1
|
Gaede AH, Wu PH, Leitch DB. Variations in touch representation in the hummingbird and zebra finch forebrain. Curr Biol 2024; 34:2739-2747.e3. [PMID: 38815578 DOI: 10.1016/j.cub.2024.04.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 03/25/2024] [Accepted: 04/30/2024] [Indexed: 06/01/2024]
Abstract
Somatosensation is essential for animals to perceive the external world through touch, allowing them to detect physical contact, temperature, pain, and body position. Studies on rodent vibrissae have highlighted the organization and processing in mammalian somatosensory pathways.1,2 Comparative research across vertebrates is vital for understanding evolutionary influences and ecological specialization on somatosensory systems. Birds, with their diverse morphologies, sensory abilities, and behaviors, serve as ideal models for investigating the evolution of somatosensation. Prior studies have uncovered tactile-responsive areas within the avian telencephalon, particularly in pigeons,3,4,5,6 parrots,7 and finches,8 but variations in somatosensory maps and responses across avian species are not fully understood. This study aims to explore somatotopic organization and neural coding in the telencephalon of Anna's hummingbirds (Calypte anna) and zebra finches (Taeniopygia guttata) by using in vivo extracellular electrophysiology to record activity in response to controlled tactile stimuli on various body regions. These findings reveal unique representations of body regions across distinct forebrain somatosensory nuclei, indicating significant differences in the extent of areas dedicated to certain body surfaces, which may correlate with their behavioral importance.
Collapse
Affiliation(s)
- Andrea H Gaede
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, 4 Royal College Street, London NW1 0TU, UK.
| | - Pei-Hsuan Wu
- Department of Zoology, University of British Columbia, #3051 - 6270 University Blvd. Vancouver, BC V6T 1Z4, Canada
| | - Duncan B Leitch
- Department of Zoology, University of British Columbia, #3051 - 6270 University Blvd. Vancouver, BC V6T 1Z4, Canada; Department of Integrative Biology & Physiology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095, USA.
| |
Collapse
|
2
|
Gaede AH, Gutiérrez-Ibáñez C, Wu PH, Pilon MC, Altshuler DL, Wylie DR. Topography of visual and somatosensory inputs to the pontine nuclei in zebra finches (Taeniopygia guttata). J Comp Neurol 2024; 532:e25556. [PMID: 37938923 DOI: 10.1002/cne.25556] [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: 05/09/2023] [Revised: 07/25/2023] [Accepted: 10/17/2023] [Indexed: 11/10/2023]
Abstract
Birds have a comprehensive network of sensorimotor projections extending from the forebrain and midbrain to the cerebellum via the pontine nuclei, but the organization of these circuits in the pons is not thoroughly described. Inputs to the pontine nuclei include two retinorecipient areas, nucleus lentiformis mesencephali (LM) and nucleus of the basal optic root (nBOR), which are important structures for analyzing optic flow. Other crucial regions for visuomotor control include the retinorecipient ventral lateral geniculate nucleus (GLv), and optic tectum (TeO). These visual areas, together with the somatosensory area of the anterior (rostral) Wulst, which is homologous to the primary somatosensory cortex in mammals, project to the medial and lateral pontine nuclei (PM, PL). In this study, we used injections of fluorescent tracers to study the organization of these visual and somatosensory inputs to the pontine nuclei in zebra finches. We found a topographic organization of inputs to PM and PL. The PM has a lateral subdivision that predominantly receives projections from the ipsilateral anterior Wulst. The medial PM receives bands of inputs from the ipsilateral GLv and the nucleus laminaris precommisulis, located medial to LM. We also found that the lateral PL receives a strong ipsilateral projection from TeO, while the medial PL and region between the PM and PL receive less prominent projections from nBOR, bilaterally. We discuss these results in the context of the organization of pontine inputs to the cerebellum and possible functional implications of diverse somato-motor and visuomotor inputs and parcellation in the pontine nuclei.
