1
|
Beetz MJ. A perspective on neuroethology: what the past teaches us about the future of neuroethology. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2024; 210:325-346. [PMID: 38411712 PMCID: PMC10995053 DOI: 10.1007/s00359-024-01695-5] [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: 12/13/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 02/28/2024]
Abstract
For 100 years, the Journal of Comparative Physiology-A has significantly supported research in the field of neuroethology. The celebration of the journal's centennial is a great time point to appreciate the recent progress in neuroethology and to discuss possible avenues of the field. Animal behavior is the main source of inspiration for neuroethologists. This is illustrated by the huge diversity of investigated behaviors and species. To explain behavior at a mechanistic level, neuroethologists combine neuroscientific approaches with sophisticated behavioral analysis. The rapid technological progress in neuroscience makes neuroethology a highly dynamic and exciting field of research. To summarize the recent scientific progress in neuroethology, I went through all abstracts of the last six International Congresses for Neuroethology (ICNs 2010-2022) and categorized them based on the sensory modalities, experimental model species, and research topics. This highlights the diversity of neuroethology and gives us a perspective on the field's scientific future. At the end, I highlight three research topics that may, among others, influence the future of neuroethology. I hope that sharing my roots may inspire other scientists to follow neuroethological approaches.
Collapse
Affiliation(s)
- M Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, 97074, Würzburg, Germany.
| |
Collapse
|
2
|
Are frog calls relatively difficult to locate by mammalian predators? J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023; 209:11-30. [PMID: 36508005 DOI: 10.1007/s00359-022-01594-7] [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: 10/26/2022] [Accepted: 11/08/2022] [Indexed: 12/14/2022]
Abstract
Frogs call in acoustically dense choruses to attract conspecific females. Their calls can potentially reveal their location to predators, many of which are mammals. However, frogs and mammals have very different acoustic receivers and mechanisms for determining sound source direction. We argue that frog calls may have been selected so that they are harder to locate with the direction-finding mechanisms of mammals. We focus on interaural time delay (ITD) estimation using delay-line coincidence detection (place code), and a binaural excitatory/inhibitory (E/I) ITD mechanism found in mammals with small heads (population code). We identify four "strategies" which frogs may employ to exploit the weaknesses of either mechanism. The first two strategies used by the frog confound delay estimation to increase direction ambiguity using highly periodic calls or narrowband calls. The third strategy relies on using short pulses. The E/I mechanism is susceptible to noise with sounds being pulled to the medial plane when signal-to-noise ratio is low. Together, these three strategies compromise both ongoing and onset determination of location using either mechanism. Finally, frogs call in dense choruses using various means for controlling synchrony, maintaining chorus tenure, and abruptly switching off calling, all of which serve to confound location finding. Of these strategies, only chorusing adversely impacts the localization performance of frogs' acoustic receivers. We illustrate these strategies with an analysis of calls from three different frog species.
Collapse
|
3
|
Crawford MA, Schmidt WF, Broadhurst CL, Wang Y. Lipids in the origin of intracellular detail and speciation in the Cambrian epoch and the significance of the last double bond of docosahexaenoic acid in cell signaling. Prostaglandins Leukot Essent Fatty Acids 2021; 166:102230. [PMID: 33588307 DOI: 10.1016/j.plefa.2020.102230] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/06/2020] [Accepted: 12/15/2020] [Indexed: 11/24/2022]
Abstract
One of the great unanswered biological questions is the absolute necessity of the polyunsaturated lipid docosahexaenoic acid (DHA; 22:6n-3) in retinal and neural tissues. Everything from the simple eye spot of dinoflagellates to cephalopods to every class of vertebrates uses DHA, yet it is abundant only in cold water marine food chains. Docosapentaenoic acids (DPAs; 22:5n-6 and especially 22:5n-3) are fairly plentiful in food chains yet cannot substitute for DHA. About 600 million years ago, multi-cellular, air breathing systems evolved rapidly and 32 phyla came into existence in a short geological time span; the "Cambrian Explosion". Eukaryotic intracellular detail requires cell membranes, which are constructed of complex lipids, and proteins. Proteins and nucleic acids would have been abundant during the first 2.5-5 billion years of anaerobic life but lipids, especially unsaturated fatty acids, would not. We hypothesize lipid biology was a key driver of the Cambrian Explosion, because it alone provides for compartmentalization and specialization within cells DHA has six methylene interrupted double bonds providing controlled electron flow at precise energy levels; this is essential for visual acuity and truthful execution of the neural pathways which make up our recollections, information processing and consciousness. The last double bond is critical for the evolution and function of the photoreceptor and neuronal and synaptic signaling systems. It completes a quantum mechanical device for the regulation of current flow with absolute signal precision based on electron tunneling (ET). DHA's methylene interruption distance is < 6 Å, making ET transfer between the π-orbitals feasible throughout the molecule. The possibility fails if one double bond is removed and replaced by a saturated bond as in the DPAs. The molecular biophysical foundation of neural signaling can also include the discrete pattern of paired spin states that arise in the DHA double bond and methylene regions. The complexity depends upon the number of C13 and H1 molecular sites in which spin states are coupled. Electron wave harmonics with entanglement and cohesion provide a mechanism for learning and memory, and power cognition and complex human brain functions.
