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Rogalla MM, Quass GL, Yardley H, Martinez-Voigt C, Ford AN, Wallace G, Dileepkumar D, Corfas G, Apostolides PF. Population coding of auditory space in the dorsal inferior colliculus persists with altered binaural cues. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.13.612867. [PMID: 39314270 PMCID: PMC11419156 DOI: 10.1101/2024.09.13.612867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Sound localization is critical for real-world hearing, such as segregating overlapping sound streams. For optimal flexibility, central representations of auditory space must adapt to peripheral changes in binaural cue availability, such as following asymmetric hearing loss in adulthood. However, whether the mature auditory system can reliably encode spatial auditory representations upon abrupt changes in binaural input is unclear. Here we use 2-photon Ca2+ imaging in awake head-fixed mice to determine how the higher-order "shell" layers of the inferior colliculus (IC) encode sound source location in the frontal azimuth, under binaural conditions and after acute monaural hearing loss induced by an ear plug ipsilateral to the imaged hemisphere. Spatial receptive fields were typically broad and not exclusively contralateral: Neurons responded reliably to multiple positions in the contra- and ipsi-lateral hemifields, with preferred positions tiling the entire frontal azimuth. Ear plugging broadened receptive fields and reduced spatial selectivity in a subset of neurons, in agreement with an inhibitory influence of ipsilateral sounds. However ear plugging also enhanced spatial tuning and/or unmasked receptive fields in other neurons, shifting the distribution of preferred angles ipsilaterally with minimal impact on the neuronal population's overall spatial resolution; these effects occurred within 2 hours of ear plugging. Consequently, linear classifiers trained on fluorescence data from control and ear-plugged conditions had similar classification accuracy when tested on held out data from within, but not across hearing conditions. Spatially informative neuronal population codes therefore arise rapidly following monaural hearing loss, in absence of overt experience.
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Affiliation(s)
- Meike M. Rogalla
- Kresge Hearing Research Institute & Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, United States
| | - Gunnar L. Quass
- Kresge Hearing Research Institute & Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, United States
| | - Harry Yardley
- Kresge Hearing Research Institute & Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, United States
| | - Clara Martinez-Voigt
- Kresge Hearing Research Institute & Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, United States
| | - Alexander N. Ford
- Kresge Hearing Research Institute & Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, United States
| | - Gunseli Wallace
- Kresge Hearing Research Institute & Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, United States
| | - Deepak Dileepkumar
- Kresge Hearing Research Institute & Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, United States
| | - Gabriel Corfas
- Kresge Hearing Research Institute & Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, United States
| | - Pierre F. Apostolides
- Kresge Hearing Research Institute & Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, United States
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, United States
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2
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Quass GL, Rogalla MM, Ford AN, Apostolides PF. Mixed Representations of Sound and Action in the Auditory Midbrain. J Neurosci 2024; 44:e1831232024. [PMID: 38918064 PMCID: PMC11270520 DOI: 10.1523/jneurosci.1831-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 06/05/2024] [Accepted: 06/14/2024] [Indexed: 06/27/2024] Open
Abstract
Linking sensory input and its consequences is a fundamental brain operation. During behavior, the neural activity of neocortical and limbic systems often reflects dynamic combinations of sensory and task-dependent variables, and these "mixed representations" are suggested to be important for perception, learning, and plasticity. However, the extent to which such integrative computations might occur outside of the forebrain is less clear. Here, we conduct cellular-resolution two-photon Ca2+ imaging in the superficial "shell" layers of the inferior colliculus (IC), as head-fixed mice of either sex perform a reward-based psychometric auditory task. We find that the activity of individual shell IC neurons jointly reflects auditory cues, mice's actions, and behavioral trial outcomes, such that trajectories of neural population activity diverge depending on mice's behavioral choice. Consequently, simple classifier models trained on shell IC neuron activity can predict trial-by-trial outcomes, even when training data are restricted to neural activity occurring prior to mice's instrumental actions. Thus, in behaving mice, auditory midbrain neurons transmit a population code that reflects a joint representation of sound, actions, and task-dependent variables.
