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Peng F, Harper NS, Mishra AP, Auksztulewicz R, Schnupp JWH. Dissociable Roles of the Auditory Midbrain and Cortex in Processing the Statistical Features of Natural Sound Textures. J Neurosci 2024; 44:e1115232023. [PMID: 38267259 PMCID: PMC10919253 DOI: 10.1523/jneurosci.1115-23.2023] [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: 07/04/2023] [Revised: 11/23/2023] [Accepted: 12/11/2023] [Indexed: 01/26/2024] Open
Abstract
Sound texture perception takes advantage of a hierarchy of time-averaged statistical features of acoustic stimuli, but much remains unclear about how these statistical features are processed along the auditory pathway. Here, we compared the neural representation of sound textures in the inferior colliculus (IC) and auditory cortex (AC) of anesthetized female rats. We recorded responses to texture morph stimuli that gradually add statistical features of increasingly higher complexity. For each texture, several different exemplars were synthesized using different random seeds. An analysis of transient and ongoing multiunit responses showed that the IC units were sensitive to every type of statistical feature, albeit to a varying extent. In contrast, only a small proportion of AC units were overtly sensitive to any statistical features. Differences in texture types explained more of the variance of IC neural responses than did differences in exemplars, indicating a degree of "texture type tuning" in the IC, but the same was, perhaps surprisingly, not the case for AC responses. We also evaluated the accuracy of texture type classification from single-trial population activity and found that IC responses became more informative as more summary statistics were included in the texture morphs, while for AC population responses, classification performance remained consistently very low. These results argue against the idea that AC neurons encode sound type via an overt sensitivity in neural firing rate to fine-grain spectral and temporal statistical features.
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Affiliation(s)
- Fei Peng
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
| | - Nicol S Harper
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 2JD, United Kingdom
| | - Ambika P Mishra
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
| | - Ryszard Auksztulewicz
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
- Center for Cognitive Neuroscience Berlin, Free University Berlin, Berlin 14195, Germany
| | - Jan W H Schnupp
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
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Huang B, Yan L, Li Y, Liu W, Liu M, Xiao Z, Huang J. Urethane Improves the Response of Auditory Neurons to Tone. Front Cell Neurosci 2022; 16:855968. [PMID: 35783092 PMCID: PMC9240349 DOI: 10.3389/fncel.2022.855968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 05/12/2022] [Indexed: 11/21/2022] Open
Abstract
Urethane has little effect on nervous system and is often used in neuroscience studies. However, the effect of urethane in neurons is not thoroughly clear. In this study, we investigated changes in neuron responses to tones in inferior colliculus during urethane anesthesia. As urethane was metabolized, the best and characteristic frequencies did not obviously change, but the minimal threshold (MT) remained relatively stable or was elevated. The frequency tuning bandwidth at 60 dB SPL (BW60dBSPL) remained unchanged or decreased, and the average evoked spike of effective frequencies at 60 dB SPL (ES60dBSPL) gradually decreased. Although the average evoked spike of effective frequencies at a tone intensity of 20 dB SPL above MT (ES20dBSPLaboveMT) decreased, the frequency tuning bandwidth at a tone intensity of 20 dB SPL above MT (BW20dBSPLaboveMT) did not change. In addition, the changes in MT, ES60dBSPL, BW60dBSPL, and ES20dBSPLaboveMT increased with the MT in pre-anesthesia awake state (MTpre−anesthesiaawake). In some neurons, the MT was lower, BW60dBSPL was broader, and ES60dBSPL and ES20dBSPLaboveMT were higher in urethane anesthesia state than in pre-anesthesia awake state. During anesthesia, the inhibitory effect of urethane reduced the ES20dBSPLaboveMT, but did not change the MT, characteristic frequency, or BW20dBSPLaboveMT. In the recording session with the strongest neuron response, the first spike latency did not decrease, and the spontaneous spike did not increase. Therefore, we conclude that urethane can reduce/not change the MT, increase the evoked spike, or broaden/not change the frequency tuning range, and eventually improve the response of auditory neurons to tone with or without “pushing down” the tonal receptive field in thresholding model. The improved effect increases with the MTpre−anesthesiaawake of neurons. The changes induced by the inhibitory and improved effects of urethane abide by similar regularities, but the change directions are contrary. The improvement mechanism may be likely due to the increase in the ratio of excitatory/inhibitory postsynaptic inputs to neurons.
