Auditory Perception Induces Cortical and Thalamic Event-Related Desynchronization in the Mouse
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Studies of human perception have shown early cortical signals for primary information encoding, and later signals for higher order processing. An important late signal is the cortical event-related desynchronization (ERD) in the alpha (8-12Hz) and beta (12-30Hz) frequency band, which has been linked to human perceptual awareness. Detailed mechanistic investigation of the ERD would be greatly facilitated by availability of a suitable animal model. We conducted local field potential recordings in the mouse frontal association cortex (FrA), thalamic intralaminar centrolateral nucleus (Cl), primary auditory cortex (A1), and primary visual cortex (V1) during two auditory tasks. Fully audible brief 50 ms stimuli with both tasks produced early broadband gamma (30-100Hz) frequency activity at 0-250ms, followed by a late cortical alpha/beta ERD 250 – 750 ms after stimulus onset. The ERD was statistically significant in FrA and A1, but not in V1. Interestingly, a significant ERD was also observed in thalamic Cl. The magnitude of the ERD at full stimulus intensity, and the slope of the relationship between stimulus intensity versus ERD magnitude, were both largest in FrA, and smaller in Cl and A1. Conversely, for early broadband gamma activity the magnitude at full intensity and slopes were largest in A1, smaller in Cl and smaller still in FrA. These findings suggest that mice, like humans, process perceptual signals in hierarchically organized corticothalamic networks, and strongly support mice as a promising platform for further investigation of the ERD to better understand the origin and function of this robust yet understudied electrophysiological phenomenon.
Significance Statement
Auditory-induced alpha/beta event-related desynchronizations (ERDs), decreases in cortical activity between 8 and 30Hz following auditory stimulus presentation, are thought to represent systems underlying higher perception and cognition. However, fundamental mechanistic studies are difficult in humans, the dominant organism for studying this phenomenon. In this study we assess mice as a potential alternative model organism. Our results demonstrate that mice exhibit auditory-induced alpha/beta ERDs, that this response is also present in subcortical regions of the mouse brain, and that the cortical ERD is largest and most strongly related to auditory stimulus amplitude in association cortex rather than in primary auditory cortex. These results support the efficacy of mice as an ideal model organism for further examination of alpha/beta ERDs.
