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Rodriguez-Santiago M, Ruppert A, Gall MD, Hoke K, Bee MA, Baugh AT. In your CORT: Corticosterone and its receptors in the brain underlie mate choosiness in female Cope's gray treefrogs (Hyla chrysoscelis). Horm Behav 2024; 159:105477. [PMID: 38245919 DOI: 10.1016/j.yhbeh.2024.105477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/23/2024]
Abstract
Selecting an attractive mate can involve trade-offs related to investment in sampling effort. Glucocorticoids like corticosterone (CORT) are involved in resolving energetic trade-offs. However, CORT is rarely studied in the context of mate choice, despite its elevated levels during reproductive readiness and the energetic transitions that characterize reproduction. Few systems are as well suited as anuran amphibians to evaluate how females resolve energetic trade-offs during mate choice. Phonotaxis tests provide a robust bioassay of mate choice that permit the precise measurement of inter-individual variation in traits such as choosiness-the willingness to pursue the most attractive mate despite costs. In Cope's gray treefrogs (Hyla chrysoscelis), females exhibit remarkable variation in circulating CORT as well as choosiness during mate choice, and a moderate dose of exogenous CORT rapidly (<1 h) and reliably induce large increases in choosiness. Here we measured the expression of glucocorticoid (GR) and mineralocorticoid (MR) receptors in the brains of females previously treated with exogenous CORT and tested for mate choosiness. We report a large decrease in GR expression in the hindbrain and midbrain of females that were treated with the moderate dosage of CORT-the same treatment group that exhibited a dramatic increase in choosiness following CORT treatment. This association, however, does not appear to be causal, as only forebrain GR levels, which are not affected by CORT injection, are positively associated with variation in choosiness. No strong effects were found for MR. We discuss these findings and suggest future studies to test the influence of glucocorticoids on mate choice.
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Affiliation(s)
| | - Annika Ruppert
- Department of Ecology, Evolution, and Behavior, University of Minnesota - Twin Cities, 1479 Gortner Ave, St. Paul, MN 55108, USA
| | - Megan D Gall
- Department of Biology, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604, USA
| | - Kim Hoke
- Department of Biology, Colorado State University, 200 W Lake St., Fort Collins, CO 80523, USA
| | - Mark A Bee
- Department of Ecology, Evolution, and Behavior, University of Minnesota - Twin Cities, 1479 Gortner Ave, St. Paul, MN 55108, USA; Graduate Program in Neuroscience, University of Minnesota - Twin Cities, 321 Church Street SE, Minneapolis, MN 55455, USA
| | - Alexander T Baugh
- Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA.
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Gerhardt HC, Bee MA, Christensen-Dalsgaard J. Neuroethology of sound localization in anurans. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023; 209:115-129. [PMID: 36201014 DOI: 10.1007/s00359-022-01576-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/23/2022] [Accepted: 09/22/2022] [Indexed: 02/07/2023]
Abstract
Albert Feng pioneered the study of neuroethology of sound localization in anurans by combining behavioral experiments on phonotaxis with detailed investigations of neural processing of sound direction from the periphery to the central nervous system. The main advantage of these studies is that many species of female frogs readily perform phonotaxis towards loudspeakers emitting the species-specific advertisement call. Behavioral studies using synthetic calls can identify which parameters are important for phonotaxis and also quantify localization accuracy. Feng was the first to investigate binaural processing using single-unit recordings in the first two auditory nuclei in the central auditory pathway and later investigated the directional properties of auditory nerve fibers with free-field stimulation. These studies showed not only that the frog ear is inherently directional by virtue of acoustical coupling or crosstalk between the two eardrums, but also confirmed that there are extratympanic pathways that affect directionality in the low-frequency region of the frog's hearing range. Feng's recordings in the midbrain also showed that directional information is enhanced by cross-midline inhibition. An important contribution toward the end of his career involved his participation in neuroethological research with a team of scientists working with frogs that produce ultrasonic calls.
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Affiliation(s)
- H Carl Gerhardt
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA.
| | - Mark A Bee
- Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities, 1479 Gortner Ave, St. Paul, MN, 55108, USA
- Graduate Program in Neuroscience, University of Minnesota-Twin Cities, 321 Church Street SE, Minneapolis, MN, 55455, USA
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3
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Descending projections to the auditory midbrain: evolutionary considerations. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023; 209:131-143. [PMID: 36323876 PMCID: PMC9898193 DOI: 10.1007/s00359-022-01588-5] [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: 05/01/2022] [Revised: 10/12/2022] [Accepted: 10/14/2022] [Indexed: 11/06/2022]
Abstract
The mammalian inferior colliculus (IC) is massively innervated by multiple descending projection systems. In addition to a large projection from the auditory cortex (AC) primarily targeting the non-lemniscal portions of the IC, there are less well-characterized projections from non-auditory regions of the cortex, amygdala, posterior thalamus and the brachium of the IC. By comparison, the frog auditory midbrain, known as the torus semicircularis, is a large auditory integration center that also receives descending input, but primarily from the posterior thalamus and without a projection from a putative cortical homolog: the dorsal pallium. Although descending projections have been implicated in many types of behaviors, a unified understanding of their function has not yet emerged. Here, we take a comparative approach to understanding the various top-down modulators of the IC to gain insights into their functions. One key question that we identify is whether thalamotectal projections in mammals and amphibians are homologous and whether they interact with evolutionarily more newly derived projections from the cerebral cortex. We also consider the behavioral significance of these descending pathways, given anurans' ability to navigate complex acoustic landscapes without the benefit of a corticocollicular projection. Finally, we suggest experimental approaches to answer these questions.
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Auerbach BD, Gritton HJ. Hearing in Complex Environments: Auditory Gain Control, Attention, and Hearing Loss. Front Neurosci 2022; 16:799787. [PMID: 35221899 PMCID: PMC8866963 DOI: 10.3389/fnins.2022.799787] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 01/18/2022] [Indexed: 12/12/2022] Open
Abstract
Listening in noisy or complex sound environments is difficult for individuals with normal hearing and can be a debilitating impairment for those with hearing loss. Extracting meaningful information from a complex acoustic environment requires the ability to accurately encode specific sound features under highly variable listening conditions and segregate distinct sound streams from multiple overlapping sources. The auditory system employs a variety of mechanisms to achieve this auditory scene analysis. First, neurons across levels of the auditory system exhibit compensatory adaptations to their gain and dynamic range in response to prevailing sound stimulus statistics in the environment. These adaptations allow for robust representations of sound features that are to a large degree invariant to the level of background noise. Second, listeners can selectively attend to a desired sound target in an environment with multiple sound sources. This selective auditory attention is another form of sensory gain control, enhancing the representation of an attended sound source while suppressing responses to unattended sounds. This review will examine both “bottom-up” gain alterations in response to changes in environmental sound statistics as well as “top-down” mechanisms that allow for selective extraction of specific sound features in a complex auditory scene. Finally, we will discuss how hearing loss interacts with these gain control mechanisms, and the adaptive and/or maladaptive perceptual consequences of this plasticity.
