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Straight PJ, Gignac PM, Kuenzel WJ. A histological and diceCT-derived 3D reconstruction of the avian visual thalamofugal pathway. Sci Rep 2024; 14:8447. [PMID: 38600121 PMCID: PMC11006926 DOI: 10.1038/s41598-024-58788-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 04/03/2024] [Indexed: 04/12/2024] Open
Abstract
Amniotes feature two principal visual processing systems: the tectofugal and thalamofugal pathways. In most mammals, the thalamofugal pathway predominates, routing retinal afferents through the dorsolateral geniculate complex to the visual cortex. In most birds, the thalamofugal pathway often plays the lesser role with retinal afferents projecting to the principal optic thalami, a complex of several nuclei that resides in the dorsal thalamus. This thalamic complex sends projections to a forebrain structure called the Wulst, the terminus of the thalamofugal visual system. The thalamofugal pathway in birds serves many functions such as pattern discrimination, spatial memory, and navigation/migration. A comprehensive analysis of avian species has unveiled diverse subdivisions within the thalamic and forebrain structures, contingent on species, age, and techniques utilized. In this study, we documented the thalamofugal system in three dimensions by integrating histological and contrast-enhanced computed tomography imaging of the avian brain. Sections of two-week-old chick brains were cut in either coronal, sagittal, or horizontal planes and stained with Nissl and either Gallyas silver or Luxol Fast Blue. The thalamic principal optic complex and pallial Wulst were subdivided on the basis of cell and fiber density. Additionally, we utilized the technique of diffusible iodine-based contrast-enhanced computed tomography (diceCT) on a 5-week-old chick brain, and right eyeball. By merging diceCT data, stained histological sections, and information from the existing literature, a comprehensive three-dimensional model of the avian thalamofugal pathway was constructed. The use of a 3D model provides a clearer understanding of the structural and spatial organization of the thalamofugal system. The ability to integrate histochemical sections with diceCT 3D modeling is critical to better understanding the anatomical and physiologic organization of complex pathways such as the thalamofugal visual system.
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Affiliation(s)
- Parker J Straight
- Poultry Science Department, University of Arkansas, Fayetteville, AR, USA.
| | - Paul M Gignac
- Cellular and Molecular Medicine Department, University of Arizona Health Sciences, Tucson, AZ, USA
- MicroCT Imaging Consortium for Research and Outreach, University of Arkansas, Fayetteville, AR, USA
| | - Wayne J Kuenzel
- Poultry Science Department, University of Arkansas, Fayetteville, AR, USA
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2
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Nimpf S, Kaplan HS, Nordmann GC, Cushion T, Keays DA. Long-term, high-resolution in vivo calcium imaging in pigeons. CELL REPORTS METHODS 2024; 4:100711. [PMID: 38382523 PMCID: PMC10921020 DOI: 10.1016/j.crmeth.2024.100711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 11/05/2023] [Accepted: 01/26/2024] [Indexed: 02/23/2024]
Abstract
In vivo 2-photon calcium imaging has led to fundamental advances in our understanding of sensory circuits in mammalian species. In contrast, few studies have exploited this methodology in birds, with investigators primarily relying on histological and electrophysiological techniques. Here, we report the development of in vivo 2-photon calcium imaging in awake pigeons. We show that the genetically encoded calcium indicator GCaMP6s, delivered by the adeno-associated virus rAAV2/7, allows high-quality, stable, and long-term imaging of neuronal populations at single-cell and single-dendrite resolution in the pigeon forebrain. We demonstrate the utility of our setup by investigating the processing of colors in the visual Wulst, the avian homolog of the visual cortex. We report that neurons in the Wulst are color selective and display diverse response profiles to light of different wavelengths. This technology provides a powerful tool to decipher the operating principles that underlie sensory encoding in birds.
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Affiliation(s)
- Simon Nimpf
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilian-University Munich, Planegg-Martinsried, 82152 Munich, Germany.
| | - Harris S Kaplan
- Harvard University, Department of Molecular and Cellular Biology, 16 Divinity Avenue, Cambridge, MA 02138, USA
| | - Gregory C Nordmann
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilian-University Munich, Planegg-Martinsried, 82152 Munich, Germany
| | - Thomas Cushion
- University of Cambridge, Department of Physiology, Development & Neuroscience, Downing Street, Cambridge CB2 3EG, UK
| | - David A Keays
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilian-University Munich, Planegg-Martinsried, 82152 Munich, Germany; University of Cambridge, Department of Physiology, Development & Neuroscience, Downing Street, Cambridge CB2 3EG, UK; Research Institute of Molecular Pathology, Vienna Biocenter, Campus-Vienna-Biocenter 1, Vienna 1030, Austria.