Collapse
Affiliation(s)
- Michael A Crawford
- The Department of Metabolism and Institute of Brain Cemistry and Human Nutrition, Digestion and Reproduction. Chelsea and Westminster Hospital Campus, Imperial College, London SW10 9NH, United Kingdom.
| | - Walter F Schmidt
- United States Department of Agriculture Agricultural Research Service, Beltsville, MD, USA
| | - C Leigh Broadhurst
- United States Department of Agriculture Agricultural Research Service, Beltsville, MD, USA
| | - Yiqun Wang
- The Department of Metabolism and Institute of Brain Cemistry and Human Nutrition, Digestion and Reproduction. Chelsea and Westminster Hospital Campus, Imperial College, London SW10 9NH, United Kingdom
| |
Collapse
|
4
|
Shifman AR, Sun Y, Benoit CM, Lewis JE. Dynamics of a neuronal pacemaker in the weakly electric fish Apteronotus. Sci Rep 2020; 10:16707. [PMID: 33028878 PMCID: PMC7542169 DOI: 10.1038/s41598-020-73566-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/14/2020] [Indexed: 12/04/2022] Open
Abstract
The precise timing of neuronal activity is critical for normal brain function. In weakly electric fish, the medullary pacemaker network (PN) sets the timing for an oscillating electric organ discharge (EOD) used for electric sensing. This network is the most precise biological oscillator known, with sub-microsecond variation in oscillator period. The PN consists of two principle sets of neurons, pacemaker and relay cells, that are connected by gap junctions and normally fire in synchrony, one-to-one with each EOD cycle. However, the degree of gap junctional connectivity between these cells appears insufficient to provide the population averaging required for the observed temporal precision of the EOD. This has led to the hypothesis that individual cells themselves fire with high precision, but little is known about the oscillatory dynamics of these pacemaker cells. As a first step towards testing this hypothesis, we have developed a biophysical model of a pacemaker neuron action potential based on experimental recordings. We validated the model by comparing the changes in oscillatory dynamics produced by different experimental manipulations. Our results suggest that this relatively simple model can capture a large range of channel dynamics exhibited by pacemaker cells, and will thus provide a basis for future work on network synchrony and precision.
Collapse
Affiliation(s)
- Aaron R Shifman
- Department of Biology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada. .,Center for Neural Dynamics, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada. .,uOttawa Brain and Mind Research Institute, Ottawa, Ontario, K1H 8M5, Canada.
