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Peckham H. Introducing the Neuroplastic Narrative: a non-pathologizing biological foundation for trauma-informed and adverse childhood experience aware approaches. Front Psychiatry 2023; 14:1103718. [PMID: 37283710 PMCID: PMC10239852 DOI: 10.3389/fpsyt.2023.1103718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 04/20/2023] [Indexed: 06/08/2023] Open
Abstract
Most people accessing mental health services have adverse childhood experiences (ACEs) and/or histories of complex trauma. In recognition of this, there are calls to move away from medical model approaches and move toward trauma-informed approaches which privilege the impact of life experience over underlying pathology in the etiology of emotional and psychological suffering. Trauma-informed approaches lack a biological narrative linking trauma and adversity to later suffering. In its absence, this suffering is diagnosed and treated as a mental illness. This study articulates the Neuroplastic Narrative, a neuroecological theory that fills this gap, conceptualizing emotional and psychological suffering as the cost of surviving and adapting to the impinging environments of trauma and adversity. The Neuroplastic Narrative privileges lived experience and recognizes that our experiences become embedded in our biology through evolved mechanisms that ultimately act to preserve survival in the service of reproduction. Neuroplasticity refers to the capacity of neural systems to adapt and change. Our many evolved neuroplastic mechanisms including epigenetics, neurogenesis, synaptic plasticity, and white matter plasticity allow us to learn from, and adapt to, past experiences. This learning and adaption in turn allows us to better anticipate and physiologically prepare for future experiences that (nature assumes) are likely to occur, based on past experiences. However, neuroplastic mechanisms cannot discriminate between experiences; they function to embed experience regardless of the quality of that experience, generating vicious or virtuous cycles of psychobiological anticipation, to help us survive or thrive in futures that resemble our privileged or traumatic pasts. The etiology of suffering that arises from this process is not a pathology (a healthy brain is a brain that can adapt to experience) but is the evolutionary cost of surviving traumatizing environments. Misidentifying this suffering as a pathology and responding with diagnosis and medication is not trauma-informed and may cause iatrogenic harm, in part through perpetuating stigma and exacerbating the shame which attends complex trauma and ACEs. As an alternative, this study introduces the Neuroplastic Narrative, which is situated within an evolutionary framework. The Neuroplastic Narrative complements both Life History and Attachment Theory and provides a non-pathologizing, biological foundation for trauma-informed and Adverse Childhood Experience aware approaches.
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Affiliation(s)
- Haley Peckham
- Centre for Mental Health Nursing, School of Health Sciences, University of Melbourne, Carlton, VIC, Australia
- Department of Psychology, University of Exeter, Exeter, United Kingdom
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2
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Pull CD, Petkova I, Watrobska C, Pasquier G, Perez Fernandez M, Leadbeater E. Ecology dictates the value of memory for foraging bees. Curr Biol 2022; 32:4279-4285.e4. [PMID: 35987212 PMCID: PMC9616731 DOI: 10.1016/j.cub.2022.07.062] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/22/2022] [Accepted: 07/22/2022] [Indexed: 12/14/2022]
Abstract
"Ecological intelligence" hypotheses posit that animal learning and memory evolve to meet the demands posed by foraging and, together with social intelligence and cognitive buffer hypotheses, provide a key framework for understanding cognitive evolution.1-5 However, identifying the critical environments where cognitive investment reaps significant benefits has proved challenging.6-8 Here, we capitalize upon seasonal variation in forage availability for a social insect model (Bombus terrestris audax) to establish how the benefits of short-term memory, assayed using a radial arm maze (RAM), vary with resource availability. Following a staggered design over 2 years, whereby bees from standardized colonies at identical life-history stages underwent cognitive testing before foraging in the wild, we found that RAM performance predicts foraging efficiency-a key determinant of colony fitness-in plentiful spring foraging conditions but that this relationship is reversed during the summer floral dearth. Our results suggest that the selection for enhanced cognitive abilities is unlikely to be limited to harsh environments where food is hard to find or extract,5,9-11 highlighting instead that the challenges of rich and plentiful environments, which present multiple options in short succession, could be a broad driver in the evolution of certain cognitive traits. VIDEO ABSTRACT.
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Affiliation(s)
- Christopher D. Pull
- Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK,Corresponding author
| | - Irina Petkova
- Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Cecylia Watrobska
- Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Grégoire Pasquier
- Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Marta Perez Fernandez
- Department of Geography, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Ellouise Leadbeater
- Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
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3
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Understanding hippocampal neural plasticity in captivity: Unique contributions of spatial specialists. Learn Behav 2022; 50:55-70. [PMID: 35237946 DOI: 10.3758/s13420-021-00504-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2021] [Indexed: 01/01/2023]
Abstract
Neural plasticity in the hippocampus has been studied in a wide variety of model systems, including in avian species where the hippocampus underlies specialized spatial behaviours. Examples of such behaviours include navigating to a home roost over long distances by homing pigeons or returning to a potential nest site for egg deposit by brood parasites. The best studied example, however, is food storing in parids and the interaction between this behaviour and changes in hippocampus volume and neurogenesis. However, understanding the interaction between brain and behaviour necessitates research that includes studies with at least some form of captivity, which may itself affect hippocampal plasticity. Captivity might particularly affect spatial specialists where free-ranging movement on a large scale is especially important in daily, and seasonal, behaviours. This review examines how captivity might affect hippocampal plasticity in avian spatial specialists and specifically food-storing parids, and also considers how the effects of captivity may be mitigated by researchers studying hippocampal plasticity when the goal is understanding the relationship between behaviour and hippocampal change.
