Collaborators within the IfN: Frank Ohl, Matthias Deliano, Henning Scheich

National Cooperations

Prof. Dr. Marlies Knipper:
Mol. Neurobiology, Hearing Research Center Prof. Zenner, University of Tübingen
Project on neurophysiological and behavioral phenotyping of mutant mice.

Prof. Dr. Georg Klump:
Institute for Biology, University of Oldenburg. Project on the neurophysiological basis of object recognition within the new DFG-Transregio-SFB “Das aktive Gehör”

International Cooperations

Prof. Dr. Robert Zatorre:
Department of Neuropsychology, McGill University Montreal, Canada. fMRI-Projekt on pitch representation in human auditory cortex.

Lecturer PD Dr. John M. Crook:
University of Newcastle upon Tyne, United Kingdom. Project on GABAA-mediated inhibition in gerbil auditory cortex.

Prof. Dr. Christian Kaernbach:
Karl-Franzens-University Graz. Project on the neurophysiological representation of periodic noise in auditory cortex.

Candidates:
Anke Deutscher
Simone Kurt
Ines Schrottge
Christoph Moeller

Support:
BMBF, MK LSA, DFG

One of the most salient aspect of acoustic signals, including speech, are periodic amplitude modulations (AM) of carriers, the analysis of which plays an important role for the temporal quality of acoustic percepts (rhythm and roughness for low modulation frequencies (fm)) and for tasks like speaker recognition and speaker discrimination in acoustically rich environments ("cocktail-party-effect": high fm). Two different codes, for high and low fm, respectively, have been identified in the primary field of the auditory cortex (AI) of Mongolian gerbils. An area with a circular topographic representation of high fm (periodotopy; cf. Figure) which may facilitate the equivalent interaction of representations of different fm has been identified both with electrophysiological recording [1] and with optical recording of intrinsic signals [3]. We currently investigate whether such a topography may serve as the basis of some neural implementation of a "winner take all" algorithm, which may be used in the so-called "cocktail-party" task. In contrast, low fm are represented in AI via a non-topographical, temporal code. We carry out chronic recording of units which represent low fm by this temporal code. First results show that these units increase their temporal resolution and coding abilities of fm with discrimination training of AM (cf. [2, 4]). Furthermore, only those units seem to be involved in the plastic changes that also code for the spectral content of the AM.

Figure:
Circular periodotopic map in the gerbil primary auditory cortex.

Key publications

1. Schulze, H.; Langner, G. (1997) Periodicity coding in the primary auditory cortex of the Mongolian gerbil (Meriones unguiculatus): Two different coding strategies for pitch and rhythm? J. Comp. Physiol. A,181:651-663.

2. Schulze, H.; Scheich, H. (1999) Discrimination learning of amplitude modulated tones in Mongolian gerbils. Neurosci. Lett., 261:13-16.

3. Schulze, H.; Hess, A.; Ohl, F.W.; Scheich, H. (2002) Superposition of horseshoe-like periodicity and linear tonotopic maps in auditory cortex of the Mongolian gerbil. Europ. J. Neurosci, 15:1077-1084

4. Schulze, H.; Neubauer, H.; Ohl, F.W.; Hess, A.; Scheich, H. (2002) Representation of stimulus periodicity and its learning induced plasticity in the auditory cortex: Recent findings and new perspectives. Acta Acustica united with Acustica, 88:399-407

For more information visit: www.schulze-holger.de