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Affiliation(s)
- Gunnar L Quass
- Department of Otolaryngology-Head & Neck Surgery, Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Meike M Rogalla
- Department of Otolaryngology-Head & Neck Surgery, Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Alexander N Ford
- Department of Otolaryngology-Head & Neck Surgery, Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Pierre F Apostolides
- Department of Otolaryngology-Head & Neck Surgery, Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, Michigan 48109
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109
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van den Berg MM, Wong AB, Houtak G, Williamson RS, Borst JGG. Sodium salicylate improves detection of amplitude-modulated sound in mice. iScience 2024; 27:109691. [PMID: 38736549 PMCID: PMC11088340 DOI: 10.1016/j.isci.2024.109691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/14/2024] [Accepted: 04/05/2024] [Indexed: 05/14/2024] Open
Abstract
Salicylate is commonly used to induce tinnitus in animals, but its underlying mechanism of action is still debated. We therefore tested its effects on the firing properties of neurons in the mouse inferior colliculus (IC). Salicylate induced a large decrease in the spontaneous activity and an increase of ∼20 dB SPL in the minimum threshold of single units. In response to sinusoidally modulated noise (SAM noise) single units showed both an increase in phase locking and improved rate coding. Mice also became better at detecting amplitude modulations, and a simple threshold model based on the IC population response could reproduce this improvement. The responses to dynamic random chords (DRCs) suggested that the improved AM encoding was due to a linearization of the cochlear output, resulting in larger contrasts during SAM noise. These effects of salicylate are not consistent with the presence of tinnitus, but should be taken into account when studying hyperacusis.
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Affiliation(s)
- Maurits M. van den Berg
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| | - Aaron B. Wong
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| | - Ghais Houtak
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| | - Ross S. Williamson
- Pittsburgh Hearing Research Center, Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - J. Gerard G. Borst
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
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Shi K, Quass GL, Rogalla MM, Ford AN, Czarny JE, Apostolides PF. Population coding of time-varying sounds in the nonlemniscal inferior colliculus. J Neurophysiol 2024; 131:842-864. [PMID: 38505907 PMCID: PMC11381119 DOI: 10.1152/jn.00013.2024] [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: 01/10/2024] [Revised: 02/29/2024] [Accepted: 03/15/2024] [Indexed: 03/21/2024] Open
Abstract
The inferior colliculus (IC) of the midbrain is important for complex sound processing, such as discriminating conspecific vocalizations and human speech. The IC's nonlemniscal, dorsal "shell" region is likely important for this process, as neurons in these layers project to higher-order thalamic nuclei that subsequently funnel acoustic signals to the amygdala and nonprimary auditory cortices, forebrain circuits important for vocalization coding in a variety of mammals, including humans. However, the extent to which shell IC neurons transmit acoustic features necessary to discern vocalizations is less clear, owing to the technical difficulty of recording from neurons in the IC's superficial layers via traditional approaches. Here, we use two-photon Ca2+ imaging in mice of either sex to test how shell IC neuron populations encode the rate and depth of amplitude modulation, important sound cues for speech perception. Most shell IC neurons were broadly tuned, with a low neurometric discrimination of amplitude modulation rate; only a subset was highly selective to specific modulation rates. Nevertheless, neural network classifier trained on fluorescence data from shell IC neuron populations accurately classified amplitude modulation rate, and decoding accuracy was only marginally reduced when highly tuned neurons were omitted from training data. Rather, classifier accuracy increased monotonically with the modulation depth of the training data, such that classifiers trained on full-depth modulated sounds had median decoding errors of ∼0.2 octaves. Thus, shell IC neurons may transmit time-varying signals via a population code, with perhaps limited reliance on the discriminative capacity of any individual neuron.NEW & NOTEWORTHY The IC's shell layers originate a "nonlemniscal" pathway important for perceiving vocalization sounds. However, prior studies suggest that individual shell IC neurons are broadly tuned and have high response thresholds, implying a limited reliability of efferent signals. Using Ca2+ imaging, we show that amplitude modulation is accurately represented in the population activity of shell IC neurons. Thus, downstream targets can read out sounds' temporal envelopes from distributed rate codes transmitted by populations of broadly tuned neurons.
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Affiliation(s)
- Kaiwen Shi
- Department of Otolaryngology-Head & Neck Surgery, Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Gunnar L Quass
- Department of Otolaryngology-Head & Neck Surgery, Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Meike M Rogalla
- Department of Otolaryngology-Head & Neck Surgery, Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Alexander N Ford
- Department of Otolaryngology-Head & Neck Surgery, Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Jordyn E Czarny
- Department of Otolaryngology-Head & Neck Surgery, Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Pierre F Apostolides
- Department of Otolaryngology-Head & Neck Surgery, Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, Michigan, United States
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States
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Kraakman B, Solovjova S, Borst JGG, Wong AB. Headplate Installation and Craniotomy for Awake In Vivo Electrophysiological Recordings or Two-Photon Imaging of the Mouse Inferior Colliculus. Bio Protoc 2023; 13:e4902. [PMID: 38156034 PMCID: PMC10751242 DOI: 10.21769/bioprotoc.4902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/29/2023] [Accepted: 11/06/2023] [Indexed: 12/30/2023] Open
Abstract
The inferior colliculus (IC) is an important processing center in the auditory system, which also receives non-auditory sensory input. The IC consists of several subnuclei whose functional role in (non-) auditory processing and plastic response properties are best approached by studying awake animals, preferably in a longitudinal fashion. The increasing use of mice in auditory research, the availability of genetic models, and the superficial location of the IC in the mouse have made it an attractive species for studying IC function. Here, we describe a protocol for exposing the mouse IC for up to a few weeks for in vivo imaging or electrophysiology in a stable manner. This method allows for a broader sampling of the IC while maintaining the brain surface in good quality and without reopening the craniotomy. Moreover, as it is adaptable for both electrophysiological recordings of the entire IC and imaging of the dorsal IC surface, it can be applied to answer a multitude of questions. Key features • A surgical protocol for long-term physiological recordings from the same or separate neuronal populations in the inferior colliculus. • Optimized for awake in vivo experiments in the house mouse (Mus musculus).