| | - Yiren Sun
- Department of Biology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.,Center for Neural Dynamics, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.,uOttawa Brain and Mind Research Institute, Ottawa, Ontario, K1H 8M5, Canada
| | - Chloé M Benoit
- Department of Biology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.,Center for Neural Dynamics, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.,uOttawa Brain and Mind Research Institute, Ottawa, Ontario, K1H 8M5, Canada
| | - John E Lewis
- Department of Biology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.,Center for Neural Dynamics, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.,uOttawa Brain and Mind Research Institute, Ottawa, Ontario, K1H 8M5, Canada
| |
Collapse
|
5
|
Effect of Stimulus-Dependent Spike Timing on Population Coding of Sound Location in the Owl's Auditory Midbrain. eNeuro 2020; 7:ENEURO.0244-19.2020. [PMID: 32188709 PMCID: PMC7189487 DOI: 10.1523/eneuro.0244-19.2020] [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: 06/24/2019] [Revised: 02/07/2020] [Accepted: 02/18/2020] [Indexed: 11/21/2022] Open
Abstract
In the auditory system, the spectrotemporal structure of acoustic signals determines the temporal pattern of spikes. Here, we investigated this effect in neurons of the barn owl's auditory midbrain (Tyto furcata) that are selective for auditory space and whether it can influence the coding of sound direction. We found that in the nucleus where neurons first become selective to combinations of sound localization cues, reproducibility of spike trains across repeated trials of identical sounds, a metric of across-trial temporal fidelity of spiking patterns evoked by a stimulus, was maximal at the sound direction that elicited the highest firing rate. We then tested the hypothesis that this stimulus-dependent patterning resulted in rate co-modulation of cells with similar frequency and spatial selectivity, driving stimulus-dependent synchrony of population responses. Tetrodes were used to simultaneously record multiple nearby units in the optic tectum (OT), where auditory space is topographically represented. While spiking of neurons in OT showed lower reproducibility across trials compared with upstream nuclei, spike-time synchrony between nearby OT neurons was highest for sounds at their preferred direction. A model of the midbrain circuit explained the relationship between stimulus-dependent reproducibility and synchrony, and demonstrated that this effect can improve the decoding of sound location from the OT output. Thus, stimulus-dependent spiking patterns in the auditory midbrain can have an effect on spatial coding. This study reports a functional connection between spike patterning elicited by spectrotemporal features of a sound and the coding of its location.
Collapse
|
6
|
Sanculi D, Pannoni KE, Bushong EA, Crump M, Sung M, Popat V, Zaher C, Hicks E, Song A, Mofakham N, Li P, Antzoulatos EG, Fioravante D, Ellisman MH, DeBello WM. Toric Spines at a Site of Learning. eNeuro 2020; 7:ENEURO.0197-19.2019. [PMID: 31822521 PMCID: PMC6944481 DOI: 10.1523/eneuro.0197-19.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 10/23/2019] [Accepted: 11/02/2019] [Indexed: 11/21/2022] Open
Abstract
We discovered a new type of dendritic spine. It is found on space-specific neurons in the barn owl inferior colliculus, a site of experience-dependent plasticity. Connectomic analysis revealed dendritic protrusions of unusual morphology including topological holes, hence termed "toric" spines (n = 76). More significantly, presynaptic terminals converging onto individual toric spines displayed numerous active zones (up to 49) derived from multiple axons (up to 11) with incoming trajectories distributed widely throughout 3D space. This arrangement is suited to integrate input sources. Dense reconstruction of two toric spines revealed that they were unconnected with the majority (∼84%) of intertwined axons, implying a high capacity for information storage. We developed an ex vivo slice preparation and provide the first published data on space-specific neuron intrinsic properties, including cellular subtypes with and without toric-like spines. We propose that toric spines are a cellular locus of sensory integration and behavioral learning.
