# The representation of omitted sounds in the mouse auditory cortex

## TL;DR

The study shows that when mice expect a sound but it is omitted, their auditory cortex responds in a specific way, suggesting a prediction error mechanism.

## Contribution

The study identifies a distinct neuronal response to omitted sounds in the mouse auditory cortex, suggesting an integrated prediction error signal.

## Key findings

- Omission responses in the mouse auditory cortex are time-locked to expected sound onsets and localized to specific cortical layers.
- These responses differ from offset and deviant responses in shape, size, and spatial distribution.
- Omission responses correlate with behavioral changes like pupil dilation and facial motion.

## Abstract

Humans and animals use predictions to optimize their behavior, however, the underlying neuronal implementation remains elusive. We address this using omitted sounds on the macro- and microscale of the auditory cortex of female, normal hearing mice using high-speed imaging. Neuronal responses to the omission of expected sounds were time-locked to expected stimulus onset, localized to layer 1-4 of higher auditory area (Temporal Association Area, TeA), and continued to rise until the following stimulus. The omission responses differed from offset and deviant responses in their temporal shape, size and spatial localization. Omissions and sequence statistics correlated with behavioral changes by timed pupil dilation and rapid facial motions. While stimulus responses showed partial entrainment, omission responses maintained a distinct, unentrained shape. The localized omission response in TeA is consistent with a hierarchical organization of predictive processing. However, the continued rise suggests an integrated, absolute prediction error, instead of a direct representation of prediction or prediction error, which would terminate with the omission.

In this study, the authors present that expected-sound omissions in mouse auditory cortex evoked distinct, time-locked activity in layers 1–4 of the Temporal Association Area, suggesting a higher-order, integrated prediction error.