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Zhang X, Hedwig B. Sound processing in the cricket brain: evidence for a pulse duration filter. J Neurophysiol 2023; 130:953-966. [PMID: 37701942 PMCID: PMC10649838 DOI: 10.1152/jn.00252.2023] [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: 06/26/2023] [Revised: 08/28/2023] [Accepted: 08/28/2023] [Indexed: 09/14/2023] Open
Abstract
The auditory system of female crickets allows them to specifically recognize and approach the species-specific male calling song, defined by sound pulses and silent intervals. Auditory brain neurons form a delay-line and coincidence detector network tuned to the pulse period of the male song. We analyzed the impact of changes in pulse duration on the behavior and the responses of the auditory neurons and the network. We confirm that the ascending neuron AN1 and the local neuron LN2 copy the temporal structure of the song. During ongoing long sound pulses, the delay-line neuron LN5 shows additional rebound responses and the coincidence detector neuron LN3 can generate additional bursts of activity, indicating that these may be driven by intrinsic oscillations of the network. Moreover, the response of the feature detector neuron LN4 is shaped by a combination of inhibitory and excitatory synaptic inputs, and LN4 responds even to long sound pulses with a short depolarization and burst of spikes, like to a sound pulse of natural duration. This response property of LN4 indicates a selective auditory pulse duration filter mechanism of the pattern recognition network, which is tuned to the duration of natural pulses. Comparing the tuning of the phonotactic behavior with the tuning of the local auditory brain neurons to the same test patterns, we find no evidence that a modulation of the phonotactic behavior is reflected at the level of the feature detector neurons. This rather suggests that steering to nonattractive pulse patterns is organized at the thoracic level.NEW & NOTEWORTHY Pulse period selectivity has been reported for the cricket delay-line and coincidence detector network, whereas pulse duration selectivity is evident from behavioral tests. Pulses of increasing duration elicit responses in the pattern recognition neurons, which do not parallel the behavioral responses and indicate additional processing mechanisms. Long sound pulses elicit rhythmic rebound activity and additional bursts, whereas the feature detector neuron reveals a pulse duration filter, expanding our understanding of the pattern recognition process.
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Affiliation(s)
- Xinyang Zhang
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Berthold Hedwig
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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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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Egorova MA, Akimov AG, Khorunzhii GD, Ehret G. Frequency response areas of neurons in the mouse inferior colliculus. III. Time-domain responses: Constancy, dynamics, and precision in relation to spectral resolution, and perception in the time domain. PLoS One 2020; 15:e0240853. [PMID: 33104718 PMCID: PMC7588072 DOI: 10.1371/journal.pone.0240853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 10/04/2020] [Indexed: 11/23/2022] Open
Abstract
The auditory midbrain (central nucleus of inferior colliculus, ICC) receives multiple brainstem projections and recodes auditory information for perception in higher centers. Many neural response characteristics are represented in gradients (maps) in the three-dimensional ICC space. Map overlap suggests that neurons, depending on their ICC location, encode information in several domains simultaneously by different aspects of their responses. Thus, interdependence of coding, e.g. in spectral and temporal domains, seems to be a general ICC principle. Studies on covariation of response properties and possible impact on sound perception are, however, rare. Here, we evaluated tone-evoked single neuron activity from the mouse ICC and compared shapes of excitatory frequency-response areas (including strength and shape of inhibition within and around the excitatory area; classes I, II, III) with types of temporal response patterns and first-spike response latencies. Analyses showed covariation of sharpness of frequency tuning with constancy and precision of responding to tone onsets. Highest precision (first-spike latency jitter < 1 ms) and stable phasic responses throughout frequency-response areas were the quality mainly of class III neurons with broad frequency tuning, least influenced by inhibition. Class II neurons with narrow frequency tuning and dominating inhibitory influence were unsuitable for time domain coding with high precision. The ICC center seems specialized rather for high spectral resolution (class II presence), lateral parts for constantly precise responding to sound onsets (class III presence). Further, the variation of tone-response latencies in the frequency-response areas of individual neurons with phasic, tonic, phasic-tonic, or pauser responses gave rise to the definition of a core area, which represented a time window of about 20 ms from tone onset for tone-onset responding of the whole ICC. This time window corresponds to the roughly 20 ms shortest time interval that was found critical in several auditory perceptual tasks in humans and mice.
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Affiliation(s)
- Marina A. Egorova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexander G. Akimov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Gleb D. Khorunzhii
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Günter Ehret
- Institute of Neurobiology, University of Ulm, Ulm, Germany
- * E-mail:
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Valdizón-Rodríguez R, Kovaleva D, Faure PA. Effect of sound pressure level on contralateral inhibition underlying duration-tuned neurons in the mammalian inferior colliculus. J Neurophysiol 2019; 122:184-202. [PMID: 31017836 DOI: 10.1152/jn.00653.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Duration tuning in the mammalian inferior colliculus (IC) is created by the interaction of excitatory and inhibitory synaptic inputs. We used extracellular recordings and paired tone stimulation to measure the strength and time course of the contralateral inhibition underlying duration-tuned neurons (DTNs) in the IC of the awake bat. The onset time of a short, best duration (BD), excitatory probe tone set to +10 dB (re threshold) was varied relative to the onset of a longer-duration, nonexcitatory (NE) suppressor tone whose sound pressure level (SPL) was varied. Spikes evoked by the roving BD tone were suppressed when the stationary NE tone amplitude was at or above the BD tone threshold. When the NE tone was increased from 0 to +10 dB, the inhibitory latency became shorter than the excitatory first-spike latency and the duration of inhibition increased, but no further changes occurred at +20 dB (re BD tone threshold). We used the effective duration of inhibition as a function of the NE tone amplitude to obtain suppression-level functions that were used to estimate the inhibitory half-maximum SPL (ISPL50). We also measured rate-level functions of DTNs with single BD tones varied in SPL and modeled the excitatory half-maximum SPL (ESPL50). There was a correlation between the ESPL50 and ISPL50, and the dynamic range of excitation and inhibition were similar. We conclude that the strength of inhibition changes in proportion to excitation as a function of SPL, and this feature likely contributes to the amplitude tolerance of the responses of DTNs. NEW & NOTEWORTHY Duration-tuned neurons arise from excitatory and inhibitory synaptic inputs offset in time. We measured the strength and time course of inhibition to changes in sound level. The onset of inhibition shortened while its duration lengthened as the stimulus level increased from 0 to +10 dB re threshold; however, no further changes were observed at +20 dB. Excitatory rate-level and inhibitory suppression-level response functions were strongly correlated, suggesting a mechanism for level tolerance in duration tuning.
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Affiliation(s)
| | - Dominika Kovaleva
- Department of Psychology, Neuroscience & Behaviour, McMaster University , Hamilton, Ontario , Canada
| | - Paul A Faure
- Department of Psychology, Neuroscience & Behaviour, McMaster University , Hamilton, Ontario , Canada
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Roque L, Gaskins C, Gordon-Salant S, Goupell MJ, Anderson S. Age Effects on Neural Representation and Perception of Silence Duration Cues in Speech. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2019; 62:1099-1116. [PMID: 31026197 PMCID: PMC6802877 DOI: 10.1044/2018_jslhr-h-ascc7-18-0076] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/26/2018] [Accepted: 08/12/2018] [Indexed: 06/09/2023]
Abstract
Purpose Degraded temporal processing associated with aging may be a contributing factor to older adults' hearing difficulties, especially in adverse listening environments. This degraded processing may affect the ability to distinguish between words based on temporal duration cues. The current study investigates the effects of aging and hearing loss on cortical and subcortical representation of temporal speech components and on the perception of silent interval duration cues in speech. Method Identification functions for the words DISH and DITCH were obtained on a 7-step continuum of silence duration (0-60 ms) prior to the final fricative in participants who are younger with normal hearing (YNH), older with normal hearing (ONH), and older with hearing impairment (OHI). Frequency-following responses and cortical auditory-evoked potentials were recorded to the 2 end points of the continuum. Auditory brainstem responses to clicks were obtained to verify neural integrity and to compare group differences in auditory nerve function. A multiple linear regression analysis was conducted to determine the peripheral or central factors that contributed to perceptual performance. Results ONH and OHI participants required longer silence durations to identify DITCH than did YNH participants. Frequency-following responses showed reduced phase locking and poorer morphology, and cortical auditory-evoked potentials showed prolonged latencies in ONH and OHI participants compared with YNH participants. No group differences were noted for auditory brainstem response Wave I amplitude or Wave V/I ratio. After accounting for the possible effects of hearing loss, linear regression analysis revealed that both midbrain and cortical processing contributed to the variance in the DISH-DITCH perceptual identification functions. Conclusions These results suggest that age-related deficits in the ability to encode silence duration cues may be a contributing factor in degraded speech perception. In particular, degraded response morphology relates to performance on perceptual tasks based on silence duration contrasts between words.
