1
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Reyes-Pinto R, Rojas MJ, Letelier JC, Marín GJ, Mpodozis J. Early Development of the Thalamo-Pallial Stage of the Tectofugal Visual Pathway in the Chicken (Gallus gallus). J Comp Neurol 2024; 532:e25657. [PMID: 38987912 DOI: 10.1002/cne.25657] [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: 04/15/2024] [Revised: 06/13/2024] [Accepted: 06/27/2024] [Indexed: 07/12/2024]
Abstract
The tectofugal pathway is a highly conserved visual pathway in all amniotes. In birds and mammals, retinorecipient neurons located in the midbrain roof (optic tectum/superior colliculus) are the source of ascending projections to thalamic relays (nucleus rotundus/caudal pulvinar), which in turn project to specific pallial regions (visual dorsal ventricular ridge [vDVR]/temporal cortex) organized according to a columnar recurrent arrangement of interlaminar circuits. Whether or to which extent these striking hodological correspondences arise from comparable developmental processes is at present an open question, mainly due to the scarcity of data about the ontogeny of the avian tectofugal system. Most of the previous developmental studies of this system in birds have focused on the establishment of the retino-tecto-thalamic connectivity, overlooking the development of the thalamo-pallial-intrapallial circuit. In this work, we studied the latter in chicken embryos by means of immunohistochemical assays and precise ex vivo crystalline injections of biocytin and DiI. We found that the layered organization of the vDVR as well as the system of homotopic reciprocal connections between vDVR layers were present as early as E8. A highly organized thalamo-vDVR projection was also present at this stage. Our immunohistochemical assays suggest that both systems of projections emerge simultaneously even earlier. Combined with previous findings, these results reveal that, in striking contrast with mammals, the peripheral and central stages of the avian tectofugal pathway develop along different timelines, with a tecto-thalamo-intrapallial organization arising before and possibly independently of the retino-isthmo-tectal circuit.
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Affiliation(s)
- Rosana Reyes-Pinto
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Center for Integrative Biology, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - María-José Rojas
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Juan-Carlos Letelier
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Gonzalo J Marín
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
| | - Jorge Mpodozis
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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2
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Huang S, Hu P, Zhao Z, Shi L. Dynamic Nonlinear Spatial Integrations on Encoding Contrasting Stimuli of Tectal Neurons. Animals (Basel) 2024; 14:1577. [PMID: 38891623 PMCID: PMC11171053 DOI: 10.3390/ani14111577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/23/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024] Open
Abstract
Animals detect targets using a variety of visual cues, with the visual salience of these cues determining which environmental features receive priority attention and further processing. Surround modulation plays a crucial role in generating visual saliency, which has been extensively studied in avian tectal neurons. Recent work has reported that the suppression of tectal neurons induced by motion contrasting stimulus is stronger than that by luminance contrasting stimulus. However, the underlying mechanism remains poorly understood. In this study, we built a computational model (called Generalized Linear-Dynamic Modulation) which incorporates independent nonlinear tuning mechanisms for excitatory and inhibitory inputs. This model aims to describe how tectal neurons encode contrasting stimuli. The results showed that: (1) The dynamic nonlinear integration structure substantially improved the accuracy (significant difference (p < 0.001, paired t-test) in the goodness of fit between the two models) of the predicted responses to contrasting stimuli, verifying the nonlinear processing performed by tectal neurons. (2) The modulation difference between luminance and motion contrasting stimuli emerged from the predicted response by the full model but not by that with only excitatory synaptic input (spatial luminance: 89 ± 2.8% (GL_DM) vs. 87 ± 2.1% (GL_DMexc); motion contrasting stimuli: 87 ± 1.7% (GL_DM) vs. 83 ± 2.2% (GL_DMexc)). These results validate the proposed model and further suggest the role of dynamic nonlinear spatial integrations in contextual visual information processing, especially in spatial integration, which is important for object detection performed by birds.