Collapse
Affiliation(s)
- Andrea H Gaede
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | | | - Pei-Hsuan Wu
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Madison C Pilon
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Douglas R Wylie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
3
|
Baliga VB, Dakin R, Wylie DR, Altshuler DL. Hummingbirds use distinct control strategies for forward and hovering flight. Proc Biol Sci 2024; 291:20232155. [PMID: 38196357 PMCID: PMC10777153 DOI: 10.1098/rspb.2023.2155] [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: 09/20/2023] [Accepted: 12/08/2023] [Indexed: 01/11/2024] Open
Abstract
The detection of optic flow is important for generating optomotor responses to mediate retinal image stabilization, and it can also be used during ongoing locomotion for centring and velocity control. Previous work in hummingbirds has separately examined the roles of optic flow during hovering and when centring through a narrow passage during forward flight. To develop a hypothesis for the visual control of forward flight velocity, we examined the behaviour of hummingbirds in a flight tunnel where optic flow could be systematically manipulated. In all treatments, the animals exhibited periods of forward flight interspersed with bouts of spontaneous hovering. Hummingbirds flew fastest when they had a reliable signal of optic flow. All optic flow manipulations caused slower flight, suggesting that hummingbirds had an expected optic flow magnitude that was disrupted. In addition, upward and downward optic flow drove optomotor responses for maintaining altitude during forward flight. When hummingbirds made voluntary transitions to hovering, optomotor responses were observed to all directions. Collectively, these results are consistent with hummingbirds controlling flight speed via mechanisms that use an internal forward model to predict expected optic flow whereas flight altitude and hovering position are controlled more directly by sensory feedback from the environment.
Collapse
Affiliation(s)
- Vikram B. Baliga
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Roslyn Dakin
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
- Department of Biology, Carleton University, Ottawa, Ontario, Canada K1S 5B6
| | - Douglas R. Wylie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2R3
| | - Douglas L. Altshuler
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| |
Collapse
|
4
|
Gutiérrez-Ibáñez C, Wylie DR, Altshuler DL. From the eye to the wing: neural circuits for transforming optic flow into motor output in avian flight. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023; 209:839-854. [PMID: 37542566 DOI: 10.1007/s00359-023-01663-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/07/2023]
Abstract
Avian flight is guided by optic flow-the movement across the retina of images of surfaces and edges in the environment due to self-motion. In all vertebrates, there is a short pathway for optic flow information to reach pre-motor areas: retinal-recipient regions in the midbrain encode optic flow, which is then sent to the cerebellum. One well-known role for optic flow pathways to the cerebellum is the control of stabilizing eye movements (the optokinetic response). However, the role of this pathway in controlling locomotion is less well understood. Electrophysiological and tract tracing studies are revealing the functional connectivity of a more elaborate circuit through the avian cerebellum, which integrates optic flow with other sensory signals. Here we review the research supporting this framework and identify the cerebellar output centres, the lateral (CbL) and medial (CbM) cerebellar nuclei, as two key nodes with potentially distinct roles in flight control. The CbM receives bilateral optic flow information and projects to sites in the brainstem that suggest a primary role for flight control over time, such as during forward flight. The CbL receives monocular optic flow and other types of visual information. This site provides feedback to sensory areas throughout the brain and has a strong projection the nucleus ruber, which is known to have a dominant role in forelimb muscle control. This arrangement suggests primary roles for the CbL in the control of wing morphing and for rapid maneuvers.
Collapse
Affiliation(s)
| | - Douglas R Wylie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada.
| | - Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
| |
Collapse
|
5
|
Wylie DR, Gaede AH, Gutiérrez-Ibáñez C, Wu PH, Pilon MC, Azargoon S, Altshuler DL. Topography of optic flow processing in olivo-cerebellar pathways in zebra finches (Taeniopygia guttata). J Comp Neurol 2023; 531:640-662. [PMID: 36648211 DOI: 10.1002/cne.25454] [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: 09/16/2022] [Revised: 12/08/2022] [Accepted: 12/20/2022] [Indexed: 01/18/2023]
Abstract
In birds, the nucleus of the basal optic root (nBOR) and the nucleus lentiformis mesencephali (LM) are brainstem nuclei involved in the analysis of optic flow. A major projection site of both nBOR and LM is the medial column of the inferior olive (IO), which provides climbing fibers to the vestibulocerebellum. This pathway has been well documented in pigeons, but not other birds. Recent works have highlighted that zebra finches show specializations with respect to optic flow processing, which may be reflected in the organization of optic flow pathways to the IO. In this study, we characterized the organization of these pathways in zebra finches. We found that the medial column consists of at least eight subnuclei (i-viii) visible in Nissl-stained tissue. Using anterograde traces we found that the projections from LM and nBOR to the IO were bilateral, but heavier to the ipsilateral side, and showed a complementary pattern: LM projected to subnucleus i, whereas nBOR projected to subnuclei ii and v. Using retrograde tracers, we found that these subnuclei (i, ii and v) projected to the vestibulocerebellum (folia IXcd and X), whereas the other subnuclei projected to IXab and the lateral margin of VII and VIII. The nBOR also projected ipsilaterally to the caudo-medial dorsal lamella of the IO, which the retrograde experiments showed as projecting to the medial margin of VII and VIII. We compare these results with previous studies in other avian species.