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Hamza IM, Mobarak YM, Hafez HS. Hippocampus anatomical structure and distribution of agrin proteoglycan and ryanodine receptor expression boost bird food caching behavior. THE EUROPEAN ZOOLOGICAL JOURNAL 2021. [DOI: 10.1080/24750263.2021.1885757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- I. M. Hamza
- Faculty of Science, Zoology Department, Suez University, Suez, Egypt
| | - Y. M. Mobarak
- Faculty of Science, Zoology Department, Suez University, Suez, Egypt
| | - H. S. Hafez
- Faculty of Science, Zoology Department, Suez University, Suez, Egypt
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5
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LaDage LD. Broadening the functional and evolutionary understanding of postnatal neurogenesis using reptilian models. ACTA ACUST UNITED AC 2020; 223:223/15/jeb210542. [PMID: 32788272 DOI: 10.1242/jeb.210542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The production of new neurons in the brains of adult animals was first identified by Altman and Das in 1965, but it was not until the late 20th century when methods for visualizing new neuron production improved that there was a dramatic increase in research on neurogenesis in the adult brain. We now know that adult neurogenesis is a ubiquitous process that occurs across a wide range of taxonomic groups. This process has largely been studied in mammals; however, there are notable differences between mammals and other taxonomic groups in how, why and where new neuron production occurs. This Review will begin by describing the processes of adult neurogenesis in reptiles and identifying the similarities and differences in these processes between reptiles and model rodent species. Further, this Review underscores the importance of appreciating how wild-caught animals vary in neurogenic properties compared with laboratory-reared animals and how this can be used to broaden the functional and evolutionary understanding of why and how new neurons are produced in the adult brain. Studying variation in neural processes across taxonomic groups provides an evolutionary context to adult neurogenesis while also advancing our overall understanding of neurogenesis and brain plasticity.
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Affiliation(s)
- Lara D LaDage
- Division of Mathematics and Natural Sciences, Penn State Altoona, 3000 Ivyside Dr., Altoona, PA 16601, USA
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Sonnenberg BR, Branch CL, Pitera AM, Bridge E, Pravosudov VV. Natural Selection and Spatial Cognition in Wild Food-Caching Mountain Chickadees. Curr Biol 2019; 29:670-676.e3. [DOI: 10.1016/j.cub.2019.01.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/05/2018] [Accepted: 01/02/2019] [Indexed: 12/16/2022]
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7
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Spatial memory and cognitive flexibility trade-offs: to be or not to be flexible, that is the question. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2018.02.019] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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8
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Ashton BJ, Thornton A, Ridley AR. An intraspecific appraisal of the social intelligence hypothesis. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170288. [PMID: 30104433 PMCID: PMC6107571 DOI: 10.1098/rstb.2017.0288] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2018] [Indexed: 12/16/2022] Open
Abstract
The prevailing hypotheses for the evolution of cognition focus on either the demands associated with group living (the social intelligence hypothesis (SIH)) or ecological challenges such as finding food. Comparative studies testing these hypotheses have generated highly conflicting results; consequently, our understanding of the drivers of cognitive evolution remains limited. To understand how selection shapes cognition, research must incorporate an intraspecific approach, focusing on the causes and consequences of individual variation in cognition. Here, we review the findings of recent intraspecific cognitive research to investigate the predictions of the SIH. Extensive evidence from our own research on Australian magpies (Cracticus tibicen dorsalis), and a number of other taxa, suggests that individuals in larger social groups exhibit elevated cognitive performance and, in some cases, elevated reproductive fitness. Not only do these findings demonstrate how the social environment has the potential to shape cognitive evolution, but crucially, they demonstrate the importance of considering both genetic and developmental factors when attempting to explain the causes of cognitive variation.This article is part of the theme issue 'Causes and consequences of individual differences in cognitive abilities'.
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Affiliation(s)
- Benjamin J Ashton
- Centre for Evolutionary Biology, University of Western Australia, Western Australia 6009, Australia
| | - Alex Thornton
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Exeter TR10 9FE, UK
| | - Amanda R Ridley
- Centre for Evolutionary Biology, University of Western Australia, Western Australia 6009, Australia
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9
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Maille A, Schradin C. Survival is linked with reaction time and spatial memory in African striped mice. Biol Lett 2017; 12:rsbl.2016.0346. [PMID: 27484646 DOI: 10.1098/rsbl.2016.0346] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/13/2016] [Indexed: 11/12/2022] Open
Abstract
Studying the association between fitness and cognition in free-living animals is a fundamental step in the elucidation of the evolution of cognition. We assessed whether survival until the onset of the breeding season was related to reaction time or spatial memory in the African striped mouse Rhabdomys pumilio, a rodent that has to survive summer drought before breeding. We tested a total of 90 individuals at the beginning of summer. Female survival was related to a faster response to predation stimuli. Male survival increased with greater spatial memory, possibly because it is important for males to remember the configuration of the environment during dispersal. This study revealed that individual variation in reaction time and spatial memory can be related to survival probability, which is important for understanding the selection pressures acting on basic cognitive traits.
