scholarly journals Beyond Endocasts: Using Predicted Brain-Structure Volumes of Extinct Birds to Assess Neuroanatomical and Behavioral Inferences

Diversity ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 34 ◽  
Author(s):  
Catherine M. Early ◽  
Ryan C. Ridgely ◽  
Lawrence M. Witmer
Keyword(s):  
Optic Tectum ◽  
Brain Structure ◽  
Brain Size ◽  
Prediction Method ◽  
Brain Structures ◽  
Analytical Framework ◽  
Skull Morphology ◽  
Surface Areas ◽  
Structure Surface ◽  
The Brain

The shape of the brain influences skull morphology in birds, and both traits are driven by phylogenetic and functional constraints. Studies on avian cranial and neuroanatomical evolution are strengthened by data on extinct birds, but complete, 3D-preserved vertebrate brains are not known from the fossil record, so brain endocasts often serve as proxies. Recent work on extant birds shows that the Wulst and optic lobe faithfully represent the size of their underlying brain structures, both of which are involved in avian visual pathways. The endocasts of seven extinct birds were generated from microCT scans of their skulls to add to an existing sample of endocasts of extant birds, and the surface areas of their Wulsts and optic lobes were measured. A phylogenetic prediction method based on Bayesian inference was used to calculate the volumes of the brain structures of these extinct birds based on the surface areas of their overlying endocast structures. This analysis resulted in hyperpallium volumes of five of these extinct birds and optic tectum volumes of all seven extinct birds. Phylogenetic ANCOVA (phyANCOVA) were performed on regressions of the brain-structure volumes and endocast structure surface areas on various brain size metrics to determine if the relative sizes of these structures in any extinct birds were significantly different from those of the extant birds in the sample. Phylogenetic ANCOVA indicated that no extinct birds studied had relative hyperpallial volumes that were significantly different from the extant sample, nor were any of their optic tecta relatively hypertrophied. The optic tectum of Dinornis robustus was significantly smaller relative to brain size than any of the extant birds in our sample. This study provides an analytical framework for testing the hypotheses of potential functional behavioral capabilities of other extinct birds based on their endocasts.

scholarly journals The Antennal Pathway of Dragonfly Nymphs, from Sensilla to the Brain

Insects ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 886
Author(s):  
Silvana Piersanti ◽  
Manuela Rebora ◽  
Gianandrea Salerno ◽  
Sylvia Anton
Keyword(s):  
Brain Structure ◽  
Antennal Lobe ◽  
Sensory Information ◽  
Brain Structures ◽  
Brain Regions ◽  
Adult Brain ◽  
Published Data ◽  
Antennal Sensilla ◽  
Aquatic Life ◽  
The Brain

Dragonflies are hemimetabolous insects, switching from an aquatic life style as nymphs to aerial life as adults, confronted to different environmental cues. How sensory structures on the antennae and the brain regions processing the incoming information are adapted to the reception of fundamentally different sensory cues has not been investigated in hemimetabolous insects. Here we describe the antennal sensilla, the general brain structure, and the antennal sensory pathways in the last six nymphal instars of Libellula depressa, in comparison with earlier published data from adults, using scanning electron microscopy, and antennal receptor neuron and antennal lobe output neuron mass-tracing with tetramethylrhodamin. Brain structure was visualized with an anti-synapsin antibody. Differently from adults, the nymphal antennal flagellum harbors many mechanoreceptive sensilla, one olfactory, and two thermo-hygroreceptive sensilla at all investigated instars. The nymphal brain is very similar to the adult brain throughout development, despite the considerable differences in antennal sensilla and habitat. Like in adults, nymphal brains contain mushroom bodies lacking calyces and small aglomerular antennal lobes. Antennal fibers innervate the antennal lobe similar to adult brains and the gnathal ganglion more prominently than in adults. Similar brain structures are thus used in L. depressa nymphs and adults to process diverging sensory information.

scholarly journals The evolution of complex brains and behaviors in African cichlid fishes