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Affiliation(s)
- Benjamin D. Auerbach
- Department of Molecular and Integrative Physiology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- *Correspondence: Benjamin D. Auerbach,
| | - Howard J. Gritton
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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Gerhardt HC, Tucker MA, von Twickel A, Walkowiak W. Anuran Vocal Communication: Effects of Genome Size, Cell Number and Cell Size. BRAIN, BEHAVIOR AND EVOLUTION 2021; 96:137-146. [PMID: 34788770 DOI: 10.1159/000520913] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 11/06/2021] [Indexed: 11/19/2022]
Abstract
Significant variation in genome size occurs among anuran amphibians and can affect cell size and number. In the gray treefrog complex in North America increases in cell size in autotriploids of the diploid (Hyla chrysoscelis) altered the temporal structure of mate-attracting vocalizations and auditory selectivity for these properties. Here we show that the tetraploid species (Hyla versicolor) also has significantly fewer brain neurons than H. chrysoscelis. With regard to cell size in tissues involved in vocal communication, spinal motor neurons were larger in tetraploids than in diploids and comparable to differences in erythrocyte size; smaller increases were found in one of the three auditory centers in the torus semicircularis. Future studies should address questions about how environmental conditions during development affect cell numbers and size and the causal relationships between these cellular changes and the vocal communication system.
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Affiliation(s)
- H Carl Gerhardt
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
| | - Mitch A Tucker
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
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Fan Y, Fang K, Sun R, Shen D, Yang J, Tang Y, Fang G. Hierarchical auditory perception for species discrimination and individual recognition in the music frog. Curr Zool 2021; 68:581-591. [DOI: 10.1093/cz/zoab085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 10/01/2021] [Indexed: 11/12/2022] Open
Abstract
Abstract
The ability to discriminate species and recognize individuals is crucial for reproductive success and/or survival in most animals. However, the temporal order and neural localization of these decision-making processes has remained unclear. In this study, event-related potentials (ERPs) were measured in the telencephalon, diencephalon, and mesencephalon of the music frog Nidirana daunchina. These ERPs were elicited by calls from 1 group of heterospecifics (recorded from a sympatric anuran species) and 2 groups of conspecifics that differed in their fundamental frequencies. In terms of the polarity and position within the ERP waveform, auditory ERPs generally consist of 4 main components that link to selective attention (N1), stimulus evaluation (P2), identification (N2), and classification (P3). These occur around 100, 200, 250, and 300 ms after stimulus onset, respectively. Our results show that the N1 amplitudes differed significantly between the heterospecific and conspecific calls, but not between the 2 groups of conspecific calls that differed in fundamental frequency. On the other hand, the N2 amplitudes were significantly different between the 2 groups of conspecific calls, suggesting that the music frogs discriminated the species first, followed by individual identification, since N1 and N2 relate to selective attention and stimuli identification, respectively. Moreover, the P2 amplitudes evoked in females were significantly greater than those in males, indicating the existence of sexual dimorphism in auditory discrimination. In addition, both the N1 amplitudes in the left diencephalon and the P2 amplitudes in the left telencephalon were greater than in other brain areas, suggesting left hemispheric dominance in auditory perception. Taken together, our results support the hypothesis that species discrimination and identification of individual characteristics are accomplished sequentially, and that auditory perception exhibits differences between sexes and in spatial dominance.
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Affiliation(s)
- Yanzhu Fan
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ke Fang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
- School of Life Science, Anhui University, Hefei 230601, China
| | - Ruolei Sun
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
- School of Life Science, Anhui University, Hefei 230601, China
| | - Di Shen
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Yang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yezhong Tang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guangzhan Fang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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Baugh AT, Gall MD, Silver SC, Bee MA. Moderately elevated glucocorticoids increase mate choosiness but do not affect sexual proceptivity or preferences in female gray treefrogs. Horm Behav 2021; 130:104950. [PMID: 33556376 DOI: 10.1016/j.yhbeh.2021.104950] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 01/15/2021] [Accepted: 01/30/2021] [Indexed: 01/20/2023]
Abstract
Glucocorticoids (GCs) are rarely studied in the context of female mate choice, despite the expression of receptors for these products in sexual, sensory and decision-making brain areas. Here we investigated the effects of GC concentrations on three aspects of female sexual behavior in breeding Cope's gray treefrogs (Hyla chrysoscelis): proceptivity-a measure of sexual motivation, intraspecific mate preferences, and mate choosiness. To our knowledge this is the first experimental study on the endocrine basis of mate choosiness. We predicted that mate choosiness-forfeiting an initial mate preference to pursue a suddenly more attractive mate-would be particularly impacted by elevated GCs with moderate GC levels associated with greater choosiness. We found support for this predicted inverted-U relationship. Females in the control group (no injection) showed no change in choosiness across timepoints. In contrast, females in the vehicle, Low (20 ng g-1) and High (180 ng g-1) corticosterone groups exhibited a nominal decline in choosiness after injection, suggesting that the experience of injection has little or perhaps slightly suppressive effects on female choosiness. Females in the moderate dose group (60 ng g-1), however, exhibited a significant increase (>100%) in choosiness. Further, we found no effect of elevated GCs on sexual proceptivity or the species-typical preference for longer calls. These findings may reflect a buffering of primary sensory areas in the brain against elevated GCs. The recruitment of other cognitive processes during active decision-making, however, may facilitate GC modulation of mate choosiness, thereby promoting tactical plasticity at this critical life history juncture.
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Affiliation(s)
- Alexander T Baugh
- Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA.
| | - Megan D Gall
- Department of Biology, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604, USA
| | - Stewart C Silver
- Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA
| | - Mark A Bee
- Department of Ecology, Evolution, and Behavior, University of Minnesota - Twin Cities, 1479 Gortner Ave, St. Paul, MN 55108, USA; Graduate Program in Neuroscience, University of Minnesota - Twin Cities, 321 Church Street SE, Minneapolis, MN 55455, USA
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8
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Boyd SK. Effects of intracerebroventricular arginine vasotocin on a female amphibian proceptive behavior. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:505-513. [DOI: 10.1007/s00359-019-01340-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/29/2019] [Accepted: 05/02/2019] [Indexed: 10/26/2022]
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9
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Fan Y, Yue X, Yang J, Shen J, Shen D, Tang Y, Fang G. Preference of spectral features in auditory processing for advertisement calls in the music frogs. Front Zool 2019; 16:13. [PMID: 31168310 PMCID: PMC6509768 DOI: 10.1186/s12983-019-0314-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 04/22/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Animal vocal signals encode very important information for communication during which the importance of temporal and spectral characteristics of vocalizations is always asymmetrical and species-specific. However, it is still unknown how auditory system represents this asymmetrical and species-specific patterns. In this study, auditory event related potential (ERP) changes were evaluated in the Emei music frog (Babina daunchina) to assess the differences in eliciting neural responses of both temporal and spectral features for the telencephalon, diencephalon and mesencephalon respectively. To do this, an acoustic playback experiment using an oddball paradigm design was conducted, in which an original advertisement call (OC), its spectral feature preserved version (SC) and temporal feature preserved version (TC) were used as deviant stimuli with synthesized white noise as standard stimulus. RESULTS The present results show that 1) compared with TC, more similar ERP components were evoked by OC and SC; and 2) the P3a amplitudes in the forebrain evoked by OC were significantly higher in males than in females. CONCLUSIONS Together, the results provide evidence for suggesting neural processing for conspecific vocalization may prefer to the spectral features in the music frog, prompting speculation that the spectral features may play more important roles in auditory object perception or vocal communication in this species. In addition, the neural processing for auditory perception is sexually dimorphic.
