# Hormonal and acoustic regulation of the dopaminergic auditory efferent system: improving detection of social acoustic signals at the level of the inner ear

> **NIH NIH R15** · BROOKLYN COLLEGE · 2022 · $461,989

## Abstract

While there is ample evidence that the dopaminergic inner ear efferent system is upregulated under
environmental conditions that induce acoustic trauma, there is a major gap in knowledge about internal
regulators of this system and its functional significance under normal hearing conditions, especially in the
context of social communication. The overall objective of this application is to determine the hormonal and
acoustic signals that underlie the plasticity of dopamine innervation and its synthesis in the inner ear, which, in
turn, affects primary auditory processing and encoding of social vocalizations. The plainfin midshipman fish,
perhaps the most robust model for this kind of work has the enormous potential of uncovering regulation and
function of dopaminergic inner ear efferents in the context of social communication. Importantly, the natural
and extraordinary plasticity of the peripheral auditory system (including its dopaminergic efferents) in female
midshipman, appears to mirror conditions reflective of human hearing loss and attention. The central
hypothesis is that the dopaminergic system of the inner ear is regulated by changes in internal state via
circulating hormones and local synthesis of dopamine can be modulated by social acoustic stimuli. This
hypothesis, strongly supported by preliminary data, will be tested by the following two specifc aims: 1) Measure
hormone-induced changes in dopaminergic neurotransmission and 2) Characterize changes in dopamine
synthesis and metabolism after exposure to social acoustic signals. For the first aim circulating levels of sex
steroids and melatonin will be experimentally manipulated and changes in dopamine innervation, dopamine
receptor gene expression and dopamine synthesis and metabolism in the inner ear will be measured. For the
second aim, changes in local dopamine synthesis in the inner ear of females will be measured when exposed
to male advertisement calls and when responding and attending to social acoustic stimuli. The proposed
project is innovative, in our opinion, because it represents a substantive departure from the status quo by
employing a simple but powerful, non-mammalian vertebrate model system where hormone-driven increases
in periphery auditory sensitivity enhance encoding of social acoustic signals, and dopamine input to the inner
ear plays a role in mediating this change in auditory sensitivity. This contribution will be significant because it
will identify physiological and environmental conditions that regulate a novel biological function for dopamine in
the peripheral auditory system: increased detection of social-acoustic signals. Importantly, our results could
interpret the function of dopamine modulation of the inner ear in a natural and behaviorally relevant context
that is absent in mammalian studies thus far. Ultimately, these findings have the potential to provide insights
into how cycling (menstrual) or decline in hormones (aging) may be linked to changes in ...

## Key facts

- **NIH application ID:** 10439364
- **Project number:** 1R15DC020327-01
- **Recipient organization:** BROOKLYN COLLEGE
- **Principal Investigator:** PAUL M. FORLANO
- **Activity code:** R15 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $461,989
- **Award type:** 1
- **Project period:** 2022-05-01 → 2027-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10439364

## Citation

> US National Institutes of Health, RePORTER application 10439364, Hormonal and acoustic regulation of the dopaminergic auditory efferent system: improving detection of social acoustic signals at the level of the inner ear (1R15DC020327-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10439364. Licensed CC0.

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