BILATERAL WIDEFIELD IMAGING IN MICE REVEALS EXPERIENCE DEPENDENT ASYMMETRIC FUNCTIONAL INTERHEMISPHERIC CONNECTIVITY BETWEEN LEFT AND RIGHT AUDITORY CORTICES

Embargo until
2024-05-01
Date
2022-05-03
Journal Title
Journal ISSN
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Publisher
Johns Hopkins University
Abstract
Sensory stimuli are represented in sensory cortices on both hemispheres of the brain. In the auditory system, a lateralization of sensory cortical processing exists raising the question of how the two auditory cortices (ACx) communicate during sound processing, if there is asymmetry of the functional communication, and if the functional connectivity is sculpted by sensory experience. By using a novel-designed bilateral widefield microscope, we used in vivo calcium imaging on awake normal hearing mice (CBA/CaJ:Thy1-GCaMP6s F1) of both sexes to study sound-evoked (4 kHz-64 kHz tones) responses. ACx in both hemispheres showed a symmetric functional organization within animals but had slight variability across animals. To identify functional connections between hemispheres we calculated noise correlations between matching fields in each hemisphere. We find that matching ACx fields showed highest correlations but there was an asymmetrical connectivity between primary auditory cortex (AI), secondary auditory cortex (AII), anterior auditory field (AAF), dorsomedial field (DM), and ultrasound field (UF) across hemispheres. Similar asymmetry was present in the correlations of spontaneous activity. To contrast the necessity of auditory experience for the formation of contralateral connectivity in hearing mice, we imaged spontaneous activity of congenital deaf mice (OTOF-/-), which suffer sensorineural hearing loss from birth. We find lower and spatially non-organized functional interhemispheric connectivity in deaf mice. Our results show that there exists asymmetric functional connectivity between the two hemispheres which might contribute to lateralized functional responses and that hearing experience is crucial for the formation of asymmetric functional connectivity between hemispheres.
Description
Keywords
Auditory Cortex, Calcium Imaging, Widefield Imaging, Bilateral Imaging, Noise Correlation, Spontaneous Activity, Lateralization, Functional Connectivity
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