# Investigating human non-lemniscal inferior colliculus contributions to auditory learning with 7T MRI

> **NIH NIH K01** · NORTHWESTERN UNIVERSITY · 2024 · $135,675

## Abstract

PROJECT SUMMARY
 Human inferior colliculus (IC) plays a critical role in auditory processing. However, the anatomy and
function of the lemniscal (primary) and non-lemniscal subdivisions of IC in living humans are poorly understood
due to the technical challenges of in vivo magnetic resonance imaging (MRI) of the small midbrain structures
deep within the brain. In particular, despite predominant top-down and bottom-up theories of auditory learning,
the neural systems underlying human speech category learning is unknown. Recent advances in MRI acquisition
open the door for focused investigations into the anatomy and functional processing of human auditory midbrain.
My research environment and mentor team will allow me to gain the expertise necessary to independently
investigate the subcortical auditory system in living humans using MRI.
 In this project, we will use ultra-high field 7T MRI to quantify anatomical midbrain tissue contrast in a sub-
structure dependent manner. We will also map the structural connections from each IC subdivision throughout
the auditory system. Quantifying the specific anatomical MRI contrasts and connectivity patterns in living human
midbrain will enable future clinical applications for investigating hearing disorders such as sensorineural hearing
loss and tinnitus.
 A possible functional role for non-lemniscal IC is in learning novel speech sound categories. We will
collect 7T functional MRI at multiple timepoints during a sound-to-category learning program to assess the
contribution of IC and auditory cortex to sound category learning. Our results will elucidate whether novel
categories are learned via cortically driven plasticity (cortex represents categorical features at an earlier stage
than IC’s relevant acoustic enhancement) or stimulus feature enhancement (IC and cortex have similar time
courses of plasticity).
 Existing methods for probing auditory processing, such as the scalp-recorded frequency following
response (FFR), have both subcortical and cortical generators, but their relative contributions throughout the
auditory learning process have not been investigated in humans. Participants in our sound-to-category learning
paradigm will also undergo FFR recordings. Using representational similarity analysis, we will assess whether
sound category feature representation in FFRs primarily follows that of auditory cortex or that of IC, suggesting
the relative contribution of each generator at each phase of sound-to-category learning.
 This project implements state-of-the-art anatomical and functional 7T MRI techniques to quantify
foundational characteristics of the human inferior colliculus, a key but poorly investigated subcortical auditory
structure. The methods we utilized can be adapted to investigate other small, deep structures throughout the
human auditory system and will enhance our understanding of IC contributions to tinnitus and optimal placement
of auditory brain implants for individuals with sensorin...

## Key facts

- **NIH application ID:** 10831907
- **Project number:** 5K01DC019421-04
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Kevin Richard Sitek
- **Activity code:** K01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $135,675
- **Award type:** 5
- **Project period:** 2022-05-16 → 2027-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10831907

## Citation

> US National Institutes of Health, RePORTER application 10831907, Investigating human non-lemniscal inferior colliculus contributions to auditory learning with 7T MRI (5K01DC019421-04). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/10831907. Licensed CC0.

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