A Three-Dimensional Stereotaxic MRI Brain Atlas of the Cichlid Fish Oreochromis mossambicus

The African cichlid Oreochromis mossambicus (Mozambique tilapia) has been used as a model system in a wide range of behavioural and neurobiological studies. The increasing number of genetic tools available for this species, together with the emerging interest in its use for neurobiological studies, increased the need for an accurate hodological mapping of the tilapia brain to supplement the available histological data. The goal of our study was to elaborate a three-dimensional, high-resolution digital atlas using magnetic resonance imaging, supported by Nissl staining. Resulting images were viewed and analysed in all orientations (transverse, sagittal, and horizontal) and manually labelled to reveal structures in the olfactory bulb, telencephalon, diencephalon, optic tectum, and cerebellum. This high resolution tilapia brain atlas is expected to become a very useful tool for neuroscientists using this fish model and will certainly expand their use in future studies regarding the central nervous system.Fundação para a Ciência e a Tecnologia grant: (PTDC/PSI/71811/2006); FCT PhD fellowships: (SFRH/BD/40976/2007, SFRH/BD/44848/2008); Plurianual Programme R&D: (unit MAR-LVT-Lisboa-331)

Estradiol modulates neural response to conspecific and heterospecific song in female house sparrows: An in vivo positron emission tomography study

© 2017 Lattin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Although there is growing evidence that estradiol modulates female perception of male sexual signals, relatively little research has focused on female auditory processing. We used in vivo 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) imaging to examine the neuronal effects of estradiol and conspecific song in female house sparrows (Passer domesticus). We assessed brain glucose metabolism, a measure of neuronal activity, in females with empty implants, estradiol implants, and empty implants ~1 month after estradiol implant removal. Females were exposed to conspecific or heterospecific songs immediately prior to imaging. The activity of brain regions involved in auditory perception did not differ between females with empty implants exposed to conspecific vs. heterospecific song, but neuronal activity was significantly reduced in females with estradiol implants exposed to heterospecific song. Furthermore, our within-individual design revealed that changes in brain activity due to high estradiol were actually greater several weeks after peak hormone exposure. Overall, this study demonstrates that PET imaging is a powerful tool for assessing large-scale changes in brain activity in living songbirds, and suggests that after breeding is done, specific environmental and physiological cues are necessary for estradiol-stimulated females to lose the selectivity they display in neural response to conspecific song

Tissue Clearing and Light Sheet Microscopy: Imaging the Unsectioned Adult Zebra Finch Brain at Cellular Resolution

The inherent complexity of brain tissue, with brain cells intertwining locally and projecting to distant regions, has made three-dimensional visualization of intact brains a highly desirable but challenging task in neuroscience. The natural opaqueness of tissue has traditionally limited researchers to techniques short of single cell resolution such as computer tomography or magnetic resonance imaging. By contrast, techniques with single-cell resolution required mechanical slicing into thin sections, which entails tissue distortions that severely hinder accurate reconstruction of large volumes. Recent developments in tissue clearing and light sheet microscopy have made it possible to investigate large volumes at micrometer resolution. The value of tissue clearing has been shown in a variety of tissue types and animal models. However, its potential for examining the songbird brain remains unexplored. Songbirds are an established model system for the study of vocal learning and sensorimotor control. They share with humans the capacity to adapt vocalizations based on auditory input. Song learning and production are controlled in songbirds by the song system, which forms a network of interconnected discrete brain nuclei. Here, we use the CUBIC and iDISCO+ protocols for clearing adult songbird brain tissue. Combined with light sheet imaging, we show the potential of tissue clearing for the investigation of connectivity between song nuclei, as well as for neuroanatomy and brain vasculature studies

In vivo imaging of D\u3csub\u3e2\u3c/sub\u3e receptors and corticosteroids predict behavioural responses to captivity stress in a wild bird

© 2019, The Author(s). Individual physiological variation may underlie individual differences in behaviour in response to stressors. This study tested the hypothesis that individual variation in dopamine and corticosteroid physiology in wild house sparrows (Passer domesticus, n = 15) would significantly predict behaviour and weight loss in response to a long-term stressor, captivity. We found that individuals that coped better with captivity (fewer anxiety-related behaviours, more time spent feeding, higher body mass) had lower baseline and higher stress-induced corticosteroid titres at capture. Birds with higher striatal D2 receptor binding (examined using positron emission tomography (PET) with 11C-raclopride 24 h post-capture) spent more time feeding in captivity, but weighed less, than birds with lower D2 receptor binding. In the subset of individuals imaged a second time, D2 receptor binding decreased in captivity in moulting birds, and larger D2 decreases were associated with increased anxiety behaviours 2 and 4 weeks post-capture. This suggests changes in dopaminergic systems could be one physiological mechanism underlying negative behavioural effects of chronic stress. Non-invasive technologies like PET have the potential to transform our understanding of links between individual variation in physiology and behaviour and elucidate which neuroendocrine phenotypes predict stress resilience, a question with important implications for both humans and wildlife

