Postersession 2
Poster #: 86
Topic: MMN across species
Thursday, Sep 10, 2015
1st floor

Genuine deviance detection occurs in the inferior colliculus (IC) of the anaesthetized rat

Javier Nieto1, Guillermo V. Carbajal1, & Manuel S. Malmierca2

1Auditory Neurophysiology Laboratory, Institute of Neuroscience of Castilla y León (INCyL), University of Salamanca, Salamanca, Spain
2Auditory Neurophysiology Laboratory, Institute of Neuroscience of Castilla y León (INCyL); Department of Cell Biology and Pathology, Faculty of Medicine, University of Salamanca, Salamanca, Spain

Some neurons in the IC show a larger response to tones when presented as deviants than when presented as standards using an oddball paradigm, i.e., they show stimulus-specific adaptation (SSA). The response to the deviants could not only remain unaffected, because of its rarity due to a simple adaptation process, but also be enhanced by the fact that it breaks the regularity imposed by the standard, thus containing a component of genuine “deviance detection”.

This specific component has already been shown in numerous cases in human subjects using the “many standards control” (MSC) paradigm (Jacobsen and Schröger, 2001). Animal studies in primary auditory cortex, however are controversial. One study has reported deviance detection, mostly based on theoretical grounds (Taaseh et al., 2011). Others have failed to show genuine deviance detection (Fairley et al., 2010; Fishman and Steinschneider, 2012). 

We recorded single unit responses in the IC (45 recordings from 14 neurons) and selected one or more pairs of frequencies using the oddball paradigm and the MSC with varying frequency spacing. The preliminary results show that on average, neurons responded more strongly to the same tone when presented as deviant than in the context of the MSC, specifically for the high frequency (F2, p=0.005, paired t-test) of the pair, but not for the low (F1). Hence, our results demonstrate the presence of genuine deviance detection at the level of the IC.

Supported by the Spanish MINECO (BFU2013-43608-P) and JCYL (SA343U14)