Corticofugal modulation of midbrain sound processing in the house mouse

Yan, Jun; Ehret, Günter

doi:10.1046/j.1460-9568.2002.02046.x

Cited by 117 publications

(139 citation statements)

References 75 publications

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“…Because this protocol was identical to what was used in our previous studies (Yan and Ehret, 2002;, data were comparable with our previous findings. This protocol sampled the frequency tunings of CN neurons with a series of tone bursts separated by 250 ms.…”

Section: Methodssupporting

confidence: 84%

“…2). Such BF-related changes in auditory response magnitudes and BFs of CN neurons will be addressed later with a procedure used in our previous studies (Yan and Ehret, 2002;.…”

Section: Resultsmentioning

confidence: 99%

“…Forty-one female C57 mice (Charles River Laboratories) aged 4 -7 weeks and weighing 14.6 -24.0 g were used in this study. Animal preparation, acoustic stimulation, electrical stimulation of the auditory cortex, recording of action potentials and data processing were mostly the same as those described previously (Yan and Ehret, 2002;Jafari et al, 2007;Wu and Yan, 2007). All protocols and procedures were in accordance with the Canadian Council on Animal Care and approved by the Animal Care Committee of the University of Calgary (protocol number: M04044).…”

Section: Methodsmentioning

confidence: 99%

“…Many studies in the visual, auditory and somatosensory systems have unveiled that sensory cortices differentially modulate subcortical neuron activities in a highly specific manner (Sillito et al, 1994;Yan and Suga, 1996;Zhang et al, 1997;Jen, 2000, 2007;Yan and Ehret, 2002;Malmierca and Nuñez, 2004;Castellanos et al, 2007;Ma and Suga, 2007). In the auditory system, focal cortical activation enhances the thalamic and midbrain processing of auditory information that is encoded by activated cortical neurons .…”

Section: Introductionmentioning

confidence: 99%

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Corticofugal Modulation of Initial Sound Processing in the Brain

Luo¹,

Wang²,

Kashani³

et al. 2008

J. Neurosci.

121

116

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The brain selectively extracts the most relevant information in top-down processing manner. Does the corticofugal system, a "back projection system," constitute the neural basis of such top-down selection? Here, we show how focal activation of the auditory cortex with 500 nA electrical pulses influences the auditory information processing in the cochlear nucleus (CN) that receives almost unprocessed information directly from the ear. We found that cortical activation increased the response magnitudes and shortened response latencies of physiologically matched CN neurons, whereas decreased response magnitudes and lengthened response latencies of unmatched CN neurons. In addition, cortical activation shifted the frequency tunings of unmatched CN neurons toward those of the activated cortical neurons. Our data suggest that cortical activation selectively enhances the neural processing of particular auditory information and attenuates others at the first processing level in the brain based on sound frequencies encoded in the auditory cortex. The auditory cortex apparently implements a long-range feedback mechanism to select or filter incoming signals from the ear.

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Section: Methodssupporting

confidence: 84%

“…2). Such BF-related changes in auditory response magnitudes and BFs of CN neurons will be addressed later with a procedure used in our previous studies (Yan and Ehret, 2002;.…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Corticofugal Modulation of Initial Sound Processing in the Brain

Luo¹,

Wang²,

Kashani³

et al. 2008

J. Neurosci.

121

116

View full text Add to dashboard Cite

show abstract

“…Across taxa, the auditory midbrain is known to receive descending inputs (Mello et al, 1998;Winer et al, 1998Winer et al, , 2002Bajo and Moore, 2005). And the response properties of auditory midbrain neurons have been shown to differ depending on cortical activity (Yan and Suga, 1998;Walkowiak, 1999, 2000;Ma and Suga, 2001;Yan and Ehret, 2002).…”

Section: Stimulus-dependent Changes In Linear Tuningmentioning

confidence: 99%

Stimulus-Dependent Auditory Tuning Results in Synchronous Population Coding of Vocalizations in the Songbird Midbrain

2006

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Physiological studies in vocal animals such as songbirds indicate that vocalizations drive auditory neurons particularly well. But the neural mechanisms whereby vocalizations are encoded differently from other sounds in the auditory system are unknown. We used spectrotemporal receptive fields (STRFs) to study the neural encoding of song versus the encoding of a generic sound, modulationlimited noise, by single neurons and the neuronal population in the zebra finch auditory midbrain. The noise was designed to match song in frequency, spectrotemporal modulation boundaries, and power. STRF calculations were balanced between the two stimulus types by forcing a common stimulus subspace. We found that 91% of midbrain neurons showed significant differences in spectral and temporal tuning properties when birds heard song and when birds heard modulation-limited noise. During the processing of noise, spectrotemporal tuning was highly variable across cells. During song processing, the tuning of individual cells became more similar; frequency tuning bandwidth increased, best temporal modulation frequency increased, and spike timing became more precise. The outcome was a population response to song that encoded rapidly changing sounds with power and precision, resulting in a faithful neural representation of the temporal pattern of a song. Modeling responses to song using the tuning to modulation-limited noise showed that the population response would not encode song as precisely or robustly. We conclude that stimulus-dependent changes in auditory tuning during song processing facilitate the high-fidelity encoding of the temporal pattern of a song.

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