MRI atlas of a lizard brain

Magnetic resonance imaging (MRI) is an established technique for neuroanatomical analysis, being particularly useful in the medical sciences. However, the application of MRI to evolutionary neuroscience is still in its infancy. Few magnetic resonance brain atlases exist outside the standard model organisms in neuroscience and no magnetic resonance atlas has been produced for any reptile brain. A detailed understanding of reptilian brain anatomy is necessary to elucidate the evolutionary origin of enigmatic brain structures such as the cerebral cortex. Here, we present a magnetic resonance atlas for the brain of a representative squamate reptile, the Australian tawny dragon (Agamidae: Ctenophorus decresii), which has been the subject of numerous ecological and behavioral studies. We used a high-field 11.74T magnet, a paramagnetic contrasting-enhancing agent and minimum-deformation modeling of the brains of thirteen adult male individuals. From this, we created a high-resolution three-dimensional model of a lizard brain. The 3D-MRI model can be freely downloaded and allows a better comprehension of brain areas, nuclei, and fiber tracts, facilitating comparison with other species and setting the basis for future comparative evolution imaging studies. The MRI model and atlas of a tawny dragon brain (Ctenophorus decresii) can be viewed online and downloaded using the Wiley Biolucida Server at wiley.biolucida.net.Government of Australia, Grant/Award Numbers: APA#31/2011, IPRS#1182/2010; National Science and Engineering Research Council of Canada, Grant/Award Number: PGSD3-415253-2012; Quebec Nature and Technology Research Fund, Grant/AwardNumber: 208332; National Imaging Facility of Australia; Spanish Ministerio de Economía y Competitividad and Fondo Europeo de Desarrollo Regional, Grant/Award Number:BFU2015-68537-

Utilizing the 3D Environment to Facilitate Learning of Complex Visual Neural Pathways in the Avian Brain

Neuroanatomical pathways are difficult to study often due to the limit of methods used to visualize the anatomical and physiologic characteristics. In many studies, a neural pathway is presented using 2D representations for structural connectivity. A problem is deciding which of three planes: coronal, sagittal, or horizontal is best for visualizing the pathway’s components clearly and spatially precise for those wanting to learn and utilize that information. A 3D environment would be imperative in solving this issue. We therefore attempted to develop a means of accurately presenting detailed anatomical structures within the 3D regions they occurred. It is our hope that accurate, spatial representations of visual neural pathways will result in learning specific structures, their subdivisions, and their spatial organizations. Advancements in imaging techniques address this issue and have allowed for a new avenue of investigation for studying the morphology of anatomical systems. One such technique, diffusible iodine-based contrast-enhanced computed tomography (diceCT), has allowed for nondestructive visualization of an appropriately fixed brain. In other words, it allows one to image the entire brain, and visualize any of the three planes without damaging the specimen. We have chosen the visual tectofugal and thalamofugal pathways in an avian brain as they are some of the most well studied systems that seems to have much disparity in their anatomical organization and connectivity. The tectofugal pathway begins in the eyeball with retinal ganglion cells projecting to the optic tectum which in turn send projections to a thalamic nucleus. This thalamic nucleus then projects to a region of the forebrain, completing the ascending pathway. The thalamofugal pathway begins in the eyeball with retinal ganglion cells projecting to the lateral geniculate complex, which in turn projects bilaterally to a large terminal forebrain structure occupying the dorsomedial brain surface. For our investigation we employed two techniques: (1) a series of stacked histologic sections of four chick brains, and (2) a diceCT stained whole brain of a chick. For histological sections, we used series of coronal, sagittal, and horizontal sections stained with Nissl (cell bodies revealed) and Luxol Fast Blue or Gallyas silver myelin (fiber tracts revealed). Sections were imported into Brainmaker (Microbrightfield Biosciences), a software that stacks image sequences and reconstructs volumes based on sequential contours. For our diceCT investigation, we rendered the eyeball and brain within the skull of the bird. This allowed an accurate spatial representation of the eyeball with respect to the brain. Post model processing was essential to integrate detailed 2D images in the appropriate plane of the 3D environment. Using the histological image stacks, diceCT scanned eye and brain, and 3D editing software, we created an interactive 3D model of the avian visual tectofugal and thalamofugal pathways. The combination of histochemical sections with diceCT 3D modeling is necessary when detailed anatomical and spatial organization of complex neural pathways such as the tectofugal visual system are desired

Utilizing the 3D Environment to Facilitate Learning of Complex Visual Neural Pathways in the Avian Brain