2010 ◽  
Vol 56 (1) ◽  
pp. 144-156 ◽  
Author(s):  
Caroly A. Shumway
Keyword(s):  
Visual Acuity ◽  
Social Organization ◽  
Habitat Complexity ◽  
Brain Size ◽  
Brain Structures ◽  
Cichlid Fishes ◽  
African Cichlid ◽  
Monogamous Species ◽  
And Behavior ◽  
The Brain

Abstract In this review, I explore the effects of both social organization and the physical environment, specifically habitat complexity, on the brains and behavior of highly visual African cichlid fishes, drawing on examples from primates and birds where appropriate. In closely related fishes from the monophyletic Ectodinii clade of Lake Tanganyika, both forces influence cichlid brains and behavior. Considering social influences first, visual acuity differs with respect to social organization (monogamy versus polygyny). Both the telencephalon and amygdalar homologue, area Dm, are larger in monogamous species. Monogamous species are found to have more vasotocin-immunoreactive cells in the preoptic area of the brain. Habitat complexity also influences brain and behavior in these fishes. Total brain size, telencephalic and cerebellar size are positively correlated with habitat complexity. Visual acuity and spatial memory are enhanced in cichlids living in more complex environments. However habitat complexity and social forces affect cichlid brains differently. Taken together, our field data and plasticity data suggest that some of the species-specific neural effects of habitat complexity could be the consequence of the corresponding social correlates. Environmental forces, however, exert a broader effect on brain structures than social ones do, suggesting allometric expansion of the brain structures in concert with brain size and/or co-evolution of these structures.

scholarly journals The Deoxyglucose Method in the Ferret Brain. II. Glucose Utilization Images and Normal Values

1989 ◽  
Vol 9 (1) ◽  
pp. 43-52 ◽  
Author(s):  
C. Redies ◽  
M. Diksic ◽  
Y. L. Yamamoto
Keyword(s):  
Rate Constants ◽  
Glucose Utilization ◽  
Normal Values ◽  
Brain Size ◽  
Experimental Period ◽  
Brain Structures ◽  
Rate Limiting Step ◽  
Rate Limiting ◽  
The Brain ◽  
Deoxyglucose Method

To measure cerebral glucose utilization with the autoradiographic deoxyglucose method, the tracer transfer rate constants and lumped constants must be known. 2-Deoxyglucose (2-DG) and fluorodeoxyglucose (FDG) constants were determined in 18 gray and white matter brain structures of the anesthetized ferret. The ferret is a domestic carnivore particularly suitable for deoxyglucose studies because of its small brain size and low body weight. The average gray matter rate constants for tracer transfer across the blood-brain barrier are similar for 2-DG and FDG in the ferret brain ( K*1 = 0.21 ml/g/min and k*2 = 0.39 min−1). The rate constant for the rate-limiting step of tracer phosphorylation, k*3, is 1.6 times higher for FDG than for 2-DG (0.21 vs. 0.13 min−1). Loss of metabolized tracer is about 1–1.5%/min throughout the ferret brain for both tracers as estimated for a 180 min experimental period. Taking into account this loss, the lumped constant is 0.92 for FDG and 0.68 for 2-DG. Glucose utilization values in the brain of the anesthesized ferret range from 33 μmol/100 g/min in the corpus callosum to 104 μmol/100 g/min in the caudate nucleus. Representative glucose utilization images of coronal sections of the ferret brain are shown. Brain structures are identified on the same slices counterstained with thionin.

scholarly journals Can exercise make our children smarter?

2020 ◽  
Vol 10 (2) ◽  
Author(s):  
Nenad Stojiljković ◽  
Petar Mitić ◽  
Goran Sporiš
Keyword(s):  
White Matter ◽  
Brain Structure ◽  
Methodological Approach ◽  
Brain Structures ◽  
Structure And Function ◽  
Healthy Children ◽  
Cross Sectional ◽  
Brain Structure And Function ◽  
And Function ◽  
The Brain