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Affiliation(s)
- Blom Kraakman
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, Netherlands
| | - Sofja Solovjova
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, Netherlands
| | - J. Gerard G. Borst
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, Netherlands
| | - Aaron B. Wong
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, Netherlands
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6
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Quass GL, Rogalla MM, Ford AN, Apostolides PF. Mixed representations of sound and action in the auditory midbrain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.19.558449. [PMID: 37786676 PMCID: PMC10541616 DOI: 10.1101/2023.09.19.558449] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Linking sensory input and its consequences is a fundamental brain operation. Accordingly, neural activity of neo-cortical and limbic systems often reflects dynamic combinations of sensory and behaviorally relevant variables, and these "mixed representations" are suggested to be important for perception, learning, and plasticity. However, the extent to which such integrative computations might occur in brain regions upstream of the forebrain is less clear. Here, we conduct cellular-resolution 2-photon Ca2+ imaging in the superficial "shell" layers of the inferior colliculus (IC), as head-fixed mice of either sex perform a reward-based psychometric auditory task. We find that the activity of individual shell IC neurons jointly reflects auditory cues and mice's actions, such that trajectories of neural population activity diverge depending on mice's behavioral choice. Consequently, simple classifier models trained on shell IC neuron activity can predict trial-by-trial outcomes, even when training data are restricted to neural activity occurring prior to mice's instrumental actions. Thus in behaving animals, auditory midbrain neurons transmit a population code that reflects a joint representation of sound and action.
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Affiliation(s)
- GL Quass
- Kresge Hearing Research Institute, Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - MM Rogalla
- Kresge Hearing Research Institute, Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - AN Ford
- Kresge Hearing Research Institute, Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - PF Apostolides
- Kresge Hearing Research Institute, Department of Otolaryngology – Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
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7
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van den Berg MM, Busscher E, Borst JGG, Wong AB. Neuronal responses in mouse inferior colliculus correlate with behavioral detection of amplitude-modulated sound. J Neurophysiol 2023; 130:524-546. [PMID: 37465872 DOI: 10.1152/jn.00048.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/18/2023] [Accepted: 07/18/2023] [Indexed: 07/20/2023] Open
Abstract
Amplitude modulation (AM) is a common feature of natural sounds, including speech and animal vocalizations. Here, we used operant conditioning and in vivo electrophysiology to determine the AM detection threshold of mice as well as its underlying neuronal encoding. Mice were trained in a Go-NoGo task to detect the transition to AM within a noise stimulus designed to prevent the use of spectral side-bands or a change in intensity as alternative cues. Our results indicate that mice, compared with other species, detect high modulation frequencies up to 512 Hz well, but show much poorer performance at low frequencies. Our in vivo multielectrode recordings in the inferior colliculus (IC) of both anesthetized and awake mice revealed a few single units with remarkable phase-locking ability to 512 Hz modulation, but not sufficient to explain the good behavioral detection at that frequency. Using a model of the population response that combined dimensionality reduction with threshold detection, we reproduced the general band-pass characteristics of behavioral detection based on a subset of neurons showing the largest firing rate change (both increase and decrease) in response to AM, suggesting that these neurons are instrumental in the behavioral detection of AM stimuli by the mice.NEW & NOTEWORTHY The amplitude of natural sounds, including speech and animal vocalizations, often shows characteristic modulations. We examined the relationship between neuronal responses in the mouse inferior colliculus and the behavioral detection of amplitude modulation (AM) in sound and modeled how the former can give rise to the latter. Our model suggests that behavioral detection can be well explained by the activity of a subset of neurons showing the largest firing rate changes in response to AM.
