Recent publication highlights
Eliades SJ and Tsunada J. Effects of cortical stimulation on feedback-dependent vocal control in non-human primates. Laryngoscope, 2022 (doi: 10.1002/lary.30175)
Summary: In this article, we followed up on our 2018 paper using electrical microstimulation in auditory cortex. Here we examined whether the stimulation not only affected normal vocal production, but could interfere with the feedback-depending pitch control. We found that we could indeed affect the pitch reflex, blocking/reducing it if the stimulation site had frequency tuning near the vocal range, and actually enhancing the reflex if more distant. Read more ...
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Thomas A, Mirza N, Eliades SJ. Auditory feedback control of vocal pitch in spasmodic dysphonia. Laryngoscope, 131: 2070-2075, 2021
Summary: Spasmodic dysphonia (SD) is a vocal disordered characterized by vocal breaks during phonation. It is thought of as a focal dystonia, though its origins is unclear. Here we tested vocal pitch control in SD patients and normal controls, and found SD patients had increased pitch reflexes, suggesting a hyperactive reflex. Interestingly, there was an inverse correlation with subjective symptoms, i.e. those that were most bothered by their symptoms had the most normal pitch control. These findings may give us some new approaches to managing SD. Read more ...
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Gautam A, Brant JA, Ruckenstein M, Eliades SJ. Real-time feedback control of voice in cochlear implant recipients. Laryngoscope Inv Oto. 5: 1156-1162, 2020
Summary: In this clinical/translational study, we examined whether cochlear implant patients had the same feedback control of vocal pitch as normal individuals (and our marmosets). We found that they did, but we had to push the feedback to almost half an octave to get them to compensate! Perhaps not surprising given the poor frequency resolution of cochlear implant. Interestingly, when they did compensate, it was larger than normal individuals. This could be because, unlike normal hearing subjects, they could not hear direct feedback or bone-conductive feedback without the pitch shift. Read more ...
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Eliades S and Tsunada J. Dissociation of unit activity and gamma oscillations during vocalization in primate auditory cortex. J. Neurosci, 40: 4158-4171, 2020
Summary: Gamma oscillations have been described to reflect the activity of local inhibitory interneurons in the cortex. Here we showed that sites with strong vocal suppression also exhibit increased gamma oscillations, consistent with vocalization-induced suppression as a local cortical phenomenon rather than one inherited from subcortical pathways. These findings allow us to dissociate contributions of sensory inputs from putative top-down motor inputs, and also suggest possible circuit mechanisms within the cortex. Read more ...
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Eliades SJ and Wang X. Corollary discharge mechanisms during vocal production in marmoset monkeys. Biological Psychiatry: Cog Neurosci and Neuroimaging, 4: 805-812, 2019.
Summary: This review was part of a special issue looking at corollary discharge mechanisms in both humans and animals, with a focus of dysfunction in neuropsychiatric disease. Read more...
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Eliades SJ and Tsunada J. Auditory cortical activity drives feedback-dependent vocal control in marmosets. Nature Communications, 9, 2018 (DOI 10.1038/s41467-018-04961-8)
Summary: While the suppression of auditory cortex during human speech and animal vocal production has been well established, what behavioral role the auditory cortex actually plays to support vocal communication has been unclear. In this study we show that marmosets exhibit real-time feedback control of their vocalization frequencies, almost identically to human speech pitch control. Neurons in the auditory cortex actually predict this compensatory behavior before it happens. Finally, we used microstimulation of the auditory cortex and found that causes marmosets to rapidly (40ms !) change their vocalizations (illustrated left). This is the first critical and causal evidence for a behavioral role for the auditory cortex in vocal production. Read more...
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Eliades SJ and Miller CT. Marmoset vocal communication: Behavior and neurobiology. Dev Neurobiol, 77: 286-299, 2017
Summary: This review was part of a special issue on Marmosets in biomedical research, spanning the whole range of fields from behavior, to genetics, to neuroscience. We highly recommend anyone interested in neuroscience go to the Developmental Neurobiology website and take a look at the whole issue! Read more...
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Eliades SJ and Wang X. Contributions of sensory tuning to auditory-vocal interactions in marmoset auditory cortex. Hearing Res, 348: 98-111, 2017
Summary: This study reports on new-analysis of previous marmoset vocal production results, to examine what role sensory tuning in auditory cortex may have in neural responses during vocal production. We found that excited responses during vocalization are predictable based upon sensory tuning, but suppressed responses are not, consistent with suppression as a sensory-motor process rather than a purely sensory one. Read more...
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Eliades SJ, Crone NE, Anderson WS, Ramadoss D, Lenz FA, and Boatman-Reich D. Adaptation of High-Gamma Responses in Human Auditory Association Cortex. J Neurophysiol 112: 2147-2163, 2014
Summary: This study reports on findings of adaptation of auditory responses recorded intracranialy from human subjects using ECoG. We show that human auditory cortex responses, like those of animals, adapt with repetitive auditory stimulation. Unlike many scalp recorded EEG studies, we do not find evidence of a novelty of mismatch response when appropriate controls are used. Read more...
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Ghazanfar AA and Eliades SJ. The neurobiology of primate vocal communication. Curr Opinion in Neurobiology 28: 128-135, 2014
Summary: Recent investigations in non-human primate communication has revealed vocal behaviors for more complex than previously appreciated. Understanding the neural basis of these communicative behaviors is important as it has the potential to reveal the basic underpinnings of still more complex human speech. Here we summarize recent behavioral and physiologic investigations into primate vocal communication. Read more...
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Eliades SJ and Wang X. Comparison of auditory-vocal interactions across multiple types of vocalizations in marmoset auditory cortex. J Neurophysiol 109: 1638-1657, 2013
Summary: Auditory-vocal interaction, the modulation of auditory sensory responses during vocal production, is a poorly understood neurophysiological phenomenon in both humans and non-human primates. This sensory process likely lays a role in auditory-self monitoring during vocal production, and feedback-mediate vocal control. Previous studies have largely focused on a single type of vocalization. Here we examine auditory-vocal interactions across multiple classes of marmoset vocalizations and find that vocalization-related responses are often similar regardless of the type of vocalization produced. Read more...
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