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Affiliation(s)
- Bowan Huang
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Department of Anesthesiology, Shenzhen Traditional Chinese Medicine Hospital, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Linqing Yan
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yan Li
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Wenhui Liu
- The Seventh Affiliated Hospital, Southern Medical University, Foshan, China
| | - Manhua Liu
- The Seventh Affiliated Hospital, Southern Medical University, Foshan, China
| | - Zhongju Xiao
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- The Seventh Affiliated Hospital, Southern Medical University, Foshan, China
- *Correspondence: Zhongju Xiao
| | - Jinping Huang
- The Seventh Affiliated Hospital, Southern Medical University, Foshan, China
- Jinping Huang
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3
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Yin TC, Smith PH, Joris PX. Neural Mechanisms of Binaural Processing in the Auditory Brainstem. Compr Physiol 2019; 9:1503-1575. [DOI: 10.1002/cphy.c180036] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Slow NMDA-Mediated Excitation Accelerates Offset-Response Latencies Generated via a Post-Inhibitory Rebound Mechanism. eNeuro 2019; 6:ENEURO.0106-19.2019. [PMID: 31152098 PMCID: PMC6584069 DOI: 10.1523/eneuro.0106-19.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/17/2019] [Accepted: 05/02/2019] [Indexed: 01/03/2023] Open
Abstract
In neural circuits, action potentials (spikes) are conventionally caused by excitatory inputs whereas inhibitory inputs reduce or modulate neuronal excitability. We previously showed that neurons in the superior paraolivary nucleus (SPN) require solely synaptic inhibition to generate their hallmark offset response, a burst of spikes at the end of a sound stimulus, via a post-inhibitory rebound mechanism. In addition SPN neurons receive excitatory inputs, but their functional significance is not yet known. Here we used mice of both sexes to demonstrate that in SPN neurons, the classical roles for excitation and inhibition are switched, with inhibitory inputs driving spike firing and excitatory inputs modulating this response. Hodgkin–Huxley modeling suggests that a slow, NMDA receptor (NMDAR)-mediated excitation would accelerate the offset response. We find corroborating evidence from in vitro and in vivo recordings that lack of excitation prolonged offset-response latencies and rendered them more variable to changing sound intensity levels. Our results reveal an unsuspected function for slow excitation in improving the timing of post-inhibitory rebound firing even when the firing itself does not depend on excitation. This shows the auditory system employs highly specialized mechanisms to encode timing-sensitive features of sound offsets which are crucial for sound-duration encoding and have profound biological importance for encoding the temporal structure of speech.
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Felix RA, Chavez VA, Novicio DM, Morley BJ, Portfors CV. Nicotinic acetylcholine receptor subunit α 7-knockout mice exhibit degraded auditory temporal processing. J Neurophysiol 2019; 122:451-465. [PMID: 31116647 DOI: 10.1152/jn.00170.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The CHRNA7 gene that encodes the α7-subunit of the nicotinic acetylcholine receptor (α7-nAChR) has been associated with some autism spectrum disorders and other neurodevelopmental conditions characterized, in part, by auditory and language impairment. These conditions may include auditory processing disorders that represent impaired timing of neural activity, often accompanied by problems understanding speech. Here, we measure timing properties of sound-evoked activity via the auditory brainstem response (ABR) of α7-nAChR knockout mice of both sexes and wild-type colony controls. We find a significant timing delay in evoked ABR signals that represents midbrain activity in knockouts. We also examine spike-timing properties of neurons in the inferior colliculus, a midbrain nucleus that exhibits high levels of α7-nAChR during development. We find delays of evoked responses along with degraded spiking precision in knockout animals. We find similar timing deficits in responses of neurons in the superior paraolivary nucleus and ventral nucleus of the lateral lemniscus, which are brainstem nuclei thought to shape temporal precision in the midbrain. In addition, we find that other measures of temporal acuity including forward masking and gap detection are impaired for knockout animals. We conclude that altered temporal processing at the level of the brainstem in α7-nAChR-deficient mice may contribute to degraded spike timing in the midbrain, which may underlie the observed timing delay in the ABR signals. Our findings are consistent with a role for the α7-nAChR in types of neurodevelopmental and auditory processing disorders and we identify potential neural targets for intervention.NEW & NOTEWORTHY Disrupted signaling via the α7-nicotinic acetylcholine receptor (α7-nAChR) is associated with neurodevelopmental disorders that include impaired auditory processing. The underlying causes of dysfunction are not known but a common feature is abnormal timing of neural activity. We examined temporal processing of α7-nAChR knockout mice and wild-type controls. We found degraded spike timing of neurons in knockout animals, which manifests at the level of the auditory brainstem and midbrain.
