The Journal of Neuroscience, November 4, 2009, 29(44):13837-13849; doi:10.1523/JNEUROSCI.3475-09.2009
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Behavioral/Systems/Cognitive
Correlating Stimulus-Specific Adaptation of Cortical Neurons and Local Field Potentials in the Awake Rat
Wolfger von der Behrens,
Peter Bäuerle,
Manfred Kössl, and
Bernhard H. Gaese
Institute for Cell Biology and Neuroscience, Department of Biological Sciences, Goethe University, D-60323 Frankfurt am Main, Germany
Correspondence should be addressed to Bernhard H. Gaese, Institute for Cell Biology and Neuroscience, Department of Biological Sciences, Goethe University, Siesmayerstrasse 70A, D-60323 Frankfurt am Main, Germany. Email: gaese{at}bio.uni-frankfurt.de
Changes in the sensory environment are good indicators for behaviorally relevant events and strong triggers for the reallocation of attention. In the auditory domain, violations of a pattern of repetitive stimuli precipitate in the event-related potentials as mismatch negativity (MMN). Stimulus-specific adaptation (SSA) of single neurons in the auditory cortex has been proposed to be the cellular substrate of MMN (Nelken and Ulanovsky, 2007). However, until now, the existence of SSA in the awake auditory cortex has not been shown. In the present study, we recorded single and multiunits in parallel with evoked local field potentials (eLFPs) in the primary auditory cortex of the awake rat. Both neurons and eLFPs in the awake animal adapted in a stimulus-specific manner, and SSA was controlled by stimulus probability and frequency separation. SSA of isolated units was significant during the first stimulus-evoked "on" response but not in the following inhibition and rebound of activity. The eLFPs exhibited SSA in the first negative deflection and, to a lesser degree, in a slower positive deflection but no MMN. Spike adaptation correlated closely with adaptation of the fast negative deflection but not the positive deflection. Therefore, we conclude that single neurons in the auditory cortex of the awake rat adapt in a stimulus-specific manner and contribute to corresponding changes in eLFP but do not generate a late deviant response component directly equivalent to the human MMN. Nevertheless, the described effect may reflect a certain part of the process needed for sound discrimination.
Received July 19, 2009;
revised Oct. 2, 2009;
accepted Oct. 3, 2009.
Correspondence should be addressed to Bernhard H. Gaese, Institute for Cell Biology and Neuroscience, Department of Biological Sciences, Goethe University, Siesmayerstrasse 70A, D-60323 Frankfurt am Main, Germany. Email: gaese{at}bio.uni-frankfurt.de