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Affiliation(s)
- Shuman Huang
- Key Laboratory of Artificial Intelligence and Personalized Learning in Education of Henan Province, College of Computer and Information Engineering, Henan Normal University, Xinxiang 453007, China
| | - Pingge Hu
- Department of Automation, Tsinghua University, Beijing 100084, China;
| | - Zhenmeng Zhao
- School of Software, Henan Normal University, Xinxiang 453007, China;
| | - Li Shi
- Department of Automation, Tsinghua University, Beijing 100084, China;
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3
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Straight PJ, Gignac PM, Kuenzel WJ. Mapping the avian visual tectofugal pathway using 3D reconstruction. J Comp Neurol 2024; 532:e25558. [PMID: 38047431 DOI: 10.1002/cne.25558] [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: 04/04/2023] [Revised: 06/19/2023] [Accepted: 10/17/2023] [Indexed: 12/05/2023]
Abstract
Image processing in amniotes is usually accomplished by the thalamofugal and/or tectofugal visual systems. In laterally eyed birds, the tectofugal system dominates with functions such as color and motion processing, spatial orientation, stimulus identification, and localization. This makes it a critical system for complex avian behavior. Here, the brains of chicks, Gallus gallus, were used to produce serial brain sections in either coronal, sagittal, or horizontal planes and stained with either Nissl and Gallyas silver myelin or Luxol fast blue stain and cresyl echt violet (CEV). The emerging techniques of diffusible iodine-based contrast-enhanced computed tomography (diceCT) coupled with serial histochemistry in three planes were used to generate a comprehensive three-dimensional (3D) model of the avian tectofugal visual system. This enabled the 3D reconstruction of tectofugal circuits, including the three primary neuronal projections. Specifically, major components of the system included four regions of the retina, layers of the optic tectum, subdivisions of the nucleus rotundus in the thalamus, the entopallium in the forebrain, and supplementary components connecting into or out of this major avian visual sensory system. The resulting 3D model enabled a better understanding of the structural components and connectivity of this complex system by providing a complete spatial organization that occupied several distinct brain regions. We demonstrate how pairing diceCT with traditional histochemistry is an effective means to improve the understanding of, and thereby should generate insights into, anatomical and functional properties of complicated neural pathways, and we recommend this approach to clarify enigmatic properties of these pathways.
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Affiliation(s)
- Parker J Straight
- Poultry Science Department, University of Arkansas, Fayetteville, Arkansas, USA
| | - Paul M Gignac
- Cellular and Molecular Medicine Department, University of Arizona Health Sciences, Tucson, Arizona, USA
- Anatomy and Cell Biology Department, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Wayne J Kuenzel
- Poultry Science Department, University of Arkansas, Fayetteville, Arkansas, USA
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4
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Reynaert B, Morales C, Mpodozis J, Letelier JC, Marín GJ. A blinking focal pattern of re-entrant activity in the avian tectum. Curr Biol 2023; 33:1-14.e4. [PMID: 36446352 DOI: 10.1016/j.cub.2022.10.070] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 09/06/2022] [Accepted: 10/31/2022] [Indexed: 11/30/2022]
Abstract
Re-entrant connections are inherent to nervous system organization; however, a comprehensive understanding of their operation is still lacking. In birds, topographically organized re-entrant signals, carried by axons from the nucleus-isthmi-parvocellularis (Ipc), are distinctly recorded as bursting discharges across the optic tectum (TeO). Here, we used up to 48 microelectrodes regularly spaced on the superficial tectal layers of anesthetized pigeons to characterize the spatial-temporal pattern of this axonal re-entrant activity in response to different visual stimulation. We found that a brief luminous spot triggered repetitive waves of bursting discharges that, appearing from initial sources, propagated horizontally to areas representing up to 28° of visual space, widely exceeding the area activated by the retinal fibers. In response to visual motion, successive burst waves started along and around the stimulated tectal path, tracking the stimulus in discontinuous steps. When two stimuli were presented, the burst-wave sources alternated between the activated tectal loci, as if only one source could be active at any given time. Because these re-entrant signals boost the retinal input to higher visual areas, their peculiar dynamics mimic a blinking "spotlight," similar to the internal searching mechanism classically used to explain spatial attention. Tectal re-entry from Ipc is thus highly structured and intrinsically discontinuous, and higher tectofugal areas, which lack retinotopic organization, will thus receive incoming visual activity in a sequential and piecemeal fashion. We anticipate that analogous re-entrant patterns, perhaps hidden in less bi-dimensionally organized topographies, may organize the flow of neural activity in other parts of the brain as well.
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Affiliation(s)
- Bryan Reynaert
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile
| | - Cristian Morales
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile
| | - Jorge Mpodozis
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile
| | - Juan Carlos Letelier
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile
| | - Gonzalo J Marín
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile; Facultad de Medicina, Universidad Finis Terrae, Santiago 7501015, Chile.