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Affiliation(s)
- Yanzhu Fan
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, People’s Republic of China
| | - Xizi Yue
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
| | - Jing Yang
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, People’s Republic of China
| | - Jiangyan Shen
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, People’s Republic of China
| | - Di Shen
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, People’s Republic of China
| | - Yezhong Tang
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
| | - Guangzhan Fang
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, Chengdu, Sichuan 610041 People’s Republic of China
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10
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Fan Y, Yue X, Xue F, Cui J, Brauth SE, Tang Y, Fang G. Auditory perception exhibits sexual dimorphism and left telencephalic dominance in Xenopus laevis. Biol Open 2018; 7:7/12/bio035956. [PMID: 30509903 PMCID: PMC6310876 DOI: 10.1242/bio.035956] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Sex differences in both vocalization and auditory processing have been commonly found in vocal animals, although the underlying neural mechanisms associated with sexual dimorphism of auditory processing are not well understood. In this study we investigated whether auditory perception exhibits sexual dimorphism in Xenopus laevis. To do this we measured event-related potentials (ERPs) evoked by white noise (WN) and conspecific calls in the telencephalon, diencephalon and mesencephalon respectively. Results showed that (1) the N1 amplitudes evoked in the right telencephalon and right diencephalon of males by WN are significantly different from those evoked in females; (2) in males the N1 amplitudes evoked by conspecific calls are significantly different from those evoked by WN; (3) in females the N1 amplitude for the left mesencephalon was significantly lower than for other brain areas, while the P2 and P3 amplitudes for the right mesencephalon were the smallest; in contrast these amplitudes for the left mesencephalon were the smallest in males. These results suggest auditory perception is sexually dimorphic. Moreover, the amplitude of each ERP component (N1, P2 and P3) for the left telencephalon was the largest in females and/or males, suggesting that left telencephalic dominance exists for auditory perception in Xenopus. Summary: Investigation of auditory neural mechanisms in the South African clawed frog (Xenopus laevis) indicates that auditory perception exhibits sexual dimorphism and left telencephalic advantage.
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Affiliation(s)
- Yanzhu Fan
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin South Road, Chengdu, Sichuan, People's Republic of China.,University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, People's Republic of China
| | - Xizi Yue
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin South Road, Chengdu, Sichuan, People's Republic of China
| | - Fei Xue
- Sichuan Key Laboratory of Conservation Biology for Endangered Wildlife, Chengdu Research Base of Giant Panda Breeding, 26 Panda Road, Northern Suburb, Chengdu, Sichuan 610081, People's Republic of China
| | - Jianguo Cui
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin South Road, Chengdu, Sichuan, People's Republic of China
| | - Steven E Brauth
- Department of Psychology, University of Maryland, College Park, MD20742, USA
| | - Yezhong Tang
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin South Road, Chengdu, Sichuan, People's Republic of China
| | - Guangzhan Fang
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin South Road, Chengdu, Sichuan, People's Republic of China
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11
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Auditory sensitivity exhibits sexual dimorphism and seasonal plasticity in music frogs. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:1029-1044. [DOI: 10.1007/s00359-018-1301-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 09/18/2018] [Accepted: 10/21/2018] [Indexed: 12/26/2022]
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12
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Burmeister SS. Neurobiology of Female Mate Choice in Frogs: Auditory Filtering and Valuation. Integr Comp Biol 2018; 57:857-864. [PMID: 29048536 DOI: 10.1093/icb/icx098] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mate choice is a decision making process with profound implication for the reproductive success of both the sender and the chooser. Preferences for conspecific over heterospecific males and for some conspecifics over others are typically mediated by a female's response to signals produced by males. And although one can experimentally describe a female's preference function, there is relatively little understood about the neural mechanisms mediating these preferences. In anurans, mating preferences have often been explained in terms of sensory biases. Indeed, in the túngara frog (Physalaemus pustulosus), the auditory system appears to act as a filter for conspecific calls. However, auditory responses are not good predictors of intraspecific mating preferences in túngara frogs. Rather, neural activity in the preoptic area, which can be gated by estradiol, is a better predictor of mating preferences. A similar pattern holds in spadefoot toads (Spea bombifrons): the preoptic area, but not the auditory midbrain, integrates physiological cues in its response to mating calls in a pattern that predicts preferences. Neuroanatomically, the anuran preoptic area is poised to mediate forebrain influences on auditory response of the midbrain and it has descending projections to the medulla and spinal cord that could directly influence motor responses. Indeed, lesions of the preoptic area abolish phonotaxis. A role for the preoptic area in mating preferences is supported by studies in mammals that show the preoptic area is required for the expression of preferences. Further, activity of the preoptic area correlates with mating preference in fish. This leads to a model for the neurobiological mechanisms of mate choice, in which sensory systems filter relevant signals from irrelevant ones, but the preoptic area assigns value to the range of relevant signals.
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Affiliation(s)
- Sabrina S Burmeister
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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13
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Baugh AT, Ryan MJ. Vasotocin induces sexually dimorphic effects on acoustically-guided behavior in a tropical frog. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:265-273. [DOI: 10.1007/s00359-017-1155-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/27/2017] [Accepted: 02/17/2017] [Indexed: 12/23/2022]
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14
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Patel MB, Sons S, Yudintsev G, Lesicko AMH, Yang L, Taha GA, Pierce SM, Llano DA. Anatomical characterization of subcortical descending projections to the inferior colliculus in mouse. J Comp Neurol 2017; 525:885-900. [PMID: 27560718 PMCID: PMC5222726 DOI: 10.1002/cne.24106] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 07/29/2016] [Accepted: 08/01/2016] [Indexed: 12/18/2022]
Abstract
Descending projections from the thalamus and related structures to the midbrain are evolutionarily highly conserved. However, the basic organization of this auditory thalamotectal pathway has not yet been characterized. The purpose of this study was to obtain a better understanding of the anatomical and neurochemical features of this pathway. Analysis of the distributions of retrogradely labeled cells after focal injections of retrograde tracer into the inferior colliculus (IC) of the mouse revealed that most of the subcortical descending projections originated in the brachium of the IC and the paralaminar portions of the auditory thalamus. In addition, the vast majority of thalamotectal cells were found to be negative for the calcium-binding proteins calbindin, parvalbumin, or calretinin. Using two different strains of GAD-GFP mice, as well as immunostaining for GABA, we found that a subset of neurons in the brachium of the IC is GABAergic, suggesting that part of this descending pathway is inhibitory. Finally, dual retrograde injections into the IC and amygdala plus corpus striatum as well into the IC and auditory cortex did not reveal any double labeling. These data suggest that the thalamocollicular pathway comprises a unique population of thalamic neurons that do not contain typical calcium-binding proteins and do not project to other paralaminar thalamic forebrain targets, and that a previously undescribed descending GABAergic pathway emanates from the brachium of the IC. J. Comp. Neurol. 525:885-900, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Mili B Patel
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Stacy Sons
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Georgiy Yudintsev
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | | | - Luye Yang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Gehad A Taha
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Scott M Pierce
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Daniel A Llano
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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15
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Baugh AT, Ryan MJ, Bernal XE, Rand AS, Bee MA. Female túngara frogs do not experience the continuity illusion. Behav Neurosci 2015; 130:62-74. [PMID: 26692450 DOI: 10.1037/bne0000115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In humans and some nonhuman vertebrates, a sound containing brief silent gaps can be rendered perceptually continuous by inserting noise into the gaps. This so-called "continuity illusion" arises from a phenomenon known as "auditory induction" and results in the perception of complete auditory objects despite fragmentary or incomplete acoustic information. Previous studies of auditory induction in gray treefrogs (Hyla versicolor and H. chrysoscelis) have demonstrated an absence of this phenomenon. These treefrog species produce pulsatile (noncontinuous) vocalizations, whereas studies of auditory induction in other taxa, including humans, often present continuous sounds (e.g., frequency-modulated sweeps). This study investigated the continuity illusion in a frog (Physalaemus pustulosus) with an advertisement vocalization that is naturally continuous and thus similar to the tonal sweeps used in human psychophysical studies of auditory induction. In a series of playback experiments, female subjects were presented with sets of stimuli that included complete calls, calls with silent gaps, and calls with silent gaps filled with noise. The results failed to provide evidence of auditory induction. Current evidence, therefore, suggests that mammals and birds experience auditory induction, but frogs may not. This emerging pattern of taxonomic differences is considered in light of potential methodological, neurophysiological, and functional explanations.