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Affiliation(s)
- Audrey Maille
- IPHC-DEPE, Université de Strasbourg, 67087 Strasbourg, France School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa Museum National d'Histoire Naturelle, 75005 Paris, France
| | - Carsten Schradin
- IPHC-DEPE, Université de Strasbourg, 67087 Strasbourg, France School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Mikhalevich I, Powell R, Logan C. Is behavioural flexibility evidence of cognitive complexity? How evolution can inform comparative cognition. Interface Focus 2017; 7:20160121. [PMID: 28479981 PMCID: PMC5413892 DOI: 10.1098/rsfs.2016.0121] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Behavioural flexibility is often treated as the gold standard of evidence for more sophisticated or complex forms of animal cognition, such as planning, metacognition and mindreading. However, the evidential link between behavioural flexibility and complex cognition has not been explicitly or systematically defended. Such a defence is particularly pressing because observed flexible behaviours can frequently be explained by putatively simpler cognitive mechanisms. This leaves complex cognition hypotheses open to 'deflationary' challenges that are accorded greater evidential weight precisely because they offer putatively simpler explanations of equal explanatory power. This paper challenges the blanket preference for simpler explanations, and shows that once this preference is dispensed with, and the full spectrum of evidence-including evolutionary, ecological and phylogenetic data-is accorded its proper weight, an argument in support of the prevailing assumption that behavioural flexibility can serve as evidence for complex cognitive mechanisms may begin to take shape. An adaptive model of cognitive-behavioural evolution is proposed, according to which the existence of convergent trait-environment clusters in phylogenetically disparate lineages may serve as evidence for the same trait-environment clusters in other lineages. This, in turn, could permit inferences of cognitive complexity in cases of experimental underdetermination, thereby placing the common view that behavioural flexibility can serve as evidence for complex cognition on firmer grounds.
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Affiliation(s)
- Irina Mikhalevich
- School of Mind and Brain, Humboldt-Universitat zu Berlin, Berlin, Germany
| | - Russell Powell
- Department of Philosophy, Boston University, Boston, MA 02215, USA
| | - Corina Logan
- Department of Zoology, University of Cambridge, Cambridge, UK
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Mazengenya P, Bhagwandin A, Nkomozepi P, Manger PR, Ihunwo AO. Putative adult neurogenesis in two domestic pigeon breeds (Columba livia domestica): racing homer versus utility carneau pigeons. Neural Regen Res 2017; 12:1086-1096. [PMID: 28852390 PMCID: PMC5558487 DOI: 10.4103/1673-5374.211187] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Generation of neurons in the brains of adult birds has been studied extensively in the telencephalon of song birds and few studies are reported on the distribution of PCNA and DCX in the telencephalon of adult non-song learning birds. We report here on adult neurogenesis throughout the brains of two breeds of adult domestic pigeons (Columba livia domestica), the racing homer and utility carneau using endogenous immunohistochemical markers proliferating cell nuclear antigen (PCNA) for proliferating cells and doublecortin (DCX) for immature and migrating neurons. The distribution of PCNA and DCX immunoreactivity was very similar in both pigeon breeds with only a few minor differences. In both pigeons, PCNA and DCX immunoreactivity was observed in the olfactory bulbs, walls of the lateral ventricle, telencephalic subdivisions of the pallium and subpallium, diencephalon, mesencephalon and cerebellum. Generally, the olfactory bulbs and telencephalon had more PCNA and DCX cells than other regions. Two proliferative hotspots were evident in the dorsal and ventral poles of the lateral ventricles. PCNA- and DCX-immunoreactive cells migrated radially from the walls of the lateral ventricle into the parenchyma. In most telencephalic regions, the density of PCNA- and DCX-immunoreactive cells increased from rostral to caudal, except in the mesopallium where the density decreased from rostral to middle levels and then increased caudally. DCX immunoreactivity was more intense in fibres than in cell bodies and DCX-immunoreactive cells included small granular cells, fusiform bipolar cells, large round and or polygonal multipolar cells. The similarity in the distribution of proliferating cells and new neurons in the telencephalon of the two breeds of pigeons may suggest that adult neurogenesis is a conserved trait as an ecological adaptation irrespective of body size.
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Affiliation(s)
- Pedzisai Mazengenya
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Adhil Bhagwandin
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Pilani Nkomozepi
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Amadi O Ihunwo
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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12
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LaDage LD. Factors That Modulate Neurogenesis: A Top-Down Approach. BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:184-190. [PMID: 27560485 DOI: 10.1159/000446906] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although hippocampal neurogenesis in the adult brain has been conserved across the vertebrate lineage, laboratory studies have primarily examined this phenomenon in rodent models. This approach has been successful in elucidating important factors and mechanisms that can modulate rates of hippocampal neurogenesis, including hormones, environmental complexity, learning and memory, motor stimulation, and stress. However, recent studies have found that neurobiological research on neurogenesis in rodents may not easily translate to, or explain, neurogenesis patterns in nonrodent systems, particularly in species examined in the field. This review examines some of the evolutionary and ecological variables that may also modulate neurogenesis patterns. This 'top-down' and more naturalistic approach, which incorporates ecology and natural history, particularly of nonmodel species, may allow for a more comprehensive understanding of the functional significance of neurogenesis.