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3
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Balanoff A, Ferrer E, Saleh L, Gignac PM, Gold MEL, Marugán-Lobón J, Norell M, Ouellette D, Salerno M, Watanabe A, Wei S, Bever G, Vaska P. Quantitative functional imaging of the pigeon brain: implications for the evolution of avian powered flight. Proc Biol Sci 2024; 291:20232172. [PMID: 38290541 PMCID: PMC10827418 DOI: 10.1098/rspb.2023.2172] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 01/03/2024] [Indexed: 02/01/2024] Open
Abstract
The evolution of flight is a rare event in vertebrate history, and one that demands functional integration across multiple anatomical/physiological systems. The neuroanatomical basis for such integration and the role that brain evolution assumes in behavioural transformations remain poorly understood. We make progress by (i) generating a positron emission tomography (PET)-based map of brain activity for pigeons during rest and flight, (ii) using these maps in a functional analysis of the brain during flight, and (iii) interpreting these data within a macroevolutionary context shaped by non-avian dinosaurs. Although neural activity is generally conserved from rest to flight, we found significant increases in the cerebellum as a whole and optic flow pathways. Conserved activity suggests processing of self-movement and image stabilization are critical when a bird takes to the air, while increased visual and cerebellar activity reflects the importance of integrating multimodal sensory information for flight-related movements. A derived cerebellar capability likely arose at the base of maniraptoran dinosaurs, where volumetric expansion and possible folding directly preceded paravian flight. These data represent an important step toward establishing how the brain of modern birds supports their unique behavioural repertoire and provide novel insights into the neurobiology of the bird-like dinosaurs that first achieved powered flight.
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Affiliation(s)
- Amy Balanoff
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
| | - Elizabeth Ferrer
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
- Samuel Merritt University, Oakland, CA 94609, USA
| | - Lemise Saleh
- Department of Biomedical Engineering and Radiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Paul M. Gignac
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
- Department of Cellular and Molecular Medicine, University of Arizona College of Medicine, Tucson, AZ 85724, USA
| | - M. Eugenia L. Gold
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
- Department of Biology, Suffolk University, Boston, MA 02108, USA
| | - Jesús Marugán-Lobón
- Unidad de Paleontología, Departamento Biología, Universidad Autónoma de Madrid, 28049 Cantoblanco (Madrid), Spain
| | - Mark Norell
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
| | | | - Michael Salerno
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Akinobu Watanabe
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, USA
- Life Sciences Department, Vertebrates Division, Natural History Museum, London SW7 5BD, UK
| | - Shouyi Wei
- Department of Physics, New York Proton Center, New York, NY 10035, USA
| | - Gabriel Bever
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
| | - Paul Vaska
- Department of Biomedical Engineering and Radiology, Stony Brook University, Stony Brook, NY 11794, USA
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Pusch R, Clark W, Rose J, Güntürkün O. Visual categories and concepts in the avian brain. Anim Cogn 2023; 26:153-173. [PMID: 36352174 PMCID: PMC9877096 DOI: 10.1007/s10071-022-01711-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 10/19/2022] [Accepted: 10/25/2022] [Indexed: 11/11/2022]
Abstract
Birds are excellent model organisms to study perceptual categorization and concept formation. The renewed focus on avian neuroscience has sparked an explosion of new data in the field. At the same time, our understanding of sensory and particularly visual structures in the avian brain has shifted fundamentally. These recent discoveries have revealed how categorization is mediated in the avian brain and has generated a theoretical framework that goes beyond the realm of birds. We review the contribution of avian categorization research-at the methodical, behavioral, and neurobiological levels. To this end, we first introduce avian categorization from a behavioral perspective and the common elements model of categorization. Second, we describe the functional and structural organization of the avian visual system, followed by an overview of recent anatomical discoveries and the new perspective on the avian 'visual cortex'. Third, we focus on the neurocomputational basis of perceptual categorization in the bird's visual system. Fourth, an overview of the avian prefrontal cortex and the prefrontal contribution to perceptual categorization is provided. The fifth section outlines how asymmetries of the visual system contribute to categorization. Finally, we present a mechanistic view of the neural principles of avian visual categorization and its putative extension to concept learning.