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Affiliation(s)
| | - Michael J Ryan
- Department of Integrative Biology, The University of Texas at Austin
| | | | | | - Mark A Bee
- Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities
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16
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Fang G, Yang P, Xue F, Cui J, Brauth SE, Tang Y. Sound Classification and Call Discrimination Are Decoded in Order as Revealed by Event-Related Potential Components in Frogs. BRAIN, BEHAVIOR AND EVOLUTION 2015; 86:232-45. [DOI: 10.1159/000441215] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 09/20/2015] [Indexed: 11/19/2022]
Abstract
Species that use communication sounds to coordinate social and reproductive behavior must be able to distinguish vocalizations from nonvocal sounds as well as to identify individual vocalization types. In this study we sought to identify the neural localization of the processes involved and the temporal order in which they occur in an anuran species, the music frog Babina daunchina. To do this we measured telencephalic and mesencephalic event-related potentials (ERPs) elicited by synthesized white noise (WN), highly sexually attractive (HSA) calls produced by males from inside nests and male calls of low sexual attractiveness (LSA) produced outside of nests. Each stimulus possessed similar temporal structures. The results showed the following: (1) the amplitudes of the first negative ERP component (N1) at ∼100 ms differed significantly between WN and conspecific calls but not between HSA and LSA calls, indicating that discrimination between conspecific calls and nonvocal sounds occurs in ∼100 ms, (2) the amplitudes of the second positive ERP component (P2) at ∼200 ms in the difference waves between HSA calls and WN were significantly higher than between LSA calls and WN in the right telencephalon, implying that call characteristic identification occurs in ∼200 ms and (3) WN evoked a larger third positive ERP component (P3) at ∼300 ms than conspecific calls, suggesting the frogs had classified the conspecific calls into one category and perceived WN as novel. Thus, both the detection of sounds and the identification of call characteristics are accomplished quickly in a specific temporal order, as reflected by ERP components. In addition, the most dynamic ERP patterns appeared in the left mesencephalon and the right telencephalon, indicating the two brain regions might play key roles in anuran vocal communication.
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17
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Ward JL, Love EK, Baugh AT, Gordon NM, Tanner JC, Bee MA. Progesterone and prostaglandin F2α induce species-typical female preferences for male sexual displays in Cope's gray treefrog (Hyla chrysoscelis). Physiol Behav 2015; 152:280-7. [PMID: 26454212 DOI: 10.1016/j.physbeh.2015.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 01/28/2023]
Abstract
Endocrine systems play critical roles in facilitating sexual behavior in seasonally breeding vertebrates. Much of the research exploring this topic has focused on the endocrine correlates of signaling behavior in males and sexual proceptivity in females. What is less understood is how hormones promote the expression of the often complex and highly selective set of stimulus-response behaviors that are observed in naturally breeding animals. In female frogs, phonotaxis is a robust and sensitive bioassay of mate choice and is exhibited by gravid females during the breeding season. In stark contrast, females exhibit low phonotactic responsiveness outside the breeding season, but the administration of hormones can induce sexual proceptivity. Here we test the hypothesis that manipulation of a minimal set of reproductive hormones-progesterone and prostaglandin F2α-are capable of evoking not only proceptive behavior in non-breeding females, but also the patterns of intraspecific selectivity for male sexual displays observed in gravid females tested during the breeding season. Specifically, we investigated whether preferences for faster call rates, longer call durations, and higher call efforts were similar between breeding and hormone-treated females of Cope's gray treefrog (Hyla chrysoscelis). Hormone injections induced patterns of selective phonotaxis in non-breeding females that were remarkably similar to those observed in breeding females. These results suggest that there may be an important contribution of hormonal pleiotropy in regulating this complex, acoustically-guided sexual behavior. Our findings also support the idea that hormonal induction could be used to evaluate hypotheses about selective mate choice, and its underlying mechanisms, using non-breeding females.
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Affiliation(s)
- Jessica L Ward
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, USA
| | - Elliot K Love
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, USA
| | | | - Noah M Gordon
- Department of Biology, University of Evansville, Evansville, IN, USA
| | - Jessie C Tanner
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, USA
| | - Mark A Bee
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, USA.
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18
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Ponnath A, Farris HE. Sound-by-sound thalamic stimulation modulates midbrain auditory excitability and relative binaural sensitivity in frogs. Front Neural Circuits 2014; 8:85. [PMID: 25120437 PMCID: PMC4111082 DOI: 10.3389/fncir.2014.00085] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 07/04/2014] [Indexed: 11/13/2022] Open
Abstract
Descending circuitry can modulate auditory processing, biasing sensitivity to particular stimulus parameters and locations. Using awake in vivo single unit recordings, this study tested whether electrical stimulation of the thalamus modulates auditory excitability and relative binaural sensitivity in neurons of the amphibian midbrain. In addition, by using electrical stimuli that were either longer than the acoustic stimuli (i.e., seconds) or presented on a sound-by-sound basis (ms), experiments addressed whether the form of modulation depended on the temporal structure of the electrical stimulus. Following long duration electrical stimulation (3-10 s of 20 Hz square pulses), excitability (spikes/acoustic stimulus) to free-field noise stimuli decreased by 32%, but returned over 600 s. In contrast, sound-by-sound electrical stimulation using a single 2 ms duration electrical pulse 25 ms before each noise stimulus caused faster and varied forms of modulation: modulation lasted <2 s and, in different cells, excitability either decreased, increased or shifted in latency. Within cells, the modulatory effect of sound-by-sound electrical stimulation varied between different acoustic stimuli, including for different male calls, suggesting modulation is specific to certain stimulus attributes. For binaural units, modulation depended on the ear of input, as sound-by-sound electrical stimulation preceding dichotic acoustic stimulation caused asymmetric modulatory effects: sensitivity shifted for sounds at only one ear, or by different relative amounts for both ears. This caused a change in the relative difference in binaural sensitivity. Thus, sound-by-sound electrical stimulation revealed fast and ear-specific (i.e., lateralized) auditory modulation that is potentially suited to shifts in auditory attention during sound segregation in the auditory scene.
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Affiliation(s)
- Abhilash Ponnath
- Neuroscience Center, Louisiana State University Health Sciences Center New Orleans, LA, USA ; Department of Otolaryngology and Biocommunication, Louisiana State University Health Sciences Center New Orleans, LA, USA
| | - Hamilton E Farris
- Neuroscience Center, Louisiana State University Health Sciences Center New Orleans, LA, USA ; Department of Otolaryngology and Biocommunication, Louisiana State University Health Sciences Center New Orleans, LA, USA ; Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center New Orleans, LA, USA
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19
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Gall MD, Wilczynski W. Prior experience with conspecific signals enhances auditory midbrain responsiveness to conspecific vocalizations. J Exp Biol 2014; 217:1977-82. [DOI: 10.1242/jeb.096883] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
There is a long history in neuroethology of investigating how communication signals influence the brain and behavior. It has become increasingly clear that brain areas associated with sensory processing are plastic in adults and that this plasticity is related to reproductive condition. However, the role of communication signal reception in adult auditory plasticity has received relatively little attention. Here, we investigated whether the reception of communication signals (a frog chorus) could enhance the responsiveness of the auditory system to future reception of communication signals (a single male call). We found that animals that had been exposed to 10 days of a male chorus had stronger auditory midbrain immediate early gene expression than animals that had been exposed to 10 days of random tones when tested with 30 min of male calls or 30 min of tones. Our results suggest that exposure to dynamic social stimuli, like frog choruses, may play an important role in shaping the neural and behavioral responses to communication signals.