Collapse
Affiliation(s)
- Douglas R Wylie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Andrea H Gaede
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK.,Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Pei-Hsuan Wu
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Madison C Pilon
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Sarina Azargoon
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
6
|
Development of the horizontal optocollic reflex in juvenile barn owls (Tyto furcata pratincola). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:479-492. [PMID: 35695937 PMCID: PMC9250920 DOI: 10.1007/s00359-022-01555-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/19/2022] [Indexed: 10/25/2022]
Abstract
Adult barn owls and primates possess an almost symmetric monocular rotational horizontal optocollic reflex. In primates, the reflex is initially asymmetric and becomes symmetric with time after birth. The condition in barn owls has not been studied so far. Here, we present data on the development of this reflex in this bird. We tested juvenile barn owls from the time before they open their eyes after hatching to the time they reach adult feather length. Wide-field visual patterns served as stimuli. They were presented at different rotational speeds in binocular and monocular settings. The binocular horizontal optocollic responses of juvenile barn owls were symmetric and adult-like on the first day that the birds responded to the stimulus. The monocular responses showed different rates of development in respect to stimulus velocity and stimulus direction. For velocities up to 20 deg/s, the monocular reflex was also adult-like on the first day that the birds responded to the stimulus. An initially higher asymmetry for 30 deg/s compared to adults disappeared within about two weeks. The development at even higher velocities remained unclear.
Collapse
|
7
|
Smyth G, Baliga VB, Gaede AH, Wylie DR, Altshuler DL. Specializations in optic flow encoding in the pretectum of hummingbirds and zebra finches. Curr Biol 2022; 32:2772-2779.e4. [DOI: 10.1016/j.cub.2022.04.076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 03/28/2022] [Accepted: 04/26/2022] [Indexed: 10/18/2022]
|
8
|
Gaede AH, Baliga VB, Smyth G, Gutiérrez-Ibáñez C, Altshuler DL, Wylie DR. Response properties of optic flow neurons in the accessory optic system of hummingbirds versus zebra finches and pigeons. J Neurophysiol 2022; 127:130-144. [PMID: 34851761 DOI: 10.1152/jn.00437.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Optokinetic responses function to maintain retinal image stabilization by minimizing optic flow that occurs during self-motion. The hovering ability of hummingbirds is an extreme example of this behavior. Optokinetic responses are mediated by direction-selective neurons with large receptive fields in the accessory optic system (AOS) and pretectum. Recent studies in hummingbirds showed that, compared with other bird species, 1) the pretectal nucleus lentiformis mesencephali (LM) is hypertrophied, 2) LM has a unique distribution of direction preferences, and 3) LM neurons are more tightly tuned to stimulus velocity. In this study, we sought to determine if there are concomitant changes in the nucleus of the basal optic root (nBOR) of the AOS. We recorded the visual response properties of nBOR neurons to large-field-drifting random dot patterns and sine-wave gratings in Anna's hummingbirds and zebra finches and compared these with archival data from pigeons. We found no differences with respect to the distribution of direction preferences: Neurons responsive to upward, downward, and nasal-to-temporal motion were equally represented in all three species, and neurons responsive to temporal-to-nasal motion were rare or absent (<5%). Compared with zebra finches and pigeons, however, hummingbird nBOR neurons were more tightly tuned to stimulus velocity of random dot stimuli. Moreover, in response to drifting gratings, hummingbird nBOR neurons are more tightly tuned in the spatiotemporal domain. These results, in combination with specialization in LM, support a hypothesis that hummingbirds have evolved to be "optic flow specialists" to cope with the optomotor demands of sustained hovering flight.NEW & NOTEWORTHY Hummingbirds have specialized response properties to optic flow in the pretectal nucleus lentiformis mesencephali (LM). The LM works with the nucleus of the basal optic root (nBOR) of the accessory optic system (AOS) to process global visual motion, but whether the neural response specializations observed in the LM extend to the nBOR is unknown. Hummingbird nBOR neurons are more tightly tuned to visual stimulus velocity, and in the spatiotemporal domain, compared with two nonhovering species.