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Affiliation(s)
- Roland Pusch
- Biopsychology, Faculty of Psychology, Ruhr University Bochum, 44780, Bochum, Germany
| | - William Clark
- Neural Basis of Learning, Faculty of Psychology, Ruhr University Bochum, 44780, Bochum, Germany
| | - Jonas Rose
- Neural Basis of Learning, Faculty of Psychology, Ruhr University Bochum, 44780, Bochum, Germany
| | - Onur Güntürkün
- Biopsychology, Faculty of Psychology, Ruhr University Bochum, 44780, Bochum, Germany.
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Clark W, Colombo M. Seeing the Forest for the Trees, and the Ground Below My Beak: Global and Local Processing in the Pigeon's Visual System. Front Psychol 2022; 13:888528. [PMID: 35756294 PMCID: PMC9218864 DOI: 10.3389/fpsyg.2022.888528] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/20/2022] [Indexed: 11/13/2022] Open
Abstract
Non-human animals tend to solve behavioral tasks using local information. Pigeons are particularly biased toward using the local features of stimuli to guide behavior in small-scale environments. When behavioral tasks are performed in large-scale environments, pigeons are much better global processors of information. The local and global strategies are mediated by two different fovea in the pigeon retina that are associated with the tectofugal and thalamofugal pathways. We discuss the neural mechanisms of pigeons' bias for local information within the tectofugal pathway, which terminates at an intermediate stage of extracting shape complexity. We also review the evidence suggesting that the thalamofugal pathway participates in global processing in pigeons and is primarily engaged in constructing a spatial representation of the environment in conjunction with the hippocampus.
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Affiliation(s)
- William Clark
- Department of Psychology, University of Otago, Dunedin, New Zealand
| | - Michael Colombo
- Department of Psychology, University of Otago, Dunedin, New Zealand
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Kavet R, Brain J. Cryptochromes in Mammals and Birds: Clock or Magnetic Compass? Physiology (Bethesda) 2021; 36:183-194. [PMID: 33904789 DOI: 10.1152/physiol.00040.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Species throughout the animal kingdom use the Earth's magnetic field (MF) to navigate using either or both of two mechanisms. The first relies on magnetite crystals in tissue where their magnetic moments align with the MF to transduce a signal transmitted to the central nervous system. The second and the subject of this paper involves cryptochrome (CRY) proteins located in cone photoreceptors distributed across the retina, studied most extensively in birds. According to the "Radical Pair Mechanism" (RPM), blue/UV light excites CRY's flavin cofactor (FAD) to generate radical pairs whose singlet-to-triplet interconversion rate is modulated by an external MF. The signaling product of the RPM produces an impression of the field across the retinal surface. In birds, the resulting signal on the optic nerve is transmitted along the thalamofugal pathway to the primary visual cortex, which projects to brain regions concerned with image processing, memory, and executive function. The net result is a bird's orientation to the MF's inclination: its vector angle relative to the Earth's surface. The quality of ambient light (e.g., polarization) provides additional input to the compass. In birds, the Type IV CRY isoform appears pivotal to the compass, given its positioning within retinal cones; a cytosolic location therein indicating no role in the circadian clock; relatively steady diurnal levels (unlike Type II CRY's cycling); and a full complement of FAD (essential for photosensitivity). The evidence indicates that mammalian Type II CRY isoforms play a light-independent role in the cellular molecular clock without a photoreceptive function.