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Affiliation(s)
- Richard A Felix
- School of Biological Sciences and the Department of Integrated Physiology and Neuroscience, Washington State University Vancouver, Vancouver, Washington
| | - Vicente A Chavez
- School of Biological Sciences and the Department of Integrated Physiology and Neuroscience, Washington State University Vancouver, Vancouver, Washington
| | - Dyana M Novicio
- School of Biological Sciences and the Department of Integrated Physiology and Neuroscience, Washington State University Vancouver, Vancouver, Washington
| | | | - Christine V Portfors
- School of Biological Sciences and the Department of Integrated Physiology and Neuroscience, Washington State University Vancouver, Vancouver, Washington
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Kopp-Scheinpflug C, Sinclair JL, Linden JF. When Sound Stops: Offset Responses in the Auditory System. Trends Neurosci 2018; 41:712-728. [DOI: 10.1016/j.tins.2018.08.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/30/2018] [Accepted: 08/10/2018] [Indexed: 11/17/2022]
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Gómez-Álvarez M, Gourévitch B, Felix RA, Nyberg T, Hernández-Montiel HL, Magnusson AK. Temporal information in tones, broadband noise, and natural vocalizations is conveyed by differential spiking responses in the superior paraolivary nucleus. Eur J Neurosci 2018; 48:2030-2049. [PMID: 30019495 DOI: 10.1111/ejn.14073] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/12/2018] [Accepted: 06/26/2018] [Indexed: 12/31/2022]
Abstract
Communication sounds across all mammals consist of multiple frequencies repeated in sequence. The onset and offset of vocalizations are potentially important cues for recognizing distinct units, such as phonemes and syllables, which are needed to perceive meaningful communication. The superior paraolivary nucleus (SPON) in the auditory brainstem has been implicated in the processing of rhythmic sounds. Here, we compared how best frequency tones (BFTs), broadband noise (BBN), and natural mouse calls elicit onset and offset spiking in the mouse SPON. The results demonstrate that onset spiking typically occurs in response to BBN, but not BFT stimulation, while spiking at the sound offset occurs for both stimulus types. This effect of stimulus bandwidth on spiking is consistent with two of the established inputs to the SPON from the octopus cells (onset spiking) and medial nucleus of the trapezoid body (offset spiking). Natural mouse calls elicit two main spiking peaks. The first spiking peak, which is weak or absent with BFT stimulation, occurs most consistently during the call envelope, while the second spiking peak occurs at the call offset. This suggests that the combined spiking activity in the SPON elicited by vocalizations reflects the entire envelope, that is, the coarse amplitude waveform. Since the output from the SPON is purely inhibitory, it is speculated that, at the level of the inferior colliculus, the broadly tuned first peak may improve the signal-to-noise ratio of the subsequent, more call frequency-specific peak. Thus, the SPON may provide a dual inhibition mechanism for tracking phonetic boundaries in social-vocal communication.