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Affiliation(s)
- Lara D LaDage
- Division of Mathematics and Natural Sciences, Penn State University Altoona, Altoona, Pa., USA
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13
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Dunlap KD. Fish Neurogenesis in Context: Assessing Environmental Influences on Brain Plasticity within a Highly Labile Physiology and Morphology. BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:156-166. [DOI: 10.1159/000446907] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Fish have unusually high rates of brain cell proliferation and neurogenesis during adulthood, and the rates of these processes are greatly influenced by the environment. This high level of cell proliferation and its responsiveness to environmental change indicate that such plasticity might be a particularly important mechanism underlying behavioral plasticity in fish. However, as part of their highly labile physiology and morphology, fish also respond to the environment through processes that affect cell proliferation but that are not specific to behavioral change. For example, the environment has nonspecific influences on cell proliferation all over the body via its effect on body temperature and growth rate. In addition, some fish species also have an unusual capacity for sex change and somatic regeneration, and both of these processes likely involve widespread changes in cell proliferation. Thus, in evaluating the possible behavioral role of adult brain cell proliferation, it is important to distinguish regionally specific responses in behaviorally relevant brain nuclei from global proliferative changes across the whole brain or body. In this review, I first highlight how fish differ from other vertebrates, particularly birds and mammals, in ways that have a bearing on the interpretation of brain plasticity. I then summarize the known effects of the physical and social environment, sex change, and predators on brain cell proliferation and neurogenesis, with a particular emphasis on whether the effects are regionally specific. Finally, I review evidence that environmentally induced changes in brain cell proliferation and neurogenesis in fish are mediated by hormones and play a role in behavioral responses to the environment.
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Vistoropsky Y, Heiblum R, Smorodinsky NI, Barnea A. Active immunization against vasoactive intestinal polypeptide decreases neuronal recruitment and inhibits reproduction in zebra finches. J Comp Neurol 2016; 524:2516-28. [PMID: 26801210 DOI: 10.1002/cne.23971] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 11/26/2015] [Accepted: 01/19/2016] [Indexed: 01/21/2023]
Abstract
Neurogenesis and neuronal recruitment occur in adult brains of many vertebrates, and the hypothesis is that these phenomena contribute to the brain plasticity that enables organisms to adjust to environmental changes. In mammals, vasoactive intestinal polypeptide (VIP) is known to have many neuroprotective properties, but in the avian brain, although widely distributed, its role in neuronal recruitment is not yet understood. In the present study we actively immunized adult zebra finches against VIP conjugated to KLH and compared neuronal recruitment in their brains, with brains of control birds, which were immunized against KLH. We looked at two forebrain regions: the nidopallium caudale (NC), which plays a role in vocal communication, and the hippocampus (HC), which is involved in the processing of spatial information. Our data demonstrate that active immunization against VIP reduces neuronal recruitment, inhibits reproduction, and induces molting, with no change in plasma prolactin levels. Thus, our observations suggest that VIP has a direct positive role in neuronal recruitment and reproduction in birds. J. Comp. Neurol. 524:2516-2528, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Yulia Vistoropsky
- Department of Natural and Life Sciences, The Open University of Israel, Ra'anana, 43107, Israel
| | - Rachel Heiblum
- Department of Natural and Life Sciences, The Open University of Israel, Ra'anana, 43107, Israel
| | - Nechama-Ina Smorodinsky
- Department of Cell Research & Immunology, The George Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 61391, Israel
| | - Anat Barnea
- Department of Natural and Life Sciences, The Open University of Israel, Ra'anana, 43107, Israel
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15
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Guigueno MF, MacDougall-Shackleton SA, Sherry DF. Sex and seasonal differences in hippocampal volume and neurogenesis in brood-parasitic brown-headed cowbirds (Molothrus ater). Dev Neurobiol 2016; 76:1275-1290. [PMID: 27455512 DOI: 10.1002/dneu.22421] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 07/14/2016] [Accepted: 07/22/2016] [Indexed: 12/22/2022]
Abstract
Brown-headed cowbirds (Molothrus ater) are one of few species in which females show more complex space use than males. Female cowbirds search for, revisit, and parasitize host nests and, in a previous study, outperformed males on an open field spatial search task. Previous research reported a female-biased sex difference in the volume of the hippocampus, a region of the brain involved in spatial memory. Neurons produced by adult neurogenesis may be involved in the formation of new memories and replace older neurons that could cause interference in memory. We tested for sex and seasonal differences in hippocampal volume and neurogenesis of brood-parasitic brown-headed cowbirds and the closely related non-brood-parasitic red-winged blackbird (Agelaius phoeniceus) to determine whether there were differences in the hippocampus that reflected space use in the wild. Females had a larger hippocampus than males in both species, but hippocampal neurogenesis, measured by doublecortin immunoreactivity (DCX+), was greater in female than in male cowbirds in the absence of any sex difference in blackbirds, supporting the hypothesis of hippocampal specialization in female cowbirds. Cowbirds of both sexes had a larger hippocampus with greater hippocampal DCX+ than blackbirds. Hippocampus volume remained stable between breeding conditions, but DCX+ was greater post-breeding, indicating that old memories may be lost through hippocampal reorganization following breeding. Our results support, in part, the hypothesis that the hippocampus of cowbirds is specialized for brood parasitism. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1275-1290, 2016.
