽  
Empirical Support ◽  
Brain Regions ◽  
Self Control ◽  
Invasion Success ◽  
The Relationship

Despite considerable interest in the forces shaping the relationship between brain size and cognitive abilities, it remains controversial whether larger-brained animals are, indeed, better problem-solvers. Recently, several comparative studies have revealed correlations between brain size and traits thought to require advanced cognitive abilities, such as innovation, behavioral flexibility, invasion success, and self-control. However, the general assumption that animals with larger brains have superior cognitive abilities has been heavily criticized, primarily because of the lack of experimental support for it. Here, we designed an experiment to inquire whether specific neuroanatomical or socioecological measures predict success at solving a novel technical problem among species in the mammalian order Carnivora. We presented puzzle boxes, baited with food and scaled to accommodate body size, to members of 39 carnivore species from nine families housed in multiple North American zoos. We found that species with larger brains relative to their body mass were more successful at opening the boxes. In a subset of species, we also used virtual brain endocasts to measure volumes of four gross brain regions and show that some of these regions improve model prediction of success at opening the boxes when included with total brain size and body mass. Socioecological variables, including measures of social complexity and manual dexterity, failed to predict success at opening the boxes. Our results, thus, fail to support the social brain hypothesis but provide important empirical support for the relationship between relative brain size and the ability to solve this novel technical problem.

scholarly journals Intraspecific brain size variation between coexisting sunfish ecotypes

2018 ◽  
Vol 285 (1890) ◽  
pp. 20181971 ◽  
Author(s):  
Caleb J. Axelrod ◽  
Frédéric Laberge ◽  
Beren W. Robinson
Keyword(s):  
Brain Size ◽  
Divergence Time ◽  
Size Variation ◽  
Open Water ◽  
Brain Regions ◽  
Cognitive Demands ◽  
Physiological Processes ◽  
Littoral Habitat ◽  
Pelagic Habitat ◽  
The Relationship

Variation in spatial complexity and foraging requirements between habitats can impose different cognitive demands on animals that may influence brain size. However, the relationship between ecologically related cognitive performance and brain size is not well established. We test whether variation in relative brain size and brain region size is associated with habitat use within a population of pumpkinseed sunfish composed of different ecotypes that inhabit either the structurally complex shoreline littoral habitat or simpler open-water pelagic habitat. Sunfish using the littoral habitat have on average 8.3% larger brains than those using the pelagic habitat. We found little difference in the proportional sizes of five brain regions between ecotypes. The results suggest that cognitive demands on sunfish may be reduced in the pelagic habitat given no habitat-specific differences in body condition. They also suggest that either a short divergence time or physiological processes may constrain changes to concerted, global modifications of brain size between sunfish ecotypes.

scholarly journals Understanding primate brain evolution

2007 ◽  
Vol 362 (1480) ◽  
pp. 649-658 ◽  
Author(s):  
R.I.M Dunbar ◽  
Susanne Shultz
Keyword(s):  
Life History ◽  
Path Analysis ◽  
Group Size ◽  
Brain Size ◽  
Brain Evolution ◽  
Primate Brain ◽  
The Social ◽  
Large Brain ◽  
Brain Data ◽  
The Relationship

We present a detailed reanalysis of the comparative brain data for primates, and develop a model using path analysis that seeks to present the coevolution of primate brain (neocortex) and sociality within a broader ecological and life-history framework. We show that body size, basal metabolic rate and life history act as constraints on brain evolution and through this influence the coevolution of neocortex size and group size. However, they do not determine either of these variables, which appear to be locked in a tight coevolutionary system. We show that, within primates, this relationship is specific to the neocortex. Nonetheless, there are important constraints on brain evolution; we use path analysis to show that, in order to evolve a large neocortex, a species must first evolve a large brain to support that neocortex and this in turn requires adjustments in diet (to provide the energy needed) and life history (to allow sufficient time both for brain growth and for ‘software’ programming). We review a wider literature demonstrating a tight coevolutionary relationship between brain size and sociality in a range of mammalian taxa, but emphasize that the social brain hypothesis is not about the relationship between brain/neocortex size and group size per se ; rather, it is about social complexity and we adduce evidence to support this. Finally, we consider the wider issue of how mammalian (and primate) brains evolve in order to localize the social effects.

scholarly journals Cerebellum and Emotion in Morality

2021 ◽  
Author(s):  
Hyemin Han
Keyword(s):  
Large Scale ◽  
Functional Neuroimaging ◽  
Brain Regions ◽  
Moral Functioning ◽  
Neuroimaging Data ◽  
Crus I ◽  
The Right ◽  
Brain Image Analysis ◽  
The Relationship

In the current chapter, I examined the relationship between the cerebellum, emotion, and morality with evidence from large-scale neuroimaging data analysis. Although the aforementioned relationship has not been well studied in neuroscience, recent studies have shown that the cerebellum is closely associated with emotional and social processes at the neural level. Also, debates in the field of moral philosophy, psychology, and neuroscience have supported the importance of emotion in moral functioning. Thus, I explored the potentially important but less-studies topic with NeuroSynth, a tool for large-scale brain image analysis, while addressing issues associated with reverse inference. The result from analysis demonstrated that brain regions in the cerebellum, the right Crus I and Crus II in particular, were specifically associated with morality in general. I discussed the potential implications of the finding based on clinical and functional neuroimaging studies of the cerebellum, emotional functioning, and neural networks for diverse psychological processes.