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Affiliation(s)
- Marcelo Gómez-Álvarez
- Unit of Audiology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Boris Gourévitch
- Unité de Génétique et Physiologie de l'Audition, INSERM, Institut Pasteur, Sorbonne Université Paris, Paris, France.,CNRS, Paris, France
| | | | - Tobias Nyberg
- Division of Neuronic Engineering, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Hebert L Hernández-Montiel
- Laboratorio de Neurobiología y Bioingeniería Celular, Clínica del Sistema Nervioso, Universidad Autónoma de Querétaro, Santiago de Querétaro, México
| | - Anna K Magnusson
- Unit of Audiology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
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8
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Martin LM, García-Rosales F, Beetz MJ, Hechavarría JC. Processing of temporally patterned sounds in the auditory cortex of Seba's short-tailed bat,Carollia perspicillata. Eur J Neurosci 2018; 46:2365-2379. [PMID: 28921742 DOI: 10.1111/ejn.13702] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 11/29/2022]
Abstract
This article presents a characterization of cortical responses to artificial and natural temporally patterned sounds in the bat species Carollia perspicillata, a species that produces vocalizations at rates above 50 Hz. Multi-unit activity was recorded in three different experiments. In the first experiment, amplitude-modulated (AM) pure tones were used as stimuli to drive auditory cortex (AC) units. AC units of both ketamine-anesthetized and awake bats could lock their spikes to every cycle of the stimulus modulation envelope, but only if the modulation frequency was below 22 Hz. In the second experiment, two identical communication syllables were presented at variable intervals. Suppressed responses to the lagging syllable were observed, unless the second syllable followed the first one with a delay of at least 80 ms (i.e., 12.5 Hz repetition rate). In the third experiment, natural distress vocalization sequences were used as stimuli to drive AC units. Distress sequences produced by C. perspicillata contain bouts of syllables repeated at intervals of ~60 ms (16 Hz). Within each bout, syllables are repeated at intervals as short as 14 ms (~71 Hz). Cortical units could follow the slow temporal modulation flow produced by the occurrence of multisyllabic bouts, but not the fast acoustic flow created by rapid syllable repetition within the bouts. Taken together, our results indicate that even in fast vocalizing animals, such as bats, cortical neurons can only track the temporal structure of acoustic streams modulated at frequencies lower than 22 Hz.
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Affiliation(s)
- Lisa M Martin
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Straße 13, 60438, Frankfurt/Main, Germany
| | - Francisco García-Rosales
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Straße 13, 60438, Frankfurt/Main, Germany
| | - M Jerome Beetz
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Straße 13, 60438, Frankfurt/Main, Germany
| | - Julio C Hechavarría
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Straße 13, 60438, Frankfurt/Main, Germany
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9
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Felix Ii RA, Gourévitch B, Gómez-Álvarez M, Leijon SCM, Saldaña E, Magnusson AK. Octopus Cells in the Posteroventral Cochlear Nucleus Provide the Main Excitatory Input to the Superior Paraolivary Nucleus. Front Neural Circuits 2017; 11:37. [PMID: 28620283 PMCID: PMC5449481 DOI: 10.3389/fncir.2017.00037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 05/19/2017] [Indexed: 12/26/2022] Open
Abstract
Auditory streaming enables perception and interpretation of complex acoustic environments that contain competing sound sources. At early stages of central processing, sounds are segregated into separate streams representing attributes that later merge into acoustic objects. Streaming of temporal cues is critical for perceiving vocal communication, such as human speech, but our understanding of circuits that underlie this process is lacking, particularly at subcortical levels. The superior paraolivary nucleus (SPON), a prominent group of inhibitory neurons in the mammalian brainstem, has been implicated in processing temporal information needed for the segmentation of ongoing complex sounds into discrete events. The SPON requires temporally precise and robust excitatory input(s) to convey information about the steep rise in sound amplitude that marks the onset of voiced sound elements. Unfortunately, the sources of excitation to the SPON and the impact of these inputs on the behavior of SPON neurons have yet to be resolved. Using anatomical tract tracing and immunohistochemistry, we identified octopus cells in the contralateral cochlear nucleus (CN) as the primary source of excitatory input to the SPON. Cluster analysis of miniature excitatory events also indicated that the majority of SPON neurons receive one type of excitatory input. Precise octopus cell-driven onset spiking coupled with transient offset spiking make SPON responses well-suited to signal transitions in sound energy contained in vocalizations. Targets of octopus cell projections, including the SPON, are strongly implicated in the processing of temporal sound features, which suggests a common pathway that conveys information critical for perception of complex natural sounds.