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Affiliation(s)
- Mélanie F Guigueno
- Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada. .,Department of Biology, University of Western Ontario, London, Ontario, Canada.
| | - Scott A MacDougall-Shackleton
- Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada.,Department of Biology, University of Western Ontario, London, Ontario, Canada.,Department of Psychology, University of Western Ontario, London, Ontario, Canada
| | - David F Sherry
- Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada.,Department of Biology, University of Western Ontario, London, Ontario, Canada.,Department of Psychology, University of Western Ontario, London, Ontario, Canada
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Lieberwirth C, Pan Y, Liu Y, Zhang Z, Wang Z. Hippocampal adult neurogenesis: Its regulation and potential role in spatial learning and memory. Brain Res 2016; 1644:127-40. [PMID: 27174001 PMCID: PMC5064285 DOI: 10.1016/j.brainres.2016.05.015] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 05/05/2016] [Accepted: 05/08/2016] [Indexed: 12/24/2022]
Abstract
Adult neurogenesis, defined here as progenitor cell division generating functionally integrated neurons in the adult brain, occurs within the hippocampus of numerous mammalian species including humans. The present review details various endogenous (e.g., neurotransmitters) and environmental (e.g., physical exercise) factors that have been shown to influence hippocampal adult neurogenesis. In addition, the potential involvement of adult-generated neurons in naturally-occurring spatial learning behavior is discussed by summarizing the literature focusing on traditional animal models (e.g., rats and mice), non-traditional animal models (e.g., tree shrews), as well as natural populations (e.g., chickadees and Siberian chipmunk).
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Affiliation(s)
| | - Yongliang Pan
- Program in Molecular and Translational Medicine, School of Medicine, Huzhou University, Huzhou 313000, PR China; State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, PR China.
| | - Yan Liu
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA
| | - Zhibin Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, PR China
| | - Zuoxin Wang
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA
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Surbhi, Rastogi A, Malik S, Rani S, Kumar V. Seasonal neuronal plasticity in song-control and auditory forebrain areas in subtropical nonmigratory and palearctic-indian migratory male songbirds. J Comp Neurol 2016; 524:2914-29. [DOI: 10.1002/cne.24000] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Surbhi
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo-U.S. Center for Biological Timing, University of Delhi; Delhi 110 007 India
- Department of Zoology; University of Delhi; Delhi 110 007 India
| | - Ashutosh Rastogi
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo-U.S. Center for Biological Timing, University of Delhi; Delhi 110 007 India
- Department of Zoology; University of Lucknow; Lucknow 226 007 India
| | - Shalie Malik
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo-U.S. Center for Biological Timing, University of Delhi; Delhi 110 007 India
- Department of Zoology; University of Lucknow; Lucknow 226 007 India
| | - Sangeeta Rani
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo-U.S. Center for Biological Timing, University of Delhi; Delhi 110 007 India
- Department of Zoology; University of Lucknow; Lucknow 226 007 India
| | - Vinod Kumar
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo-U.S. Center for Biological Timing, University of Delhi; Delhi 110 007 India
- Department of Zoology; University of Delhi; Delhi 110 007 India
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Trading new neurons for status: Adult hippocampal neurogenesis in eusocial Damaraland mole-rats. Neuroscience 2016; 324:227-37. [DOI: 10.1016/j.neuroscience.2016.03.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 02/19/2016] [Accepted: 03/07/2016] [Indexed: 11/21/2022]
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19
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Barkan S, Roll U, Yom-Tov Y, Wassenaar LI, Barnea A. Possible linkage between neuronal recruitment and flight distance in migratory birds. Sci Rep 2016; 6:21983. [PMID: 26905978 PMCID: PMC4764934 DOI: 10.1038/srep21983] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 01/05/2016] [Indexed: 01/28/2023] Open
Abstract
New neuronal recruitment in an adult animal’s brain is presumed to contribute to brain plasticity and increase the animal’s ability to contend with new and changing environments. During long-distance migration, birds migrating greater distances are exposed to more diverse spatial information. Thus, we hypothesized that greater migration distance in birds would correlate with the recruitment of new neurons into the brain regions involved with migratory navigation. We tested this hypothesis on two Palearctic migrants - reed warblers (Acrocephalus scirpaceus) and turtle doves (Streptopelia turtur), caught in Israel while returning from Africa in spring and summer. Birds were injected with a neuronal birth marker and later inspected for new neurons in brain regions known to play a role in navigation - the hippocampus and nidopallium caudolateral. We calculated the migration distance of each individual by matching feather isotopic values (δ2H and δ13C) to winter base-maps of these isotopes in Africa. Our findings suggest a positive correlation between migration distance and new neuronal recruitment in two brain regions - the hippocampus in reed warblers and nidopallium caudolateral in turtle doves. This multidisciplinary approach provides new insights into the ability of the avian brain to adapt to different migration challenges.