Collapse
Affiliation(s)
- Andrea H Gaede
- Structure and Motion Laboratory, Royal Veterinary College, University of London, Hertfordshire, United Kingdom.,Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Vikram B Baliga
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Graham Smyth
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Douglas R Wylie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
9
|
Wagner H, Pappe I, Nalbach HO. Optocollic responses in adult barn owls (Tyto furcata). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:239-251. [PMID: 34812911 PMCID: PMC8934767 DOI: 10.1007/s00359-021-01524-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 12/05/2022]
Abstract
Barn owls, like primates, have frontally oriented eyes, which allow for a large binocular overlap. While owls have similar binocular vision and visual-search strategies as primates, it is less clear whether reflexive visual behavior also resembles that of primates or is more similar to that of closer related, but lateral-eyed bird species. Test cases are visual responses driven by wide-field movement: the optokinetic, optocollic, and optomotor responses, mediated by eye, head and body movements, respectively. Adult primates have a so-called symmetric horizontal response: they show the same following behavior, if the stimulus, presented to one eye only, moves in the nasal-to-temporal direction or in the temporal-to-nasal direction. By contrast, lateral-eyed birds have an asymmetric response, responding better to temporal-to-nasal movement than to nasal-to-temporal movement. We show here that the horizontal optocollic response of adult barn owls is less asymmetric than that in the chicken for all velocities tested. Moreover, the response is symmetric for low velocities (< 20 deg/s), and similar to that of primates. The response becomes moderately asymmetric for middle-range velocities (20–40 deg/s). A definitive statement for the complex situation for higher velocities (> 40 deg/s) is not possible.
Collapse
Affiliation(s)
- Hermann Wagner
- Max-Planck-Institut für Biologische Kybernetik, Max-Planck-Ring 11, 72076, Tübingen, Germany.
- Institut für Biologie II, RWTH Aachen, Worringerweg 3, 52074, Aachen, Germany.
| | - Ina Pappe
- Max-Planck-Institut für Biologische Kybernetik, Max-Planck-Ring 11, 72076, Tübingen, Germany
- Universitätsklinik für Anaesthesiologie, Waldhörnlestrasse 22, 72072, Tübingen, Germany
| | - Hans-Ortwin Nalbach
- Max-Planck-Institut für Biologische Kybernetik, Max-Planck-Ring 11, 72076, Tübingen, Germany
| |
Collapse
|
10
|
Iwaniuk AN, Wylie DR. Sensory systems in birds: What we have learned from studying sensory specialists. J Comp Neurol 2020; 528:2902-2918. [PMID: 32133638 DOI: 10.1002/cne.24896] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/09/2020] [Accepted: 02/17/2020] [Indexed: 12/27/2022]
Abstract
"Diversity" is an apt descriptor of the research career of Jack Pettigrew as it ranged from the study of trees, to clinical conditions, to sensory neuroscience. Within sensory neuroscience, he was fascinated by the evolution of sensory systems across species. Here, we review some of his work on avian sensory specialists and research that he inspired in others. We begin with an overview of the importance of the Wulst in stereopsis and the need for further study of the Wulst in relation to binocularity across avian species. Next, we summarize recent anatomical, behavioral, and physiological studies on optic flow specializations in hummingbirds. Beyond vision, we discuss the first evidence of a tactile "fovea" in birds and how this led to detailed studies of tactile specializations in waterfowl and sensorimotor systems in parrots. We then describe preliminary studies by Pettigrew of two endemic Australian species, the plains-wanderer (Pedionomus torquatus) and letter-winged kite (Elanus scriptus), that suggest the evolution of some unique auditory and visual specializations in relation to their unique behavior and ecology. Finally, we conclude by emphasizing the importance of a comparative and integrative approach to understanding avian sensory systems and provide an example of one system that has yet to be properly examined: tactile facial bristles in birds. Through reviewing this research and offering future avenues for discovery, we hope that others also embrace the comparative approach to understanding sensory system evolution in birds and other vertebrates.