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Affiliation(s)
- Maurits M van den Berg
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Esmée Busscher
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - J Gerard G Borst
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Aaron B Wong
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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8
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Shi K, Quass GL, Rogalla MM, Ford AN, Czarny JE, Apostolides PF. Population coding of time-varying sounds in the non-lemniscal Inferior Colliculus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.14.553263. [PMID: 37645904 PMCID: PMC10461978 DOI: 10.1101/2023.08.14.553263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
The inferior colliculus (IC) of the midbrain is important for complex sound processing, such as discriminating conspecific vocalizations and human speech. The IC's non-lemniscal, dorsal "shell" region is likely important for this process, as neurons in these layers project to higher-order thalamic nuclei that subsequently funnel acoustic signals to the amygdala and non-primary auditory cortices; forebrain circuits important for vocalization coding in a variety of mammals, including humans. However, the extent to which shell IC neurons transmit acoustic features necessary to discern vocalizations is less clear, owing to the technical difficulty of recording from neurons in the IC's superficial layers via traditional approaches. Here we use 2-photon Ca2+ imaging in mice of either sex to test how shell IC neuron populations encode the rate and depth of amplitude modulation, important sound cues for speech perception. Most shell IC neurons were broadly tuned, with a low neurometric discrimination of amplitude modulation rate; only a subset were highly selective to specific modulation rates. Nevertheless, neural network classifier trained on fluorescence data from shell IC neuron populations accurately classified amplitude modulation rate, and decoding accuracy was only marginally reduced when highly tuned neurons were omitted from training data. Rather, classifier accuracy increased monotonically with the modulation depth of the training data, such that classifiers trained on full-depth modulated sounds had median decoding errors of ~0.2 octaves. Thus, shell IC neurons may transmit time-varying signals via a population code, with perhaps limited reliance on the discriminative capacity of any individual neuron.
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Affiliation(s)
- Kaiwen Shi
- Kresge Hearing Research Institute, Department of Otolaryngology — Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, MI, 48109
| | - Gunnar L. Quass
- Kresge Hearing Research Institute, Department of Otolaryngology — Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, MI, 48109
| | - Meike M. Rogalla
- Kresge Hearing Research Institute, Department of Otolaryngology — Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, MI, 48109
| | - Alexander N. Ford
- Kresge Hearing Research Institute, Department of Otolaryngology — Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, MI, 48109
| | - Jordyn E. Czarny
- Kresge Hearing Research Institute, Department of Otolaryngology — Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, MI, 48109
| | - Pierre F. Apostolides
- Kresge Hearing Research Institute, Department of Otolaryngology — Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, MI, 48109
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48109
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9
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Liu Y, Li Y, Peng Y, Yu H, Xiao Z. Bilateral Interactions in the Mouse Dorsal Inferior Colliculus Enhance the Ipsilateral Neuronal Responses and Binaural Hearing. Front Physiol 2022; 13:854077. [PMID: 35514328 PMCID: PMC9061965 DOI: 10.3389/fphys.2022.854077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 04/01/2022] [Indexed: 11/13/2022] Open
Abstract
The inferior colliculus (IC) is a critical centre for the binaural processing of auditory information. However, previous studies have mainly focused on the central nucleus of the inferior colliculus (ICC), and less is known about the dorsal nucleus of the inferior colliculus (ICD). Here, we first examined the characteristics of the neuronal responses in the mouse ICD and compared them with those in the inferior colliculus under binaural and monaural conditions using in vivo loose-patch recordings. ICD neurons exhibited stronger responses to ipsilateral sound stimulation and better binaural summation than those of ICC neurons, which indicated a role for the ICD in binaural hearing integration. According to the abundant interactions between bilateral ICDs detected using retrograde virus tracing, we further studied the effect of unilateral ICD silencing on the contralateral ICD. After lidocaine was applied, the responses of some ICD neurons (13/26), especially those to ipsilateral auditory stimuli, decreased. Using whole-cell recording and optogenetic methods, we investigated the underlying neuronal circuits and synaptic mechanisms of binaural auditory information processing in the ICD. The unilateral ICD provides both excitatory and inhibitory projections to the opposite ICD, and the advantaged excitatory inputs may be responsible for the enhanced ipsilateral responses and binaural summation of ICD neurons. Based on these results, the contralateral ICD might modulate the ipsilateral responses of the neurons and binaural hearing.