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5
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Reyes-Pinto R, Ferrán JL, Vega-Zuniga T, González-Cabrera C, Luksch H, Mpodozis J, Puelles L, Marín GJ. Change in the neurochemical signature and morphological development of the parvocellular isthmic projection to the avian tectum. J Comp Neurol 2021; 530:553-573. [PMID: 34363623 DOI: 10.1002/cne.25229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/27/2021] [Accepted: 07/30/2021] [Indexed: 11/05/2022]
Abstract
Neurons can change their classical neurotransmitters during ontogeny, sometimes going through stages of dual release. Here, we explored the development of the neurotransmitter identity of neurons of the avian nucleus isthmi parvocellularis (Ipc), whose axon terminals are retinotopically arranged in the optic tectum (TeO) and exert a focal gating effect upon the ascending transmission of retinal inputs. Although cholinergic and glutamatergic markers are both found in Ipc neurons and terminals of adult pigeons and chicks, the mRNA expression of the vesicular acetylcholine transporter, VAChT, is weak or absent. To explore how the Ipc neurotransmitter identity is established during ontogeny, we analyzed the expression of mRNAs coding for cholinergic (ChAT, VAChT, and CHT) and glutamatergic (VGluT2 and VGluT3) markers in chick embryos at different developmental stages. We found that between E12 and E18, Ipc neurons expressed all cholinergic mRNAs and also VGluT2 mRNA; however, from E16 through posthatch stages, VAChT mRNA expression was specifically diminished. Our ex vivo deposits of tracer crystals and intracellular filling experiments revealed that Ipc axons exhibit a mature paintbrush morphology late in development, experiencing marked morphological transformations during the period of presumptive dual vesicular transmitter release. Additionally, although ChAT protein immunoassays increasingly label the growing Ipc axon, this labeling was consistently restricted to sparse portions of the terminal branches. Combined, these results suggest that the synthesis of glutamate and acetylcholine, and their vesicular release, is complexly linked to the developmental processes of branching, growing and remodeling of these unique axons.
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Affiliation(s)
- Rosana Reyes-Pinto
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - José L Ferrán
- Department of Human Anatomy and Psychobiology and IMIB-Arrixaca Institute, University of Murcia, Murcia, Spain
| | - Tomas Vega-Zuniga
- Lehrstuhl für Zoologie, Technical University of Munich, Freising, Germany.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | | | - Harald Luksch
- Lehrstuhl für Zoologie, Technical University of Munich, Freising, Germany
| | - Jorge Mpodozis
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Luis Puelles
- Department of Human Anatomy and Psychobiology and IMIB-Arrixaca Institute, University of Murcia, Murcia, Spain
| | - Gonzalo J Marín
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
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6
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Basso MA, Bickford ME, Cang J. Unraveling circuits of visual perception and cognition through the superior colliculus. Neuron 2021; 109:918-937. [PMID: 33548173 PMCID: PMC7979487 DOI: 10.1016/j.neuron.2021.01.013] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/29/2020] [Accepted: 01/13/2021] [Indexed: 12/11/2022]
Abstract
The superior colliculus is a conserved sensorimotor structure that integrates visual and other sensory information to drive reflexive behaviors. Although the evidence for this is strong and compelling, a number of experiments reveal a role for the superior colliculus in behaviors usually associated with the cerebral cortex, such as attention and decision-making. Indeed, in addition to collicular outputs targeting brainstem regions controlling movements, the superior colliculus also has ascending projections linking it to forebrain structures including the basal ganglia and amygdala, highlighting the fact that the superior colliculus, with its vast inputs and outputs, can influence processing throughout the neuraxis. Today, modern molecular and genetic methods combined with sophisticated behavioral assessments have the potential to make significant breakthroughs in our understanding of the evolution and conservation of neuronal cell types and circuits in the superior colliculus that give rise to simple and complex behaviors.