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Affiliation(s)
- Megan D. Gall
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
- Biology Department, Vassar College, Poughkeepsie, NY 12604, USA
| | - Walter Wilczynski
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
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20
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Social signals increase monoamine levels in the tegmentum of juvenile Mexican spadefoot toads (Spea multiplicata). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2013; 199:681-91. [PMID: 23681220 DOI: 10.1007/s00359-013-0826-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 04/28/2013] [Accepted: 05/01/2013] [Indexed: 10/26/2022]
Abstract
Monoamines are important neuromodulators that respond to social cues and that can, in turn, modify social responses. Yet we know very little about the ontogeny of monoaminergic systems and whether they contribute to the development of social behavior. Anurans are an excellent model for studying the development of social behavior because one of its primary components, phonotaxis, is expressed early in life. To examine the effect of social signals on monoamines early in ontogeny, we presented juvenile Mexican spadefoot toads (Spea multiplicata) with a male mating call or no sound and measured norepinephrine, epinephrine, dopamine, serotonin, and a serotonin metabolite, across the brain using high-pressure liquid chromatography. Our results demonstrate that adult-like monoaminergic systems are in place shortly after metamorphosis. Perhaps more interestingly, we found that mating calls increased the level of monoamines in the juvenile tegmentum, a midbrain region involved in sensory-motor integration and that contributes to brain arousal and attention. We saw no such increase in the auditory midbrain or in forebrain regions. We suggest that changes in monoamine levels in the juvenile tegmentum may reflect the effects of social signals on arousal state and could contribute to context-dependent modulation of social behavior.
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21
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Tárano Z, Fuenmayor E. Mate Choice Based on Acoustic Features in Johnstone's Whistling FrogEleutherodactylus johnstonei: an Experimental Approach. SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2013. [DOI: 10.2994/sajh-d-12-00016.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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22
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Hurley LM, Sullivan MR. From behavioral context to receptors: serotonergic modulatory pathways in the IC. Front Neural Circuits 2012; 6:58. [PMID: 22973195 PMCID: PMC3434355 DOI: 10.3389/fncir.2012.00058] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 08/10/2012] [Indexed: 12/18/2022] Open
Abstract
In addition to ascending, descending, and lateral auditory projections, inputs extrinsic to the auditory system also influence neural processing in the inferior colliculus (IC). These types of inputs often have an important role in signaling salient factors such as behavioral context or internal state. One route for such extrinsic information is through centralized neuromodulatory networks like the serotonergic system. Serotonergic inputs to the IC originate from centralized raphe nuclei, release serotonin in the IC, and activate serotonin receptors expressed by auditory neurons. Different types of serotonin receptors act as parallel pathways regulating specific features of circuitry within the IC. This results from variation in subcellular localizations and effector pathways of different receptors, which consequently influence auditory responses in distinct ways. Serotonin receptors may regulate GABAergic inhibition, influence response gain, alter spike timing, or have effects that are dependent on the level of activity. Serotonin receptor types additionally interact in nonadditive ways to produce distinct combinatorial effects. This array of effects of serotonin is likely to depend on behavioral context, since the levels of serotonin in the IC transiently increase during behavioral events including stressful situations and social interaction. These studies support a broad model of serotonin receptors as a link between behavioral context and reconfiguration of circuitry in the IC, and the resulting possibility that plasticity at the level of specific receptor types could alter the relationship between context and circuit function.
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Affiliation(s)
- Laura M Hurley
- Department of Biology, Center for the Integrative Study of Animal Behavior, Indiana University Bloomington, IN, USA
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23
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Baugh AT, Hoke KL, Ryan MJ. Development of communication behaviour: receiver ontogeny in Túngara frogs and a prospectus for a behavioural evolutionary development. ScientificWorldJournal 2012; 2012:680632. [PMID: 22649307 PMCID: PMC3354594 DOI: 10.1100/2012/680632] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Accepted: 01/04/2012] [Indexed: 11/17/2022] Open
Abstract
Most studies addressing the development of animal communication have focused on signal production rather than receiver decoding, and similar emphasis has been given to learning over nonlearning. But receivers are an integral part of a communication network, and nonlearned mechanisms appear to be more ubiquitous than learned ones in the communication systems of most animals. Here we review the results of recent experiments and outline future directions for integrative studies on the development of a primarily nonlearned behaviour-recognition of communication signals during ontogeny in a tropical frog. The results suggest that antecedents to adult behaviours might be a common feature of developing organisms. Given the essential role that acoustic communication serves in reproduction for many organisms and that receivers can exert strong influence on the evolution of signals, understanding the evolutionary developmental basis of mate recognition will provide new insights into the evolution of communication systems.
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Affiliation(s)
- Alexander T Baugh
- Section of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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24
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Hoke KL, Pitts NL. Modulation of sensory-motor integration as a general mechanism for context dependence of behavior. Gen Comp Endocrinol 2012; 176:465-71. [PMID: 22405704 DOI: 10.1016/j.ygcen.2012.02.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 02/18/2012] [Accepted: 02/18/2012] [Indexed: 11/30/2022]
Abstract
Social communication is context-dependent, with both the production of signals and the responses of receivers tailored to each animal's internal needs and external environmental conditions. We propose that this context dependence arises because of neural modulation of the sensory-motor transformation that underlies the social behavior. Neural systems that are restricted to individual behaviors may be modulated at early stages of the sensory or motor pathways for optimal energy expenditure. However, when neural systems contribute to multiple important behaviors, we argue that the sensory-motor relay is the likely site of modulation. Plasticity in the sensory-motor relay enables subtle context dependence of the social behavior while preserving other functions of the sensory and motor systems. We review evidence that the robust responses of anurans to conspecific signals are dependent on reproductive state, sex, prior experience, and current context. A well-characterized midbrain sensory-motor relay establishes signal selectivity and gates locomotive responses to sound. The social decision-making network may modulate this auditory-motor transformation to confer context dependence of anuran reproductive responses to sound. We argue that similar modulation may be a general mechanism by which vertebrates prioritize their behaviors.
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Affiliation(s)
- Kim Lisa Hoke
- Department of Biology, Colorado State University, 1878 Campus Delivery, Fort Collins, CO 80523, USA.
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25
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Larson E, Maddox RK, Perrone BP, Sen K, Billimoria CP. Neuron-specific stimulus masking reveals interference in spike timing at the cortical level. J Assoc Res Otolaryngol 2011; 13:81-9. [PMID: 21964794 DOI: 10.1007/s10162-011-0292-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 09/08/2011] [Indexed: 11/29/2022] Open
Abstract
The auditory system is capable of robust recognition of sounds in the presence of competing maskers (e.g., other voices or background music). This capability arises despite the fact that masking stimuli can disrupt neural responses at the cortical level. Since the origins of such interference effects remain unknown, in this study, we work to identify and quantify neural interference effects that originate due to masking occurring within and outside receptive fields of neurons. We record from single and multi-unit auditory sites from field L, the auditory cortex homologue in zebra finches. We use a novel method called spike timing-based stimulus filtering that uses the measured response of each neuron to create an individualized stimulus set. In contrast to previous adaptive experimental approaches, which have typically focused on the average firing rate, this method uses the complete pattern of neural responses, including spike timing information, in the calculation of the receptive field. When we generate and present novel stimuli for each neuron that mask the regions within the receptive field, we find that the time-varying information in the neural responses is disrupted, degrading neural discrimination performance and decreasing spike timing reliability and sparseness. We also find that, while removing stimulus energy from frequency regions outside the receptive field does not significantly affect neural responses for many sites, adding a masker in these frequency regions can nonetheless have a significant impact on neural responses and discriminability without a significant change in the average firing rate. These findings suggest that maskers can interfere with neural responses by disrupting stimulus timing information with power either within or outside the receptive fields of neurons.