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Affiliation(s)
- Shay Barkan
- Department of Zoology, Tel-Aviv University, Tel-Aviv 61391, Israel
| | - Uri Roll
- School of Geography &the Environment, University of Oxford, South Parks Road, Oxford, OX1 3QY, United Kingdom.,Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, United Kingdom
| | - Yoram Yom-Tov
- Department of Zoology, Tel-Aviv University, Tel-Aviv 61391, Israel
| | - Leonard I Wassenaar
- Department of Nuclear Sciences and Applications, International Atomic Energy Agency (IAEA), Vienna, Austria
| | - Anat Barnea
- Department of Natural and Life Sciences, The Open University of Israel, Ra'anana 43107, Israel
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Ruczyński I, Clarin TMA, Siemers BM. Do greater mouse-eared bats experience a trade-off between energy conservation and learning? ACTA ACUST UNITED AC 2015; 217:4043-8. [PMID: 25392460 DOI: 10.1242/jeb.106336] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Bats, some species of rodents and some birds are able to save energy during the summer period by decreasing their body temperature and falling into torpor. Some studies indicate that torpor prevents sleeping and causes effects similar to sleep deprivation. Impairment of processes stabilizing memory slows down learning accuracy and speed. We conducted two experiments to test whether greater mouse-eared bats, Myotis myotis, which commonly use torpor during the summer period, experience a trade-off between energy savings and learning abilities. We compared learning speed and accuracy in bats that were exposed to low (7°C) and higher ambient temperatures (22°C) between training and experimental sessions. Tests were conducted in experiments with food reward (food search) and without food reward (perch search). Time spent with the skin temperature above 30°C was significantly longer for bats exposed to 22°C than for those exposed to 7°C, and longer in experiments with food reward than without food reward. We observed only a very weak tendency for better accuracy and shorter search times in bats exposed to 22°C than in those exposed to 7°C. Our data indicate that memory consolidation of bats under natural conditions is not affected by daily torpor when bats are in good condition and may therefore defend against a rapid fall into torpor. We suggest that homeostatic processes connected with the circadian rhythm allow protection of the consolidation of memory for relatively simple tasks despite time spent in torpor.
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Affiliation(s)
- Ireneusz Ruczyński
- Sensory Ecology Group, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße 11, 82319 Seewiesen, Germany Mammal Research Institute PAS, Waszkiewicza 1, 17-230 Białowieża, Poland
| | - Theresa M A Clarin
- Sensory Ecology Group, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße 11, 82319 Seewiesen, Germany
| | - Bjoern M Siemers
- Sensory Ecology Group, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße 11, 82319 Seewiesen, Germany
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Croston R, Branch CL, Kozlovsky DY, Roth TC, LaDage LD, Freas CA, Pravosudov VV. Potential Mechanisms Driving Population Variation in Spatial Memory and the Hippocampus in Food-caching Chickadees. Integr Comp Biol 2015; 55:354-71. [DOI: 10.1093/icb/icv029] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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22
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Elevation-related differences in novel environment exploration and social dominance in food-caching mountain chickadees. Behav Ecol Sociobiol 2014. [DOI: 10.1007/s00265-014-1796-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Barkan S, Yom-Tov Y, Barnea A. A possible relation between new neuronal recruitment and migratory behavior inAcrocephaluswarblers. Dev Neurobiol 2014; 74:1194-209. [DOI: 10.1002/dneu.22198] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 05/28/2014] [Accepted: 06/02/2014] [Indexed: 12/13/2022]
Affiliation(s)
- Shay Barkan
- Department of Zoology; Tel-Aviv University; Tel-Aviv 61391 Israel
| | - Yoram Yom-Tov
- Department of Zoology; Tel-Aviv University; Tel-Aviv 61391 Israel
| | - Anat Barnea
- Department of Natural and Life Sciences; The Open University of Israel; Ra'anana 43107 Israel
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Pravosudov VV, Roth II TC. Cognitive Ecology of Food Hoarding: The Evolution of Spatial Memory and the Hippocampus. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2013. [DOI: 10.1146/annurev-ecolsys-110512-135904] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Timothy C. Roth II
- Department of Psychology, Franklin and Marshall College, Lancaster, Pennsylvania 17603;
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Freas CA, Roth TC, LaDage LD, Pravosudov VV. Hippocampal neuron soma size is associated with population differences in winter climate severity in food-caching chickadees. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12125] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Cody A. Freas
- Department of Biology; MS 314, University of Nevada at Reno; Reno Nevada 89557 USA
| | - Timothy C. Roth
- Department of Psychology; Franklin & Marshall College; PO Box 3003 Lancaster Pennsylvania 17604 USA
| | - Lara D. LaDage
- Department of Biology; MS 314, University of Nevada at Reno; Reno Nevada 89557 USA
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26