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Affiliation(s)
- Michele A Basso
- Fuster Laboratory of Cognitive Neuroscience, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
| | | | - Jianhua Cang
- University of Virginia, Charlottesville, VA, USA
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7
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Wang XQ, Wang WB, Tang YZ, Dai ZD. Subdivisions of the mesencephalon and isthmus in the lizard Gekko gecko as revealed by ChAT immunohistochemistry. Anat Rec (Hoboken) 2021; 304:2014-2031. [PMID: 33554451 DOI: 10.1002/ar.24595] [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] [Received: 06/25/2020] [Revised: 12/07/2020] [Accepted: 01/05/2021] [Indexed: 11/05/2022]
Abstract
The distribution of cholinergic cell bodies and fibers was examined in the mesencephalon and isthmus of Gekko gecko. Distinct groups with prominent labeled cells were observed in the cranial nerve motor nuclei and isthmic nuclei, and weak labeled cell bodies and fibers were observed in the mesencephalic nucleus of the trigeminal nerve and the central nucleus of the torus semicircularis. After discussing the topological relationships within the tectum and isthmus, we unify the nomenclature of the caudal deep mesencephalic nucleus in lizards and the rostral magnocellular nucleus isthmi in turtles that is similar in terms of the preisthmic position, nontopographic connections with the tectum, and the same midbrain origin to the magnocellular preisthmic nucleus in birds, and may be homologous to the superficial cuneiform nucleus in mammals. None of them belong to the cholinergic nucleus isthmi, as the latter has isthmus origin and topographic reciprocal connections with the tectum. We also discuss the origin and intrinsic function of the inner longitudinal tract of the thick ChAT-ir fibers that course through the mesencephalon and diencephalon. We review the subdivisions of the mesencephalon and isthmus of Gekko gecko as revealed by ChAT immunohistochemistry, as well as the limits of the diencephalo-mesencephalic, mesencephalic-isthmo, and isthmo-rhombocephalic by the ChAT-ir cell- and fiber-poor distribution, and discuss the caudal limit of the isthmus. Our research on the subdivisions of the mesencephalon and isthmus in G. gecko as revealed by ChAT immunohistochemistry will serve as the neuroanatomical basis for subsequent relevant studies of Gekko gecko.
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Affiliation(s)
- Xiao-Qing Wang
- Institute of Bio-Inspired Structure and Surface Engineering, Jiangsu Provincial Key Laboratory of Bionic Functional Materials, College of Astronautics, Nanjing University of Aeronautics & Astronautics, Nanjing, China
| | - Wen-Bo Wang
- Institute of Bio-Inspired Structure and Surface Engineering, Jiangsu Provincial Key Laboratory of Bionic Functional Materials, College of Astronautics, Nanjing University of Aeronautics & Astronautics, Nanjing, China
| | - Ye-Zhong Tang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Zhen-Dong Dai
- Institute of Bio-Inspired Structure and Surface Engineering, Jiangsu Provincial Key Laboratory of Bionic Functional Materials, College of Astronautics, Nanjing University of Aeronautics & Astronautics, Nanjing, China
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8
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Deichler A, Carrasco D, Lopez-Jury L, Vega-Zuniga T, Márquez N, Mpodozis J, Marín GJ. A specialized reciprocal connectivity suggests a link between the mechanisms by which the superior colliculus and parabigeminal nucleus produce defensive behaviors in rodents. Sci Rep 2020; 10:16220. [PMID: 33004866 PMCID: PMC7530999 DOI: 10.1038/s41598-020-72848-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 08/06/2020] [Indexed: 12/22/2022] Open
Abstract
The parabigeminal nucleus (PBG) is the mammalian homologue to the isthmic complex of other vertebrates. Optogenetic stimulation of the PBG induces freezing and escape in mice, a result thought to be caused by a PBG projection to the central nucleus of the amygdala. However, the isthmic complex, including the PBG, has been classically considered satellite nuclei of the Superior Colliculus (SC), which upon stimulation of its medial part also triggers fear and avoidance reactions. As the PBG-SC connectivity is not well characterized, we investigated whether the topology of the PBG projection to the SC could be related to the behavioral consequences of PBG stimulation. To that end, we performed immunohistochemistry, in situ hybridization and neural tracer injections in the SC and PBG in a diurnal rodent, the Octodon degus. We found that all PBG neurons expressed both glutamatergic and cholinergic markers and were distributed in clearly defined anterior (aPBG) and posterior (pPBG) subdivisions. The pPBG is connected reciprocally and topographically to the ipsilateral SC, whereas the aPBG receives afferent axons from the ipsilateral SC and projected exclusively to the contralateral SC. This contralateral projection forms a dense field of terminals that is restricted to the medial SC, in correspondence with the SC representation of the aerial binocular field which, we also found, in O. degus prompted escape reactions upon looming stimulation. Therefore, this specialized topography allows binocular interactions in the SC region controlling responses to aerial predators, suggesting a link between the mechanisms by which the SC and PBG produce defensive behaviors.