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Affiliation(s)
- Eric Larson
- Department of Biomedical Engineering, Hearing Research Center, Boston University, Boston, MA 02215, USA.
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26
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Nityananda V, Bee MA. Finding your mate at a cocktail party: frequency separation promotes auditory stream segregation of concurrent voices in multi-species frog choruses. PLoS One 2011; 6:e21191. [PMID: 21698268 PMCID: PMC3115990 DOI: 10.1371/journal.pone.0021191] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 05/22/2011] [Indexed: 11/18/2022] Open
Abstract
Vocal communication in crowded social environments is a difficult problem for both humans and nonhuman animals. Yet many important social behaviors require listeners to detect, recognize, and discriminate among signals in a complex acoustic milieu comprising the overlapping signals of multiple individuals, often of multiple species. Humans exploit a relatively small number of acoustic cues to segregate overlapping voices (as well as other mixtures of concurrent sounds, like polyphonic music). By comparison, we know little about how nonhuman animals are adapted to solve similar communication problems. One important cue enabling source segregation in human speech communication is that of frequency separation between concurrent voices: differences in frequency promote perceptual segregation of overlapping voices into separate "auditory streams" that can be followed through time. In this study, we show that frequency separation (ΔF) also enables frogs to segregate concurrent vocalizations, such as those routinely encountered in mixed-species breeding choruses. We presented female gray treefrogs (Hyla chrysoscelis) with a pulsed target signal (simulating an attractive conspecific call) in the presence of a continuous stream of distractor pulses (simulating an overlapping, unattractive heterospecific call). When the ΔF between target and distractor was small (e.g., ≤3 semitones), females exhibited low levels of responsiveness, indicating a failure to recognize the target as an attractive signal when the distractor had a similar frequency. Subjects became increasingly more responsive to the target, as indicated by shorter latencies for phonotaxis, as the ΔF between target and distractor increased (e.g., ΔF = 6-12 semitones). These results support the conclusion that gray treefrogs, like humans, can exploit frequency separation as a perceptual cue to segregate concurrent voices in noisy social environments. The ability of these frogs to segregate concurrent voices based on frequency separation may involve ancient hearing mechanisms for source segregation shared with humans and other vertebrates.
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Affiliation(s)
- Vivek Nityananda
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Twin Cities, St. Paul, Minnesota, United States of America
| | - Mark A. Bee
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Twin Cities, St. Paul, Minnesota, United States of America
- * E-mail:
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27
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Hoke KL, Ryan MJ, Wilczynski W. Sexually dimorphic sensory gating drives behavioral differences in tungara frogs. ACTA ACUST UNITED AC 2011; 213:3463-72. [PMID: 20889827 DOI: 10.1242/jeb.043992] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Males and females can differ both in the social behaviors they perform and in the contexts in which they engage in these behaviors. One possible mechanism of sex differences in behavior is a sexual dimorphism in the relay of sensory information to motor areas, but no studies have examined the role of such a relay in vertebrate sexually dimorphic behaviors. We used egr-1 expression as a marker of neural activation in frogs exposed to conspecific and heterospecific acoustic signals to compare activation patterns throughout the brains of males and females. We determined how the sexes differ in the transformation of social signals into motor responses in the context of social communication. We examined the relationships between egr-1 mRNA levels in the auditory midbrain and forebrain areas, as well as how forebrain expression related to the behavioral responses of the animals. Forebrain network activation patterns and forebrain-behavior relationships were similar in males and females. By contrast, we found a sex difference in the relationship between midbrain and forebrain activation; midbrain auditory responses predicted forebrain responses in females but not in males. This sex difference suggests that sensory inputs differentially regulate motor systems underlying social behaviors in males and females. This sensorimotor transformation may be a common locus for generating sex differences in behavior.
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Affiliation(s)
- Kim L Hoke
- Section of Integrative Biology, University of Texas at Austin, 1 University Station C0930, Austin, TX 78712, USA.
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28
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The behavioral neuroscience of anuran social signal processing. Curr Opin Neurobiol 2010; 20:754-63. [PMID: 20863685 DOI: 10.1016/j.conb.2010.08.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 08/23/2010] [Accepted: 08/25/2010] [Indexed: 12/11/2022]
Abstract
Acoustic communication is the major component of social behavior in anuran amphibians (frogs and toads) and has served as a neuroethological model for the nervous system's processing of social signals related to mate choice decisions. The male's advertisement or mating call is its most conspicuous social signal, and the nervous system's analysis of the call is a progressive process. As processing proceeds through neural systems, response properties become more specific to the signal and, in addition, neural activity gradually shifts from representing sensory (auditory periphery and brainstem) to sensorimotor (diencephalon) to motor (forebrain) components of a behavioral response. A comparative analysis of many anuran species shows that the first stage in biasing responses toward conspecific signals over heterospecific signals, and toward particular features of conspecific signals, lies in the tuning of the peripheral auditory system. Biases in processing signals are apparent through the brainstem auditory system, where additional feature detection neurons are added by the time processing reaches the level of the midbrain. Recent work using immediate early gene expression as a marker of neural activity suggests that by the level of the midbrain and forebrain, the differential neural representation of conspecific and heterospecific signals involves both changes in mean activity levels across multiple subnuclei, and in the functional correlations among acoustically active areas. Our data show that in frogs the auditory midbrain appears to play an important role in controlling behavioral responses to acoustic social signals by acting as a regulatory gateway between the stimulus analysis of the brainstem and the behavioral and physiological control centers of the forebrain. We predict that this will hold true for other vertebrate groups such as birds and fish that produce acoustic social signals, and perhaps also in fish where electroreception or vibratory sensing through the lateral line systems plays a role in social signaling, as in all these cases ascending sensory information converges onto midbrain nuclei which relay information to higher brain centers.
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29
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Schwartz JJ, Huth K, Hunce R, Lentine B. Effect of anomalous pulse timing on call discrimination by females of the gray treefrog (Hyla versicolor): behavioral correlates of neurobiology. J Exp Biol 2010; 213:2066-72. [DOI: 10.1242/jeb.043372] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Research has demonstrated that certain midbrain neurons of anurans ‘count’ interpulse intervals (IPIs). Some neurons fire after exposure to fewer intervals than do others. Counting can be reset to zero if an IPI falls outside the cell's tolerance range. We tested female gray treefrogs for behavioral correlates of these neural response patterns using phonotaxis tests in order to gain a better understanding of the mechanistic bases of female responses to calls. For example, previous work demonstrated females often prefer longer to shorter pulsed advertisement calls, even when the former occur at lower rates. Call attractiveness can also be reduced when pulse duration and timing have been manipulated experimentally or disrupted by acoustic interference. In this study, female responses were consistent with neural data, emphasizing the importance of IPIs. Females discriminated in favor of calls with normal interpulse timing relative to those in which a single IPI was too long or too short. Our data suggest that neural resetting of interval counting by inappropriate intervals may more strongly influence females than reduced firing in response to such intervals on an individual basis. Data also suggest a transition point between 125 ms and 175 ms at which an interval between pulse strings is treated as an interval between calls.