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Affiliation(s)
- Richard A Felix Ii
- Unit of Audiology, Department of Clinical Science, Intervention and Technology, Karolinska InstitutetStockholm, Sweden
| | - Boris Gourévitch
- Institut Pasteur, Unité de Génétique et Physiologie de l'AuditionParis, France.,Institut National de la Santé et de la Recherche Médicale, UMRS 1120Paris, France.,Université Pierre et Marie CurieParis, France
| | - Marcelo Gómez-Álvarez
- Unit of Audiology, Department of Clinical Science, Intervention and Technology, Karolinska InstitutetStockholm, Sweden.,Neuroscience Institute of Castilla y León (INCyL), Universidad de SalamancaSalamanca, Spain.,Institute of Biomedical Research of Salamanca (IBSAL)Salamanca, Spain
| | - Sara C M Leijon
- Unit of Audiology, Department of Clinical Science, Intervention and Technology, Karolinska InstitutetStockholm, Sweden
| | - Enrique Saldaña
- Neuroscience Institute of Castilla y León (INCyL), Universidad de SalamancaSalamanca, Spain.,Institute of Biomedical Research of Salamanca (IBSAL)Salamanca, Spain
| | - Anna K Magnusson
- Unit of Audiology, Department of Clinical Science, Intervention and Technology, Karolinska InstitutetStockholm, Sweden
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10
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Felix RA, Elde CJ, Nevue AA, Portfors CV. Serotonin modulates response properties of neurons in the dorsal cochlear nucleus of the mouse. Hear Res 2016; 344:13-23. [PMID: 27838373 DOI: 10.1016/j.heares.2016.10.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/10/2016] [Accepted: 10/26/2016] [Indexed: 01/15/2023]
Abstract
The neurochemical serotonin (5-hydroxytryptamine, 5-HT) is involved in a variety of behavioral functions including arousal, reward, and attention, and has a role in several complex disorders of the brain. In the auditory system, 5-HT fibers innervate a number of subcortical nuclei, yet the modulatory role of 5-HT in nearly all of these areas remains poorly understood. In this study, we examined spiking activity of neurons in the dorsal cochlear nucleus (DCN) following iontophoretic application of 5-HT. The DCN is an early site in the auditory pathway that receives dense 5-HT fiber input from the raphe nuclei and has been implicated in the generation of auditory disorders marked by neuronal hyperexcitability. Recordings from the DCN in awake mice demonstrated that iontophoretic application of 5-HT had heterogeneous effects on spiking rate, spike timing, and evoked spiking threshold. We found that 56% of neurons exhibited increases in spiking rate during 5-HT delivery, while 22% had decreases in rate and the remaining neurons had no change. These changes were similar for spontaneous and evoked spiking and were typically accompanied by changes in spike timing. Spiking increases were associated with lower first spike latencies and jitter, while decreases in spiking generally had opposing effects on spike timing. Cases in which 5-HT application resulted in increased spiking also exhibited lower thresholds compared to the control condition, while cases of decreased spiking had no threshold change. We also found that the 5-HT2 receptor subtype likely has a role in mediating increased excitability. Our results demonstrate that 5-HT can modulate activity in the DCN of awake animals and that it primarily acts to increase neuronal excitability, in contrast to other auditory regions where it largely has a suppressive role. Modulation of DCN function by 5-HT has implications for auditory processing in both normal hearing and disordered states.