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Affiliation(s)
- Alfonso Deichler
- Laboratorio de Neurobiología Y Biología del Conocer, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras, 3425, Santiago, Chile.
| | - Denisse Carrasco
- Laboratorio de Neurobiología Y Biología del Conocer, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras, 3425, Santiago, Chile
| | - Luciana Lopez-Jury
- Laboratorio de Neurobiología Y Biología del Conocer, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras, 3425, Santiago, Chile
| | - Tomas Vega-Zuniga
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Natalia Márquez
- Laboratorio de Neurobiología Y Biología del Conocer, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras, 3425, Santiago, Chile
| | - Jorge Mpodozis
- Laboratorio de Neurobiología Y Biología del Conocer, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras, 3425, Santiago, Chile
| | - Gonzalo J Marín
- Laboratorio de Neurobiología Y Biología del Conocer, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras, 3425, Santiago, Chile.
- Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile.
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9
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Entrainment within neuronal response in optic tectum of pigeon to video displays. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:845-855. [PMID: 32809044 DOI: 10.1007/s00359-020-01442-6] [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] [Received: 03/04/2020] [Revised: 07/28/2020] [Accepted: 08/03/2020] [Indexed: 12/19/2022]
Abstract
The cathode ray tube (CRT) is a common and important tool that has been in use for decades, with which behavioral and visual neuroscientists deliver specific visual images generated by computers. Considering the operating principle of the CRT, the image it presents can flick at a constant rate, which will introduce distractions to the visual experiments on subjects with higher temporal resolutions. While this entrainment has been proved common in recordings of the primary visual cortex of mammals, it is uncertain whether it also exists in the intermediate to deep layers of pigeon's optic tectum, which is relevant to the spatial attention. Here, we present continuous visual stimuli with different refresh rates and luminances couples shown on a CRT to pigeons. The recordings in the intermediate to deep layers of optic tectum were significantly phase locking to the refresh of the CRT, and lower refresh rates of the CRT with higher brightness more likely introduced artifacts in electrophysiological recordings of pigeons, which may seriously damage their visual information perception.
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10
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Fernández M, Morales C, Durán E, Fernández‐Colleman S, Sentis E, Mpodozis J, Karten HJ, Marín GJ. Parallel organization of the avian sensorimotor arcopallium: Tectofugal visual pathway in the pigeon (
Columba livia
). J Comp Neurol 2019; 528:597-623. [DOI: 10.1002/cne.24775] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Máximo Fernández
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
| | - Cristian Morales
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
| | - Ernesto Durán
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
| | | | - Elisa Sentis
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
| | - Jorge Mpodozis
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
| | - Harvey J. Karten
- Department of Neurosciences, School of MedicineUniversity of California San Diego California
| | - Gonzalo J. Marín
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
- Facultad de MedicinaUniversidad Finis Terrae Santiago Chile
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11
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Masterson SP, Zhou N, Akers BK, Dang W, Bickford ME. Ultrastructural and optogenetic dissection of V1 corticotectal terminal synaptic properties. J Comp Neurol 2018; 527:833-842. [PMID: 30255935 DOI: 10.1002/cne.24538] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/27/2018] [Accepted: 09/06/2018] [Indexed: 11/08/2022]
Abstract
The superior colliculus (SC) is a major site of sensorimotor integration in which sensory inputs are processed to initiate appropriate motor responses. Projections from the primary visual cortex (V1) to the SC have been shown to exert a substantial influence on visually induced behavior, including "freezing." However, it is unclear how V1 corticotectal terminals affect SC circuits to mediate these effects. To investigate this, we used anatomical and optogenetic techniques to examine the synaptic properties of V1 corticotectal terminals. Electron microscopy revealed that V1 corticotectal terminals labeled by anterograde transport primarily synapse (93%) on dendrites that do not contain gamma aminobutyric acid (GABA). This preference was confirmed using optogenetic techniques to photoactivate V1 corticotectal terminals in slices of the SC maintained in vitro. In a mouse line in which GABAergic SC interneurons express green fluorescent protein (GFP), few GFP-labeled cells (11%) responded to activation of corticotectal terminals. In contrast, 67% of non-GABAergic cells responded to activation of V1 corticotectal terminals. Biocytin-labeling of recorded neurons revealed that wide-field vertical (WFV) and non-WFV cells were activated by V1 corticotectal inputs. However, WFV cells were activated in the most uniform manner; 85% of these cells responded with excitatory postsynaptic potentials (EPSPs) that maintained stable amplitudes when activated with light trains at 1-20 Hz. In contrast, in the majority of non-WFV cells, the amplitude of evoked EPSPs varied across trials. Our results suggest that V1 corticotectal projections may initiate freezing behavior via uniform activation of the WFV cells, which project to the pulvinar nucleus.