Purpose. The aim of this study is to reveal the effects of exercise on the brain structure and function in children, and to analyze methodological approach applied in the researches of this topic. Methods. This literature review provides an overview of important findings in this fast growing research domain. Results from cross-sectional, longitudinal, and interventional studies of the influence of exercise on the brain structure and function of healthy children are reviewed and discussed. Results. The majority of researches are done as cross sectional studies based on the exploring correlation between the level of physical activity and characteristics of brain structure and function. Results of the studies indicate that exercise has positive correlation with improved cognition and beneficial changes to brain function in children. Physically active children have greater white matter integrity in several white matter tracts (corpus callosum, corona radiata, and superior longitudinal fasciculus), have greater volume of gray matter in the hippocampus and basal ganglia than their physically inactive counterparts. The longitudinal/interventional studies also showed that exercise (mainly aerobic) improve cognitive performance of children and causes changes observed on functional magnetic resonance imaging scans (fMRI) located in prefrontal and parietal regions. Conclusion. Previous researches undoubtable proved that exercise can make positive changes of the brain structures in children, specifically the volume of the hippocampus which is the center of learning and memory. Finally the researchers agree that the most influential type of exercise on changes of brain structure and functions are the aerobic exercises. 

scholarly journals Neonatal Clonazepam Administration Induced Long-Lasting Changes in GABAA and GABAB Receptors

2020 ◽  
Vol 21 (9) ◽  
pp. 3184
Author(s):  
Hana Kubová ◽  
Zdeňka Bendová ◽  
Simona Moravcová ◽  
Dominika Pačesová ◽  
Luisa Rocha ◽  
...  
Keyword(s):  
Gabaa Receptor ◽  
Receptor Binding ◽  
Brain Structure ◽  
Gabab Receptor ◽  
Brain Structures ◽  
Emotional Behavior ◽  
Gabab Receptors ◽  
Behavioral Impairment ◽  
Almost All ◽  
The Brain

Benzodiazepines (BZDs) are widely used in patients of all ages. Unlike adults, neonatal animals treated with BZDs exhibit a variety of behavioral deficits later in life; however, the mechanisms underlying these deficits are poorly understood. This study aims to examine whether administration of clonazepam (CZP; 1 mg/kg/day) in 7–11-day-old rats affects Gama aminobutyric acid (GABA)ergic receptors in both the short and long terms. Using RT-PCR and quantitative autoradiography, we examined the expression of the selected GABAA receptor subunits (α1, α2, α4, γ2, and δ) and the GABAB B2 subunit, and GABAA, benzodiazepine, and GABAB receptor binding 48 h, 1 week, and 2 months after treatment discontinuation. Within one week after CZP cessation, the expression of the α2 subunit was upregulated, whereas that of the δ subunit was downregulated in both the hippocampus and cortex. In the hippocampus, the α4 subunit was downregulated after the 2-month interval. Changes in receptor binding were highly dependent on the receptor type, the interval after treatment cessation, and the brain structure. GABAA receptor binding was increased in almost all of the brain structures after the 48-h interval. BZD-binding was decreased in many brain structures involved in the neuronal networks associated with emotional behavior, anxiety, and cognitive functions after the 2-month interval. Binding of the GABAB receptors changed depending on the interval and brain structure. Overall, the described changes may affect both synaptic development and functioning and may potentially cause behavioral impairment.

scholarly journals Relative Brain Size and Its Relation with the Associative Pallium in Birds

2016 ◽  
Vol 87 (2) ◽  
pp. 69-77 ◽  
Author(s):  
Ferran Sayol ◽  
Louis Lefebvre ◽  
Daniel Sol
Keyword(s):  
Brain Size ◽  
Large Fraction ◽  
Biological Significance ◽  
Size Variation ◽  
Brain Structures ◽  
Brain Regions ◽  
Whole Brain ◽  
Small Areas ◽  
Mosaic Evolution ◽  
The Brain

Despite growing interest in the evolution of enlarged brains, the biological significance of brain size variation remains controversial. Much of the controversy is over the extent to which brain structures have evolved independently of each other (mosaic evolution) or in a coordinated way (concerted evolution). If larger brains have evolved by the increase of different brain regions in different species, it follows that comparisons of the whole brain might be biologically meaningless. Such an argument has been used to criticize comparative attempts to explain the existing variation in whole-brain size among species. Here, we show that pallium areas associated with domain-general cognition represent a large fraction of the entire brain, are disproportionally larger in large-brained birds and accurately predict variation in the whole brain when allometric effects are appropriately accounted for. While this does not question the importance of mosaic evolution, it suggests that examining specialized, small areas of the brain is not very helpful for understanding why some birds have evolved such large brains. Instead, the size of the whole brain reflects consistent variation in associative pallium areas and hence is functionally meaningful for comparative analyses.