Collapse
Affiliation(s)
- Daniel Sanculi
- Center for Neuroscience, University of California, Davis, CA 95618
| | | | - Eric A Bushong
- National Center for Molecular Imaging Research, University of California, La Jolla, CA 92093
| | - Michael Crump
- Center for Neuroscience, University of California, Davis, CA 95618
| | - Michelle Sung
- Center for Neuroscience, University of California, Davis, CA 95618
| | - Vyoma Popat
- Center for Neuroscience, University of California, Davis, CA 95618
| | - Camilia Zaher
- Center for Neuroscience, University of California, Davis, CA 95618
| | - Emma Hicks
- Center for Neuroscience, University of California, Davis, CA 95618
| | - Ashley Song
- Center for Neuroscience, University of California, Davis, CA 95618
| | - Nikan Mofakham
- Center for Neuroscience, University of California, Davis, CA 95618
| | - Peining Li
- Center for Neuroscience, University of California, Davis, CA 95618
| | | | | | - Mark H Ellisman
- National Center for Molecular Imaging Research, University of California, La Jolla, CA 92093
| | | |
Collapse
|
7
|
Malinowski ST, Wolf J, Kuenzel T. Intrinsic and Synaptic Dynamics Contribute to Adaptation in the Core of the Avian Central Nucleus of the Inferior Colliculus. Front Neural Circuits 2019; 13:46. [PMID: 31379514 PMCID: PMC6646678 DOI: 10.3389/fncir.2019.00046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 07/01/2019] [Indexed: 11/13/2022] Open
Abstract
The reduction of neuronal responses to repeated stimulus presentation occurs in many sensory neurons, also in the inferior colliculus of birds. The cellular mechanisms that cause response adaptation are not well described. Adaptation must be explicable by changes in the activity of input neurons, short-term synaptic plasticity of the incoming connections, excitability changes of the neuron under consideration or influences of inhibitory or modulatory network connections. Using whole-cell recordings in acute brain slices of the embryonic chicken brain we wanted to understand the intrinsic and synaptic contributions to adaptation in the core of the central nucleus of the inferior colliculus (ICCc). We described two neuron types in the chicken ICCc based on their action potential firing patterns: Phasic/onset neurons showed strong intrinsic adaptation but recovered more rapidly. Tonic/sustained firing neurons had weaker adaptation but often had additional slow components of recovery from adaptation. Morphological analysis suggested two neuron classes, but no physiological parameter aligned with this classification. Chicken ICCc neurons received mostly mixed AMPA- and NMDA-type glutamatergic synaptic inputs. In the majority of ICCc neurons the input synapses underwent short-term depression. With a simulation of the putative population output activity of the chicken ICCc we showed that the different adaptation profiles of the neuron classes could shift the emphasize of stimulus encoding from transients at long intervals to ongoing parts at short intervals. Thus, we report here that description of biophysical and synaptic properties can help to explain adaptive phenomena in central auditory neurons.
Collapse
Affiliation(s)
- Sebastian T Malinowski
- Auditory Neurophysiology Group, Department of Chemosensation, RWTH Aachen University, Aachen, Germany.,Department of Chemosensation, RWTH Aachen University, Aachen, Germany
| | - Jana Wolf
- Auditory Neurophysiology Group, Department of Chemosensation, RWTH Aachen University, Aachen, Germany
| | - Thomas Kuenzel
- Auditory Neurophysiology Group, Department of Chemosensation, RWTH Aachen University, Aachen, Germany
| |
Collapse
|
8
|
Carrillo RR, Naveros F, Ros E, Luque NR. A Metric for Evaluating Neural Input Representation in Supervised Learning Networks. Front Neurosci 2019; 12:913. [PMID: 30618549 PMCID: PMC6302114 DOI: 10.3389/fnins.2018.00913] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 11/20/2018] [Indexed: 11/13/2022] Open
Abstract
Supervised learning has long been attributed to several feed-forward neural circuits within the brain, with particular attention being paid to the cerebellar granular layer. The focus of this study is to evaluate the input activity representation of these feed-forward neural networks. The activity of cerebellar granule cells is conveyed by parallel fibers and translated into Purkinje cell activity, which constitutes the sole output of the cerebellar cortex. The learning process at this parallel-fiber-to-Purkinje-cell connection makes each Purkinje cell sensitive to a set of specific cerebellar states, which are roughly determined by the granule-cell activity during a certain time window. A Purkinje cell becomes sensitive to each neural input state and, consequently, the network operates as a function able to generate a desired output for each provided input by means of supervised learning. However, not all sets of Purkinje cell responses can be assigned to any set of input states due to the network's own limitations (inherent to the network neurobiological substrate), that is, not all input-output mapping can be learned. A key limiting factor is the representation of the input states through granule-cell activity. The quality of this representation (e.g., in terms of heterogeneity) will determine the capacity of the network to learn a varied set of outputs. Assessing the quality of this representation is interesting when developing and studying models of these networks to identify those neuron or network characteristics that enhance this representation. In this study we present an algorithm for evaluating quantitatively the level of compatibility/interference amongst a set of given cerebellar states according to their representation (granule-cell activation patterns) without the need for actually conducting simulations and network training. The algorithm input consists of a real-number matrix that codifies the activity level of every considered granule-cell in each state. The capability of this representation to generate a varied set of outputs is evaluated geometrically, thus resulting in a real number that assesses the goodness of the representation.