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Affiliation(s)
- S P Masterson
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky
| | - N Zhou
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky
| | - B K Akers
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky
| | - W Dang
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky
| | - M E Bickford
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky
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12
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Deichler A, Carrasco D, Gonzalez-Cabrera C, Letelier JC, Marín G, Mpodozis J. The nucleus pretectalis principalis: A pretectal structure hidden in the mammalian thalamus. J Comp Neurol 2018; 527:372-391. [DOI: 10.1002/cne.24540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 08/29/2018] [Accepted: 09/12/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Alfonso Deichler
- Departamento de Biología, Facultad de Ciencias; Universidad de Chile; Ñuñoa Chile
| | - Denisse Carrasco
- Departamento de Biología, Facultad de Ciencias; Universidad de Chile; Ñuñoa Chile
| | - Cristian Gonzalez-Cabrera
- Departamento de Anatomía, Escuela de Medicina; Pontificia Universidad Católica de Chile; Santiago Chile
| | - Juan C. Letelier
- Departamento de Biología, Facultad de Ciencias; Universidad de Chile; Ñuñoa Chile
| | - Gonzalo Marín
- Departamento de Biología, Facultad de Ciencias; Universidad de Chile; Ñuñoa Chile
- Facultad de Medicina; Universidad Finis Terrae; Santiago Chile
| | - Jorge Mpodozis
- Departamento de Biología, Facultad de Ciencias; Universidad de Chile; Ñuñoa Chile
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"Shepherd's crook" neurons drive and synchronize the enhancing and suppressive mechanisms of the midbrain stimulus selection network. Proc Natl Acad Sci U S A 2018; 115:E7615-E7623. [PMID: 30026198 DOI: 10.1073/pnas.1804517115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The optic tectum (TeO), or superior colliculus, is a multisensory midbrain center that organizes spatially orienting responses to relevant stimuli. To define the stimulus with the highest priority at each moment, a network of reciprocal connections between the TeO and the isthmi promotes competition between concurrent tectal inputs. In the avian midbrain, the neurons mediating enhancement and suppression of tectal inputs are located in separate isthmic nuclei, facilitating the analysis of the neural processes that mediate competition. A specific subset of radial neurons in the intermediate tectal layers relay retinal inputs to the isthmi, but at present it is unclear whether separate neurons innervate individual nuclei or a single neural type sends a common input to several of them. In this study, we used in vitro neural tracing and cell-filling experiments in chickens to show that single neurons innervate, via axon collaterals, the three nuclei that comprise the isthmotectal network. This demonstrates that the input signals representing the strength of the incoming stimuli are simultaneously relayed to the mechanisms promoting both enhancement and suppression of the input signals. By performing in vivo recordings in anesthetized chicks, we also show that this common input generates synchrony between both antagonistic mechanisms, demonstrating that activity enhancement and suppression are closely coordinated. From a computational point of view, these results suggest that these tectal neurons constitute integrative nodes that combine inputs from different sources to drive in parallel several concurrent neural processes, each performing complementary functions within the network through different firing patterns and connectivity.
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Stacho M, Letzner S, Theiss C, Manns M, Güntürkün O. A GABAergic tecto-tegmento-tectal pathway in pigeons. J Comp Neurol 2016; 524:2886-913. [DOI: 10.1002/cne.23999] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 03/10/2016] [Accepted: 03/10/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Martin Stacho
- Department of Biopsychology, Faculty of Psychology, Institute of Cogntive Neuroscience; Ruhr-University Bochum; 44801 Bochum Germany
| | - Sara Letzner
- Department of Biopsychology, Faculty of Psychology, Institute of Cogntive Neuroscience; Ruhr-University Bochum; 44801 Bochum Germany
| | - Carsten Theiss
- Department of Cytology, Faculty of Medicine; Ruhr-University Bochum; 44801 Bochum Germany
| | - Martina Manns
- Department of Biopsychology, Faculty of Psychology, Institute of Cogntive Neuroscience; Ruhr-University Bochum; 44801 Bochum Germany
| | - Onur Güntürkün
- Department of Biopsychology, Faculty of Psychology, Institute of Cogntive Neuroscience; Ruhr-University Bochum; 44801 Bochum Germany
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