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Affiliation(s)
| | | | | | | | - Zhongju Xiao
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
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10
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Oberle HM, Ford AN, Dileepkumar D, Czarny J, Apostolides PF. Synaptic mechanisms of top-down control in the non-lemniscal inferior colliculus. eLife 2022; 10:e72730. [PMID: 34989674 PMCID: PMC8735864 DOI: 10.7554/elife.72730] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 12/19/2021] [Indexed: 01/05/2023] Open
Abstract
Corticofugal projections to evolutionarily ancient, subcortical structures are ubiquitous across mammalian sensory systems. These 'descending' pathways enable the neocortex to control ascending sensory representations in a predictive or feedback manner, but the underlying cellular mechanisms are poorly understood. Here, we combine optogenetic approaches with in vivo and in vitro patch-clamp electrophysiology to study the projection from mouse auditory cortex to the inferior colliculus (IC), a major descending auditory pathway that controls IC neuron feature selectivity, plasticity, and auditory perceptual learning. Although individual auditory cortico-collicular synapses were generally weak, IC neurons often integrated inputs from multiple corticofugal axons that generated reliable, tonic depolarizations even during prolonged presynaptic activity. Latency measurements in vivo showed that descending signals reach the IC within 30 ms of sound onset, which in IC neurons corresponded to the peak of synaptic depolarizations evoked by short sounds. Activating ascending and descending pathways at latencies expected in vivo caused a NMDA receptor-dependent, supralinear excitatory postsynaptic potential summation, indicating that descending signals can nonlinearly amplify IC neurons' moment-to-moment acoustic responses. Our results shed light upon the synaptic bases of descending sensory control and imply that heterosynaptic cooperativity contributes to the auditory cortico-collicular pathway's role in plasticity and perceptual learning.
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Affiliation(s)
- Hannah M Oberle
- Kresge Hearing Research Institute & Department of Otolaryngology, University of MichiganAnn ArborUnited States
- Neuroscience Graduate Program, University of MichiganAnn ArborUnited States
| | - Alexander N Ford
- Kresge Hearing Research Institute & Department of Otolaryngology, University of MichiganAnn ArborUnited States
| | - Deepak Dileepkumar
- Kresge Hearing Research Institute & Department of Otolaryngology, University of MichiganAnn ArborUnited States
| | - Jordyn Czarny
- Kresge Hearing Research Institute & Department of Otolaryngology, University of MichiganAnn ArborUnited States
| | - Pierre F Apostolides
- Kresge Hearing Research Institute & Department of Otolaryngology, University of MichiganAnn ArborUnited States
- Molecular and Integrative Physiology, University of Michigan Medical SchoolAnn ArborUnited States
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11
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Valdés-Baizabal C, Casado-Román L, Bartlett EL, Malmierca MS. In vivo whole-cell recordings of stimulus-specific adaptation in the inferior colliculus. Hear Res 2020; 399:107978. [PMID: 32402412 DOI: 10.1016/j.heares.2020.107978] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/17/2020] [Accepted: 04/18/2020] [Indexed: 12/31/2022]
Abstract
The inferior colliculus is an auditory structure where inputs from multiple lower centers converge, allowing the emergence of complex coding properties of auditory information such as stimulus-specific adaptation. Stimulus-specific adaptation is the adaptation of neuronal responses to a specific repeated stimulus, which does not entirely generalize to other new stimuli. This phenomenon provides a mechanism to emphasize saliency and potentially informative sensory inputs. Stimulus-specific adaptation has been traditionally studied analyzing the somatic spiking output. However, studies that correlate within the same inferior colliculus neurons their intrinsic properties, subthreshold responses and the level of acoustic stimulus-specific adaptation are still pending. For this, we recorded in vivo whole-cell patch-clamp neurons in the mouse inferior colliculus while stimulating with current injections or the classic auditory oddball paradigm. Our data based on cases of ten neuron, suggest that although passive properties were similar, intrinsic properties differed between adapting and non-adapting neurons. Non-adapting neurons showed a sustained-regular firing pattern that corresponded to central nucleus neurons and adapting neurons at the inferior colliculus cortices showed variable firing patterns. Our current results suggest that synaptic stimulus-specific adaptation was variable and could not be used to predict the presence of spiking stimulus-specific adaptation. We also observed a small trend towards hyperpolarized membrane potentials in adapting neurons and increased synaptic inhibition with consecutive stimulus repetitions in all neurons. This finding indicates a more simple type of adaptation, potentially related to potassium conductances. Hence, these data represent a modest first step in the intracellular study of stimulus-specific adaptation in inferior colliculus neurons in vivo that will need to be expanded with pharmacological manipulations to disentangle specific ionic channels participation.
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Affiliation(s)
- Catalina Valdés-Baizabal
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León, University of Salamanca, 37007, Salamanca, Spain; The Salamanca Institute for Biomedical Research (IBSAL), 37007, Salamanca, Spain
| | - Lorena Casado-Román
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León, University of Salamanca, 37007, Salamanca, Spain; The Salamanca Institute for Biomedical Research (IBSAL), 37007, Salamanca, Spain
| | - Edward L Bartlett
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Manuel S Malmierca
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León, University of Salamanca, 37007, Salamanca, Spain; The Salamanca Institute for Biomedical Research (IBSAL), 37007, Salamanca, Spain; Department of Cell Biology and Pathology, Faculty of Medicine, Campus Miguel de Unamuno, University of Salamanca, 37007, Salamanca, Spain.