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Affiliation(s)
- Richard A Felix
- School of Biological Sciences and Integrative Physiology and Neuroscience, Washington State University, Vancouver, WA, USA.
| | - Cameron J Elde
- School of Biological Sciences and Integrative Physiology and Neuroscience, Washington State University, Vancouver, WA, USA
| | - Alexander A Nevue
- School of Biological Sciences and Integrative Physiology and Neuroscience, Washington State University, Vancouver, WA, USA
| | - Christine V Portfors
- School of Biological Sciences and Integrative Physiology and Neuroscience, Washington State University, Vancouver, WA, USA
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11
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Nevue AA, Felix RA, Portfors CV. Dopaminergic projections of the subparafascicular thalamic nucleus to the auditory brainstem. Hear Res 2016; 341:202-209. [PMID: 27620513 DOI: 10.1016/j.heares.2016.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 09/01/2016] [Accepted: 09/07/2016] [Indexed: 11/18/2022]
Abstract
Neuromodulators can alter the response properties of sensory neurons, including those in the auditory system. Dopamine, which plays a major role in reward and movement, has been shown to alter neural responses in the auditory brainstem and midbrain. Recently we identified the subparafascicular thalamic nucleus (SPF), part of the A11 dopaminergic cell group, as the source of dopamine to the inferior colliculus (IC). The superior olivary complex (SOC) is also a likely target of dopaminergic projections from the SPF because it receives projections from the SPF and contains fibers and terminals immunoreactive for tyrosine hydroxylase, the rate limiting enzyme in dopamine synthesis. However, it is unknown if the projections from the SPF to SOC are dopaminergic, and if single neurons in the SPF project to both the IC and SOC. Using anterograde tracing combined with fluorescent immunohistochemistry, we found that the SPF sends dopaminergic projections to the superior paraolivary nucleus and the medial nucleus of the trapezoid body, but not the lateral superior olive. We confirmed these projections using a retrograde tracer. By making dual retrograde deposits in the IC and SOC, we found that individual dopaminergic cells innervate both the IC and SOC. These results suggest dopaminergic innervation, likely released in a context dependent manner, occurs at multiple levels of the auditory pathway.
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Affiliation(s)
- Alexander A Nevue
- School of Biological Sciences, Washington State University Vancouver, 14204 NE Salmon Creek Ave, Vancouver, WA 98686, USA.
| | - Richard A Felix
- Integrative Physiology and Neuroscience, Washington State University Vancouver, 14204 NE Salmon Creek Ave, Vancouver, WA 98686, USA.
| | - Christine V Portfors
- School of Biological Sciences, Washington State University Vancouver, 14204 NE Salmon Creek Ave, Vancouver, WA 98686, USA.
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12
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Lee CM, Osman AF, Volgushev M, Escabí MA, Read HL. Neural spike-timing patterns vary with sound shape and periodicity in three auditory cortical fields. J Neurophysiol 2016; 115:1886-904. [PMID: 26843599 DOI: 10.1152/jn.00784.2015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 01/29/2016] [Indexed: 11/22/2022] Open
Abstract
Mammals perceive a wide range of temporal cues in natural sounds, and the auditory cortex is essential for their detection and discrimination. The rat primary (A1), ventral (VAF), and caudal suprarhinal (cSRAF) auditory cortical fields have separate thalamocortical pathways that may support unique temporal cue sensitivities. To explore this, we record responses of single neurons in the three fields to variations in envelope shape and modulation frequency of periodic noise sequences. Spike rate, relative synchrony, and first-spike latency metrics have previously been used to quantify neural sensitivities to temporal sound cues; however, such metrics do not measure absolute spike timing of sustained responses to sound shape. To address this, in this study we quantify two forms of spike-timing precision, jitter, and reliability. In all three fields, we find that jitter decreases logarithmically with increase in the basis spline (B-spline) cutoff frequency used to shape the sound envelope. In contrast, reliability decreases logarithmically with increase in sound envelope modulation frequency. In A1, jitter and reliability vary independently, whereas in ventral cortical fields, jitter and reliability covary. Jitter time scales increase (A1 < VAF < cSRAF) and modulation frequency upper cutoffs decrease (A1 > VAF > cSRAF) with ventral progression from A1. These results suggest a transition from independent encoding of shape and periodicity sound cues on short time scales in A1 to a joint encoding of these same cues on longer time scales in ventral nonprimary cortices.
