# Vulnerability to Hearing Loss After the Developmental Critical Period

> **NIH NIH F32** · NEW YORK UNIVERSITY · 2020 · $5,621

## Abstract

PROJECT SUMMARY
Experimental studies of developmental hearing loss (HL) typically focus on a critical period (CP) during which
sensory deprivation can permanently disrupt neural function. However, childhood HL often emerges
progressively after birth and extends through adolescence, leading to significant perceptual deficits.
Furthermore, the magnitude of these deficits increases with longer periods of undetected HL. This suggests that
auditory function remains vulnerable to HL after a CP has ended, and implicates HL duration as the key
independent variable. However, the impact of developmental HL that occurs after the CP is poorly understood.
Therefore, the goal of this proposal is to study the effect of HL on neural and behavioral processing during a
clinically relevant period that extends through sexual maturation. An experimental paradigm will be used that
allows one to parse peripheral and central mechanisms: transient earplug insertion which, when removed, leave
the periphery undamaged at the time of testing. This proposal will address the core hypothesis that
developmental HL induced after the critical period can disrupt cellular properties in the auditory cortex when the
duration is sufficiently long, thereby impairing auditory perception and cortical encoding. There are two
experimental Aims. Specific Aim 1 will determine whether long duration HL induced after the CP permanently
disrupts auditory perception. Bilateral earplugs will be used to induce HL at two postnatal ages, beginning within
the CP or after it ends, and extending through sexual maturity. After earplug removal and recovery of normal
audiometric thresholds, animals will be trained and tested on an amplitude modulation (AM) detection task using
an aversive Go/Nogo procedure. AM detection thresholds will be measured from psychometric functions and
compared between HL animals and littermate controls. Auditory brainstem responses will be collected to
determine whether long duration developmental HL induces changes to the auditory brainstem. Specific Aim 2
will determine whether long duration HL induced after the CP alters auditory cortex cellular properties, thereby
diminishing the sensory encoding of AM stimuli during a detection task. Whole-cell recordings will be obtained
from auditory cortex layer 2/3 pyramidal neurons to examine cortical synaptic and firing properties. Auditory
cortex neuron responses will be recorded from chronically implanted 64 channel electrode arrays as awake-
behaving animals perform the AM detection task. Neural responses to AM will be used to calculate neurometric
functions that can be directly compared to behavioral performance, as well as between HL and control animals.
Together, these experiments will reveal whether CNS cellular mechanisms remain vulnerable to developmental
deprivation even after the CP ends, and will provide a new understanding of HL that extends into adolescence.

## Key facts

- **NIH application ID:** 9926076
- **Project number:** 5F32DC018195-02
- **Recipient organization:** NEW YORK UNIVERSITY
- **Principal Investigator:** Kelsey Anbuhl
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $5,621
- **Award type:** 5
- **Project period:** 2019-09-01 → 2020-09-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9926076

## Citation

> US National Institutes of Health, RePORTER application 9926076, Vulnerability to Hearing Loss After the Developmental Critical Period (5F32DC018195-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9926076. Licensed CC0.

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