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12
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Wong AB, Borst JGG. Tonotopic and non-auditory organization of the mouse dorsal inferior colliculus revealed by two-photon imaging. eLife 2019; 8:49091. [PMID: 31612853 PMCID: PMC6834370 DOI: 10.7554/elife.49091] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 10/13/2019] [Indexed: 12/17/2022] Open
Abstract
The dorsal (DCIC) and lateral cortices (LCIC) of the inferior colliculus are major targets of the auditory and non-auditory cortical areas, suggesting a role in complex multimodal information processing. However, relatively little is known about their functional organization. We utilized in vivo two-photon Ca2+ imaging in awake mice expressing GCaMP6s in GABAergic or non-GABAergic neurons in the IC to investigate their spatial organization. We found different classes of temporal responses, which we confirmed with simultaneous juxtacellular electrophysiology. Both GABAergic and non-GABAergic neurons showed spatial microheterogeneity in their temporal responses. In contrast, a robust, double rostromedial-caudolateral gradient of frequency tuning was conserved between the two groups, and even among the subclasses. This, together with the existence of a subset of neurons sensitive to spontaneous movements, provides functional evidence for redefining the border between DCIC and LCIC.
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Affiliation(s)
- Aaron Benson Wong
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - J Gerard G Borst
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
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13
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Chen C, Song S. Differential cell-type dependent brain state modulations of sensory representations in the non-lemniscal mouse inferior colliculus. Commun Biol 2019; 2:356. [PMID: 31583287 PMCID: PMC6769006 DOI: 10.1038/s42003-019-0602-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/23/2019] [Indexed: 02/01/2023] Open
Abstract
Sensory responses of the neocortex are strongly influenced by brain state changes. However, it remains unclear whether and how the sensory responses of the midbrain are affected. Here we addressed this issue by using in vivo two-photon calcium imaging to monitor the spontaneous and sound-evoked activities in the mouse inferior colliculus (IC). We developed a method enabling us to image the first layer of non-lemniscal IC (IC shell L1) in awake behaving mice. Compared with the awake state, spectral tuning selectivity of excitatory neurons was decreased during isoflurane anesthesia. Calcium imaging in behaving animals revealed that activities of inhibitory neurons were highly correlated with locomotion. Compared with stationary periods, spectral tuning selectivity of excitatory neurons was increased during locomotion. Taken together, our studies reveal that neuronal activities in the IC shell L1 are brain state dependent, whereas the brain state modulates the excitatory and inhibitory neurons differentially.
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Affiliation(s)
- Chenggang Chen
- Tsinghua Laboratory of Brain and Intelligence and Department of Biomedical Engineering, Beijing Innovation Center for Future Chip, Center for Brain-Inspired Computing Research, McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084 China
| | - Sen Song
- Tsinghua Laboratory of Brain and Intelligence and Department of Biomedical Engineering, Beijing Innovation Center for Future Chip, Center for Brain-Inspired Computing Research, McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084 China
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14
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White-Schwoch T, Nicol T, Warrier CM, Abrams DA, Kraus N. Individual Differences in Human Auditory Processing: Insights From Single-Trial Auditory Midbrain Activity in an Animal Model. Cereb Cortex 2018; 27:5095-5115. [PMID: 28334187 DOI: 10.1093/cercor/bhw293] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 08/29/2016] [Indexed: 11/13/2022] Open
Abstract
Auditory-evoked potentials are classically defined as the summations of synchronous firing along the auditory neuraxis. Converging evidence supports a model whereby timing jitter in neural coding compromises listening and causes variable scalp-recorded potentials. Yet the intrinsic noise of human scalp recordings precludes a full understanding of the biological origins of individual differences in listening skills. To delineate the mechanisms contributing to these phenomena, in vivo extracellular activity was recorded from inferior colliculus in guinea pigs to speech in quiet and noise. Here we show that trial-by-trial timing jitter is a mechanism contributing to auditory response variability. Identical variability patterns were observed in scalp recordings in human children, implicating jittered timing as a factor underlying reduced coding of dynamic speech features and speech in noise. Moreover, intertrial variability in human listeners is tied to language development. Together, these findings suggest that variable timing in inferior colliculus blurs the neural coding of speech in noise, and propose a consequence of this timing jitter for human behavior. These results hint both at the mechanisms underlying speech processing in general, and at what may go awry in individuals with listening difficulties.
