Postersession 2
Poster #: 92
Topic: Neuronal models
Thursday, Sep 10, 2015
1st floor

Neurons in the inferior colliculus of the rat respond to the unexpected omission of repeated stimuli

Manuel S. Malmierca1, Blanca E. Niño-Aguillón2, Javier Nieto, & Jonathan Fritz3

1Cellular Biology and Pathology, University of Salamanca, Salamanca, Spain
2University of Salamanca, Salamanca, Spain
3University of Maryland, United States

The omission of an auditory stimulus often elicits an omission MMN component, revealing the predictive activity of the auditory system. The goal of the present study was to investigate whether single neurons in the auditory midbrain respond to the omission of stimuli as found in human MMN.

Responses of well isolated single units were recorded from the IC, using an oddball “omission” paradigm (10% sounds pseudorandomly omitted from a regular train of pure tones or noise bursts) at various presentation rates. Importantly, the sequence of stimuli was also recorded to ensure that no sound artifact was producing these responses. In addition, several parameters including the number of consecutive omitted responses were manipulated. Finally, we also reversibly deactivated auditory cortex while recording in the IC.

The results reveal the presence of some neurons in the IC cortex that showed a similar response to the sound and to (silent) omitted stimuli when presentation rates ≥ 8Hz. Analysis suggests that 1) intrinsic neuronal properties may determine the best presentation rate of these responses, 2) the modulation of neuronal spontaneous activity by the sound may contribute to these “omission” responses, 3) that entrainment in the IC could be inherited from the auditory cortex in a top-down fashion.

Our findings are in agreement with the temporal window of integration concept for the human auditory system (Yabe et al. 1997) and may explain the basic mechanisms that generate omission responses in the MMN literature.

Supported by BFU2013-43608, JCYL(SA343U14), JCYL-fellowship(ERIDI2007-2013). BENA and JD contributed equally