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Affiliation(s)
- Lindsey Roque
- Department of Hearing and Speech Sciences, University of Maryland, College Park
| | - Casey Gaskins
- Department of Hearing and Speech Sciences, University of Maryland, College Park
| | - Sandra Gordon-Salant
- Department of Hearing and Speech Sciences, University of Maryland, College Park
- Neuroscience and Cognitive Science Program, University of Maryland, College Park
| | - Matthew J. Goupell
- Department of Hearing and Speech Sciences, University of Maryland, College Park
- Neuroscience and Cognitive Science Program, University of Maryland, College Park
| | - Samira Anderson
- Department of Hearing and Speech Sciences, University of Maryland, College Park
- Neuroscience and Cognitive Science Program, University of Maryland, College Park
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Wang X, Cheng YL, Yang DD, Si WJ, Jen PHS, Yang CH, Chen QC. Focal electrical stimulation of dorsal nucleus of the lateral lemniscus modulates auditory response properties of inferior collicular neurons in the albino mouse. Hear Res 2019; 377:292-306. [PMID: 30857650 DOI: 10.1016/j.heares.2019.01.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 01/27/2019] [Accepted: 01/31/2019] [Indexed: 11/28/2022]
Abstract
The inferior colliculus (IC) receives and integrates excitatory and inhibitory inputs from many bilateral lower auditory nuclei, intrinsic projections within IC, contralateral IC through the commissure of IC and from the auditory cortex (AC). These excitatory and inhibitory inputs from both ascending and descending auditory pathways contribute significantly to auditory response properties and temporal signal processing in IC. The present study examines the contribution of gamma-aminobutyric acid-ergic (GABAergic) inhibition of dorsal nucleus of the lateral lemniscus (DNLL) in influencing the response properties and amplitude sensitivity of contralateral IC neurons using focal electrical stimulation of contralateral DNLL and by the application of bicuculline to the recording site of modulated IC neurons. Focal electrical stimulation of contralateral DNLL produces inhibition (78.1%), facilitation (7.1%) or no effect (14.8%) in the number of spikes, firing duration and the first-spike latency of modulated IC neurons. The degree of modulation is inversely correlated to the difference in best frequency (BF) between electrically stimulated DNLL neurons and modulated IC neurons (p < 0.01). The application of bicuculline to the recording site of modulated IC neurons abolishes the inhibitory effect of focal electrical stimulation of DNLL neurons. DNLL inhibition also modulates the amplitude sensitivity of IC neurons by changing the dynamic range (DR) and the slope of rate-amplitude function (RAF) of modulated IC neurons. Possible biological significance of these findings in relation to auditory signal processing is discussed.
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Affiliation(s)
- Xin Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Yan-Ling Cheng
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Dan-Dan Yang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Wen-Juan Si
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Philip H-S Jen
- Division of Biological Sciences, University of Missouri-Columbia, MO, 65211, USA.
| | - Cui-Hong Yang
- School of Mathematics and Statistics, Central China Normal University, Wuhan, 430079, China
| | - Qi-Cai Chen
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
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7
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Wang H, Shen S, Zheng T, Bi L, Li B, Wang X, Yang Y, Jen PHS. The Role of the Dorsal Nucleus of the Lateral Lemniscus in Shaping the Auditory Response Properties of the Central Nucleus of the Inferior Collicular Neurons in the Albino Mouse. Neuroscience 2018; 390:30-45. [PMID: 30144510 DOI: 10.1016/j.neuroscience.2018.08.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 08/10/2018] [Accepted: 08/13/2018] [Indexed: 11/17/2022]
Abstract
In the ascending auditory pathway, the central nucleus of the inferior colliculus (IC) receives and integrates excitatory and inhibitory inputs from many bilateral lower auditory nuclei, intrinsic projections within the IC, contralateral IC through the commissure of the IC and from the auditory cortex. All these presynaptic excitatory and inhibitory inputs dynamically shape and modulate the auditory response properties of individual IC neurons. For this reason, acoustic response properties vary among individual IC neurons due to different activity pattern of presynaptic inputs. The present study examines modulation of auditory response properties of IC neurons by combining sound stimulation with focal electrical stimulation of the contralateral dorsal nucleus of the lateral lemniscus (referred to as ESDNLL) in the albino mouse. Brief ESDNLL produces variation (increase or decrease) in the number of impulses, response latency and discharge duration of modulated IC neurons. Additionally, 30-minute short-term ESDNLL alone produces variation in the best frequency (BF) and minimum threshold (MT) of modulated IC neurons. These varied response parameters recover in different manner and time course among individual modulated IC neurons. Possible pathways and neural mechanisms underlying these findings are discussed.
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Affiliation(s)
- Huimei Wang
- College of Special Education, Binzhou Medical College, Yantai, Shandong, People's Republic of China
| | - Shuang Shen
- College of Special Education, Binzhou Medical College, Yantai, Shandong, People's Republic of China
| | - Tihua Zheng
- College of Special Education, Binzhou Medical College, Yantai, Shandong, People's Republic of China
| | - Liyan Bi
- College of Special Education, Binzhou Medical College, Yantai, Shandong, People's Republic of China
| | - Bo Li
- College of Special Education, Binzhou Medical College, Yantai, Shandong, People's Republic of China
| | - Xin Wang
- College of Life Science, Central China Normal University, Wuhan, People's Republic of China
| | - Ying Yang
- College of Special Education, Binzhou Medical College, Yantai, Shandong, People's Republic of China.
| | - Philip H-S Jen
- College of Special Education, Binzhou Medical College, Yantai, Shandong, People's Republic of China; Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO, USA.
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8
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Brecht EJ, Barsz K, Gross B, Walton JP. Increasing GABA reverses age-related alterations in excitatory receptive fields and intensity coding of auditory midbrain neurons in aged mice. Neurobiol Aging 2017; 56:87-99. [PMID: 28532644 DOI: 10.1016/j.neurobiolaging.2017.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 03/18/2017] [Accepted: 04/04/2017] [Indexed: 11/25/2022]
Abstract
A key feature of age-related hearing loss is a reduction in the expression of inhibitory neurotransmitters in the central auditory system. This loss is partially responsible for changes in central auditory processing, as inhibitory receptive fields play a critical role in shaping neural responses to sound stimuli. Vigabatrin (VGB), an antiepileptic agent that irreversibly inhibits γ-amino butyric acid (GABA) transaminase, leads to increased availability of GABA throughout the brain. This study used multi-channel electrophysiology measurements to assess the excitatory frequency response areas in old CBA mice to which VGB had been administered. We found a significant post-VGB reduction in the proportion of V-type shapes, and an increase in primary-like excitatory frequency response areas. There was also a significant increase in the mean maximum driven spike rates across the tonotopic frequency range of all treated animals, consistent with observations that GABA buildup within the central auditory system increases spike counts of neural receptive fields. This increased spiking is also seen in the rate-level functions and seems to explain the improved low-frequency thresholds.
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Affiliation(s)
- Elliott J Brecht
- Department of Chemical and Biomedical Engineering, University of South Florida, Tampa, FL, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL, USA
| | - Kathy Barsz
- School of Nursing, University of Rochester, Rochester, NY, USA
| | - Benjamin Gross
- Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL, USA; Department of Physics, University of South Florida, Tampa, FL, USA
| | - Joseph P Walton
- Department of Chemical and Biomedical Engineering, University of South Florida, Tampa, FL, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL, USA; Department of Communication Sciences and Disorders, University of South Florida, Tampa, FL, USA.
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Valdizón-Rodríguez R, Faure PA. Frequency tuning of synaptic inhibition underlying duration-tuned neurons in the mammalian inferior colliculus. J Neurophysiol 2017; 117:1636-1656. [PMID: 28100657 PMCID: PMC5380776 DOI: 10.1152/jn.00807.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 01/13/2017] [Accepted: 01/16/2017] [Indexed: 11/22/2022] Open
Abstract
Inhibition plays an important role in creating the temporal response properties of duration-tuned neurons (DTNs) in the mammalian inferior colliculus (IC). Neurophysiological and computational studies indicate that duration selectivity in the IC is created through the convergence of excitatory and inhibitory synaptic inputs offset in time. We used paired-tone stimulation and extracellular recording to measure the frequency tuning of the inhibition acting on DTNs in the IC of the big brown bat (Eptesicus fuscus). We stimulated DTNs with pairs of tones differing in duration, onset time, and frequency. The onset time of a short, best-duration (BD), probe tone set to the best excitatory frequency (BEF) was varied relative to the onset of a longer-duration, nonexcitatory (NE) tone whose frequency was varied. When the NE tone frequency was near or within the cell's excitatory bandwidth (eBW), BD tone-evoked spikes were suppressed by an onset-evoked inhibition. The onset of the spike suppression was independent of stimulus frequency, but both the offset and duration of the suppression decreased as the NE tone frequency departed from the BEF. We measured the inhibitory frequency response area, best inhibitory frequency (BIF), and inhibitory bandwidth (iBW) of each cell. We found that the BIF closely matched the BEF, but the iBW was broader and usually overlapped the eBW measured from the same cell. These data suggest that temporal selectivity of midbrain DTNs is created and preserved by having cells receive an onset-evoked, constant-latency, broadband inhibition that largely overlaps the cell's excitatory receptive field. We conclude by discussing possible neural sources of the inhibition.NEW & NOTEWORTHY Duration-tuned neurons (DTNs) arise from temporally offset excitatory and inhibitory synaptic inputs. We used single-unit recording and paired-tone stimulation to measure the spectral tuning of the inhibitory inputs to DTNs. The onset of inhibition was independent of stimulus frequency; the offset and duration of inhibition systematically decreased as the stimulus departed from the cell's best excitatory frequency. Best inhibitory frequencies matched best excitatory frequencies; however, inhibitory bandwidths were more broadly tuned than excitatory bandwidths.
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Affiliation(s)
| | - Paul A Faure
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
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10
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Akimov AG, Egorova MA, Ehret G. Spectral summation and facilitation in on- and off-responses for optimized representation of communication calls in mouse inferior colliculus. Eur J Neurosci 2017; 45:440-459. [PMID: 27891665 DOI: 10.1111/ejn.13488] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 11/17/2016] [Accepted: 11/21/2016] [Indexed: 12/01/2022]
Abstract
Selectivity for processing of species-specific vocalizations and communication sounds has often been associated with the auditory cortex. The midbrain inferior colliculus, however, is the first center in the auditory pathways of mammals integrating acoustic information processed in separate nuclei and channels in the brainstem and, therefore, could significantly contribute to enhance the perception of species' communication sounds. Here, we used natural wriggling calls of mouse pups, which communicate need for maternal care to adult females, and further 15 synthesized sounds to test the hypothesis that neurons in the central nucleus of the inferior colliculus of adult females optimize their response rates for reproduction of the three main harmonics (formants) of wriggling calls. The results confirmed the hypothesis showing that average response rates, as recorded extracellularly from single units, were highest and spectral facilitation most effective for both onset and offset responses to the call and call models with three resolved frequencies according to critical bands in perception. In addition, the general on- and/or off-response enhancement in almost half the investigated 122 neurons favors not only perception of single calls but also of vocalization rhythm. In summary, our study provides strong evidence that critical-band resolved frequency components within a communication sound increase the probability of its perception by boosting the signal-to-noise ratio of neural response rates within the inferior colliculus for at least 20% (our criterion for facilitation). These mechanisms, including enhancement of rhythm coding, are generally favorable to processing of other animal and human vocalizations, including formants of speech sounds.