scholarly journals Reduced Brain Volume and White Matter Alterations in Shank3-Deficient Rats

2020 ◽  
Author(s):  
Carla Esther Meyer Golden ◽  
Victoria X Wang ◽  
Hala Harony-Nicolas ◽  
Patrick R. Hof ◽  
Joseph Buxbaum
Keyword(s):  
White Matter ◽  
Brain Structure ◽  
Brain Volume ◽  
Diffusion Tensor ◽  
Brain Size ◽  
Brain Regions ◽  
Autism Spectrum ◽  
Wild Type ◽  
Microstructural Alterations ◽  
The Brain

Abstract Background: Mutations and deletions in the SHANK3 synaptic gene cause the major neurodevelopmental features of Phelan-McDermid syndrome (PMS). The SHANK3 gene encodes a key structural component of excitatory synapses that is important for synaptogenesis. PMS is characterized by intellectual disability, autism spectrum disorder, cognitive deficits, physical dysmorphic features, sensory hyporeactivity, and alterations in the size of multiple brain regions. Clinical assessments and limited imaging studies have revealed a reduction in volume of multiple brain regions. They have also found white matter thinning and microstructural alterations to be persistent in patients with PMS. While many of these impairments have been replicated in mouse models of PMS, the brain structure of a rat model has not yet been studied. Methods: We assessed the brain structure of haploinsufficient and homozygous Shank3-deficient rats that model the behavioral deficits of PMS with magnetic resonance and diffusion tensor imaging, and compared their brain structure to wild type littermates.Results: Both gray and white matter structures were smaller in Shank3-deficient rats, leading to an overall reduction in brain size compared to wild type littermates. The largest region to be diminished in size was the neocortex. Some regions involved in sensory processing and white matter regions were also reduced in size. Lastly, the microstructure of two white matter tracts, the external capsule and fornix, was abnormal.Conclusions: Shank3-deficient rats replicate the reduced brain volume and altered white matter phenotypes present in individuals with PMS. Therefore, the brain regions that were altered represent potential cross-species structural biomarkers that warrant further study.

scholarly journals The microanatomy of the central nervous system and brain of the Indo-Pacific seahorse, Hippocampus barbouri, during development

2020 ◽  
Vol 37 ◽  
pp. 1-11
Author(s):  
Sinlapachai Senarat ◽  
Jes Kettratad ◽  
Gen Kaneko ◽  
Thatpon Kamnurdnin ◽  
Chanyut Sudtongkong
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Purkinje Cells ◽  
Optic Tectum ◽  
Brain Structures ◽  
Brain Morphology ◽  
Medium Size ◽  
Reproductive Behaviors ◽  
The Central Nervous System ◽  
The Brain

The central nervous system (CNS) of Teleostei is a complex system of self-governance and its morphology is reflected in the physiological and reproductive behaviors. The Indo-Pacific seahorse, Hippocampus barbouri Jordan & Richardson, 1908, is a new candidate species for aquaculture in Thailand. In this study, we investigated the brain morphology of H. barbouri across various developmental windows. Light microscopic observations of adult brains revealed a large optic tectum in the mesencephalon, whereas the cerebral hemispheres and the cerebellum are of medium size. The detailed brain structures were generally similar to those of other teleosts; however, only five distinct layers were present in the optic tectum, including the stratum marginale, stratum opticum, stratum album central, stratum griseum central, and stratum periventriculae, versus six layers observed in other fish. One day after birth (1 DAB) the brain was a packed structure without any clear sub-structures. The number of capillaries in the optic tectum began to increase at 6 DAB, and at 14 DAB several features, including small blood vessels in the optic tectum and Purkinje cells, became noticeable. By 35 DAB, the optic tectum became highly vascularized and included five layers. Additionally, large Purkinje cells were developed in the cerebellum. Based on the brain development pattern, we speculate that the predatory ability of this fish starts to develop from 6 to 14 days after birth.