Collapse
Affiliation(s)
- Richard R Carrillo
- Department of Computer Architecture and Technology, University of Granada, Granada, Spain.,Centro de Investigación en Tecnologías de la Información y de las Comunicaciones (CITIC-UGR), University of Granada, Granada, Spain
| | - Francisco Naveros
- Department of Computer Architecture and Technology, University of Granada, Granada, Spain.,Centro de Investigación en Tecnologías de la Información y de las Comunicaciones (CITIC-UGR), University of Granada, Granada, Spain
| | - Eduardo Ros
- Department of Computer Architecture and Technology, University of Granada, Granada, Spain.,Centro de Investigación en Tecnologías de la Información y de las Comunicaciones (CITIC-UGR), University of Granada, Granada, Spain
| | - Niceto R Luque
- Department of Computer Architecture and Technology, University of Granada, Granada, Spain.,Centro de Investigación en Tecnologías de la Información y de las Comunicaciones (CITIC-UGR), University of Granada, Granada, Spain.,Aging in Vision and Action, Institut de la Vision, Inserm-UPMC-CNRS, Paris, France
| |
Collapse
|
9
|
Aralla R, Ashida G, Köppl C. Binaural responses in the auditory midbrain of chicken (Gallus gallus). Eur J Neurosci 2018; 51:1290-1304. [PMID: 29582488 DOI: 10.1111/ejn.13891] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 02/20/2018] [Accepted: 02/26/2018] [Indexed: 11/29/2022]
Abstract
The auditory midbrain is the location in which neurons represent binaural acoustic information necessary for sound localization. The external nucleus of the midbrain inferior colliculus (IC) of the barn owl is a classic example of an auditory space map, but it is unknown to what extent the principles underlying its formation generalize to other, less specialized animals. We characterized the spiking responses of 139 auditory neurons in the IC of the chicken (Gallus gallus) in vivo, focusing on their sensitivities to the binaural localization cues of interaural time (ITD) and level (ILD) differences. Most units were frequency-selective, with best frequencies distributed unevenly into low-frequency and high-frequency (> 2 kHz) clusters. Many units showed sensitivity to either ITD (65%) or ILD (66%) and nearly half to both (47%). ITD selectivity was disproportionately more common among low-frequency units, while ILD-only selective units were predominantly tuned to high frequencies. ILD sensitivities were diverse, and we thus developed a decision tree defining five types. One rare type with a bell-like ILD tuning was also selective for ITD but typically not frequency-selective, and thus matched the characteristics of neurons in the auditory space map of the barn owl. Our results suggest that generalist birds such as the chicken show a prominent representation of ITD and ILD cues in the IC, providing complementary information for sound localization, according to the duplex theory. A broadband response type narrowly selective for both ITD and ILD may form the basis for a representation of auditory space.
Collapse
Affiliation(s)
- Roberta Aralla
- Department of Neuroscience, School of Medicine and Health Sciences, Research Center for Neurosensory Sciences and Cluster of Excellence 'Hearing4all', Carl von Ossietzky University, Carl von Ossietzky Strasse 9-11, 26129, Oldenburg, Germany
| | - Go Ashida
- Department of Neuroscience, School of Medicine and Health Sciences, Research Center for Neurosensory Sciences and Cluster of Excellence 'Hearing4all', Carl von Ossietzky University, Carl von Ossietzky Strasse 9-11, 26129, Oldenburg, Germany
| | - Christine Köppl
- Department of Neuroscience, School of Medicine and Health Sciences, Research Center for Neurosensory Sciences and Cluster of Excellence 'Hearing4all', Carl von Ossietzky University, Carl von Ossietzky Strasse 9-11, 26129, Oldenburg, Germany
| |
Collapse
|
10
|
Abstract
Most behaviors in mammals are directly or indirectly guided by prior experience and therefore depend on the ability of our brains to form memories. The ability to form an association between an initially possibly neutral sensory stimulus and its behavioral relevance is essential for our ability to navigate in a changing environment. The formation of a memory is a complex process involving many areas of the brain. In this chapter we review classic and recent work that has shed light on the specific contribution of sensory cortical areas to the formation of associative memories. We discuss synaptic and circuit mechanisms that mediate plastic adaptations of functional properties in individual neurons as well as larger neuronal populations forming topographically organized representations. Furthermore, we describe commonly used behavioral paradigms that are used to study the mechanisms of memory formation. We focus on the auditory modality that is receiving increasing attention for the study of associative memory in rodent model systems. We argue that sensory cortical areas may play an important role for the memory-dependent categorical recognition of previously encountered sensory stimuli.