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Affiliation(s)
- Alexander G Akimov
- Sechnov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Marina A Egorova
- Sechnov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Günter Ehret
- Institute of Neurobiology, University of Ulm, D-89069, Ulm, Germany
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11
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Macías S, Hechavarría JC, Kössl M. Sharp temporal tuning in the bat auditory midbrain overcomes spectral-temporal trade-off imposed by cochlear mechanics. Sci Rep 2016; 6:29129. [PMID: 27374258 PMCID: PMC4931582 DOI: 10.1038/srep29129] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 06/15/2016] [Indexed: 11/23/2022] Open
Abstract
In the cochlea of the mustached bat, cochlear resonance produces extremely sharp frequency tuning to the dominant frequency of the echolocation calls, around 61 kHz. Such high frequency resolution in the cochlea is accomplished at the expense of losing temporal resolution because of cochlear ringing, an effect that is observable not only in the cochlea but also in the cochlear nucleus. In the midbrain, the duration of sounds is thought to be analyzed by duration-tuned neurons, which are selective to both stimulus duration and frequency. We recorded from 57 DTNs in the auditory midbrain of the mustached bat to assess if a spectral-temporal trade-off is present. Such spectral-temporal trade-off is known to occur as sharp tuning in the frequency domain which results in poorer resolution in the time domain, and vice versa. We found that a specialized sub-population of midbrain DTNs tuned to the bat's mechanical cochlear resonance frequency escape the cochlear spectral-temporal trade-off. We also show evidence that points towards an underlying neuronal inhibition that appears to be specific only at the resonance frequency.
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Affiliation(s)
- Silvio Macías
- Institut für Zellbiologie und Neurowissenschaft, Goethe Universität Frankfurt am Main, Germany
| | - Julio C. Hechavarría
- Institut für Zellbiologie und Neurowissenschaft, Goethe Universität Frankfurt am Main, Germany
| | - Manfred Kössl
- Institut für Zellbiologie und Neurowissenschaft, Goethe Universität Frankfurt am Main, Germany
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Phasic, suprathreshold excitation and sustained inhibition underlie neuronal selectivity for short-duration sounds. Proc Natl Acad Sci U S A 2016; 113:E1927-35. [PMID: 26976602 DOI: 10.1073/pnas.1520971113] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sound duration is important in acoustic communication, including speech recognition in humans. Although duration-selective auditory neurons have been found, the underlying mechanisms are unclear. To investigate these mechanisms we combined in vivo whole-cell patch recordings from midbrain neurons, extraction of excitatory and inhibitory conductances, and focal pharmacological manipulations. We show that selectivity for short-duration stimuli results from integration of short-latency, sustained inhibition with delayed, phasic excitation; active membrane properties appeared to amplify responses to effective stimuli. Blocking GABAA receptors attenuated stimulus-related inhibition, revealed suprathreshold excitation at all stimulus durations, and decreased short-pass selectivity without changing resting potentials. Blocking AMPA and NMDA receptors to attenuate excitation confirmed that inhibition tracks stimulus duration and revealed no evidence of postinhibitory rebound depolarization inherent to coincidence models of duration selectivity. These results strongly support an anticoincidence mechanism of short-pass selectivity, wherein inhibition and suprathreshold excitation show greatest temporal overlap for long duration stimuli.
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Distribution of glutamatergic, GABAergic, and glycinergic neurons in the auditory pathways of macaque monkeys. Neuroscience 2015; 310:128-51. [PMID: 26391919 DOI: 10.1016/j.neuroscience.2015.09.041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 09/14/2015] [Accepted: 09/14/2015] [Indexed: 11/23/2022]
Abstract
Macaque monkeys use complex communication calls and are regarded as a model for studying the coding and decoding of complex sound in the auditory system. However, little is known about the distribution of excitatory and inhibitory neurons in the auditory system of macaque monkeys. In this study, we examined the overall distribution of cell bodies that expressed mRNAs for VGLUT1, and VGLUT2 (markers for glutamatergic neurons), GAD67 (a marker for GABAergic neurons), and GLYT2 (a marker for glycinergic neurons) in the auditory system of the Japanese macaque. In addition, we performed immunohistochemistry for VGLUT1, VGLUT2, and GAD67 in order to compare the distribution of proteins and mRNAs. We found that most of the excitatory neurons in the auditory brainstem expressed VGLUT2. In contrast, the expression of VGLUT1 mRNA was restricted to the auditory cortex (AC), periolivary nuclei, and cochlear nuclei (CN). The co-expression of GAD67 and GLYT2 mRNAs was common in the ventral nucleus of the lateral lemniscus (VNLL), CN, and superior olivary complex except for the medial nucleus of the trapezoid body, which expressed GLYT2 alone. In contrast, the dorsal nucleus of the lateral lemniscus, inferior colliculus, thalamus, and AC expressed GAD67 alone. The absence of co-expression of VGLUT1 and VGLUT2 in the medial geniculate, medial superior olive, and VNLL suggests that synaptic responses in the target neurons of these nuclei may be different between rodents and macaque monkeys.
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Effect of echolocation behavior-related constant frequency-frequency modulation sound on the frequency tuning of inferior collicular neurons in Hipposideros armiger. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2015; 201:783-94. [PMID: 26026915 DOI: 10.1007/s00359-015-1018-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 05/11/2015] [Accepted: 05/19/2015] [Indexed: 12/19/2022]
Abstract
In constant frequency-frequency modulation (CF-FM) bats, the CF-FM echolocation signals include both CF and FM components, yet the role of such complex acoustic signals in frequency resolution by bats remains unknown. Using CF and CF-FM echolocation signals as acoustic stimuli, the responses of inferior collicular (IC) neurons of Hipposideros armiger were obtained by extracellular recordings. We tested the effect of preceding CF or CF-FM sounds on the shape of the frequency tuning curves (FTCs) of IC neurons. Results showed that both CF-FM and CF sounds reduced the number of FTCs with tailed lower-frequency-side of IC neurons. However, more IC neurons experienced such conversion after adding CF-FM sound compared with CF sound. We also found that the Q 20 value of the FTC of IC neurons experienced the largest increase with the addition of CF-FM sound. Moreover, only CF-FM sound could cause an increase in the slope of the neurons' FTCs, and such increase occurred mainly in the lower-frequency edge. These results suggested that CF-FM sound could increase the accuracy of frequency analysis of echo and cut-off low-frequency elements from the habitat of bats more than CF sound.
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15
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Suga N. Neural processing of auditory signals in the time domain: Delay-tuned coincidence detectors in the mustached bat. Hear Res 2015; 324:19-36. [DOI: 10.1016/j.heares.2015.02.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 02/15/2015] [Accepted: 02/24/2015] [Indexed: 11/25/2022]
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16
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Level-tolerant duration selectivity in the auditory cortex of the velvety free-tailed bat Molossus molossus. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2015; 201:461-70. [DOI: 10.1007/s00359-015-0993-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 02/20/2015] [Accepted: 02/20/2015] [Indexed: 11/26/2022]
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17
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Abstract
Frequency modulated (FM) sweeps are common in species-specific vocalizations, including human speech. Auditory neurons selective for the direction and rate of frequency change in FM sweeps are present across species, but the synaptic mechanisms underlying such selectivity are only beginning to be understood. Even less is known about mechanisms of experience-dependent changes in FM sweep selectivity. We present three network models of synaptic mechanisms of FM sweep direction and rate selectivity that explains experimental data: (1) The 'facilitation' model contains frequency selective cells operating as coincidence detectors, summing up multiple excitatory inputs with different time delays. (2) The 'duration tuned' model depends on interactions between delayed excitation and early inhibition. The strength of delayed excitation determines the preferred duration. Inhibitory rebound can reinforce the delayed excitation. (3) The 'inhibitory sideband' model uses frequency selective inputs to a network of excitatory and inhibitory cells. The strength and asymmetry of these connections results in neurons responsive to sweeps in a single direction of sufficient sweep rate. Variations of these properties, can explain the diversity of rate-dependent direction selectivity seen across species. We show that the inhibitory sideband model can be trained using spike timing dependent plasticity (STDP) to develop direction selectivity from a non-selective network. These models provide a means to compare the proposed synaptic and spectrotemporal mechanisms of FM sweep processing and can be utilized to explore cellular mechanisms underlying experience- or training-dependent changes in spectrotemporal processing across animal models. Given the analogy between FM sweeps and visual motion, these models can serve a broader function in studying stimulus movement across sensory epithelia.
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Rocha-Muniz CN, Befi-Lopes DM, Schochat E. Sensitivity, specificity and efficiency of speech-evoked ABR. Hear Res 2014; 317:15-22. [PMID: 25262622 DOI: 10.1016/j.heares.2014.09.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 08/29/2014] [Accepted: 09/09/2014] [Indexed: 11/28/2022]
Abstract
We determined the sensitivity, specificity and efficiency of speech-evoked Auditory Brainstem Response (ABR) as a diagnostic support for Auditory Processing Disorder (APD) and specific language impairment (SLI). Speech-evoked ABRs were elicited using the five-formant syllable/da/. The waveforms V, A, C, D, E, F, and O of all groups were analyzed. The sensitivity and specificity were calculated, and receiver operating characteristic analyses were performed to determine the optimum cut-off. Seventy-five children who were native speakers of Brazilian-Portuguese participated. The participants included 25 children with APD, 25 children with SLI and 25 with typical development. Statistical analysis demonstrated a cut-off for latency values of 6.48, 7.51, 17.82, 22.33, 30.79, 39.54 and 48.00 for V, A, C, D, E, F, and O waves, respectively. The A wave exhibited superior balance for the APD group. For the SLI group, the A, D and O waves exhibited the best balance. Furthermore, when analyzing the APD and SLI groups separately, better sensitivity values were observed for the SLI group than the APD group. Speech-evoked ABR is a useful test to identify auditory processing disorders and language impairment. Furthermore, this study represented an important step forward in establishing the clinical utility of speech-evoked ABR in Brazilian Portuguese-speaking children.