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Affiliation(s)
- Christopher M Lee
- Department of Psychology, University of Connecticut, Storrs, Connecticut
| | - Ahmad F Osman
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; and
| | - Maxim Volgushev
- Department of Psychology, University of Connecticut, Storrs, Connecticut
| | - Monty A Escabí
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; and Department of Electrical and Computer Engineering, University of Connecticut, Storrs, Connecticut
| | - Heather L Read
- Department of Psychology, University of Connecticut, Storrs, Connecticut; Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; and
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13
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Felix RA, Magnusson AK, Berrebi AS. The superior paraolivary nucleus shapes temporal response properties of neurons in the inferior colliculus. Brain Struct Funct 2015; 220:2639-52. [PMID: 24973970 PMCID: PMC4278952 DOI: 10.1007/s00429-014-0815-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 06/04/2014] [Indexed: 10/25/2022]
Abstract
The mammalian superior paraolivary nucleus (SPON) is a major source of GABAergic inhibition to neurons in the inferior colliculus (IC), a well-studied midbrain nucleus that is the site of convergence and integration for the majority ascending auditory pathways en route to the cortex. Neurons in the SPON and IC exhibit highly precise responses to temporal sound features, which are important perceptual cues for naturally occurring sounds. To determine how inhibitory input from the SPON contributes to the encoding of temporal information in the IC, a reversible inactivation procedure was conducted to silence SPON neurons, while recording responses to amplitude-modulated tones and silent gaps between tones in the IC. The results show that SPON-derived inhibition shapes responses of onset and sustained units in the IC via different mechanisms. Onset neurons appear to be driven primarily by excitatory inputs and their responses are shaped indirectly by SPON-derived inhibition, whereas sustained neurons are heavily influenced directly by transient offset inhibition from the SPON. The findings also demonstrate that a more complete dissection of temporal processing pathways is critical for understanding how biologically important sounds are encoded by the brain.
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Affiliation(s)
- Richard A. Felix
- Department of Otolaryngology–Head and Neck Surgery and the Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, West Virginia 26506 USA
| | - Anna K. Magnusson
- Center for Hearing and Communication Research, Karolinska Institutet and Department of Clinical Science, Intervention and Technology, Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Albert S. Berrebi
- Department of Otolaryngology–Head and Neck Surgery and the Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, West Virginia 26506 USA
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Noda T, Takahashi H. Anesthetic effects of isoflurane on the tonotopic map and neuronal population activity in the rat auditory cortex. Eur J Neurosci 2015; 42:2298-311. [PMID: 26118739 DOI: 10.1111/ejn.13007] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 06/23/2015] [Accepted: 06/24/2015] [Indexed: 12/01/2022]
Abstract
Since its discovery nearly four decades ago, sequential microelectrode mapping using hundreds of recording sites has been able to reveal a precise tonotopic organization of the auditory cortex. Despite concerns regarding the effects that anesthesia might have on neuronal responses to tones, anesthesia was essential for these experiments because such dense mapping was elaborate and time-consuming. Here, taking an 'all-at-once' approach, we investigated how isoflurane modifies spatiotemporal activities by using a dense microelectrode array. The array covered the entire auditory cortex in rats, including the core and belt cortices. By comparing neuronal activity in the awake state with activity under isoflurane anesthesia, we made four observations. First, isoflurane anesthesia did not modify the tonotopic topography within the auditory cortex. Second, in terms of general response properties, isoflurane anesthesia decreased the number of active single units and increased their response onset latency. Third, in terms of tuning properties, isoflurane anesthesia shifted the response threshold without changing the shape of the frequency response area and decreased the response quality. Fourth, in terms of population activities, isoflurane anesthesia increased the noise correlations in discharges and phase synchrony in local field potential (LFP) oscillations, suggesting that the anesthesia made neuronal activities redundant at both single-unit and LFP levels. Thus, while isoflurane anesthesia had little effect on the tonotopic topography, its profound effects on neuronal activities decreased the encoding capacity of the auditory cortex.