Cerebellum size is positively correlated with geographic distribution range in anurans

2018 ◽  
Vol 68 (3) ◽  
pp. 309-320 ◽  
Author(s):  
Chun Lin Zhao ◽  
Long Jin ◽  
Mao Jun Zhong ◽  
Feng Xie ◽  
Jian Ping Jiang ◽  
...  
Keyword(s):  
Brain Size ◽  
Behavioral Flexibility ◽  
Brain Regions ◽  
Geographic Range ◽  
Phylogenetic Comparative Methods ◽  
Animal Kingdom ◽  
Geographic Ranges ◽  
Unpredictable Environments ◽  
Energetic Constraints ◽  
The Relationship

AbstractThe ‘cognitive buffer’ hypothesis predicts that the costs of relatively large brains are compensated for later in life by the increased benefits of large brains providing a higher chance of survival under changing environments through flexible behaviors in the animal kingdom. Thus, animals that live in a larger range (with a higher probability of environmental variation) are expected to have larger brains than those that live in a restricted geographic range. Here, to test the prediction of the ‘cognitive buffer’ hypothesis that larger brains should be expected to occur in species living in geographic ranges of larger size, we analyzed the relationship between the size of the geographic range and brain size and the size of various brain regions among 42 species of anurans using phylogenetic comparative methods. The results show that there is no correlation between relative brain size and size of the species’ geographic range when correcting for phylogenetic effects and body size. Our findings suggest that the effects of the cognitive buffer and the energetic constraints on brains result in non-significant variation in overall brain size. However, the geographic range is positively correlated with cerebellum size, but not with optic tecta, suggesting that species distributed in a wider geographic range do not exhibit larger optic tecta which would provide behavioral flexibility to allow for an early escape from potential predators and discovery of new food resources in unpredictable environments.

The relationships between brain regions and forelimb dexterity in marsupials (Marsupialia): a comparative test of the principle of proper mass

2000 ◽  
Vol 48 (1) ◽  
pp. 99 ◽  
Author(s):  
Andrew N. Iwaniuk ◽  
John E. Nelson ◽  
Ian Q. Whishaw
Keyword(s):  
Brain Cortex ◽  
Brain Size ◽  
Brain Regions ◽  
Brain Morphology ◽  
Proper Mass ◽  
Contrast Analysis ◽  
Independent Contrast ◽  
The Relationship ◽  
The Brain ◽  
Forelimb Movements

A behavioural index of forelimb dexterity and comparative statistics were used to analyse the relationships between proximal (shoulder, upper and lower forelimb) and distal (wrist, forepaw, digits) forelimb dexterity and four aspects of brain morphology (overall brain, cortex, cerebellum and telencephalon sizes) in 18 species of marsupials. On the basis of the principle of proper mass, it was expected that an increase in forelimb dexterity (either proximal or distal) would be positively correlated with the size of the brain and the three brain components. Using independent contrast analysis to remove the effects of phylogeny revealed three significant correlations between: cortex size and distal dexterity, cerebellum size and proximal dexterity, and telencephalon size and distal dexterity. The relationship between cortex size and distal dexterity was subsequently corroborated by Spearman rank correlations. These results suggest that the execution of finely coordinated forelimb movements may not be dependent upon overall brain size, but may be dependent upon the size of brain components, thus supporting the principle of proper mass.

scholarly journals Why big brains? A comparison of models for both primate and carnivore brain size evolution

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261185
Author(s):  
Helen Rebecca Chambers ◽  
Sandra Andrea Heldstab ◽  
Sean J. O’Hara
Keyword(s):  
Life History ◽  
Brain Size ◽  
Size Variation ◽  
Ecological Factors ◽  
Brain Evolution ◽  
Brain Regions ◽  
Home Range Size ◽  
Careful Consideration ◽  
Social Brain ◽  
Multiple Variables

Despite decades of research, much uncertainty remains regarding the selection pressures responsible for brain size variation. Whilst the influential social brain hypothesis once garnered extensive support, more recent studies have failed to find support for a link between brain size and sociality. Instead, it appears there is now substantial evidence suggesting ecology better predicts brain size in both primates and carnivores. Here, different models of brain evolution were tested, and the relative importance of social, ecological, and life-history traits were assessed on both overall encephalisation and specific brain regions. In primates, evidence is found for consistent associations between brain size and ecological factors, particularly diet; however, evidence was also found advocating sociality as a selection pressure driving brain size. In carnivores, evidence suggests ecological variables, most notably home range size, are influencing brain size; whereas, no support is found for the social brain hypothesis, perhaps reflecting the fact sociality appears to be limited to a select few taxa. Life-history associations reveal complex selection mechanisms to be counterbalancing the costs associated with expensive brain tissue through extended developmental periods, reduced fertility, and extended maximum lifespan. Future studies should give careful consideration of the methods chosen for measuring brain size, investigate both whole brain and specific brain regions where possible, and look to integrate multiple variables, thus fully capturing all of the potential factors influencing brain size.

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