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Affiliation(s)
| | | | - Eliane Schochat
- University of Sao Paulo School of Medicine (USP), São Paulo, Brazil
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19
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Aubie B, Sayegh R, Fremouw T, Covey E, Faure PA. Decoding stimulus duration from neural responses in the auditory midbrain. J Neurophysiol 2014; 112:2432-45. [PMID: 25122706 DOI: 10.1152/jn.00360.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurons with responses selective for the duration of an auditory stimulus are called duration-tuned neurons (DTNs). Temporal specificity in their spiking suggests that one function of DTNs is to encode stimulus duration; however, the efficacy of duration encoding by DTNs has yet to be investigated. Herein, we characterize the information content of individual cells and a population of DTNs from the mammalian inferior colliculus (IC) by measuring the stimulus-specific information (SSI) and estimated Fisher information (FI) of spike count responses. We found that SSI was typically greatest for those stimulus durations that evoked maximum spike counts, defined as best duration (BD) stimuli, and that FI was maximal for stimulus durations off BD where sensitivity to a change in duration was greatest. Using population data, we demonstrate that a maximum likelihood estimator (MLE) can accurately decode stimulus duration from evoked spike counts. We also simulated a two-alternative forced choice task by having MLE models decide whether two durations were the same or different. With this task we measured the just-noticeable difference threshold for stimulus duration and calculated the corresponding Weber fractions across the stimulus domain. Altogether, these results demonstrate that the spiking responses of DTNs from the mammalian IC contain sufficient information for the CNS to encode, decode, and discriminate behaviorally relevant auditory signal durations.
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Affiliation(s)
- Brandon Aubie
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Riziq Sayegh
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Thane Fremouw
- Department of Psychology, University of Maine, Orono, Maine; and
| | - Ellen Covey
- Department of Psychology, University of Washington, Seattle, Washington
| | - Paul A Faure
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada;
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20
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Sayegh R, Aubie B, Faure PA. Dichotic sound localization properties of duration-tuned neurons in the inferior colliculus of the big brown bat. Front Physiol 2014; 5:215. [PMID: 24959149 PMCID: PMC4050336 DOI: 10.3389/fphys.2014.00215] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 05/20/2014] [Indexed: 11/13/2022] Open
Abstract
Electrophysiological studies on duration-tuned neurons (DTNs) from the mammalian auditory midbrain have typically evoked spiking responses from these cells using monaural or free-field acoustic stimulation focused on the contralateral ear, with fewer studies devoted to examining the electrophysiological properties of duration tuning using binaural stimulation. Because the inferior colliculus (IC) receives convergent inputs from lower brainstem auditory nuclei that process sounds from each ear, many midbrain neurons have responses shaped by binaural interactions and are selective to binaural cues important for sound localization. In this study, we used dichotic stimulation to vary interaural level difference (ILD) and interaural time difference (ITD) acoustic cues and explore the binaural interactions and response properties of DTNs and non-DTNs from the IC of the big brown bat (Eptesicus fuscus). Our results reveal that both DTNs and non-DTNs can have responses selective to binaural stimulation, with a majority of IC neurons showing some type of ILD selectivity, fewer cells showing ITD selectivity, and a number of neurons showing both ILD and ITD selectivity. This study provides the first demonstration that the temporally selective responses of DTNs from the vertebrate auditory midbrain can be selective to binaural cues used for sound localization in addition to having spiking responses that are selective for stimulus frequency, amplitude, and duration.
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Affiliation(s)
- Riziq Sayegh
- McMaster Batlab, Department of Psychology, Neuroscience & Behaviour, McMaster University Hamilton, ON, Canada
| | - Brandon Aubie
- McMaster Batlab, Department of Psychology, Neuroscience & Behaviour, McMaster University Hamilton, ON, Canada
| | - Paul A Faure
- McMaster Batlab, Department of Psychology, Neuroscience & Behaviour, McMaster University Hamilton, ON, Canada
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21
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Morrison JA, Farzan F, Fremouw T, Sayegh R, Covey E, Faure PA. Organization and trade-off of spectro-temporal tuning properties of duration-tuned neurons in the mammalian inferior colliculus. J Neurophysiol 2014; 111:2047-60. [PMID: 24572091 DOI: 10.1152/jn.00850.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurons throughout the mammalian central auditory pathway respond selectively to stimulus frequency and amplitude, and some are also selective for stimulus duration. First found in the auditory midbrain or inferior colliculus (IC), these duration-tuned neurons (DTNs) provide a potential neural mechanism for encoding temporal features of sound. In this study, we investigated how having an additional neural response filter, one selective to the duration of an auditory stimulus, influences frequency tuning and neural organization by recording single-unit responses and measuring the dorsal-ventral position and spectral-temporal tuning properties of auditory DTNs from the IC of the awake big brown bat (Eptesicus fuscus). Like other IC neurons, DTNs were tonotopically organized and had either V-shaped, U-shaped, or O-shaped frequency tuning curves (excitatory frequency response areas). We hypothesized there would be an interaction between frequency and duration tuning in DTNs, as electrical engineering theory for resonant filters dictates a trade-off in spectral-temporal resolution: sharp tuning in the frequency domain results in poorer resolution in the time domain and vice versa. While the IC is a more complex signal analyzer than an electrical filter, a similar operational trade-off could exist in the responses of DTNs. Our data revealed two patterns of spectro-temporal sensitivity and spatial organization within the IC: DTNs with sharp frequency tuning and broad duration tuning were located in the dorsal IC, whereas cells with wide spectral tuning and narrow temporal tuning were found in the ventral IC.
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Affiliation(s)
- James A Morrison
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Faranak Farzan
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Thane Fremouw
- Department of Psychology, University of Maine, Orono, Maine; and
| | - Riziq Sayegh
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Ellen Covey
- Department of Psychology, University of Washington, Seattle, Washington
| | - Paul A Faure
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada;
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22
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Wang N, Wang X, Yang X, Tang J, Xiao Z. Interdependent effects of sound duration and amplitude on neuronal onset response in mice inferior colliculus. Brain Res 2014; 1543:209-22. [PMID: 24201024 DOI: 10.1016/j.brainres.2013.10.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/10/2013] [Accepted: 10/21/2013] [Indexed: 11/30/2022]
Abstract
In this study, we adopted iso-frequency pure tone bursts to investigate the interdependent effects of sound amplitude/intensity and duration on mice inferior colliculus (IC) neuronal onset responses. On the majority of the sampled neurons (n=57, 89.1%), sound amplitude and duration had effects on the neuronal response to each other by showing complex changes of the rat-intensity function/duration selectivity types and/or best amplitudes (BAs)/durations (BDs), evaluated by spike counts. These results suggested that the balance between the excitatory and inhibitory inputs set by one acoustic parameter, amplitude or duration, affected the neuronal spike counts responses to the other. Neuronal duration selectivity types were altered easily by the low-amplitude sounds while the changes of rate-intensity function types had no obvious preferred stimulus durations. However, the first spike latencies (FSLs) of the onset response neurons were relative stable to iso-amplitude sound durations and changing systematically along with the sound levels. The superimposition of FSL and duration threshold (DT) as a function of stimulus amplitude after normalization indicated that the effects of the sound levels on FSLs are considered on DT actually.
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Affiliation(s)
- Ningqian Wang
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou 510515, China
| | - Xiao Wang
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou 510515, China
| | - Xiaoli Yang
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou 510515, China
| | - Jie Tang
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou 510515, China
| | - Zhongju Xiao
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou 510515, China.
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23
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Abstract
AbstractOffset neurons which respond to the termination of the sound stimulation may play important roles in auditory temporal information processing, sound signal recognition, and complex distinction. Two additional possible mechanisms were reviewed: neural inhibition and the intrinsic conductance property of offset neuron membranes. The underlying offset response was postulated to be located in the superior paraolivary nucleus of mice. The biological significance of the offset neurons was discussed as well.
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24
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Trujillo M, Razak KA. Altered cortical spectrotemporal processing with age-related hearing loss. J Neurophysiol 2013; 110:2873-86. [DOI: 10.1152/jn.00423.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Presbycusis (age-related hearing loss) is a prevalent disability associated with aging that impairs spectrotemporal processing, but the mechanisms of such changes remain unclear. The goal of this study was to quantify cortical responses to frequency-modulated (FM) sweeps in a mouse model of presbycusis. Previous studies showed that cortical neurons in young mice are selective for the rate of frequency change in FM sweeps. Here single-unit data on cortical selectivity and response variability to FM sweeps of either direction and different rates (0.08–20 kHz/ms) were compared across young (1–3 mo), middle-aged (6–8 mo), and old (14–20 mo) groups. Three main findings are reported. First, there is a reduction in FM rate selectivity in the old group. Second, there is a slowing of the sweep rates at which neurons likely provide best detection and discrimination of sweep rates. Third, there is an increase in trial-to-trial variability in the magnitude and timing of spikes in response to sweeps. These changes were only observed in neurons that were selective for the fast or intermediate range of sweep rates and not in neurons that preferred slow sweeps or were nonselective. Increased variability of response magnitude, but not changes in temporal fidelity or selectivity, was seen even in the middle-aged group. The results show that spectrotemporal processing becomes slow and noisy with presbycusis in specific types of neurons, suggesting receptive field mechanisms that are altered. These data suggest neural correlates of presbycusis-related reduction in the ability of humans to process rapid spectrotemporal changes.