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Affiliation(s)
| | - Joseph Brain
- Environmental Physiology, Molecular, and Integrative Physiological Sciences Program, Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
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7
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Light-incubation effects on lateralisation of single unit responses in the visual Wulst of domestic chicks. Brain Struct Funct 2021; 227:497-513. [PMID: 33783595 PMCID: PMC8844149 DOI: 10.1007/s00429-021-02259-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 03/16/2021] [Indexed: 12/27/2022]
Abstract
Since the ground-breaking discovery that in-egg light exposure triggers the emergence of visual lateralisation, domestic chicks became a crucial model for research on the interaction of environmental and genetic influences for brain development. In domestic chick embryos, light exposure induces neuroanatomical asymmetries in the strength of visual projections from the thalamus to the visual Wulst. Consequently, the right visual Wulst receives more bilateral information from the two eyes than the left one. How this impacts visual Wulst's physiology is still unknown. This paper investigates the visual response properties of neurons in the left and right Wulst of dark- and light-incubated chicks, studying the effect of light incubation on bilaterally responsive cells that integrate information from both eyes. We recorded from a large number of visually responsive units, providing the first direct evidence of lateralisation in the neural response properties of units of the visual Wulst. While we confirm that some forms of lateralisation are induced by embryonic light exposure, we found also many cases of light-independent asymmetries. Moreover, we found a strong effect of in-egg light exposure on the general development of the functional properties of units in the two hemispheres. This indicates that the effect of embryonic stimulation goes beyond its contribution to the emergence of some forms of lateralisation, with influences on the maturation of visual units in both hemispheres.
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8
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Hsiao YT, Chen TC, Yu PH, Huang DS, Hu FR, Chuong CM, Chang FC. Connectivity between nidopallium caudolateral and visual pathways in color perception of zebra finches. Sci Rep 2020; 10:19382. [PMID: 33168854 PMCID: PMC7653952 DOI: 10.1038/s41598-020-76542-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 10/29/2020] [Indexed: 11/24/2022] Open
Abstract
Researchers demonstrated an elegant ability for red discrimination in zebra finches. It is interested to understand whether red activates exhibit much stronger response than other colors in neural network levels. To reveal the question, local field potentials (LFPs) was recorded and analyzed in two visual pathways, the thalamofugal and the tectofugal pathways, of zebra finches. Human studies demonstrate visual associated telencephalons communicate with higher order brain areas such as prefrontal cortex. The present study determined whether a comparable transmission occurs in zebra finches. Telencephalic regions of the thalamofugal (the visual Wulst) and the tectofugal pathway (the entopallium) with their higher order telencephalon, nidopallium caudolateral (NCL) were simultaneously recorded. LFPs of relay nuclei (the nucleus rotundus, ROT) of tectofugal pathway were also acquired. We demonstrated that LFP powers in the tectofugal pathway were higher than those in the thalamofugal pathway when illuminating blue lights. In addition, the LFP synchronization was stronger between the entopallium and NCL. LFPs also revealed a higher Granger causality from the direction of entopallium to NCL and from ROT to entopallium. These results suggest that zebra finches' tectofugal pathway predominately processing color information from ROT to NCL, relayed by entopallium, and blue could trigger the strongest response.
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Affiliation(s)
- Yi-Tse Hsiao
- Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan
| | - Ta-Ching Chen
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan
| | - Pin-Huan Yu
- Institute of Veterinary Clinical Science, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan
| | - Ding-Siang Huang
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Fung-Rong Hu
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Cheng-Ming Chuong
- Department of Pathology, University of Southern California, Los Angeles, CA, USA
| | - Fang-Chia Chang
- Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan.
- Graduate Institute of Acupuncture Science, College of Chinese Medicine, China Medical University, Taichung, Taiwan.
- Department of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
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9
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Knudsen EI. Evolution of neural processing for visual perception in vertebrates. J Comp Neurol 2020; 528:2888-2901. [PMID: 32003466 PMCID: PMC7586818 DOI: 10.1002/cne.24871] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/23/2020] [Accepted: 01/23/2020] [Indexed: 01/22/2023]
Abstract
Visual perception requires both visual information and attention. This review compares, across classes of vertebrates, the functional and anatomical characteristics of (a) the neural pathways that process visual information about objects, and (b) stimulus selection pathways that determine the objects to which an animal attends. Early in the evolution of vertebrate species, visual perception was dominated by information transmitted via the midbrain (retinotectal) visual pathway, and attention was probably controlled primarily by a selection network in the midbrain. In contrast, in primates, visual perception is dominated by information transmitted via the forebrain (retinogeniculate) visual pathway, and attention is mediated largely by networks in the forebrain. In birds and nonprimate mammals, both the retinotectal and retinogeniculate pathways contribute critically to visual information processing, and both midbrain and forebrain networks play important roles in controlling attention. The computations and processing strategies in birds and mammals share some strikingly similar characteristics despite over 300 million years of independent evolution and being implemented by distinct brain architectures. The similarity of these functional characteristics suggests that they provide valuable advantages to visual perception in advanced visual systems. A schema is proposed that describes the evolution of the pathways and computations that enable visual perception in vertebrate species.