Collapse
Affiliation(s)
- Andrew N Iwaniuk
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Douglas R Wylie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
11
|
Isakhani H, Aouf N, Kechagias-Stamatis O, Whidborne JF. A Furcated Visual Collision Avoidance System for an Autonomous Microrobot. IEEE Trans Cogn Dev Syst 2020. [DOI: 10.1109/tcds.2018.2858742] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
12
|
|
13
|
Clark CJ, Rankin D. Subtle, pervasive genetic correlation between the sexes in the evolution of dimorphic hummingbird tail ornaments*. Evolution 2019; 74:528-543. [DOI: 10.1111/evo.13881] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 10/22/2019] [Indexed: 01/16/2023]
Affiliation(s)
- Christopher J. Clark
- Department of Evolution, Ecology, and Organismal Biology University of California, Riverside Riverside CA 92521
| | - David Rankin
- Department of Evolution, Ecology, and Organismal Biology University of California, Riverside Riverside CA 92521
| |
Collapse
|
14
|
Gaede AH, Gutierrez-Ibanez C, Armstrong MS, Altshuler DL, Wylie DR. Pretectal projections to the oculomotor cerebellum in hummingbirds (Calypte anna), zebra finches (Taeniopygia guttata), and pigeons (Columba livia). J Comp Neurol 2019; 527:2644-2658. [PMID: 30950058 DOI: 10.1002/cne.24697] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 04/01/2019] [Accepted: 04/02/2019] [Indexed: 12/20/2022]
Abstract
In birds, optic flow is processed by a retinal-recipient nucleus in the pretectum, the nucleus lentiformis mesencephali (LM), which then projects to the cerebellum, a key site for sensorimotor integration. Previous studies have shown that the LM is hypertrophied in hummingbirds, and that LM cell response properties differ between hummingbirds and other birds. Given these differences in anatomy and physiology, we ask here if there are also species differences in the connectivity of the LM. The LM is separated into lateral and medial subdivisions, which project to the oculomotor cerebellum and the vestibulocerebellum. In pigeons, the projection to the vestibulocerebellum largely arises from the lateral LM; the projection to the oculomotor cerebellum largely arises from the medial LM. Here, using retrograde tracing, we demonstrate differences in the distribution of projections in these pathways between Anna's hummingbirds (Calypte anna), zebra finches (Taeniopygia guttata), and pigeons (Columba livia). In all three species, the projections to the vestibulocerebellum were largely from lateral LM. In contrast, projections to the oculomotor cerebellum in hummingbirds and zebra finches do not originate in the medial LM (as in pigeons) but instead largely arise from pretectal structures just medial, the nucleus laminaris precommissuralis and nucleus principalis precommissuralis. These species differences in projection patterns provide further evidence that optic flow circuits differ among bird species with distinct modes of flight.
Collapse
Affiliation(s)
- Andrea H Gaede
- Neuroscience and Mental Health Institute and Department of Psychology, University of Alberta, Edmonton, Alberta, Canada.,Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Cristian Gutierrez-Ibanez
- Neuroscience and Mental Health Institute and Department of Psychology, University of Alberta, Edmonton, Alberta, Canada
| | - Melissa S Armstrong
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Douglas R Wylie
- Neuroscience and Mental Health Institute and Department of Psychology, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
15
|
Ou J, Rosa S, Berchowitz LE, Li W. Induced pluripotent stem cells as a tool for comparative physiology: lessons from the thirteen-lined ground squirrel. J Exp Biol 2019; 222:jeb196493. [PMID: 31585999 PMCID: PMC6806009 DOI: 10.1242/jeb.196493] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Comparative physiologists are often interested in adaptive physiological phenomena found in unconventional model organisms; however, research on these species is frequently constrained by the limited availability of investigative tools. Here, we propose that induced pluripotent stem cells (iPSCs) from unconventional model organisms may retain certain species-specific features that can consequently be investigated in depth in vitro; we use hibernating mammals as an example. Many species (including ground squirrels, bats and bears) can enter a prolonged state of physiological dormancy known as hibernation to survive unfavorable seasonal conditions. Our understanding of the mechanisms underpinning the rapid transition and adaptation to a hypothermic, metabolically suppressed winter torpor state remains limited partially because of the lack of an easily accessible model. To address the fascinating unanswered questions underlying hibernation biology, we have developed a powerful model system: iPSCs from a hibernating species, the thirteen-lined ground squirrel (Ictidomys tridecemlineatus). These stem cells can potentially be differentiated into any cell type, and can be used for the analysis of cell-autonomous mechanisms that facilitate adaptation to hibernation and for comparisons with non-hibernators. Furthermore, we can manipulate candidate molecular and cellular pathways underlying relevant physiological phenomena by pharmacological or RNAi-based methods, and CRISPR/Cas9 gene editing. Moreover, iPSC strategies can be applied to other species (e.g. seals, naked mole rats, humming birds) for in vitro studies on adaptation to extreme physiological conditions. In this Commentary, we discuss factors to consider when attempting to generate iPSCs from unconventional model organisms, based on our experience with the thirteen-lined ground squirrel.