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Affiliation(s)
- Michael Trujillo
- Graduate Neuroscience Program and Department of Psychology, University of California, Riverside, California
| | - Khaleel A. Razak
- Graduate Neuroscience Program and Department of Psychology, University of California, Riverside, California
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25
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Heron J, Hotchkiss J, Aaen-Stockdale C, Roach NW, Whitaker D. A neural hierarchy for illusions of time: duration adaptation precedes multisensory integration. J Vis 2013; 13:13.14.4. [PMID: 24306853 DOI: 10.1167/13.14.4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Perceived time is inherently malleable. For example, adaptation to relatively long or short sensory events leads to a repulsive aftereffect such that subsequent events appear to be contracted or expanded (duration adaptation). Perceived visual duration can also be distorted via concurrent presentation of discrepant auditory durations (multisensory integration). The neural loci of both distortions remain unknown. In the current study we use a psychophysical approach to establish their relative positioning within the sensory processing hierarchy. We show that audiovisual integration induces marked distortions of perceived visual duration. We proceed to use these distorted durations as visual adapting stimuli yet find subsequent visual duration aftereffects to be consistent with physical rather than perceived visual duration. Conversely, the concurrent presentation of adapted auditory durations with nonadapted visual durations results in multisensory integration patterns consistent with perceived, rather than physical, auditory duration. These results demonstrate that recent sensory history modifies human duration perception prior to the combination of temporal information across sensory modalities and provides support for adaptation mechanisms mediated by duration selective neurons situated in early areas of the visual and auditory nervous system (Aubie, Sayegh, & Faure, 2012; Duysens, Schaafsma, & Orban, 1996; Leary, Edwards, & Rose, 2008).
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Affiliation(s)
- James Heron
- Bradford School of Optometry and Vision Science, University of Bradford, Bradford, UK
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26
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Anderson S, Parbery-Clark A, White-Schwoch T, Kraus N. Auditory brainstem response to complex sounds predicts self-reported speech-in-noise performance. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2013; 56:31-43. [PMID: 22761320 PMCID: PMC3648418 DOI: 10.1044/1092-4388(2012/12-0043)] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
PURPOSE To compare the ability of the auditory brainstem response to complex sounds (cABR) to predict subjective ratings of speech understanding in noise on the Speech, Spatial, and Qualities of Hearing Scale (SSQ; Gatehouse & Noble, 2004) relative to the predictive ability of the Quick Speech-in-Noise test (QuickSIN; Killion, Niquette, Gudmundsen, Revit, & Banerjee, 2004) and pure-tone hearing thresholds. METHOD Participants included 111 middle- to older-age adults (range = 45-78) with audiometric configurations ranging from normal hearing levels to moderate sensorineural hearing loss. In addition to using audiometric testing, the authors also used such evaluation measures as the QuickSIN, the SSQ, and the cABR. RESULTS Multiple linear regression analysis indicated that the inclusion of brainstem variables in a model with QuickSIN, hearing thresholds, and age accounted for 30% of the variance in the Speech subtest of the SSQ, compared with significantly less variance (19%) when brainstem variables were not included. CONCLUSION The authors' results demonstrate the cABR's efficacy for predicting self-reported speech-in-noise perception difficulties. The fact that the cABR predicts more variance in self-reported speech-in-noise (SIN) perception than either the QuickSIN or hearing thresholds indicates that the cABR provides additional insight into an individual's ability to hear in background noise. In addition, the findings underscore the link between the cABR and hearing in noise.
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Affiliation(s)
- Samira Anderson
- Auditory Neuroscience Laboratory, Northwestern University, Evanston, IL, USA.
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27
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Trujillo M, Carrasco MM, Razak K. Response properties underlying selectivity for the rate of frequency modulated sweeps in the auditory cortex of the mouse. Hear Res 2013; 298:80-92. [PMID: 23340378 DOI: 10.1016/j.heares.2012.12.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 12/10/2012] [Accepted: 12/21/2012] [Indexed: 10/27/2022]
Abstract
This study focused on the response properties underlying selectivity for the rate of frequency modulated (FM) sweeps in the auditory cortex of anesthetized C57bl/6 (C57) mice. Linear downward FM sweeps with rates between 0.08 and 20 kHz/ms were tested. We show that at least two different response properties predict FM rate selectivity: sideband inhibition and duration tuning. Sideband inhibition was determined using the two-tone inhibition paradigm in which excitatory and inhibitory tones were presented with different delays. Sideband inhibition was present in the majority (88%, n = 53) of neurons. The spectrotemporal properties of sideband inhibition predicted rate selectivity and exclusion of the sideband from the sweep reduced/eliminated rate tuning. The second property predictive of sweep rate selectivity was duration tuning for tones. Theoretically, if a neuron is selective for the duration that a sweep spends in the excitatory frequency tuning curve, then rate selectivity will ensue. Duration tuning for excitatory tones was present and predicted rate selectivity in ∼34% of neurons (n = 97). Both sideband inhibition and duration tuning predicted rate selectivity equally well, but sideband inhibition was present in a larger percentage of neurons suggesting that it is the dominant mechanism in the C57 mouse auditory cortex. Similar mechanisms shape sweep rate selectivity in the auditory system of bats and mice and movement-velocity selectivity in the visual system, suggesting similar solutions to analogous problems across sensory systems. This study provides baseline data on basic spectrotemporal processing in the C57 strain for elucidation of changes that occur in presbycusis.
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Affiliation(s)
- Michael Trujillo
- Neuroscience Program and Psychology Department, University of California, Riverside, CA 92521, USA
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28
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Ayala YA, Malmierca MS. Stimulus-specific adaptation and deviance detection in the inferior colliculus. Front Neural Circuits 2013; 6:89. [PMID: 23335883 PMCID: PMC3547232 DOI: 10.3389/fncir.2012.00089] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Accepted: 11/02/2012] [Indexed: 11/26/2022] Open
Abstract
Deviancy detection in the continuous flow of sensory information into the central nervous system is of vital importance for animals. The task requires neuronal mechanisms that allow for an efficient representation of the environment by removing statistically redundant signals. Recently, the neuronal principles of auditory deviance detection have been approached by studying the phenomenon of stimulus-specific adaptation (SSA). SSA is a reduction in the responsiveness of a neuron to a common or repetitive sound while the neuron remains highly sensitive to rare sounds (Ulanovsky et al., 2003). This phenomenon could enhance the saliency of unexpected, deviant stimuli against a background of repetitive signals. SSA shares many similarities with the evoked potential known as the “mismatch negativity,” (MMN) and it has been linked to cognitive process such as auditory memory and scene analysis (Winkler et al., 2009) as well as to behavioral habituation (Netser et al., 2011). Neurons exhibiting SSA can be found at several levels of the auditory pathway, from the inferior colliculus (IC) up to the auditory cortex (AC). In this review, we offer an account of the state-of-the art of SSA studies in the IC with the aim of contributing to the growing interest in the single-neuron electrophysiology of auditory deviance detection. The dependence of neuronal SSA on various stimulus features, e.g., probability of the deviant stimulus and repetition rate, and the roles of the AC and inhibition in shaping SSA at the level of the IC are addressed.
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Affiliation(s)
- Yaneri A Ayala
- Laboratory for the Neurobiology of Hearing, Auditory Neurophysiology Unit, Institute of Neuroscience of Castilla y León, University of Salamanca Salamanca, Spain
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29
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Pérez-González D, Malmierca MS. Variability of the time course of stimulus-specific adaptation in the inferior colliculus. Front Neural Circuits 2012; 6:107. [PMID: 23293586 PMCID: PMC3530767 DOI: 10.3389/fncir.2012.00107] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 12/03/2012] [Indexed: 01/25/2023] Open
Abstract
Stimulus-specific adaptation (SSA) is the ability of some neurons to respond better to rare than to frequent, repetitive stimuli. In the auditory system, SSA has been found at the level of the midbrain, thalamus, and cortex. While previous studies have used the whole overall neuronal response to characterize SSA, here we present a detailed analysis on the variations within the time course of the evoked responses. The extracellular activity of well isolated single neurons from the inferior colliculus (IC) was recorded during stimulation using an oddball paradigm, which is able to elicit SSA. At the same time, these responses were evaluated before, during, and after the microiontophoretic application of gabazine, a specific antagonist of GABA(A) receptors, to study the contribution of inhibition to the responses of these neurons. We then analyzed the difference signal (DS), which is the difference in the PSTH in response to rare and frequent stimuli. We found that, even in a sample of neurons showing strong SSA (i.e., showing larger preference for rare stimuli), the DS was variable and one third of the neurons contained portions that responded significantly better to the frequent stimuli than to the rare. This variability is not observed when averaging the responses of multiple cells. Furthermore, the blockade of GABA(A) receptors increased the number of neurons showing portions that responded better to the frequent stimuli, indicating that inhibition in the IC refines and sharpens SSA in the neural responses.
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Affiliation(s)
- David Pérez-González
- Auditory Neurophysiology Laboratory, Institute of Neuroscience of Castilla y León, University of Salamanca Salamanca, Spain
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30
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Ouda L, Syka J. Immunocytochemical profiles of inferior colliculus neurons in the rat and their changes with aging. Front Neural Circuits 2012; 6:68. [PMID: 23049499 PMCID: PMC3448074 DOI: 10.3389/fncir.2012.00068] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 09/04/2012] [Indexed: 12/04/2022] Open
Abstract
The inferior colliculus (IC) plays a strategic role in the central auditory system in relaying and processing acoustical information, and therefore its age-related changes may significantly influence the quality of the auditory function. A very complex processing of acoustical stimuli occurs in the IC, as supported also by the fact that the rat IC contains more neurons than all other subcortical auditory structures combined. GABAergic neurons, which predominantly co-express parvalbumin (PV), are present in the central nucleus of the IC in large numbers and to a lesser extent in the dorsal and external/lateral cortices of the IC. On the other hand, calbindin (CB) and calretinin (CR) are prevalent in the dorsal and external cortices of the IC, with only a few positive neurons in the central nucleus. The relationship between CB and CR expression in the IC and any neurotransmitter system has not yet been well established, but the distribution and morphology of the immunoreactive neurons suggest that they are at least partially non-GABAergic cells. The expression of glutamate decarboxylase (GAD) (a key enzyme for GABA synthesis) and calcium binding proteins (CBPs) in the IC of rats undergoes pronounced changes with aging that involve mostly a decline in protein expression and a decline in the number of immunoreactive neurons. Similar age-related changes in GAD, CB, and CR expression are present in the IC of two rat strains with differently preserved inner ear function up to late senescence (Long-Evans and Fischer 344), which suggests that these changes do not depend exclusively on peripheral deafferentation but are, at least partially, of central origin. These changes may be associated with the age-related deterioration in the processing of the temporal parameters of acoustical stimuli, which is not correlated with hearing threshold shifts, and therefore may contribute to central presbycusis.