Collapse
Affiliation(s)
- Dominik Aschauer
- Institute of Physiology, Focus Program Translational Neurosciences (FTN), University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Simon Rumpel
- Institute of Physiology, Focus Program Translational Neurosciences (FTN), University Medical Center, Johannes Gutenberg University, Mainz, Germany.
| |
Collapse
|
11
|
Ferger R, Pawlowsky K, Singheiser M, Wagner H. Response adaptation in the barn owl's auditory space map. J Neurophysiol 2017; 119:1235-1247. [PMID: 29357460 DOI: 10.1152/jn.00769.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Response adaptation is the change of the firing rate of neurons induced by a preceding stimulus. It can be found in many sensory systems and throughout the auditory pathway. We investigated response adaptation in the external nucleus of the inferior colliculus (ICX) of barn owls ( Tyto furcata), a nocturnal bird of prey and specialist in sound localization. Individual neurons in the ICX represent locations in auditory space by maximally responding to combinations of interaural time and level differences (ITD and ILD). Neuronal responses were recorded extracellularly under ketamine-diazepam anesthesia. Response adaptation was observed in three double stimulation paradigms. In two paradigms, the same binaural parameters for both stimuli were chosen. A variation of the level of the second stimulus yielded a level increase sufficient to compensate for adaptation around 5 dB. Introducing a silent interstimulus interval (ISI) resulted in recovery from adaptation. The time course of recovery was followed by varying the ISI, and full recovery was found after an ISI of 50 ms. In a third paradigm, the ITD of the second stimulus was varied to investigate the representation of ITD under adaptive conditions. We found that adaptation led to an increased precision and improved selectivity while the best ITD was stable. These changes of representation remained for longer ISIs than were needed to recover from response adaptation at the best ITD. Stimuli with non-best ITDs could also induce similar adaptive effects if the neurons responded to these ITDs. NEW & NOTEWORTHY We demonstrate and characterize response adaptation in neurons of the auditory space map in the barn owl's midbrain with acoustic double-stimulation paradigms. An increase of the second level by 5 dB compensated for the observed adaptive effect. Recovery from adaptation was faster than in upstream nuclei of the auditory pathway. Our results also show that response adaptation might improve precision and selectivity in the representation of interaural time difference.
Collapse
Affiliation(s)
- Roland Ferger
- Institute of Biology II, RWTH Aachen University , Aachen , Germany
| | | | | | - Hermann Wagner
- Institute of Biology II, RWTH Aachen University , Aachen , Germany
| |
Collapse
|
12
|
Tellers P, Lehmann J, Führ H, Wagner H. Envelope contributions to the representation of interaural time difference in the forebrain of barn owls. J Neurophysiol 2017; 118:1871-1887. [PMID: 28679844 DOI: 10.1152/jn.01166.2015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 06/29/2017] [Accepted: 06/29/2017] [Indexed: 11/22/2022] Open
Abstract
Birds and mammals use the interaural time difference (ITD) for azimuthal sound localization. While barn owls can use the ITD of the stimulus carrier frequency over nearly their entire hearing range, mammals have to utilize the ITD of the stimulus envelope to extend the upper frequency limit of ITD-based sound localization. ITD is computed and processed in a dedicated neural circuit that consists of two pathways. In the barn owl, ITD representation is more complex in the forebrain than in the midbrain pathway because of the combination of two inputs that represent different ITDs. We speculated that one of the two inputs includes an envelope contribution. To estimate the envelope contribution, we recorded ITD response functions for correlated and anticorrelated noise stimuli in the barn owl's auditory arcopallium. Our findings indicate that barn owls, like mammals, represent both carrier and envelope ITDs of overlapping frequency ranges, supporting the hypothesis that carrier and envelope ITD-based localization are complementary beyond a mere extension of the upper frequency limit.NEW & NOTEWORTHY The results presented in this study show for the first time that the barn owl is able to extract and represent the interaural time difference (ITD) information conveyed by the envelope of a broadband acoustic signal. Like mammals, the barn owl extracts the ITD of the envelope and the carrier of a signal from the same frequency range. These results are of general interest, since they reinforce a trend found in neural signal processing across different species.
