Nima Zargarnezhad

Ph.D. Student in Neuroscience, Western University

My research centers on organization and naturalistic experimentation. I study the functional organization of the human brain as it responds to naturalistic stimulation, and how the mind organizes auditory information in complex, naturalistic environments.

Nima Zargarnezhad Download CV

I am a Ph.D. student in the Neuroscience graduate program at the University of Western Ontario, with a collaborative specialization in Machine Learning in Health and Biomedical Sciences, jointly supervised by Dr. Ingrid Johnsrude and Dr. Jörn Diedrichsen.

I study the functional organization of the human brain and how the auditory information is organized in the human mind.Both threads of my work return to the same idea of organization studied through naturalistic experimentation. In both threads of my research I acknowledge that although the fundamental processes in the brain and mind are shared across humans, there are individual differences that should be taken into account for more effective, personalized clinical translation.

I came to Western in 2021 as a Master's student in the Neuroscience and collaborative specialization in Music Cognition programs, supervised by Dr. Ingrid Johnsrude, after completing my B.Sc. in Electrical Engineering, specialized in Bioelectrics, at Sharif University of Technology in Tehran, Iran. That path from engineering into neuroscience is a large part of why I value interdisciplinary collaboration; I find that the most practical questions and the most useful models tend to come from where different fields and perspectives meet.

Currently, I serve as a Career Development and Mentoring Manager in the Organization for Human Brain Mapping Student and Postdoc Special Interest Group. Outside the lab, you can most often find me playing cello, analyzing music, baking, reading fantasy, or trying to pick up a new hobby.

Projects

In all my research projects, I study organization at different scales in the human brain and mind. I observe the brain under naturalistic conditions, as much as possible, to learn about the brain and mind beyond simple or reductionist experimental settings. Furthermore, individual differences play a cruicial role in my research; although the fundamental processes in the brain and mind are shared across humans, there are individual differences that should be taken into account for more effective, personalized clinical translation.

Functional Organization of the Human Brain

The functional organization of the human brain is not only informative about cognitive processes but can also be useful in clinical applications such as diagnosis and identification of abnormalities or predicting treatment outcomes. In a series of projects, I aim to develop methods that are particularly useful in the surgical treatment of epilepsy.

Functional connectivity reliability

Functional Connectivity Reliability and Individual Variability: Movie-Watching vs. Resting-State

Functional connectivity is a very popular approach in capturing the functional organization of the human brain. As the connectivity patterns differ under different cognitive states and in different cognitive tasks, the paradigm under which connectivity is obtained will determine what aspects of functional organization are observed. Resting-state (RS) is the most popular paradigm for connectivity studies, yet because different individuals' experiences vary in terms of mental processes and cognitive states during scan time, the obtained connectivity patterns show inflated individual variability. On the other hand, paradigms such as movie-watching (MW) or narrative listening synchronize the sensory and perceptual input across participants. It has been shown that the brain activity of the people who are watching the same movie synchronizes in time in certain regions. In this study, I investigate how much of this inter-subject synchrony extends to the connectivity patterns. I also compare resting-state and movie-watching paradigms in terms of their similarities, differences, inter-subject reliability, generalizability across the group, and their ability to predict idiosyncratic patterns. The findings in this study will help researchers and clinicians make more informed decisions about how to observe functional connectivity according to their specific application.

Auditory Scene Analysis & Spatial Hearing

In a crowded room, the brain effortlessly separates one voice from many. I study cues that make this possible and how they interact. I am especially interested in the role of spatial cues, as they are a very common cue in daily settings yet are less studied. I use the AudioDome (a cutting-edge auditory virtual environment loudspeaker array) to simulate complex auditory scenes in my experiments.

AudioDome

Focality of Sound Source Reproduction by 9th-Order Ambisonics in the AudioDome

Before using higher-order ambisonics technology in perceptual auditory research, I was curious about its utility for human experimentation. I quantified the minimum audible angles on the horizontal plane and showed that ambisonic sound sources are as focal as they should be for human listeners. I also showed that the focality of virtual sound sources is uniform and independent of the sound source's distance from the loudspeakers. However, participants were reporting unexpected perceptions of the elevation of the sound sources, which I showed are due to high-frequency distortions in ambisonic reproduction, through both acoustic measurements and a behavioral experiment. This study provides insights into auditory scene reproduction technology selection based on experimental needs.

Read the paper (JASA) ↗
Stream segregation

Interactions of Pitch and Spatial Cues in the Perceptual Segregation of Auditory Streams

Auditory scene analysis or the ability to combine and dissociate sound components with auditory objects is a (mathematically) complex problem that the auditory system solves. The solution depends on a variety of sources of information and cues. Two of the strongest cues are pitch and location (sound components that share the same repetition rate or come from the same location are grouped together and those that are different are associated with different auditory objects). In this project, I ask what the perceptual weight of pitch and spatial cues is relative to each other. Is the answer different for people with different hearing backgrounds? Are musicians with ensemble-performance experience or music conductors more reliant on spatial cues? I introduce and utilize a two-dimensional psychoacoustic model to answer these questions.

Publications & Presentations

Peer-reviewed articles, preprints, theses, and conference contributions

Symposia

Posters

Workshops

Resources

Code and data available for reuse

AudioDome Module
2025 · Python

AudioDome Module

Software · Western University

A Python toolkit for writing custom scripts to control Western's AudioDome in experimental settings. It provides the building blocks for stimulus presentation and spatial audio rendering through Python.

View on GitHub ↗ Tutorial video ↗
HATS recordings
2025 · Dataset

AudioDome HATS Recordings

Open Science Framework

Head-and-Torso Simulator binaural recordings of spatialized sinusoidal sweeps presented through Western's AudioDome. Accompanies the JASA 2025 manuscript.

Open on OSF ↗ Related paper ↗

Press & Media

Media appearances and features

Video · Western University

Decoding How the Brain Interprets Sound

Western University

Behind the Research with president Alan Shepard series: Hearing and Auditory Neuroscience at Western.

Watch ↗
Across Acoustics podcast
Podcast · Jul 2025

Reproducing Soundscapes with the AudioDome

Across Acoustics (Acoustical Society of America)

Nima Zargarnezhad and Dr. Ingrid Johnsrudediscuss discuss their auditory research and talk about auditory virtual environment technologies, why they matter to auditory perception research and their experiments and their findings in the JASA paper.

Listen ↗
AIP Publishing
Press Feature · Apr 2025

Simulate Sound in 3D at a Finer Scale than Humans Can Perceive

AIP Publishing News

Featured author spotlight on the JASA publication, highlighting the AudioDome and its implications for immersive audio and hearing science.

Read article ↗

Contact

Please do not hesitate to reach out to me by email or the social media below. I am always glad to hear from students, fellow researchers, and anyone curious about the work.

Emailnzargarn@uwo.ca Google ScholarPublications & citations ResearchGate ResearchGateNima-Zargarnezhad ORCID0009-0002-8553-7538 GitHubgithub.com/NimaZN LinkedInnima-zargarnezhad Bluesky@nimazn.bsky.social X@Nima_ZN