Collapse
Affiliation(s)
- Jingxing Ou
- Retinal Neurophysiology Section, National Eye Institute, US National Institutes of Health, Bethesda, MD 20892, USA
| | - Sarah Rosa
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA
- Taub Institute for Research on Alzheimer's and the Aging Brain, New York, NY 10032, USA
| | - Luke E Berchowitz
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA
- Taub Institute for Research on Alzheimer's and the Aging Brain, New York, NY 10032, USA
| | - Wei Li
- Retinal Neurophysiology Section, National Eye Institute, US National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
16
|
Benson RBJ, Starmer-Jones E, Close RA, Walsh SA. Comparative analysis of vestibular ecomorphology in birds. J Anat 2018; 231:990-1018. [PMID: 29156494 DOI: 10.1111/joa.12726] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/18/2017] [Indexed: 02/06/2023] Open
Abstract
The bony labyrinth of vertebrates houses the semicircular canals. These sense rotational accelerations of the head and play an essential role in gaze stabilisation during locomotion. The sizes and shapes of the semicircular canals have hypothesised relationships to agility and locomotory modes in many groups, including birds, and a burgeoning palaeontological literature seeks to make ecological interpretations from the morphology of the labyrinth in extinct species. Rigorous tests of form-function relationships for the vestibular system are required to support these interpretations. We test the hypothesis that the lengths, streamlines and angles between the semicircular canals are related to body size, wing kinematics and flying style in birds. To do this, we applied geometric morphometrics and multivariate phylogenetic comparative methods to a dataset of 64 three-dimensional reconstructions of the endosseous labyrinth obtained using micro-computed tomography scanning of bird crania. A strong relationship between centroid size of the semicircular canals and body size indicates that larger birds have longer semicircular canals compared with their evolutionary relatives. Wing kinematics related to manoeuvrability (and quantified using the brachial index) explain a small additional portion of the variance in labyrinth size. We also find strong evidence for allometric shape change in the semicircular canals of birds, indicating that major aspects of the shape of the avian labyrinth are determined by spatial constraints. The avian braincase accommodates a large brain, a large eye and large semicircular canals compared with other tetrapods. Negative allometry of these structures means that the restriction of space within the braincase is intense in small birds. This may explain our observation that the angles between planes of the semicircular canals of birds deviate more strongly from orthogonality than those of mammals, and especially from agile, gliding and flying mammals. Furthermore, we find little support for relationships between labyrinth shape and flying style or wing kinematics. Overall, our results suggest that the topological problem of fitting long semicircular canals into a spatially constrained braincase is more important in determining the shape of the avian labyrinth than the specifics of locomotory style or agility. Our results tentatively indicate a link between visual acuity and proportional size of the labyrinth among birds. This suggests that the large labyrinths of birds compared with other tetrapods may result from their generally high visual acuities, and not directly from their ability to fly. The endosseous labyrinths of extinct birds and their close dinosaurian relatives may allow broad inferences about flight or vision, but so far provide few specific insights into detailed aspects of locomotion.