Neuroanatomical pathways are difficult to study often due to the limit of methods used to visualize the anatomical and physiologic characteristics. In many studies, a neural pathway is presented using 2D representations for structural connectivity. A problem is deciding which of three planes: coronal, sagittal, or horizontal is best for visualizing the pathway’s components clearly and spatially precise for those wanting to learn and utilize that information. A 3D environment would be imperative in solving this issue. We therefore attempted to develop a means of accurately presenting detailed anatomical structures within the 3D regions they occurred. It is our hope that accurate, spatial representations of visual neural pathways will result in learning specific structures, their subdivisions, and their spatial organizations. Advancements in imaging techniques address this issue and have allowed for a new avenue of investigation for studying the morphology of anatomical systems. One such technique, diffusible iodine-based contrast-enhanced computed tomography (diceCT), has allowed for nondestructive visualization of an appropriately fixed brain. In other words, it allows one to image the entire brain, and visualize any of the three planes without damaging the specimen. We have chosen the visual tectofugal and thalamofugal pathways in an avian brain as they are some of the most well studied systems that seems to have much disparity in their anatomical organization and connectivity. The tectofugal pathway begins in the eyeball with retinal ganglion cells projecting to the optic tectum which in turn send projections to a thalamic nucleus. This thalamic nucleus then projects to a region of the forebrain, completing the ascending pathway. The thalamofugal pathway begins in the eyeball with retinal ganglion cells projecting to the lateral geniculate complex, which in turn projects bilaterally to a large terminal forebrain structure occupying the dorsomedial brain surface. For our investigation we employed two techniques: (1) a series of stacked histologic sections of four chick brains, and (2) a diceCT stained whole brain of a chick. For histological sections, we used series of coronal, sagittal, and horizontal sections stained with Nissl (cell bodies revealed) and Luxol Fast Blue or Gallyas silver myelin (fiber tracts revealed). Sections were imported into Brainmaker (Microbrightfield Biosciences), a software that stacks image sequences and reconstructs volumes based on sequential contours. For our diceCT investigation, we rendered the eyeball and brain within the skull of the bird. This allowed an accurate spatial representation of the eyeball with respect to the brain. Post model processing was essential to integrate detailed 2D images in the appropriate plane of the 3D environment. Using the histological image stacks, diceCT scanned eye and brain, and 3D editing software, we created an interactive 3D model of the avian visual tectofugal and thalamofugal pathways. The combination of histochemical sections with diceCT 3D modeling is necessary when detailed anatomical and spatial organization of complex neural pathways such as the tectofugal visual system are desired

The social brain : how social stimuli are translated into neuroendocrine signals

Tese de doutoramento, Biologia (Ecofisiologia), Universidade de Lisboa, Faculdade de Ciências, 2014Animals continuously fine-tune the expression of social behaviors according to daily fluctuations on their social environment. But how does the social environment influence brain and behavior and what are the underlying physiologic, molecular and genetic mechanisms? Behavioral flexibility depends on neural plasticity of circuits underlying social behavior, which is achieved by social regulation of brain gene expression. Different neurogenomic states emerge in response to different external stimuli and switches between states are orchestrated by signaling pathways interfacing the social environment and the genotype. The goal of this thesis is to understand how social environment influences brain genomic transcription: (1) during a complex social interaction in zebrafish and (2) after stimulation with context-specific social olfactory stimuli in the Mozambique tilapia. Zebrafish, Danio rerio, has long been used as a model organism in developmental biology and genetics. Despite of their limited behavioral repertoire, the available genetic tools make it a promising model for the study of social behavior. In contrast, the Mozambique tilapia, Oreochromis mossambicus, has a rich behavioral repertoire in which visual and chemical information are conveyed to conspecifics, although having limited brain anatomy information and less genetic tools available. Our research suggests that the outcome of a single social interaction in zebrafish has consequences for subsequent behavior and significant impact on their brain transcriptome. These responses to social interactions seem to involve cognitive appraisal of stimuli, since the objective structure of the event does not trigger a genomic response but rather the appraisal the individual makes of the event. In tilapia, different chemical social cues not only affect neural activity of the olfactory epithelium but also elicit specific patterns of gene activation in brain areas related to olfactory processing. This reinforces the idea of an extensive transcriptional plasticity of teleost genomes, especially in response to rapid changes in social environment.Fundação para a Ciência e a Tecnologia (FCT, SFRH/BD/40976/2007, Programa Operacional Ciência e Inovação 2010 - POCI 2010

Language and Linguistics in a Complex World Data, Interdisciplinarity, Transfer, and the Next Generation. ICAME41 Extended Book of Abstracts

This is a collection of papers, work-in-progress reports, and other contributions that were part of the ICAME41 digital conference

Language and Linguistics in a Complex World Data, Interdisciplinarity, Transfer, and the Next Generation. ICAME41 Extended Book of Abstracts

This is a collection of papers, work-in-progress reports, and other contributions that were part of the ICAME41 digital conference