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Affiliation(s)
- Ladislav Ouda
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic Prague, Czech Republic
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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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Williams AJ, Fuzessery ZM. Multiple mechanisms shape FM sweep rate selectivity: complementary or redundant? Front Neural Circuits 2012; 6:54. [PMID: 22912604 PMCID: PMC3421451 DOI: 10.3389/fncir.2012.00054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 07/30/2012] [Indexed: 11/16/2022] Open
Abstract
Auditory neurons in the inferior colliculus (IC) of the pallid bat have highly rate selective responses to downward frequency modulated (FM) sweeps attributable to the spectrotemporal pattern of their echolocation call (a brief FM pulse). Several mechanisms are known to shape FM rate selectivity within the pallid bat IC. Here we explore how two mechanisms, stimulus duration and high-frequency inhibition (HFI), can interact to shape FM rate selectivity within the same neuron. Results from extracellular recordings indicated that a derived duration-rate function (based on tonal response) was highly predictive of the shape of the FM rate response. Longpass duration selectivity for tones was predictive of slowpass rate selectivity for FM sweeps, both of which required long stimulus durations and remained intact following iontophoretic blockade of inhibitory input. Bandpass duration selectivity for tones, sensitive to only a narrow range of tone durations, was predictive of bandpass rate selectivity for FM sweeps. Conversion of the tone duration response from bandpass to longpass after blocking inhibition was coincident with a change in FM rate selectivity from bandpass to slowpass indicating an active inhibitory component to the formation of bandpass selectivity. Independent of the effect of duration tuning on FM rate selectivity, the presence of HFI acted as a fastpass FM rate filter by suppressing slow FM sweep rates. In cases where both mechanisms were present, both had to be eliminated, by removing inhibition, before bandpass FM rate selectivity was affected. It is unknown why the auditory system utilizes multiple mechanisms capable of shaping identical forms of FM rate selectivity though it may represent distinct but convergent modes of neural signaling directed at shaping response selectivity for important biologically relevant sounds.
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Affiliation(s)
- Anthony J Williams
- Department of Zoology and Physiology, University of Wyoming Laramie, WY, USA
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Abstract
Signal duration is important for identifying sound sources and determining signal meaning. Duration-tuned neurons (DTNs) respond preferentially to a range of stimulus durations and maximally to a best duration (BD). Duration-tuned neurons are found in the auditory midbrain of many vertebrates, although studied most extensively in bats. Studies of DTNs across vertebrates have identified cells with BDs and temporal response bandwidths that mirror the range of species-specific vocalizations. Neural tuning to stimulus duration appears to be universal among hearing vertebrates. Herein, we test the hypothesis that neural mechanisms underlying duration selectivity may be similar across vertebrates. We instantiated theoretical mechanisms of duration tuning in computational models to systematically explore the roles of excitatory and inhibitory receptor strengths, input latencies, and membrane time constant on duration tuning response profiles. We demonstrate that models of duration tuning with similar neural circuitry can be tuned with species-specific parameters to reproduce the responses of in vivo DTNs from the auditory midbrain. To relate and validate model output to in vivo responses, we collected electrophysiological data from the inferior colliculus of the awake big brown bat, Eptesicus fuscus, and present similar in vivo data from the published literature on DTNs in rats, mice, and frogs. Our results support the hypothesis that neural mechanisms of duration tuning may be shared across vertebrates despite species-specific differences in duration selectivity. Finally, we discuss how the underlying mechanisms of duration selectivity relate to other auditory feature detectors arising from the interaction of neural excitation and inhibition.
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Jen PHS, Wu CH, Wang X. Dynamic temporal signal processing in the inferior colliculus of echolocating bats. Front Neural Circuits 2012; 6:27. [PMID: 22586374 PMCID: PMC3347223 DOI: 10.3389/fncir.2012.00027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 04/20/2012] [Indexed: 11/17/2022] Open
Abstract
In nature, communication sounds among animal species including humans are typical complex sounds that occur in sequence and vary with time in several parameters including amplitude, frequency, duration as well as separation, and order of individual sounds. Among these multiple parameters, sound duration is a simple but important one that contributes to the distinct spectral and temporal attributes of individual biological sounds. Likewise, the separation of individual sounds is an important temporal attribute that determines an animal's ability in distinguishing individual sounds. Whereas duration selectivity of auditory neurons underlies an animal's ability in recognition of sound duration, the recovery cycle of auditory neurons determines a neuron's ability in responding to closely spaced sound pulses and therefore, it underlies the animal's ability in analyzing the order of individual sounds. Since the multiple parameters of naturally occurring communication sounds vary with time, the analysis of a specific sound parameter by an animal would be inevitably affected by other co-varying sound parameters. This is particularly obvious in insectivorous bats, which rely on analysis of returning echoes for prey capture when they systematically vary the multiple pulse parameters throughout a target approach sequence. In this review article, we present our studies of dynamic variation of duration selectivity and recovery cycle of neurons in the central nucleus of the inferior colliculus of the frequency-modulated bats to highlight the dynamic temporal signal processing of central auditory neurons. These studies use single pulses and three biologically relevant pulse-echo (P-E) pairs with varied duration, gap, and amplitude difference similar to that occurring during search, approach, and terminal phases of hunting by bats. These studies show that most collicular neurons respond maximally to a best tuned sound duration (BD). The sound duration to which these neurons are tuned correspond closely to the behaviorally relevant sounds occurring at different phases of hunting. The duration selectivity of these collicular neurons progressively increases with decrease in the duration of pulse and echo, P-E gap, and P-E amplitude difference. GABAergic inhibition plays an important role in shaping the duration selectivity of these collicular neurons. The duration selectivity of these neurons is systematically organized along the tonotopic axis of the inferior colliculus and is closely correlated with the graded spatial distribution of GABAA receptors. Duration-selective collicular neurons have a wide range of recovery cycle covering the P-E intervals occurring throughout the entire target approaching sequences. Collicular neurons with low best frequency and short BD recover rapidly when stimulated with P-E pairs with short duration and small P-E amplitude difference, whereas neurons with high best frequency and long BD recover rapidly when stimulated with P-E pairs with long duration and large P-E amplitude difference. This dynamic variation of echo duration selectivity and recovery cycle of collicular neurons may serve as the neural basis underlying successful hunting by bats. Conceivably, high best frequency neurons with long BD would be suitable for echo recognition during search and approach phases of hunting when the returning echoes are high in frequency, large in P-E amplitude difference, long in duration but low in repetition rate. Conversely, low best frequency neurons with shorter BD and sharper duration selectivity would be suitable for echo recognition during the terminal phase of hunting when the highly repetitive echoes are low in frequency, small in P-E amplitude difference, and short in duration. Furthermore, the tonotopically organized duration selectivity would make it possible to facilitate the recruitment of different groups of collicular neurons along the tonotopic axis for effective processing of the returning echoes throughout the entire course of hunting.
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Affiliation(s)
- Philip H-S Jen
- Division of Biological Sciences and Interdisciplinary Neurobiology Program, University of Missouri, Columbia MO, USA
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Pérez-González D, Hernández O, Covey E, Malmierca MS. GABA(A)-mediated inhibition modulates stimulus-specific adaptation in the inferior colliculus. PLoS One 2012; 7:e34297. [PMID: 22479591 PMCID: PMC3315508 DOI: 10.1371/journal.pone.0034297] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 02/28/2012] [Indexed: 01/27/2023] Open
Abstract
The ability to detect novel sounds in a complex acoustic context is crucial for survival. Neurons from midbrain through cortical levels adapt to repetitive stimuli, while maintaining responsiveness to rare stimuli, a phenomenon called stimulus-specific adaptation (SSA). The site of origin and mechanism of SSA are currently unknown. We used microiontophoretic application of gabazine to examine the role of GABA(A)-mediated inhibition in SSA in the inferior colliculus, the midbrain center for auditory processing. We found that gabazine slowed down the process of adaptation to high probability stimuli but did not abolish it, with response magnitude and latency still depending on the probability of the stimulus. Blocking GABA(A) receptors increased the firing rate to high and low probability stimuli, but did not completely equalize the responses. Together, these findings suggest that GABA(A)-mediated inhibition acts as a gain control mechanism that enhances SSA by modifying the responsiveness of the neuron.
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Affiliation(s)
- David Pérez-González
- Auditory Neurophysiology Unit, Institute of Neuroscience of Castilla y León, University of Salamanca, Salamanca, Spain
| | - Olga Hernández
- Auditory Neurophysiology Unit, Institute of Neuroscience of Castilla y León, University of Salamanca, Salamanca, Spain
- Faculty of Medicine, Department of Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
| | - Ellen Covey
- Auditory Neurophysiology Unit, Institute of Neuroscience of Castilla y León, University of Salamanca, Salamanca, Spain
- Department of Psychology, University of Washington, Seattle, Washington United States of America
| | - Manuel S. Malmierca
- Auditory Neurophysiology Unit, Institute of Neuroscience of Castilla y León, University of Salamanca, Salamanca, Spain
- Faculty of Medicine, Department of Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
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36
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Macías S, Mora EC, Hechavarría JC, Kössl M. Duration tuning in the inferior colliculus of the mustached bat. J Neurophysiol 2011; 106:3119-28. [PMID: 21917994 DOI: 10.1152/jn.00294.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We studied duration tuning in neurons of the inferior colliculus (IC) of the mustached bat. Duration-tuned neurons in the IC of the mustached bat fall into three main types: short (16 of 136), band (34 of 136), and long (29 of 136) pass. The remaining 51 neurons showed no selectivity for the duration of sounds. The distribution of best durations was double peaked with maxima around 3 and 17 ms, which correlate with the duration of the short frequency-modulated (FM) and the long constant-frequency (CF) signals emitted by Pteronotus parnellii. Since there are no individual neurons with a double-peaked duration response profile, both types of temporal processing seem to be well segregated in the IC. Most short- and band-pass units with best frequency in the CF2 range responded to best durations > 9 ms (66%, 18 of 27 units). However, there is no evidence for a bias toward longer durations as there is for neurons tuned to the frequency range of the FM component of the third harmonic, where 83% (10 of 12 neurons) showed best durations longer than 9 ms. In most duration-tuned neurons, response areas as a function of stimulus duration and intensity showed either V or U shape, with duration tuning retained across the range of sound levels tested. Duration tuning was affected by changes in sound pressure level in only six neurons. In all duration-tuned neurons, latencies measured at the best duration were longer than best durations, suggesting that behavioral decisions based on analysis of the duration of the pulses would not be expected to be complete until well after the stimulus has occurred.