Collapse
Affiliation(s)
- Philipp Tellers
- Institute of Biology II, RWTH Aachen University, Aachen, Germany; and
| | - Jessica Lehmann
- Lehrstuhl A für Mathematik, RWTH Aachen University, Aachen, Germany
| | - Hartmut Führ
- Lehrstuhl A für Mathematik, RWTH Aachen University, Aachen, Germany
| | - Hermann Wagner
- Institute of Biology II, RWTH Aachen University, Aachen, Germany; and
| |
Collapse
|
13
|
Belekhova MG, Kenigfest NB, Chudinova TV, Vesselkin NP. Distribution of calcium-binding proteins, parvalbumin and calbindin, in the midbrain auditory center (MLd) of a pigeon. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2016; 466:1-4. [PMID: 27021359 DOI: 10.1134/s001249661601004x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Indexed: 11/23/2022]
Abstract
Immunohistochemical distribution of calcium-binding proteins, parvalbumin (PV) and calbindin (CB), has been studied in the mesencephalic auditory center (MLd) of pigeon (Columba livia). In the central region of the MLd (core, ICC), an overlap in distribution of the PVand CB-immunopositive (ip) neurons and neuropil has been observed, with different patterns in the central and peripheral parts. In the peripheral region of the MLd (belt, ICS, and ICX), both neurons and neuropil contained only CB. A selective CB chemospecificity of the belt, ICS, and ICX is an evolutionary conserved feature characteristic of all avian species. Interspecies differences in the distribution of PV and CB immunoreactivity in the ICC are a result of adaptive functional specialization, which provides specific processing of different aspects of the auditory information.
Collapse
Affiliation(s)
- M G Belekhova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
| | - N B Kenigfest
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - T V Chudinova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - N P Vesselkin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| |
Collapse
|
14
|
Hunting increases phosphorylation of calcium/calmodulin-dependent protein kinase type II in adult barn owls. Neural Plast 2015; 2015:819257. [PMID: 25789177 PMCID: PMC4348593 DOI: 10.1155/2015/819257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/18/2014] [Indexed: 11/18/2022] Open
Abstract
Juvenile barn owls readily adapt to prismatic spectacles, whereas adult owls living under standard aviary conditions do not. We previously demonstrated that phosphorylation of the cyclic-AMP response element-binding protein (CREB) provides a readout of the instructive signals that guide plasticity in juveniles. Here we investigated phosphorylation of calcium/calmodulin-dependent protein kinase II (pCaMKII) in both juveniles and adults. In contrast to CREB, we found no differences in pCaMKII expression between prism-wearing and control juveniles within the external nucleus of the inferior colliculus (ICX), the major site of plasticity. For prism-wearing adults that hunted live mice and are capable of adaptation, expression of pCaMKII was increased relative to prism-wearing adults that fed passively on dead mice and are not capable of adaptation. This effect did not bear the hallmarks of instructive information: it was not localized to rostral ICX and did not exhibit a patchy distribution reflecting discrete bimodal stimuli. These data are consistent with a role for CaMKII as a permissive rather than an instructive factor. In addition, the paucity of pCaMKII expression in passively fed adults suggests that the permissive default setting is "off" in adults.
Collapse
|
15
|
Cazettes F, Fischer BJ, Pena JL. Spatial cue reliability drives frequency tuning in the barn Owl's midbrain. eLife 2014; 3:e04854. [PMID: 25531067 PMCID: PMC4291741 DOI: 10.7554/elife.04854] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 12/21/2014] [Indexed: 11/13/2022] Open
Abstract
The robust representation of the environment from unreliable sensory cues is vital for the efficient function of the brain. However, how the neural processing captures the most reliable cues is unknown. The interaural time difference (ITD) is the primary cue to localize sound in horizontal space. ITD is encoded in the firing rate of neurons that detect interaural phase difference (IPD). Due to the filtering effect of the head, IPD for a given location varies depending on the environmental context. We found that, in barn owls, at each location there is a frequency range where the head filtering yields the most reliable IPDs across contexts. Remarkably, the frequency tuning of space-specific neurons in the owl's midbrain varies with their preferred sound location, matching the range that carries the most reliable IPD. Thus, frequency tuning in the owl's space-specific neurons reflects a higher-order feature of the code that captures cue reliability.