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Affiliation(s)
- Travis White-Schwoch
- Auditory Neuroscience Laboratory (www.brainvolts.northwestern.edu) & Department of Communication Sciences, Northwestern University, Evanston, IL, 60208, USA
| | - Trent Nicol
- Auditory Neuroscience Laboratory (www.brainvolts.northwestern.edu) & Department of Communication Sciences, Northwestern University, Evanston, IL, 60208, USA
| | - Catherine M Warrier
- Auditory Neuroscience Laboratory (www.brainvolts.northwestern.edu) & Department of Communication Sciences, Northwestern University, Evanston, IL, 60208, USA
| | - Daniel A Abrams
- Auditory Neuroscience Laboratory (www.brainvolts.northwestern.edu) & Department of Communication Sciences, Northwestern University, Evanston, IL, 60208, USA.,Stanford Cognitive & Systems Neuroscience Laboratory, Stanford University, Palo Alto, CA, 94304, USA
| | - Nina Kraus
- Auditory Neuroscience Laboratory (www.brainvolts.northwestern.edu) & Department of Communication Sciences, Northwestern University, Evanston, IL, 60208, USA.,Department of Neurobiology & Physiology, Northwestern University, Evanston, IL, 60208, USA.,Department of Otolaryngology, Northwestern University, Chicago, IL, 60611, USA
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15
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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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16
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Functional Microarchitecture of the Mouse Dorsal Inferior Colliculus Revealed through In Vivo Two-Photon Calcium Imaging. J Neurosci 2015; 35:10927-39. [PMID: 26245957 DOI: 10.1523/jneurosci.0103-15.2015] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
UNLABELLED The inferior colliculus (IC) is an obligatory relay for ascending auditory inputs from the brainstem and receives descending input from the auditory cortex. The IC comprises a central nucleus (CNIC), surrounded by several shell regions, but the internal organization of this midbrain nucleus remains incompletely understood. We used two-photon calcium imaging to study the functional microarchitecture of both neurons in the mouse dorsal IC and corticocollicular axons that terminate there. In contrast to previous electrophysiological studies, our approach revealed a clear functional distinction between the CNIC and the dorsal cortex of the IC (DCIC), suggesting that the mouse midbrain is more similar to that of other mammals than previously thought. We found that the DCIC comprises a thin sheet of neurons, sometimes extending barely 100 μm below the pial surface. The sound frequency representation in the DCIC approximated the mouse's full hearing range, whereas dorsal CNIC neurons almost exclusively preferred low frequencies. The response properties of neurons in these two regions were otherwise surprisingly similar, and the frequency tuning of DCIC neurons was only slightly broader than that of CNIC neurons. In several animals, frequency gradients were observed in the DCIC, and a comparable tonotopic arrangement was observed across the boutons of the corticocollicular axons, which form a dense mesh beneath the dorsal surface of the IC. Nevertheless, acoustically responsive corticocollicular boutons were sparse, produced unreliable responses, and were more broadly tuned than DCIC neurons, suggesting that they have a largely modulatory rather than driving influence on auditory midbrain neurons. SIGNIFICANCE STATEMENT Due to its genetic tractability, the mouse is fast becoming the most popular animal model for sensory neuroscience. Nevertheless, many aspects of its neural architecture are still poorly understood. Here, we image the dorsal auditory midbrain and its inputs from the cortex, revealing a hitherto hidden level of organization and paving the way for the direct observation of corticocollicular interactions. We show that a precise functional organization exists in the mouse auditory midbrain, which has been missed by previous, more macroscopic approaches. The fine-scale distribution of sound-frequency tuning suggests that the mouse midbrain is more similar to that of other mammals than previously thought and contrasts with the more heterogeneous organization reported in imaging studies of auditory cortex.
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Zohar O, Shackleton TM, Palmer AR, Shamir M. The effect of correlated neuronal firing and neuronal heterogeneity on population coding accuracy in guinea pig inferior colliculus. PLoS One 2013; 8:e81660. [PMID: 24358120 PMCID: PMC3864845 DOI: 10.1371/journal.pone.0081660] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 10/15/2013] [Indexed: 11/18/2022] Open
Abstract
It has been suggested that the considerable noise in single-cell responses to a stimulus can be overcome by pooling information from a large population. Theoretical studies indicated that correlations in trial-to-trial fluctuations in the responses of different neurons may limit the improvement due to pooling. Subsequent theoretical studies have suggested that inherent neuronal diversity, i.e., the heterogeneity of tuning curves and other response properties of neurons preferentially tuned to the same stimulus, can provide a means to overcome this limit. Here we study the effect of spike-count correlations and the inherent neuronal heterogeneity on the ability to extract information from large neural populations. We use electrophysiological data from the guinea pig Inferior-Colliculus to capture inherent neuronal heterogeneity and single cell statistics, and introduce response correlations artificially. To this end, we generate pseudo-population responses, based on single-cell recording of neurons responding to auditory stimuli with varying binaural correlations. Typically, when pseudo-populations are generated from single cell data, the responses within the population are statistically independent. As a result, the information content of the population will increase indefinitely with its size. In contrast, here we apply a simple algorithm that enables us to generate pseudo-population responses with variable spike-count correlations. This enables us to study the effect of neuronal correlations on the accuracy of conventional rate codes. We show that in a homogenous population, in the presence of even low-level correlations, information content is bounded. In contrast, utilizing a simple linear readout, that takes into account the natural heterogeneity, even of neurons preferentially tuned to the same stimulus, within the neural population, one can overcome the correlated noise and obtain a readout whose accuracy grows linearly with the size of the population.