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Affiliation(s)
- Silvio Macías
- Department of Animal and Human Biology, Faculty of Biology, Havana University, Ciudad de La Habana, Cuba.
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37
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Williams AJ, Fuzessery ZM. Differential roles of GABAergic and glycinergic input on FM selectivity in the inferior colliculus of the pallid bat. J Neurophysiol 2011; 106:2523-35. [PMID: 21775712 DOI: 10.1152/jn.00569.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Multiple mechanisms have been shown to shape frequency-modulated (FM) selectivity within the central nucleus of the inferior colliculus (IC) in the pallid bat. In this study we focus on the mechanisms associated with sideband inhibition. The relative arrival time of inhibition compared with excitation can be used to predict FM responses as measured with a two-tone inhibition paradigm. An early-arriving low-frequency inhibition (LFI) prevents responses to upward sweeps and thus shapes direction selectivity. A late-arriving high-frequency inhibition (HFI) suppresses slow FM sweeps and thus shapes rate selectivity for downward sweeps. Iontophoretic application of gabazine (GBZ) to block GABA(A) receptors or strychnine (Strych) to block glycine receptors was used to assess the effects of removal of inhibition on each form of FM selectivity. GBZ and Strych had a similar effect on FM direction selectivity, reducing selectivity in up to 86% of neurons when both drugs were coapplied. FM rate selectivity was more resistant to drug application with less than 38% of neurons affected. In addition, only Strych could eliminate FM rate selectivity, whereas GBZ alone was ineffective. The loss of FM selectivity was directly correlated to a loss of the respective inhibitory sideband that shapes that form of selectivity. The elimination of LFI correlated to a loss of FM direction selectivity, whereas elimination of HFI correlated to a loss of FM rate selectivity. Results indicate that 1) although the majority of FM direction selectivity is created within the IC, the majority of rate selectivity is inherited from lower levels of the auditory system, 2) a loss of LFI corresponds to a loss of FM direction selectivity and is created through either GABAergic or glycinergic input, and 3) a loss of HFI corresponds to a loss of FM rate selectivity and is created mainly through glycinergic input.
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Affiliation(s)
- Anthony J Williams
- Dept. of Zoology and Physiology, Univ. of Wyoming, 1000 E. Univ. Ave., Laramie, WY 82071, USA
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38
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39
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Duration tuning in the auditory midbrain of echolocating and non-echolocating vertebrates. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 197:571-83. [PMID: 21305304 DOI: 10.1007/s00359-011-0627-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Revised: 01/03/2011] [Accepted: 01/22/2011] [Indexed: 10/18/2022]
Abstract
Neurons tuned for stimulus duration were first discovered in the auditory midbrain of frogs. Duration-tuned neurons (DTNs) have since been reported from the central auditory system of both echolocating and non-echolocating mammals, and from the central visual system of cats. We hypothesize that the functional significance of auditory duration tuning likely varies between species with different evolutionary histories, sensory ecologies, and bioacoustic constraints. For example, in non-echolocating animals such as frogs and mice the temporal filtering properties of auditory DTNs may function to discriminate species-specific communication sounds. In echolocating bats duration tuning may also be used to create cells with highly selective responses for specific rates of frequency modulation and/or pulse-echo delays. The ability to echolocate appears to have selected for high temporal acuity in the duration tuning curves of inferior colliculus neurons in bats. Our understanding of the neural mechanisms underlying sound duration selectivity has improved substantially since DTNs were first discovered almost 50 years ago, but additional research is required for a comprehensive understanding of the functional role and the behavioral significance that duration tuning plays in sensory systems.
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40
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Miller K, Covey E. Comparison of auditory responses in the medial geniculate and pontine gray of the big brown bat, Eptesicus fuscus. Hear Res 2010; 275:53-65. [PMID: 21145384 DOI: 10.1016/j.heares.2010.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 10/27/2010] [Accepted: 12/01/2010] [Indexed: 11/16/2022]
Abstract
The inferior colliculus has been well studied for its role of transmitting information from the brainstem to the thalamocortical system. However, it is also the source of a major pathway to the cerebellum, via the pontine gray (PG). We compared auditory responses from single neurons in the medial geniculate body (MGB) and PG of the awake big brown bat. MGB neurons were selective for a variety of stimulus types whereas PG neurons only responded to pure tones or simple FM sweeps. Best frequencies (BF) in MGB ranged from 8 kHz to > 80 kHz. BFs of PG neurons were all above 20 kHz with a high proportion above 60 kHz. The mean response latency was 19 ms for MGB neurons and 11 ms for PG neurons. MGB and PG contained neurons with a variety of discharge patterns but the most striking difference was the proportion of neurons with responses that lasted longer than the stimulus duration (MGB 13%, PG 58%). Both nuclei contained duration-sensitive neurons; the majority of those in MGB were band pass whereas in the PG they were long pass. Over half of the neurons in both nuclei were binaural. Differences between these nuclei are consistent with the idea that the thalamocortical pathway performs integration over time for cognitive analysis, thereby increasing selectivity and lengthening latency, while the colliculo-pontine pathway, which is more concerned with sensory-motor control, provides rapid input and a lasting trace of an auditory event.
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Affiliation(s)
- Kimberly Miller
- Department of Psychology, University of Washington, Seattle, Box 351525, WA 98195, USA
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41
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Nagtegaal AP, Borst J. In Vivo Dynamic Clamp Study of Ih in the Mouse Inferior Colliculus. J Neurophysiol 2010; 104:940-8. [DOI: 10.1152/jn.00264.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Approximately half of the cells in the mouse inferior colliculus have the hyperpolarization-activated mixed cation current Ih, yet little is known about its functional relevance in vivo. We therefore studied its contribution to the processing of sound information in single cells by making in vivo whole cell recordings from the inferior colliculus (IC) of young-adult anesthetized C57Bl/6 mice. Following pharmacological block of the endogenous channels, a dynamic clamp approach allowed us to study the responses to current injections or auditory stimuli in the presence and absence of Ih within the same neuron, thus avoiding network or developmental effects. The presence of Ih changed basic cellular properties, including depolarizing the resting membrane potential and decreasing resting membrane resistance. Sound-evoked excitatory postsynaptic potentials were smaller but at the same time reached a more positive membrane potential when Ih was present. With Ih, a subset of cells showed rebound spiking following hyperpolarizing current injection. Its presence also changed more complex cellular properties. It decreased temporal summation in response to both hyperpolarizing and depolarizing repetitive current stimuli, and resulted in small changes in the cycle-averaged membrane potential during sinusoidal amplitude modulated (SAM) tones. Furthermore, Ih minimally decreased the response to a tone following a depolarization, an effect that may make a small contribution to forward masking. Our results thus suggest that previously observed differences in IC cells are a mixture of direct effects of Ih and indirect effects due to the change in membrane potential or effects due to the co-expression with other channels.
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Affiliation(s)
- A. P. Nagtegaal
- Departments of Neuroscience and
- Otorhinolaryngology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
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42
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Pollak GD, Xie R, Gittelman JX, Andoni S, Li N. The dominance of inhibition in the inferior colliculus. Hear Res 2010; 274:27-39. [PMID: 20685288 DOI: 10.1016/j.heares.2010.05.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 05/19/2010] [Accepted: 05/19/2010] [Indexed: 11/16/2022]
Abstract
Almost all of the processing that occurs in the various lower auditory nuclei converges upon a common target in the central nucleus of the inferior colliculus (ICc) thus making the ICc the nexus of the auditory system. A variety of new response properties are formed in the ICc through the interactions among the excitatory and inhibitory inputs that converge upon it. Here we review studies that illustrate the dominant role inhibition plays in the ICc. We begin by reviewing studies of tuning curves and show how inhibition shapes the variety of tuning curves in the ICc through sideband inhibition. We then show how inhibition shapes selective response properties for complex signals, focusing on selectivity for the sweep direction of frequency modulations (FM). In the final section we consider results from in vivo whole-cell recordings that show how parameters of the incoming excitation and inhibition interact to shape directional selectivity. We show that post-synaptic potentials (PSPs) evoked by different signals can be similar but evoke markedly different spike-counts. In these cases, spike threshold acts as a non-linear amplifier that converts small differences in PSPs into large differences in spike output. Such differences between the inputs to a cell compared to the outputs from the same cell suggest that highly selective discharge properties can be created by only minor adjustments in the synaptic strengths evoked by one or both signals. These findings also suggest that plasticity of response features may be achieved with far less modifications in circuitry than previously supposed.
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Affiliation(s)
- George D Pollak
- Section of Neurobiology, The University of Texas at Austin, Austin, TX 78712, USA.
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43
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Rodríguez FA, Read HL, Escabí MA. Spectral and temporal modulation tradeoff in the inferior colliculus. J Neurophysiol 2009; 103:887-903. [PMID: 20018831 DOI: 10.1152/jn.00813.2009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The cochlea encodes sounds through frequency-selective channels that exhibit low-pass modulation sensitivity. Unlike the cochlea, neurons in the auditory midbrain are tuned for spectral and temporal modulations found in natural sounds, yet the role of this transformation is not known. We report a distinct tradeoff in modulation sensitivity and tuning that is topographically ordered within the central nucleus of the inferior colliculus (CNIC). Spectrotemporal receptive fields (STRFs) were obtained with 16-channel electrodes inserted orthogonal to the isofrequency lamina. Surprisingly, temporal and spectral characteristics exhibited an opposing relationship along the tonotopic axis. For low best frequencies (BFs), units were selective for fast temporal and broad spectral modulations. A systematic progression was observed toward slower temporal and finer spectral modulation sensitivity at high BF. This tradeoff was strongly reflected in the arrangement of excitation and inhibition and, consequently, in the modulation tuning characteristics. Comparisons with auditory nerve fibers show that these trends oppose the pattern imposed by the peripheral filters. These results suggest that spectrotemporal preferences are reordered within the tonotopic axis of the CNIC. This topographic organization has profound implications for the coding of spectrotemporal features in natural sounds and could underlie a number of perceptual phenomena.