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Affiliation(s)
- Takahiro Noda
- Research Center for Advanced Science and Technology, The University of Tokyo, Komaba 4-6-1, Meguro-ku, Tokyo, 153-8904, Japan
| | - Hirokazu Takahashi
- Research Center for Advanced Science and Technology, The University of Tokyo, Komaba 4-6-1, Meguro-ku, Tokyo, 153-8904, Japan.,PRESTO, JST, Kawaguchi, Saitama, Japan
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Gao F, Berrebi AS. Forward masking in the medial nucleus of the trapezoid body of the rat. Brain Struct Funct 2015; 221:2303-17. [PMID: 25921974 DOI: 10.1007/s00429-015-1044-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 04/10/2015] [Indexed: 10/23/2022]
Abstract
Perception of acoustic stimuli is modulated by the temporal and spectral relationship between sound components. Forward masking experiments show that the perception threshold for a probe tone is significantly impaired by a preceding masker stimulus. Forward masking has been systematically studied at the level of the auditory nerve, cochlear nucleus, inferior colliculus and auditory cortex, but not yet in the superior olivary complex. The medial nucleus of the trapezoid body (MNTB), a principal cell group of the superior olive, plays an essential role in sound localization. The MNTB receives excitatory input from the contralateral cochlear nucleus via the calyces of Held and innervates the ipsilateral lateral and medial superior olives, as well as the superior paraolivary nucleus. Here, we performed single-unit extracellular recordings in the MNTB of rats. Using a forward masking paradigm previously employed in studies of the inferior colliculus and auditory nerve, we determined response thresholds for a 20-ms characteristic frequency pure tone (the probe), and then presented it in conjunction with another tone (the masker) that was varied in intensity, duration, and frequency; we also systematically varied the masker-to-probe delay. Probe response thresholds increased and response magnitudes decreased when a masker was presented. The forward suppression effects were greater when masker level and masker duration were increased, when the masker frequency approached the MNTB unit's characteristic frequency, and as the masker-to-probe delay was shortened. Probe threshold shifts showed an exponential decay as the masker-to-probe delay increased.
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Affiliation(s)
- Fei Gao
- Departments of Otolaryngology, Head and Neck Surgery, Neurobiology and Anatomy, Sensory Neuroscience Research Center, Health Sciences Center, West Virginia University School of Medicine, PO Box 9303, Morgantown, WV, 26506, USA
| | - Albert S Berrebi
- Departments of Otolaryngology, Head and Neck Surgery, Neurobiology and Anatomy, Sensory Neuroscience Research Center, Health Sciences Center, West Virginia University School of Medicine, PO Box 9303, Morgantown, WV, 26506, USA.
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Felix RA, Vonderschen K, Berrebi AS, Magnusson AK. Development of on-off spiking in superior paraolivary nucleus neurons of the mouse. J Neurophysiol 2013; 109:2691-704. [PMID: 23515791 DOI: 10.1152/jn.01041.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The superior paraolivary nucleus (SPON) is a prominent cell group in the auditory brain stem that has been increasingly implicated in representing temporal sound structure. Although SPON neurons selectively respond to acoustic signals important for sound periodicity, the underlying physiological specializations enabling these responses are poorly understood. We used in vitro and in vivo recordings to investigate how SPON neurons develop intrinsic cellular properties that make them well suited for encoding temporal sound features. In addition to their hallmark rebound spiking at the stimulus offset, SPON neurons were characterized by spiking patterns termed onset, adapting, and burst in response to depolarizing stimuli in vitro. Cells with burst spiking had some morphological differences compared with other SPON neurons and were localized to the dorsolateral region of the nucleus. Both membrane and spiking properties underwent strong developmental regulation, becoming more temporally precise with age for both onset and offset spiking. Single-unit recordings obtained in young mice demonstrated that SPON neurons respond with temporally precise onset spiking upon tone stimulation in vivo, in addition to the typical offset spiking. Taken together, the results of the present study demonstrate that SPON neurons develop sharp on-off spiking, which may confer sensitivity to sound amplitude modulations or abrupt sound transients. These findings are consistent with the proposed involvement of the SPON in the processing of temporal sound structure, relevant for encoding communication cues.
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Affiliation(s)
- Richard A Felix
- Center for Hearing and Communication Research, Karolinska Institutet and Department of Clinical Science, Intervention and Technology, Karolinska University Hospital, Stockholm, Sweden
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