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Roth TC, Chevalier DM, LaDage LD, Pravosudov VV. Variation in hippocampal glial cell numbers in food-caching birds from different climates. Dev Neurobiol 2013; 73:480-5. [DOI: 10.1002/dneu.22074] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 12/17/2012] [Accepted: 01/25/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Timothy C. Roth
- Department of Psychology; Franklin and Marshall College; Lancaster; Pennsylvania; 17604
| | | | - Lara D. LaDage
- Department of Biology; University of Nevada; Reno; Nevada; 89509
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Pravosudov VV, Roth TC, Forister ML, Ladage LD, Kramer R, Schilkey F, van der Linden AM. Differential hippocampal gene expression is associated with climate-related natural variation in memory and the hippocampus in food-caching chickadees. Mol Ecol 2012. [PMID: 23205699 DOI: 10.1111/mec.12146] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
There is significant and often heritable variation in cognition and its underlying neural mechanisms, yet specific genetic contributions to such variation are not well characterized. Black-capped chickadees present a good model to investigate the genetic basis of cognition because they exhibit tremendous climate-related variation in memory, hippocampal morphology and neurogenesis rates throughout the North American continent, and these cognitive traits appear to have a heritable basis. We examined the hippocampal transcriptome profiles of laboratory-reared chickadees from the two most divergent populations to test whether differential gene expression in the hippocampus is associated with population differences in spatial memory, hippocampal morphology and adult hippocampal neurogenesis rates. Using high-resolution mRNA sequencing coupled to a de novo transcriptome assembly, we generated 23 295 consensus sequences, which predicted 16 206 protein sequences with 13 982 showing high similarity to known protein sequences or conserved hypothetical proteins in other species. Of these, we identified differential expression in nearly 380 genes, with 47 genes specifically linked to neurogenesis, apoptosis, synaptic function, and learning and memory processes. Many of the other differentially expressed genes, however, may be associated with other functions. Our study presents the first avian hippocampal transcriptome, and it is the first study identifying differential gene expression associated with natural variation in cognition and the hippocampus. Our results provide additional support to the hypothesis that population differences in memory, hippocampal morphology and neurogenesis in chickadees have likely resulted from natural selection that appears to act on memory and its underlying neural mechanisms.
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Affiliation(s)
- V V Pravosudov
- Department of Biology, University of Nevada, Reno, NV 89557, USA.
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Pravosudov VV, Roth TC, Forister ML, LaDage LD, Burg TM, Braun MJ, Davidson BS. Population genetic structure and its implications for adaptive variation in memory and the hippocampus on a continental scale in food-caching black-capped chickadees. Mol Ecol 2012; 21:4486-97. [DOI: 10.1111/j.1365-294x.2012.05721.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/18/2012] [Accepted: 06/20/2012] [Indexed: 01/01/2023]
Affiliation(s)
- V. V. Pravosudov
- Department of Biology; University of Nevada Reno; MS314; Reno; NV; 89557; USA
| | | | - M. L. Forister
- Department of Biology; University of Nevada Reno; MS314; Reno; NV; 89557; USA
| | - L. D. LaDage
- Department of Biology; University of Nevada Reno; MS314; Reno; NV; 89557; USA
| | - T. M. Burg
- Department of Biological Sciences; University of Lethbridge; Lethbridge; AB, T1K 3M4; Canada
| | - M. J. Braun
- Department of Vertebrate Zoology; National Museum of Natural History; Smithsonian Institution; Washington; DC, 20560; USA
| | - B. S. Davidson
- Department of Vertebrate Zoology; National Museum of Natural History; Smithsonian Institution; Washington; DC, 20560; USA
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29
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Elevation-related differences in memory and the hippocampus in mountain chickadees, Poecile gambeli. Anim Behav 2012. [DOI: 10.1016/j.anbehav.2012.04.018] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Ward BJ, Day LB, Wilkening SR, Wylie DR, Saucier DM, Iwaniuk AN. Hummingbirds have a greatly enlarged hippocampal formation. Biol Lett 2012; 8:657-9. [PMID: 22357941 DOI: 10.1098/rsbl.2011.1180] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Both field and laboratory studies demonstrate that hummingbirds (Apodiformes, Trochilidae) have exceptional spatial memory. The complexity of spatial-temporal information that hummingbirds must retain and use daily is probably subserved by the hippocampal formation (HF), and therefore, hummingbirds should have a greatly expanded HF. Here, we compare the relative size of the HF in several hummingbird species with that of other birds. Our analyses reveal that the HF in hummingbirds is significantly larger, relative to telencephalic volume, than any bird examined to date. When expressed as a percentage of telencephalic volume, the hummingbird HF is two to five times larger than that of caching and non-caching songbirds, seabirds and woodpeckers. This HF expansion in hummingbirds probably underlies their ability to remember the location, distribution and nectar content of flowers, but more detailed analyses are required to determine the extent to which this arises from an expansion of HF or a decrease in size of other brain regions.