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Liu F, Zhang M, Tang ZQ, Lu YG, Chen L. Inhibitory effects of amiloride on the current mediated by native GABA(A) receptors in cultured neurons of rat inferior colliculus. Clin Exp Pharmacol Physiol 2009; 37:435-40. [PMID: 19878215 DOI: 10.1111/j.1440-1681.2009.05325.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. The diuretic amiloride is known to modulate the activity of several types of ion channels and membrane receptors in addition to its inhibitory effects on many ion transport systems. However, the effects of amiloride on some important ion channels and receptors, such as GABA(A) receptors, in the central nervous system have not been characterized. 2. In the present study, we investigated the functional action of amiloride on native GABA(A) receptors in cultured neurons of rat inferior colliculus using whole-cell patch-clamp recordings. 3. Amiloride reversibly inhibited the amplitude of the GABA-induced current (I(GABA)) in a concentration-dependent manner (IC(50) 454 +/- 24 micromol/L) under conditions of voltage-clamp with a holding potential at -60 mV. The inhibition depended on drug application mode and was independent of membrane potential. Amiloride did not change the reversal potential of I(GABA). Moreover, amiloride induced a parallel right-ward shift in the concentration-response curve for I(GABA) without altering the maximal value and Hill coefficient. 4. The present study shows that amiloride competitively inhibits the current mediated by native GABA(A) receptors in the brain region, probably via a direct action on GABA-binding sites on the receptor. The findings suggest that the functional actions of amiloride on GABA(A) receptors may result in possible side-effects on the central nervous system in the case of direct application of this drug into the cerebrospinal fluid for treatment of diseases such as brain tumours.
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Affiliation(s)
- Feng Liu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China
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45
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Abstract
Discrimination of stimulus duration on the order of milliseconds has been observed in behavioral and neurophysiological studies across a variety of species and taxa. Several studies conducted in mammals have found neurons in the auditory midbrain (inferior colliculus) that are selective for signal duration. Duration selectivity in these cells arises from an interaction of excitatory and inhibitory events occurring at particular latencies from stimulus onset and offset. As previously shown in barn owls, coincidence of delayed, excitatory events can be used by the CNS to respond selectively to specific stimuli in auditory space. This study formulates several computational models of duration tuning that combine existing conceptual models with observed physiological responses in the auditory brainstem and midbrain to evaluate the plausibility of the proposed neural mechanisms. The computational models are able to reproduce a wide range of in vivo responses including best duration tuning, duration-selective response classes, spike counts, first-spike latencies, level tolerance to changes in signal amplitude, and neuropharmacological effects of applying inhibitory neurotransmitter antagonists to duration-tuned neurons. A unified model of duration tuning is proposed that enhances classic models of duration tuning, emphasizes similarities across the models, and simplifies our understanding of duration tuning across species and sensory modalities.
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46
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Kutscher A, Covey E. Functional role of GABAergic and glycinergic inhibition in the intermediate nucleus of the lateral lemniscus of the big brown bat. J Neurophysiol 2009; 101:3135-46. [PMID: 19369365 PMCID: PMC2694106 DOI: 10.1152/jn.00766.2007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2008] [Accepted: 03/22/2009] [Indexed: 11/22/2022] Open
Abstract
The intermediate nucleus of the lateral lemniscus (INLL) is a major input to the inferior colliculus (IC), the auditory midbrain center where multiple pathways converge to create neurons selective for specific temporal features of sound. However, little is known about how INLL processes auditory information or how it contributes to integrative processes at the IC. INLL receives excitatory projections from the cochlear nucleus and inhibitory projections from the medial nucleus of the trapezoid body (MNTB), so it must perform some form of integration. To address the question of what role inhibitory synaptic inputs play in the INLL of the big brown bat (Eptesicus fuscus), we recorded sound-evoked responses of single neurons and iontophoretically applied bicuculline to block GABA(A) receptors or strychnine to block glycine receptors. Neither bicuculline nor strychnine had a consistent effect on response latency or frequency response areas. Bicuculline increased spike counts and response durations in most units, suggesting that GABAergic input suppressed the late part of the response and provided some gain control. Strychnine reduced the responses of some units with sustained discharge patterns to one or a few spikes at stimulus onset, but increased others. INLL is the only part of the auditory system where reduced responsiveness has been seen in vivo while blocking glycine. However, in vitro studies in the MNTB suggest that glycine can be facilitatory, possibly through presynaptic action. These results show that GABA consistently reduces spike counts and response durations, whereas glycine is suppressive in some INLL neurons but facilitatory in others.
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Affiliation(s)
- Andrew Kutscher
- Department of Psychology, University of Washington, Seattle, Washington 98195-1525, USA
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47
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Wu CH, Jen PHS. Echo frequency selectivity of duration-tuned inferior collicular neurons of the big brown bat, Eptesicus fuscus, determined with pulse-echo pairs. Neuroscience 2008; 156:1028-38. [PMID: 18804149 DOI: 10.1016/j.neuroscience.2008.08.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 08/15/2008] [Accepted: 08/20/2008] [Indexed: 11/30/2022]
Abstract
During hunting, insectivorous bats such as Eptesicus fuscus progressively vary the repetition rate, duration, frequency and amplitude of emitted pulses such that analysis of an echo parameter by bats would be inevitably affected by other co-varying echo parameters. The present study is to determine the variation of echo frequency selectivity of duration-tuned inferior collicular neurons during different phases of hunting using pulse-echo (P-E) pairs as stimuli. All collicular neurons discharge maximally to a tone at a particular frequency which is defined as the best frequency (BF). Most collicular neurons also discharge maximally to a BF pulse at a particular duration which is defined as the best duration (BD). A family of echo iso-level frequency tuning curves (iso-level FTC) of these duration-tuned collicular neurons is measured with the number of impulses in response to the echo pulse at selected frequencies when the P-E pairs are presented at varied P-E duration and gap. Our data show that these duration-tuned collicular neurons have narrower echo iso-level FTC when measured with BD than with non-BD echo pulses. Also, IC neurons with low BF and short BD have narrower echo iso-level FTC than IC neurons with high BF and long BD have. The bandwidth of echo iso-level FTC significantly decreases with shortening of P-E duration and P-E gap. These data suggest that duration-tuned collicular neurons not only can facilitate bat's echo recognition but also can enhance echo frequency selectivity for prey feature analysis throughout a target approaching sequence during hunting. These data also support previous behavior studies showing that bats prepare their auditory system to analyze expected returning echoes within a time window to extract target features after pulse emission.
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Affiliation(s)
- C H Wu
- Division of Biological Sciences, Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO 65211, USA
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Yin S, Chen Z, Feng Y, Wang J, Yin S, Chen Z, Feng Y, Wang J. The roles of local inhibition mediated by gamma-aminobutyric acid (GABA)-A receptor in duration tuning in the inferior colliculus of guinea pigs. Acta Otolaryngol 2008; 128:1101-9. [PMID: 18607920 DOI: 10.1080/00016480701840122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
CONCLUSION GABA-mediated inhibition is responsible for the duration tuning in the inferior colliculus (IC) of guinea pigs, a non-echo-locating mammal. Duration tuning in this species is better demonstrated in an appropriate short time window. OBJECTIVES To investigate the role of GABA-mediated inhibition in duration tuning of neurons in the IC of guinea pigs. MATERIALS AND METHODS Duration tuning pattern was recorded by measuring the spikes of single neurons in response to broadband noise of different durations. The effect of GABA-mediated inhibition was verified by comparing the responses with and without the use of the GABA-A receptor blocker bicuculline (BIC), which was applied using micro-iontophoresis. RESULTS In addition to overall increase in responsiveness, the application of BIC was found to significantly reduce or eliminate the duration selectivity in 44 of the 67 neurons that showed clear duration tuning from a sample of total 340 neurons.
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Gerhardt HC. Phonotactic selectivity in two cryptic species of gray treefrogs: effects of differences in pulse rate, carrier frequency and playback level. J Exp Biol 2008; 211:2609-16. [PMID: 18689414 PMCID: PMC2559977 DOI: 10.1242/jeb.019612] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The two main spectral components of the advertisement calls of two species of North American gray treefrogs (Hyla chrysoscelis and H. versicolor) overlap broadly in frequency, and the frequency of each component matches the sensitivity of one of the two different auditory inner ear organs. The calls of the two species differ in the shape and repetition rate (pulse rate) of sound pulses within trills. Standard synthetic calls with one of these spectral peaks and the pulse rate typical of conspecific calls were tested against synthetic alternatives that had the same spectral peak but a different pulse rate. The results were generalized over a wide range of playback levels. Selectivity based on differences in pulse rate depended on which spectral peak was used in some tests, and greater pulse-rate selectivity was usually observed when the low-frequency rather than the high-frequency peak was used. This effect was more pronounced and occurred over a wider range of playback levels in H. versicolor than in H. chrysoscelis when the pulse rate of the alternative was higher than that of the standard call. In tests at high playback levels with an alternative of 15 pulses s(-1), however, females of H. versicolor showed greater selectivity for the standard call when the high-frequency rather than the low-frequency spectral peak was used. This last result may reflect the different ways in which females of the two species assess trains of pulses, and the broad implications for understanding the underlying auditory mechanisms are discussed.
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Affiliation(s)
- H Carl Gerhardt
- Division of Biological Sciences, University of Missouri, Columbia, MO 6521, USA.
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Responses of inferior colliculus neurons to sounds presented at different rates in anesthetized albino mouse. Hear Res 2008; 241:43-51. [DOI: 10.1016/j.heares.2008.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2007] [Revised: 04/16/2008] [Accepted: 04/24/2008] [Indexed: 11/20/2022]
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