Collapse
Affiliation(s)
- Fanny Cazettes
- Department of Neuroscience, Albert Einstein College of Medicine, New York, United States
| | - Brian J Fischer
- Department of Mathematics, Seattle University, Seattle, United States
| | - Jose L Pena
- Department of Neuroscience, Albert Einstein College of Medicine, New York, United States
| |
Collapse
|
16
|
Keating P, King AJ. Developmental plasticity of spatial hearing following asymmetric hearing loss: context-dependent cue integration and its clinical implications. Front Syst Neurosci 2013; 7:123. [PMID: 24409125 PMCID: PMC3873525 DOI: 10.3389/fnsys.2013.00123] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Accepted: 12/12/2013] [Indexed: 11/23/2022] Open
Abstract
Under normal hearing conditions, comparisons of the sounds reaching each ear are critical for accurate sound localization. Asymmetric hearing loss should therefore degrade spatial hearing and has become an important experimental tool for probing the plasticity of the auditory system, both during development and adulthood. In clinical populations, hearing loss affecting one ear more than the other is commonly associated with otitis media with effusion, a disorder experienced by approximately 80% of children before the age of two. Asymmetric hearing may also arise in other clinical situations, such as after unilateral cochlear implantation. Here, we consider the role played by spatial cue integration in sound localization under normal acoustical conditions. We then review evidence for adaptive changes in spatial hearing following a developmental hearing loss in one ear, and show that adaptation may be achieved either by learning a new relationship between the altered cues and directions in space or by changing the way different cues are integrated in the brain. We next consider developmental plasticity as a source of vulnerability, describing maladaptive effects of asymmetric hearing loss that persist even when normal hearing is provided. We also examine the extent to which the consequences of asymmetric hearing loss depend upon its timing and duration. Although much of the experimental literature has focused on the effects of a stable unilateral hearing loss, some of the most common hearing impairments experienced by children tend to fluctuate over time. We therefore propose that there is a need to bridge this gap by investigating the effects of recurring hearing loss during development, and outline recent steps in this direction. We conclude by arguing that this work points toward a more nuanced view of developmental plasticity, in which plasticity may be selectively expressed in response to specific sensory contexts, and consider the clinical implications of this.
Collapse
Affiliation(s)
- Peter Keating
- Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
| | - Andrew J. King
- Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
| |
Collapse
|
17
|
Side peak suppression in responses of an across-frequency integration model to stimuli of varying bandwidth as demonstrated analytically and by implementation. J Comput Neurosci 2013; 36:1-17. [PMID: 23715909 DOI: 10.1007/s10827-013-0460-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 04/24/2013] [Accepted: 05/01/2013] [Indexed: 10/26/2022]
Abstract
Multiplication-like sound localization models are subjected to phase ambiguities for high-frequency tonal stimuli as multiplication creates several equivalent response peaks in tuning curves. By increasing the bandwidth of the stimulus, phase ambiguities can be reduced, which is often referred to as side peak suppression. In this study we present a Jeffress-based sound localization model, and determine side peak suppression analytically. The results were verified with an implementation of the same model, and compared to physiological data of barn owls. Three types of stimuli were analyzed: pure-tone stimuli, two-tone complexes with varying frequency distances, and noise signals with variable bandwidths. As an additional parameter we also determined the half-width of the main response peak to examine the scaling of tuning curves in azimuth. Results showed that side peak suppression did not only depend on bandwidth, but also on the center frequency and the distance of the side peak to the main response peak. In particular, the analytical model predicted that side peak suppression is a function of relative bandwidth, whereas half-width is inversely proportional to center frequency, with a proportionality factor depending on relative bandwidth. The analytical approach and the implementation yielded equivalent tuning curves (deviation < 1%). Moreover, the electrophysiological data recorded in barn owls closely matched the predicted tuning curves.
Collapse
|