Electrophysiological evidence of memory-based detection of auditory regularity violations in anesthetized mice

Jari L O Kurkela,Arto Lipponen,Piia Astikainen,Iiris Kyläheiko

doi:10.1038/s41598-018-21411-z

Jari L O Kurkela, Arto Lipponen + Show 2 more

Open Access

https://doi.org/10.1038/s41598-018-21411-z

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Abstract

In humans, automatic change detection is reflected by an electrical brain response called mismatch negativity (MMN). Mismatch response is also elicited in mice, but it is unclear to what extent it is functionally similar to human MMN. We investigated this possible similarity by recording local field potentials from the auditory cortex of anesthetized mice. First, we tested whether the response to stimulus changes reflected the detection of regularity violations or adaptation to standard stimuli. Responses obtained from an oddball condition, where occasional changes in frequency were presented amongst of a standard sound, were compared to responses obtained from a control condition, where no regularities existed. To test whether the differential response to the deviant sounds in the oddball condition is dependent on sensory memory, responses from the oddball condition using 375 ms and 600 ms inter-stimulus intervals (ISI) were compared. We found a differential response to deviant sounds which was larger with the shorter than the longer ISI. Furthermore, the oddball deviant sound elicited larger response than the same sound in the control condition. These results demonstrate that the mismatch response in mice reflects detection of regularity violations and sensory memory function, as the human MMN.

Highlights

Detection of sudden changes in the auditory environment is an important task for the brain, as these changes may signal behaviourally relevant information
We studied whether a differential response to frequency changes in the oddball condition was elicited in anesthetized mice, and how it was affected by inter-stimulus intervals (ISI) and deviance frequency direction in different regions of interest
In light of the control condition, the response starting at the latency of 53.5 ms or 71.0 ms, depending on the deviant stimulus frequency (Table 4), reflected detection of regularity violations instead of mere adaptation to the human mismatch negativity (MMN)

Summary

Introduction

Detection of sudden changes in the auditory environment is an important task for the brain, as these changes may signal behaviourally relevant information. When MMN is recorded in a stimulus condition with a single standard stimulus, it is possible that deviant sounds generate larger responses than standard sounds because the cell population responding to the frequently occurring sound is less adapted than the distinct cell population responding to the rare sound[16]. The impact of this adaptation effect can be estimated by using a ‘many standards’ control condition, called an ‘equiprobable’ control condition[17,18,19,20,21]. Larger amplitude responses to the oddball deviant sound than to the control sound can be interpreted as responsiveness specific to regularity violations in the oddball condition

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