# Sex Difference in the Integration of Visual Social Stimulus and Emotional Auditory Stimulus

> **NIH NIH R21** · VIRGINIA POLYTECHNIC INST AND ST UNIV · 2024 · $200,000

## Abstract

Project Summary
Human mimicry, referred to as synchronization or the "chameleon effect," involves unconsciously imitating
gestures, behaviors, facial expressions, speech patterns, and even the emotions of others. This phenomenon is
pivotal in social interactions because it fosters social bonding, group cohesion, and cooperation by influencing
how others are perceived. Mimicry fosters conscious empathy, aiding individuals in understanding and
empathizing with the emotions and intentions of others. Meanwhile, animals also synchronize behaviors, but
there are no studies on the underlying circuit mechanisms due to the lack of laboratory paradigms. We have
developed a method to quantify the synchronization of emotional responses in mice and found that mice
synchronized conditioned freezing, which required the integration of visual social stimulus and the auditory
emotional cue. In both sexes, the positive synchronization required the ventral hippocampus (vHPC), its inputs
to the amygdala, and vision, suggesting that vHPC processes the partner's visual social stimuli and then feeds
it into the auditory fear circuit at the amygdala level to achieve synchrony by modulating freezing. Surprisingly,
vHPC inactivation caused sex-specific effects: male dyads lost the positive synchrony, but the females switched
from positive to "negative synchronization" and actively avoided aligning their freezing bouts. It suggests
fundamental sex differences in the socio-emotional integrator. We will test a hypothesis that a female-specific
superior colliculus-mediated alternative visual stream to the auditory fear circuit drives negative fear synchrony,
competing with the vHPC stream for positive synchrony. We will use chemogenetic disconnection in Aim 1 to
identify the specific synapses underlying negative synchrony and ex vivo recording in Aim 2 to identify sex
differences in the synaptic properties of the superior colliculus visual pathway. This study will generate
fundamental knowledge about sex differences in the integration of social visual information and auditory
emotional information and how the brain organizes even simple behaviors through competing circuits.

## Key facts

- **NIH application ID:** 10952141
- **Project number:** 1R21MH137592-01
- **Recipient organization:** VIRGINIA POLYTECHNIC INST AND ST UNIV
- **Principal Investigator:** Alexei Morozov
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $200,000
- **Award type:** 1
- **Project period:** 2024-07-16 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10952141

## Citation

> US National Institutes of Health, RePORTER application 10952141, Sex Difference in the Integration of Visual Social Stimulus and Emotional Auditory Stimulus (1R21MH137592-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10952141. Licensed CC0.

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