Ontogenetic Shifts in Brain Size and Brain Organization of the Atlantic Sharpnose Shark, Rhizoprionodon terraenovae

2020 ◽  
Vol 95 (3-4) ◽  
pp. 162-180
Author(s):  
Krista V. Laforest ◽  
Emily E. Peele ◽  
Kara E. Yopak
Keyword(s):  
Medulla Oblongata ◽  
Optic Tectum ◽  
Sexual Maturity ◽  
Brain Size ◽  
Relative Size ◽  
Later Life ◽  
Olfactory Bulbs ◽  
Ontogenetic Shifts ◽  
The Brain ◽  
Atlantic Sharpnose Shark

Throughout an animal’s life, species may occupy different environments and exhibit distinct life stages, known as ontogenetic shifts. The life histories of most sharks (class: Chondrichthyes) are characterized by these ontogenetic shifts, which can be defined by changes in habitat and diet as well as behavioral changes at the onset of sexual maturity. In addition, fishes experience indeterminate growth, whereby the brain and body grow throughout the organism’s life. Despite a presupposed lifelong neurogenesis in sharks, very little work has been done on ontogenetic changes in the brain, which may be informative about functional shifts in sensory and behavioral specializations. This study quantified changes in brain-body scaling and the scaling of six major brain regions (olfactory bulbs, telencephalon, diencephalon, optic tectum, cerebellum, and medulla oblongata) throughout ontogeny in the Atlantic sharpnose shark, <i>Rhizoprio­nodon terraenovae</i>. As documented in other fishes, brain size increased significantly with body mass throughout ontogeny in this species, with the steepest period of growth in early life. The telencephalon, diencephalon, optic tectum, and medulla oblongata scaled with negative allometry against the rest of the brain throughout ontogeny. However, notably, the olfactory bulbs and cerebellum scaled hyperallometrically to the rest of the brain, whereby these structures enlarged disproportionately as this species matured. Changes in the relative size of the olfactory bulbs throughout ontogeny may reflect an increased reliance on olfaction at later life history stages in <i>R. terraenovae</i>, while changes in the relative size of the cerebellum throughout ontogeny may be indicative of the ability to capture faster prey or an increase in migratory nature as this species moves to offshore habitats, associated with the onset of sexual maturity.

scholarly journals Neurogenetics and Behaviour in Insects

1984 ◽  
Vol 112 (1) ◽  
pp. 65-93 ◽  
Author(s):  
K. F. FISCHBACH ◽  
M. HEISENBERG
Keyword(s):  
Brain Development ◽  
Genetic Control ◽  
Brain Structure ◽  
Single Gene ◽  
Gene Mutations ◽  
Brain Structures ◽  
Bilateral Symmetry ◽  
Selective Advantage ◽  
The Brain

The importance of the genome for behaviour has been amply demonstrated by the tools of population genetics. A deeper understanding of the relationship between genes and behaviour requires an investigation of how they influence brain development and neuronal function. This is the objective of neurogenetics. Rigid genetic control of brain structure in insects is indicated by bilateral symmetry and by the similarity of isogenic brains (in locust). In large parts of the brain (e.g. optic lobes) the role of developmental variability seems to be as limited as in nematodes, but at closer inspection, the growth of at least some brain structures (e.g. mushroom bodies) is influenced by experience, similar to the growth of some vertebrate systems. The role of individual genes for brain development and brain function is being studied in Drosophila melanogaster. Here, many single gene mutations affecting the brain and behaviour have been isolated. They either alter the development of neural circuits or modify cellular functions of neurones. Mutations of both categories are often remarkably specific (i.e. they influence only certain functional subsystems, leaving others unaffected). Therefore, functional subsystems are to some degree ontogenetic units under independent genetic control. Telling examples are sexual dimorphisms of behaviour and brain structure. The already peripheral separation of functional pathways in the brain seems to be partially due to the selective advantage of independent genetic modifiability of functions.

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