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Affiliation(s)
- Oran Zohar
- Deptartment of Physiol, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | | | - Alan R. Palmer
- MRC Institute of Hearing Research, University Park, Nottingham, United Kingdom
| | - Maoz Shamir
- Deptartment of Physiol, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
- Department of Physics, Faculty of Natural Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
- * E-mail:
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18
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Geis HRAP, Borst JGG. Intracellular responses to frequency modulated tones in the dorsal cortex of the mouse inferior colliculus. Front Neural Circuits 2013; 7:7. [PMID: 23386812 PMCID: PMC3560375 DOI: 10.3389/fncir.2013.00007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 01/13/2013] [Indexed: 11/13/2022] Open
Abstract
Frequency modulations occur in many natural sounds, including vocalizations. The neuronal response to frequency modulated (FM) stimuli has been studied extensively in different brain areas, with an emphasis on the auditory cortex and the central nucleus of the inferior colliculus. Here, we measured the responses to FM sweeps in whole-cell recordings from neurons in the dorsal cortex of the mouse inferior colliculus. Both up- and downward logarithmic FM sweeps were presented at two different speeds to both the ipsi- and the contralateral ear. Based on the number of action potentials that were fired, between 10 and 24% of cells were selective for rate or direction of the FM sweeps. A somewhat lower percentage of cells, 6–21%, showed selectivity based on EPSP size. To study the mechanisms underlying the generation of FM selectivity, we compared FM responses with responses to simple tones in the same cells. We found that if pairs of neurons responded in a similar way to simple tones, they generally also responded in a similar way to FM sweeps. Further evidence that FM selectivity can be generated within the dorsal cortex was obtained by reconstructing FM sweeps from the response to simple tones using three different models. In about half of the direction selective neurons the selectivity was generated by spectrally asymmetric synaptic inhibition. In addition, evidence for direction selectivity based on the timing of excitatory responses was also obtained in some cells. No clear evidence for the local generation of rate selectivity was obtained. We conclude that FM direction selectivity can be generated within the dorsal cortex of the mouse inferior colliculus by multiple mechanisms.
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Affiliation(s)
- H-Rüdiger A P Geis
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam Rotterdam, Netherlands
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19
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Ayala YA, Pérez-González D, Duque D, Nelken I, Malmierca MS. Frequency discrimination and stimulus deviance in the inferior colliculus and cochlear nucleus. Front Neural Circuits 2013; 6:119. [PMID: 23335885 PMCID: PMC3544151 DOI: 10.3389/fncir.2012.00119] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 12/19/2012] [Indexed: 11/17/2022] Open
Abstract
Auditory neurons that exhibit stimulus-specific adaptation (SSA) decrease their response to common tones while retaining responsiveness to rare ones. We recorded single-unit responses from the inferior colliculus (IC) where SSA is known to occur and we explored for the first time SSA in the cochlear nucleus (CN) of rats. We assessed an important functional outcome of SSA, the extent to which frequency discriminability depends on sensory context. For this purpose, pure tones were presented in an oddball sequence as standard (high probability of occurrence) or deviant (low probability of occurrence) stimuli. To study frequency discriminability under different probability contexts, we varied the probability of occurrence and the frequency separation between tones. The neuronal sensitivity was estimated in terms of spike-count probability using signal detection theory. We reproduced the finding that many neurons in the IC exhibited SSA, but we did not observe significant SSA in our CN sample. We concluded that strong SSA is not a ubiquitous phenomenon in the CN. As predicted, frequency discriminability was enhanced in IC when stimuli were presented in an oddball context, and this enhancement was correlated with the degree of SSA shown by the neurons. In contrast, frequency discrimination by CN neurons was independent of stimulus context. Our results demonstrated that SSA is not widespread along the entire auditory pathway, and suggest that SSA increases frequency discriminability of single neurons beyond that expected from their tuning curves.
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Affiliation(s)
- Yaneri A Ayala
- Auditory Neurophysiology Laboratory, Institute of Neuroscience of Castilla y León, University of Salamanca Salamanca, Spain
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20
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Geis HRA, Borst JGG. Large GABAergic neurons form a distinct subclass within the mouse dorsal cortex of the inferior colliculus with respect to intrinsic properties, synaptic inputs, sound responses, and projections. J Comp Neurol 2012; 521:189-202. [DOI: 10.1002/cne.23170] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 04/18/2012] [Accepted: 06/07/2012] [Indexed: 11/10/2022]
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