Rapid categorization of sound objects in anesthetized rats as indexed by the electrophysiological mismatch response

Authors

  • Piia Astikainen,

    Corresponding author
    1. Department of Psychology, University of Jyväskylä, Jyväskylä, Finland
    • Address correspondence to: Piia Astikainen, Department of Psychology, Ylistönmäentie 33, 40014 University of Jyväskylä, Jyväskylä, Finland. E-mail: piia.astikainen@jyu.fi

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  • Timo Ruusuvirta,

    1. Department of Psychology, University of Turku, Turku, Finland
    2. Centre for Learning Research, University of Turku, Turku, Finland
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  • Risto Näätänen

    1. Department of Psychology, University of Tartu, Tartu, Estonia
    2. Center of Functionally Integrative Neuroscience (CFIN), University of Århus, Århus, Denmark
    3. Cognitive Brain Research Unit, Department of Psychology, University of Helsinki, Helsinki, Finland
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  • This work was supported by the Academy of Finland, grant numbers 127595 and 273134 to PA and grant number 122743 to RN. The authors are grateful to Petri Kinnunen for preparing the stimulus materials and Dr. Markku Penttonen for technical assistance.

Abstract

It is not known whether animals can, similarly to humans, categorize auditory objects based on an abstract rule in combining their physical features. We recorded local-field potentials from the dura above the primary auditory cortex in urethane-anesthetized rats presented with sound series occasionally violating a rule (e.g., “the higher the frequency, the weaker the intensity”). In a separate control condition, the same frequency and intensity levels were applied in the sound objects, but they obeyed no rule. Responses found selectively to the violations of the rule suggest that an abstract rule was represented in the rat brain, enabling auditory categorization.

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