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Affiliation(s)
- Brian J Ward
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
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Roth TC, Gallagher CM, LaDage LD, Pravosudov VV. Variation in brain regions associated with fear and learning in contrasting climates. BRAIN, BEHAVIOR AND EVOLUTION 2012; 79:181-90. [PMID: 22286546 DOI: 10.1159/000335421] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 11/25/2011] [Indexed: 12/25/2022]
Abstract
In environments where resources are difficult to obtain and enhanced cognitive capabilities might be adaptive, brain structures associated with cognitive traits may also be enhanced. In our previous studies, we documented a clear and significant relationship among environmental conditions, memory and hippocampal structure using ten populations of black-capped chickadees (Poecile atricapillus) over a large geographic range. In addition, focusing on just the two populations from the geographical extremes of our large-scale comparison, Alaska and Kansas, we found enhanced problem-solving capabilities and reduced neophobia in a captive-raised population of black-capped chickadees originating from the energetically demanding environment (Alaska) relative to conspecifics from the milder environment (Kansas). Here, we focused on three brain regions, the arcopallium (AP), the nucleus taeniae of the amygdala and the lateral striatum (LSt), that have been implicated to some extent in aspects of these behaviors in order to investigate whether potential differences in these brain areas may be associated with our previously detected differences in cognition. We compared the variation in neuron number and volumes of these regions between these populations, in both wild-caught birds and captive-raised individuals. Consistent with our behavioral observations, wild-caught birds from Kansas had a larger AP volume than their wild-caught conspecifics from Alaska, which possessed a higher density of neurons in the LSt. However, there were no other significant differences between populations in the wild-caught and captive-raised groups. Interestingly, individuals from the wild had larger LSt and AP volumes with more neurons than those raised in captivity. Overall, we provide some evidence that population-related differences in problem solving and neophobia may be associated with differences in volume and neuron numbers of our target brain regions. However, the relationship is not completely clear, and our study raises numerous questions about the relationship between the brain and behavior, especially in captive animals.
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Affiliation(s)
- Timothy C Roth
- Department of Biology, University of Nevada, Reno, Nev., USA.
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Barnea A, Pravosudov V. Birds as a model to study adult neurogenesis: bridging evolutionary, comparative and neuroethological approaches. Eur J Neurosci 2011; 34:884-907. [PMID: 21929623 PMCID: PMC3177424 DOI: 10.1111/j.1460-9568.2011.07851.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
During the last few decades, evidence has demonstrated that adult neurogenesis is a well-preserved feature throughout the animal kingdom. In birds, ongoing neuronal addition occurs rather broadly, to a number of brain regions. This review describes adult avian neurogenesis and neuronal recruitment, discusses factors that regulate these processes, and touches upon the question of their genetic control. Several attributes make birds an extremely advantageous model to study neurogenesis. First, song learning exhibits seasonal variation that is associated with seasonal variation in neuronal turnover in some song control brain nuclei, which seems to be regulated via adult neurogenesis. Second, food-caching birds naturally use memory-dependent behavior in learning the locations of thousands of food caches scattered over their home ranges. In comparison with other birds, food-caching species have relatively enlarged hippocampi with more neurons and intense neurogenesis, which appears to be related to spatial learning. Finally, migratory behavior and naturally occurring social systems in birds also provide opportunities to investigate neurogenesis. This diversity of naturally occurring memory-based behaviors, combined with the fact that birds can be studied both in the wild and in the laboratory, make them ideal for investigation of neural processes underlying learning. This can be done by using various approaches, from evolutionary and comparative to neuroethological and molecular. Finally, we connect the avian arena to a broader view by providing a brief comparative and evolutionary overview of adult neurogenesis and by discussing the possible functional role of the new neurons. We conclude by indicating future directions and possible medical applications.
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Affiliation(s)
- Anat Barnea
- Department of Natural and Life Sciences, The Open University of Israel, PO Box 808, Ra'anana 43107, Israel.
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Roth TC, LaDage LD, Freas CA, Pravosudov VV. Variation in memory and the hippocampus across populations from different climates: a common garden approach. Proc Biol Sci 2011; 279:402-10. [PMID: 21715407 DOI: 10.1098/rspb.2011.1020] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Selection for enhanced cognitive traits is hypothesized to produce enhancements to brain structures that support those traits. Although numerous studies suggest that this pattern is robust, there are several mechanisms that may produce this association. First, cognitive traits and their neural underpinnings may be fixed as a result of differential selection on cognitive function within specific environments. Second, these relationships may be the product of the selection for plasticity, where differences are produced owing to an individual's experiences in the environment. Alternatively, the relationship may be a complex function of experience, genetics and/or epigenetic effects. Using a well-studied model species (black-capped chickadee, Poecile atricapillus), we have for the first time, to our knowledge, addressed these hypotheses. We found that differences in hippocampal (Hp) neuron number, neurogenesis and spatial memory previously observed in wild chickadees persisted in hand-raised birds from the same populations, even when birds were raised in an identical environment. These findings reject the hypothesis that variation in these traits is owing solely to differences in memory-based experiences in different environments. Moreover, neuron number and neurogenesis were strikingly similar between captive-raised and wild birds from the same populations, further supporting the genetic hypothesis. Hp volume, however, did not differ between the captive-raised populations, yet was very different in their wild counterparts, supporting the experience hypothesis. Our results indicate that the production of some Hp factors may be inherited and largely independent of environmental experiences in adult life, regardless of their magnitude, in animals under high selection pressure for memory, while traits such as volume may be more plastic and modified by the environment.
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Affiliation(s)
- Timothy C Roth
- Department of Biology, University of Nevada, Reno, NV 89557, USA.
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