Collapse
Affiliation(s)
| | | | - Roger A Close
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Stig A Walsh
- Department of Natural Sciences, National Museums Scotland, Edinburgh, UK.,School of GeoSciences, The King's Buildings, Edinburgh, UK
| |
Collapse
|
17
|
Wylie DR, Gutiérrez-Ibáñez C, Gaede AH, Altshuler DL, Iwaniuk AN. Visual-Cerebellar Pathways and Their Roles in the Control of Avian Flight. Front Neurosci 2018; 12:223. [PMID: 29686605 PMCID: PMC5900027 DOI: 10.3389/fnins.2018.00223] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 03/21/2018] [Indexed: 11/20/2022] Open
Abstract
In this paper, we review the connections and physiology of visual pathways to the cerebellum in birds and consider their role in flight. We emphasize that there are two visual pathways to the cerebellum. One is to the vestibulocerebellum (folia IXcd and X) that originates from two retinal-recipient nuclei that process optic flow: the nucleus of the basal optic root (nBOR) and the pretectal nucleus lentiformis mesencephali (LM). The second is to the oculomotor cerebellum (folia VI-VIII), which receives optic flow information, mainly from LM, but also local visual motion information from the optic tectum, and other visual information from the ventral lateral geniculate nucleus (Glv). The tectum, LM and Glv are all intimately connected with the pontine nuclei, which also project to the oculomotor cerebellum. We believe this rich integration of visual information in the cerebellum is important for analyzing motion parallax that occurs during flight. Finally, we extend upon a suggestion by Ibbotson (2017) that the hypertrophy that is observed in LM in hummingbirds might be due to an increase in the processing demands associated with the pathway to the oculomotor cerebellum as they fly through a cluttered environment while feeding.
Collapse
Affiliation(s)
- Douglas R Wylie
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | | | - Andrea H Gaede
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.,Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Andrew N Iwaniuk
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| |
Collapse
|
18
|
Altshuler DL, Srinivasan MV. Comparison of Visually Guided Flight in Insects and Birds. Front Neurosci 2018; 12:157. [PMID: 29615852 PMCID: PMC5864886 DOI: 10.3389/fnins.2018.00157] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 02/27/2018] [Indexed: 11/14/2022] Open
Abstract
Over the last half century, work with flies, bees, and moths have revealed a number of visual guidance strategies for controlling different aspects of flight. Some algorithms, such as the use of pattern velocity in forward flight, are employed by all insects studied so far, and are used to control multiple flight tasks such as regulation of speed, measurement of distance, and positioning through narrow passages. Although much attention has been devoted to long-range navigation and homing in birds, until recently, very little was known about how birds control flight in a moment-to-moment fashion. A bird that flies rapidly through dense foliage to land on a branch—as birds often do—engages in a veritable three-dimensional slalom, in which it has to continually dodge branches and leaves, and find, and possibly even plan a collision-free path to the goal in real time. Each mode of flight from take-off to goal could potentially involve a different visual guidance algorithm. Here, we briefly review strategies for visual guidance of flight in insects, synthesize recent work from short-range visual guidance in birds, and offer a general comparison between the two groups of organisms.
Collapse
Affiliation(s)
- Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Mandyam V Srinivasan
- Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia.,School of Information Technology and Electrical Engineering, University of Queensland, St Lucia, QLD, Australia
| |
Collapse
|
19
|
Moore BA, Maggs DJ, Kim S, Motta MJ, Bandivadekar R, Tell LA, Murphy CJ. Clinical findings and normative ocular data for free-living Anna's (Calypte anna
) and Black-chinned (Archilochus alexandri
) Hummingbirds. Vet Ophthalmol 2018; 22:13-23. [DOI: 10.1111/vop.12560] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bret A. Moore
- William R. Pritchard Veterinary Medical Teaching Hospital; School of Veterinary Medicine; University of California-Davis; Davis CA USA
| | - David J. Maggs
- Department of Surgical and Radiological Sciences; School of Veterinary Medicine; University of California-Davis; Davis CA USA
| | - Soohyun Kim
- Department of Surgical and Radiological Sciences; School of Veterinary Medicine; University of California-Davis; Davis CA USA
| | - Monica J. Motta
- Department of Surgical and Radiological Sciences; School of Veterinary Medicine; University of California-Davis; Davis CA USA
| | - Ruta Bandivadekar
- Department of Medicine and Epidemiology; School of Veterinary Medicine; University of California-Davis; Davis CA USA
| | - Lisa A. Tell
- Department of Medicine and Epidemiology; School of Veterinary Medicine; University of California-Davis; Davis CA USA
| | - Christopher J. Murphy
- Department of Surgical and Radiological Sciences; School of Veterinary Medicine; University of California-Davis; Davis CA USA