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Affiliation(s)
- Joshua J. Schwartz
- Department of Biology and Health Sciences, Pace University, Pleasantville, NY 10570, USA
| | - Kenneth Huth
- The Wildlife Conservation Society, Bronx, NY 10460, USA
| | - Raymond Hunce
- Department of Biology and Health Sciences, Pace University, Pleasantville, NY 10570, USA
| | - Brandon Lentine
- Department of Biology and Health Sciences, Pace University, Pleasantville, NY 10570, USA
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30
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Seeba F, Schwartz JJ, Bee MA. Testing an auditory illusion in frogs: Perceptual restoration or sensory bias? Anim Behav 2010; 79:1317-1328. [PMID: 20514342 DOI: 10.1016/j.anbehav.2010.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The human auditory system perceptually restores short deleted segments of speech and other sounds (e.g. tones) when the resulting silent gaps are filled by a potential masking noise. When this phenomenon, known as 'auditory induction', occurs, listeners experience the illusion of hearing an ongoing sound continuing through the interrupting noise even though the perceived sound is not physically present. Such illusions suggest that a key function of the auditory system is to allow listeners to perceive complete auditory objects with incomplete acoustic information, as may often be the case in multisource acoustic environments. At present, however, we know little about the possible functions of auditory induction in the sound-mediated behaviours of animals. The present study used two-choice phonotaxis experiments to test the hypothesis that female grey treefrogs, Hyla chrysoscelis, experience the illusory perceptual restoration of discrete pulses in the male advertisement call when pulses are deleted and replaced by a potential masking noise. While added noise restored some attractiveness to calls with missing pulses, there was little evidence to suggest that the frogs actually experienced the illusion of perceiving the missing pulses. Instead, the added noise appeared to function as an acoustic appendage that made some calls more attractive than others as a result of sensory biases, the expression of which depended on the temporal order and acoustic structure of the added appendages.
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Affiliation(s)
- Folkert Seeba
- Animal Physiology and Behaviour Group, Carl von Ossietzky University - Oldenburg
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Miranda JA, Wilczynski W. Sex differences and androgen influences on midbrain auditory thresholds in the green treefrog, Hyla cinerea. Hear Res 2009; 252:79-88. [PMID: 19371774 DOI: 10.1016/j.heares.2009.04.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 04/08/2009] [Accepted: 04/08/2009] [Indexed: 10/20/2022]
Abstract
Reproductive hormones can modulate communication-evoked behavior by acting on neural systems associated with motivation; however, recent evidence suggests that modulation occurs at the sensory processing level as well. The anuran auditory midbrain processes communication stimuli, and is sensitive to steroid hormones. Using multiunit electrophysiology, we tested whether sex and circulating testosterone influence auditory sensitivity to pure tones and to the natural vocalization in the green treefrog, Hyla cinerea. Sex did not influence audiogram best frequencies although sexes did differ in the sensitivities at those frequencies with males more sensitive in the lower frequency range. Females were more sensitive than males in response to the natural vocalization, despite showing no difference in response to pure tones at frequencies found within the advertisement call. Thresholds to frequencies outside the range of the male advertisement call were higher in females. Additionally, circulating testosterone increased neural thresholds in females in a frequency-specific manner. These results demonstrate that sex differences are limited to frequency ranges that relate to the processing of natural vocalizations, and depend on the type of stimulus. The frequency-dependent and stimulus-dependent nature of sex and testosterone influences suggests that reproductive hormones influence the filtering properties of the auditory system.
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Affiliation(s)
- Jason A Miranda
- Institute for Neuroscience, The University of Texas at Austin, 1 University Station A8000, Austin, TX 78712, USA.
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32
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Bibikov NG, Stogova EA. Temporal peculiarities of responses of auditory system neurons of the frog Rana temporaria to tone bursts with different modulation frequencies. J EVOL BIOCHEM PHYS+ 2009. [DOI: 10.1134/s0022093009010098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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33
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Miranda JA, Wilczynski W. Female reproductive state influences the auditory midbrain response. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2009; 195:341-9. [DOI: 10.1007/s00359-008-0410-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2008] [Revised: 12/22/2008] [Accepted: 12/25/2008] [Indexed: 11/30/2022]
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34
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Acoustic modulation of immediate early gene expression in the auditory midbrain of female túngara frogs. Brain Res 2008; 1190:105-14. [DOI: 10.1016/j.brainres.2007.11.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Revised: 11/04/2007] [Accepted: 11/06/2007] [Indexed: 11/21/2022]
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35
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Lynch KS, Wilczynski W. Reproductive hormones modify reception of species-typical communication signals in a female anuran. BRAIN, BEHAVIOR AND EVOLUTION 2007; 71:143-50. [PMID: 18032889 DOI: 10.1159/000111460] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 09/12/2007] [Indexed: 12/14/2022]
Abstract
In many vertebrates, the production and reception of species-typical courtship signals occurs when gonadotropin and gonadal hormone levels are elevated. These hormones may modify sensory processing in the signal receiver in a way that enhances behavioral responses to the signal. We examined this possibility in female túngara frogs (Physalaemus pustulosus) by treating them with either gonadotropin (which elevated estradiol) or saline and exposing them to either mate choruses or silence. Expression of an activity-dependent gene, egr-1, was quantified within two sub-nuclei of the auditory midbrain to investigate whether gonadotropin plus chorus exposure induced greater egr-1 induction than either of these stimuli alone. The laminar nucleus (LN), a sub-nucleus of the torus semicircularis that contains steroid receptors, exhibited elevated egr-1 induction in response to chorus exposure and gonadotropin treatment. Further analysis revealed that neither chorus exposure nor gonadotropin treatment alone elevated egr-1 expression in comparison to baseline levels whereas gonadotropin + chorus exposure did. This suggests that mate signals and hormones together produce an additive effect so that together they induce more egr-1 expression than either alone. Our previously published studies of female túngara frogs reveal that (1) gonadotropin-induced estradiol elevations also increase behavioral responses to male signals, and (2) reception of male signals elevates estradiol levels in the female. Here, we report data that reveal a novel mechanism by which males exploit female sensory processing to increase behavioral responses to their courtship signals.
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Affiliation(s)
- Kathleen S Lynch
- Institute for Neuroscience, University of Texas, Austin, Tex, USA.
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36
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Cortical interference effects in the cocktail party problem. Nat Neurosci 2007; 10:1601-7. [PMID: 17994016 DOI: 10.1038/nn2009] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Accepted: 10/10/2007] [Indexed: 11/08/2022]
Abstract
Humans and animals must often discriminate between complex natural sounds in the presence of competing sounds (maskers). Although the auditory cortex is thought to be important in this task, the impact of maskers on cortical discrimination remains poorly understood. We examined neural responses in zebra finch (Taeniopygia guttata) field L (homologous to primary auditory cortex) to target birdsongs that were embedded in three different maskers (broadband noise, modulated noise and birdsong chorus). We found two distinct forms of interference in the neural responses: the addition of spurious spikes occurring primarily during the silent gaps between song syllables and the suppression of informative spikes occurring primarily during the syllables. Both effects systematically degraded neural discrimination as the target intensity decreased relative to that of the masker. The behavioral performance of songbirds degraded in a parallel manner. Our results identify neural interference that could explain the perceptual interference at the heart of the cocktail party problem.
