Substrates of auditory frequency integration in a nucleus of the lateral lemniscus

Yavuzoglu, Asuman; Schofield, Brett R.; Wenstrup, Jeffrey J.

doi:10.1016/j.neuroscience.2010.04.073

Cited by 15 publications

(21 citation statements)

References 88 publications

(139 reference statements)

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“…Presumably, forward masking in the MNTB could interact with both mechanisms of sound localization, and contribute to the directional sensitivity of forward masking observed in the auditory cortex by Reale and Brugge (2000). The MNTB also provides inhibitory input to the intermediate nucleus of the lateral lemniscus (INLL), whose neurons produce a form of spectral integration, whereby the responses to best frequency stimuli are suppressed by sounds within a frequency band at least one octave lower (Yavuzoglu et al 2010). Because this spectral integration requires concurrent stimuli, any effects of forward masking would arise only in complex acoustic environments, where multiple sounds are present during overlapping time periods.…”

Section: Discussionmentioning

confidence: 99%

Forward masking in the medial nucleus of the trapezoid body of the rat

Gao

Berrebi

2015

Brain Struct Funct

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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 location. The MNTB receives excitatory input from the contralateral cochlear nucleus via the calyces of Held and innervates the ipsilateral lateral and medial superior olives (LSO and MSO), as well as the superior paraolivary nucleus (SPON). 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 (CF) 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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Section: Discussionmentioning

confidence: 99%

Forward masking in the medial nucleus of the trapezoid body of the rat

Gao

Berrebi

2015

Brain Struct Funct

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“…We recently described details of materials and methods for generating acoustic signals and recording neural potentials (Yavuzoglu et al, 2010). Only key elements are included here.…”

Section: Methodsmentioning

confidence: 99%

Circuitry Underlying Spectrotemporal Integration in the Auditory Midbrain

Yavuzoglu¹,

Schofield²,

Wenstrup³

2011

J. Neurosci.

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Combination sensitivity in central auditory neurons is a form of spectrotemporal integration in which excitatory responses to sounds at one frequency are facilitated by sounds within a distinctly different frequency band. Combination-sensitive neurons respond selectively to acoustic elements of sonar echoes or social vocalizations. In mustached bats, this response property originates in high frequency representations of the inferior colliculus (IC) and depends on low- and high-frequency-tuned glycinergic inputs. To identify source of these inputs, we combined glycine immunohistochemistry with retrograde tract-tracing. Tracers were deposited at high-frequency (>56 kHz), combination-sensitive recording sites in IC. Most glycine-immunopositive, retrogradely labeled cells were in ipsilateral ventral and intermediate nuclei of the lateral lemniscus (VNLL and INLL), with some double-labeling in ipsilateral lateral and medial superior olivary nuclei (LSO and MSO). Generally, double-labeled cells were in expected high-frequency tonotopic areas, but some VNLL and INLL labeling appeared to be in low-frequency representations. To test whether these nuclei provide low-frequency-tuned input to the high-frequency IC, we combined retrograde tracing from IC combination-sensitive sites with anterograde tracing from low-frequency-tuned sites in the anteroventral cochlear nucleus (AVCN). Only VNLL and INLL contained retrogradely labeled cells near (≤50 µm) anterogradely labeled boutons. These cells likely receive excitatory low-frequency input from AVCN. Results suggest that combination-sensitive facilitation arises through convergence of high-frequency glycinergic inputs from VNLL, INLL, or MSO and low-frequency glycinergic inputs from VNLL or INLL. This work establishes an anatomical basis for spectrotemporal integration in the auditory midbrain and a functional role for monaural nuclei of the lateral lemniscus.

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“…The electrode was kept in position for an additional 10 min and then removed from the brain. Details of tracer-specific techniques have been described previously (Marsh et al 2002;Yavuzoglu et al 2010). Tracer deposit sites were photographed with a SPOT RT3 camera and SPOT Advanced Plus imaging software (version 4.7) mounted on a Zeiss Axio Imager M2 fluorescence microscope.…”

Section: Verification Of Recording Locationmentioning

confidence: 99%

A novel coding mechanism for social vocalizations in the lateral amygdala

Gadziola

Grimsley

Shanbhag

et al. 2012

Journal of Neurophysiology

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The amygdala plays a central role in evaluating the significance of acoustic signals and coordinating the appropriate behavioral responses. To understand how amygdalar responses modulate auditory processing and drive emotional expression, we assessed how neurons respond to and encode information that is carried within complex acoustic stimuli. We characterized responses of single neurons in the lateral nucleus of the amygdala to social vocalizations and synthetic acoustic stimuli in awake big brown bats. Neurons typically responded to most of the social vocalizations presented (mean = nine of 11 vocalizations) but differentially modulated both firing rate and response duration. Surprisingly, response duration provided substantially more information about vocalizations than did spike rate. In most neurons, variation in response duration depended, in part, on persistent excitatory discharge that extended beyond stimulus duration. Information in persistent firing duration was significantly greater than in spike rate, and the majority of neurons displayed more information in persistent firing, which was more likely to be observed in response to aggressive vocalizations (64%) than appeasement vocalizations (25%), suggesting that persistent firing may relate to the behavioral context of vocalizations. These findings suggest that the amygdala uses a novel coding strategy for discriminating among vocalizations and underscore the importance of persistent firing in the general functioning of the amygdala.

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Substrates of auditory frequency integration in a nucleus of the lateral lemniscus

Cited by 15 publications

References 88 publications

Forward masking in the medial nucleus of the trapezoid body of the rat

Forward masking in the medial nucleus of the trapezoid body of the rat

Circuitry Underlying Spectrotemporal Integration in the Auditory Midbrain

A novel coding mechanism for social vocalizations in the lateral amygdala

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