- Department of Ophthalmology & Vision Science; School of Medicine; University of California-Davis; Davis CA USA
| |
Collapse
|
20
|
Gutierrez-Ibanez C, Gaede AH, Dannish MR, Altshuler DL, Wylie DR. The retinal projection to the nucleus lentiformis mesencephali in zebra finch (Taeniopygia guttata) and Anna's hummingbird (Calypte anna). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:369-376. [PMID: 29340763 DOI: 10.1007/s00359-018-1245-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/27/2017] [Accepted: 01/03/2018] [Indexed: 11/25/2022]
Abstract
In birds, the nucleus of the basal optic root (nBOR) and the nucleus lentiformis mesencephali (LM) are retinal recipient nuclei involved in the analysis of optic flow and the generation of the optokinetic response. In both pigeons and chickens, retinal inputs to the nBOR arise from displaced ganglion cells (DGCs), which are found at the margin of the inner nuclear and inner plexiform layers. The LM receives afferents from retinal ganglion cells, but whether DGCs also project to LM is a matter of debate. Previous work in chickens had concluded that DGCs do not project to LM, but a recent study in pigeons found that both retinal ganglion cells and DGCs project to LM. These findings leave open the question of whether there are species differences with respect to the DGC projection to LM. In the present study, we made small injections of retrograde tracer into the LM in a zebra finch and an Anna's hummingbird. In both cases, retrogradely labeled retinal ganglion cells and DGCs were observed. These results suggest that a retinal input to the LM arising from DGCs is characteristic of most, if not all, birds.
Collapse
Affiliation(s)
| | - Andrea H Gaede
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, T6G 2E9, Canada
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Max R Dannish
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Douglas R Wylie
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| |
Collapse
|
21
|
Goller B, Segre PS, Middleton KM, Dickinson MH, Altshuler DL. Visual Sensory Signals Dominate Tactile Cues during Docked Feeding in Hummingbirds. Front Neurosci 2017; 11:622. [PMID: 29184479 PMCID: PMC5694540 DOI: 10.3389/fnins.2017.00622] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/25/2017] [Indexed: 11/13/2022] Open
Abstract
Animals living in and interacting with natural environments must monitor and respond to changing conditions and unpredictable situations. Using information from multiple sensory systems allows them to modify their behavior in response to their dynamic environment but also creates the challenge of integrating different, and potentially contradictory, sources of information for behavior control. Understanding how multiple information streams are integrated to produce flexible and reliable behavior is key to understanding how behavior is controlled in natural settings. Natural settings are rarely still, which challenges animals that require precise body position control, like hummingbirds, which hover while feeding from flowers. Tactile feedback, available only once the hummingbird is docked at the flower, could provide additional information to help maintain its position at the flower. To investigate the role of tactile information for hovering control during feeding, we first asked whether hummingbirds physically interact with a feeder once docked. We quantified physical interactions between docked hummingbirds and a feeder placed in front of a stationary background pattern. Force sensors on the feeder measured a complex time course of loading that reflects the wingbeat frequency and bill movement of feeding hummingbirds, and suggests that they sometimes push against the feeder with their bill. Next, we asked whether the measured tactile interactions were used by feeding hummingbirds to maintain position relative to the feeder. We created two experimental scenarios-one in which the feeder was stationary and the visual background moved and the other where the feeder moved laterally in front of a white background. When the visual background pattern moved, docked hummingbirds pushed significantly harder in the direction of horizontal visual motion. When the feeder moved, and the background was stationary, hummingbirds generated aerodynamic force in the opposite direction of the feeder motion. These results suggest that docked hummingbirds are using visual information about the environment to maintain body position and orientation, and not actively tracking the motion of the feeder. The absence of flower tracking behavior in hummingbirds contrasts with the behavior of hawkmoths, and provides evidence that they rely primarily on the visual background rather than flower-based cues while feeding.
Collapse
Affiliation(s)
- Benjamin Goller
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Paolo S. Segre
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Kevin M. Middleton
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, United States
| | - Michael H. Dickinson
- Bioengineering and Biology, California Institute of Technology, Pasadena, CA, United States
| | | |
Collapse
|
22
|
Ibbotson M. Visual Neuroscience: Unique Neural System for Flight Stabilization in Hummingbirds. Curr Biol 2017; 27:R58-R61. [DOI: 10.1016/j.cub.2016.11.052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|