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37
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Gerhardt HC, Martínez-Rivera CC, Schwartz JJ, Marshall VT, Murphy CG. Preferences based on spectral differences in acoustic signals in four species of treefrogs (Anura: Hylidae). J Exp Biol 2007; 210:2990-8. [PMID: 17704074 DOI: 10.1242/jeb.006312] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYFrogs have two inner ear organs, each tuned to a different range of frequencies. Female treefrogs (Hylidae) of three species in which males produce calls with a bimodal spectrum (Hyla chrysoscelis, H. versicolor, H. arenicolor) preferred alternatives with a bimodal spectrum to alternatives with a single high-frequency peak. By contrast,females of H. avivoca, in which males produce calls with a single,high-frequency peak, preferred synthetic calls with a single high-frequency peak to calls with a bimodal spectrum. These results are consistent with the expectations of the matched-filter hypothesis and run counter to the predictions of the pre-existing bias hypothesis. At moderate to high playback levels (85–90 dB), females of H. avivoca and of two of three mtDNA-defined lineages of H. versicolor preferred unimodal signals with a high-frequency peak to those with a low-frequency peak. Females of H. chrysoscelis, H. arenicolor and the third lineage of H. versicolor did not show a preference, indicating that receiver mechanisms may be at least as evolutionarily labile as call structure. Spectral-peak preferences of gray treefrogs from Missouri, USA were intensity-dependent. Whereas females chose low-frequency calls at 65 dB spl, there was either no preference (H. chrysoscelis) or a preference for high-frequency calls (H. versicolor) at 85 and 90 dB spl. These non-linear effects indicate that there is an increasing influence of high-frequency energy on preferences as females approach calling males, and these results serve to emphasize that playback experiments conducted at a single level may have limited generality.
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Affiliation(s)
- H Carl Gerhardt
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA.
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Shinn-Cunningham BG, Lee AKC, Oxenham AJ. A sound element gets lost in perceptual competition. Proc Natl Acad Sci U S A 2007; 104:12223-7. [PMID: 17615235 PMCID: PMC1924568 DOI: 10.1073/pnas.0704641104] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Our ability to understand auditory signals depends on properly separating the mixture of sound arriving from multiple sources. Sound elements tend to belong to only one object at a time, consistent with the principle of disjoint allocation, although there are instances of duplex perception or coallocation, in which two sound objects share one sound element. Here we report an effect of "nonallocation," in which a sound element "disappears" when two ongoing objects compete for its ownership. When a target tone is presented either as one of a sequence of tones or simultaneously with a harmonic vowel complex, it is heard as part of the corresponding object. However, depending on the spatial configuration of the scene, if the target, the tones, and the vowel are all presented together, the target may not be perceived in either the tones or the vowel, even though it is not perceived as a separate entity. This finding suggests an asymmetry in the strength of the perceptual evidence required to reject vs. to include an element within the auditory foreground, a result with important implications for how we process complex auditory scenes containing ambiguous information.
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39
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Hoke KL, Ryan MJ, Wilczynski W. Integration of sensory and motor processing underlying social behaviour in túngara frogs. Proc Biol Sci 2007; 274:641-9. [PMID: 17254988 PMCID: PMC2197214 DOI: 10.1098/rspb.2006.0038] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Social decision making involves the perception and processing of social stimuli, the subsequent evaluation of that information in the context of the individual's internal and external milieus to produce a decision, and then culminates in behavioural output informed by that decision. We examined brain networks in an anuran communication system that relies on acoustic signals to guide simple, stereotyped motor output. We used egr-1 mRNA expression to measure neural activation in male túngara frogs, Physalaemus pustulosus, following exposure to conspecific and heterospecific calls that evoke competitive or aggressive behaviour. We found that acoustically driven activation in auditory brainstem nuclei is transformed into activation related to sensory-motor interactions in the diencephalon, followed by motor-related activation in the telencephalon. Furthermore, under baseline conditions, brain nuclei typically have correlated egr-1 mRNA levels within brain divisions. Hearing conspecific advertisement calls increases correlations between anatomically distant brain divisions; no such effect was observed in response to calls that elicit aggressive behaviour. Neural correlates of social decision making thus take multiple forms: (i) a progressive shift from sensory to motor encoding from lower to higher stages of neural processing and (ii) the emergence of correlated activation patterns among sensory and motor regions in response to behaviourally relevant social cues.
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Affiliation(s)
- Kim L Hoke
- Section of Integrative Biology, University of Texas at Austin, 1 University Station C0930, Austin, TX 78712, USA.
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Hoke KL, Burmeister SS, Fernald RD, Rand AS, Ryan MJ, Wilczynski W. Functional mapping of the auditory midbrain during mate call reception. J Neurosci 2005; 24:11264-72. [PMID: 15601932 PMCID: PMC6730357 DOI: 10.1523/jneurosci.2079-04.2004] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We examined patterns of neural activity as assayed by changes in gene expression to localize representation of acoustic mating signals in the auditory midbrain of frogs. We exposed wild-caught male Physalaemus pustulosus to conspecific mating calls that vary in their behavioral salience, nonsalient mating calls, or no sound. We measured expression of the immediate early gene egr-1 (also called ZENK, zif268, NGFI-A, and krox-24) throughout the torus semicircularis, the auditory midbrain homolog of the inferior colliculus. Differential egr-1 induction in response to the acoustic stimuli occurred in the laminar, midline, and principal nuclei of the torus semicircularis, whereas the ventral region did not show significant effects of stimulus. The laminar nucleus differentially responded to conspecific mating calls compared with nonsalient mating calls, whereas the midline and principal nuclei responded preferentially to one of two conspecific calls. These responses were not explained by simple acoustic properties of the stimuli, and they demonstrate a functional heterogeneity of auditory processing of complex biological signals within the frog midbrain. Moreover, using analyses that assess the ability of the torus semicircularis as a whole to discriminate among acoustic stimuli, we found that activity patterns in the four regions together provide more information about biologically relevant acoustic stimuli than activity in any single region.
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Affiliation(s)
- Kim L Hoke
- Section of Integrative Biology, University of Texas at Austin, Austin, Texas 78712, USA
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41
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Endepols H, Schul J, Gerhardt HC, Walkowiak W. 6-hydroxydopamine lesions in anuran amphibians: A new model system for Parkinson's disease? ACTA ACUST UNITED AC 2004; 60:395-410. [PMID: 15307145 DOI: 10.1002/neu.20047] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We investigated the effects of dopamine depletion on acoustically guided behavior of anurans by conducting phonotaxis experiments with female gray treefrogs (Hyla versicolor) before and 90 min after bilateral injections of 3, 6, or 12 microg 6-hydroxydopamine (6-OHDA) into the telencephalic ventricles. In experiments with one loudspeaker playing back a standard artificial mating call, we analyzed the effects of 6-OHDA on phonotactic response time. In choice tests we measured the degree of distraction from the standard call (20 pulses/s) by three different variants with altered pulse-rate (30/s, 40/s, 60/s). Five days after experiments, brains were immunostained for tyrosine hydroxylase. Labeled neurons were counted in the suprachiasmatic nucleus, posterior tuberculum, interpeduncular nucleus, and locus coeruleus, and correlation between neuronal numbers and behavioral scores was tested. Response times increased together with 6-OHDA concentrations, which was mainly due to longer immobile periods before the animals started movement. In choice tests the most irrelevant stimulus (60/s) distracted 6-OHDA injected females from the standard stimulus, while sham injected controls were undistracted. The number of catecholaminergic neurons decreased with increasing 6-OHDA concentration in the suprachiasmatic nucleus, posterior tuberculum, and interpeduncular nucleus. The normalized number of immunoreactive neurons in the posterior tuberculum was positively correlated with phonotaxis scores in the one-speaker test, demonstrating that motor deficits are a function of tubercular cell loss. We conclude that bilateral 6-OHDA lesions in anuran amphibians cause motor (difficulty to start movements) as well as cognitive symptoms (higher distraction by irrelevant stimuli) that have also been described for human Parkinson patients.
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Affiliation(s)
- Heike Endepols
- Institute of Zoology, University of Cologne, Cologne, Germany.
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