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Affiliation(s)
- Eric I Knudsen
- Department of Neurobiology, Stanford University, Stanford, California
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10
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Belekhova MG, Kenigfest NB, Vasilyev DS, Chudinova TV. Distribution of Calcium-Binding Proteins and Cytochrome Oxidase Activity in the Projective Zone (Wulst) of the Pigeon Thalamofugal Visual Pathway: A Discussion in the Light of Current Concepts on Homology between the Avian Wulst and the Mammalian Striate (Visual) Cortex. J EVOL BIOCHEM PHYS+ 2019. [DOI: 10.1134/s0022093019040070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Yang Y, Wang Q, Wang SR, Wang Y, Xiao Q. Representation of time interval entrained by periodic stimuli in the visual thalamus of pigeons. eLife 2017; 6:27995. [PMID: 29284554 PMCID: PMC5747522 DOI: 10.7554/elife.27995] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 11/27/2017] [Indexed: 11/13/2022] Open
Abstract
Animals use the temporal information from previously experienced periodic events to instruct their future behaviors. The retina and cortex are involved in such behavior, but it remains largely unknown how the thalamus, transferring visual information from the retina to the cortex, processes the periodic temporal patterns. Here we report that the luminance cells in the nucleus dorsolateralis anterior thalami (DLA) of pigeons exhibited oscillatory activities in a temporal pattern identical to the rhythmic luminance changes of repetitive light/dark (LD) stimuli with durations in the seconds-to-minutes range. Particularly, after LD stimulation, the DLA cells retained the entrained oscillatory activities with an interval closely matching the duration of the LD cycle. Furthermore, the post-stimulus oscillatory activities of the DLA cells were sustained without feedback inputs from the pallium (equivalent to the mammalian cortex). Our study suggests that the experience-dependent representation of time interval in the brain might not be confined to the pallial/cortical level, but may occur as early as at the thalamic level.
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Affiliation(s)
- Yan Yang
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Qian Wang
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Shu-Rong Wang
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yi Wang
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Qian Xiao
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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12
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Knudsen EI, Schwarz JS, Knudsen PF, Sridharan D. Space-Specific Deficits in Visual Orientation Discrimination Caused by Lesions in the Midbrain Stimulus Selection Network. Curr Biol 2017; 27:2053-2064.e5. [PMID: 28669762 DOI: 10.1016/j.cub.2017.06.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/10/2017] [Accepted: 06/05/2017] [Indexed: 11/15/2022]
Abstract
Perceptual decisions require both analysis of sensory information and selective routing of relevant information to decision networks. This study explores the contribution of a midbrain network to visual perception in chickens. Analysis of visual orientation information in birds takes place in the forebrain sensory area called the Wulst, as it does in the primary visual cortex (V1) of mammals. In contrast, the midbrain, which receives parallel retinal input, encodes orientation poorly, if at all. We discovered, however, that small electrolytic lesions in the midbrain severely impair a chicken's ability to discriminate orientations. Focal lesions were placed in the optic tectum (OT) and in the nucleus isthmi pars parvocellularis (Ipc)-key nodes in the midbrain stimulus selection network-in chickens trained to perform an orientation discrimination task. A lesion in the OT caused a severe impairment in orientation discrimination specifically for targets at the location in space represented by the lesioned location. Distracting stimuli increased the deficit. A lesion in the Ipc produced similar but more transient effects. We discuss the possibilities that performance deficits were caused by interference with orientation information processing (sensory deficit) versus with the routing of information in the forebrain (agnosia). The data support the proposal that the OT transmits a space-specific signal that is required to gate orientation information from the Wulst into networks that mediate behavioral decisions, analogous to the role of ascending signals from the superior colliculus (SC) in monkeys. Furthermore, our results indicate a critical role for the cholinergic Ipc in this gating process.
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Affiliation(s)
- Eric I Knudsen
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Jason S Schwarz
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Phyllis F Knudsen
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Devarajan Sridharan
- Centre for Neuroscience, Indian Institute of Science, Bengaluru 560012, India.
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