|
|
||||||||
Leibniz Institute for Neurobiology, Magdeburg, Germany
Submitted 1 June 2004; accepted in final form 3 September 2004
Animal and human studies suggest that directional categorization of frequency-modulated (FM) tones (rising vs. falling) is a function of the right auditory cortex (AC). To investigate this hemispheric specialization in more detail, we analyzed both the binaural and monaural representation of FM tones and the influence of contralateral white noise on the processing of FM tone direction. In two fMRI-experiments, FM tones with varied direction, center-frequencies, and duration were presented binaurally or monaurally without contralateral white noise (experiment 1) and with contralateral white noise (experiment 2) while the subjects had to perform the same directional categorization task. In experiment 1, contralateral FM tones led to strongest activation, binaural FM tones to intermediate, and ipsilateral FM tones to weakest activation in each AC. This is in accordance with binaural response properties of neurons in animal AC. In experiment 2, contralateral white noise had no significant effect on the activation of left AC by FM tones, whereas in right AC, it led to a significant increase in activation for ipsilateral FM tones. This result provides further support for the critical role of right AC for directional categorization of FM tones, which for ipsilateral input has to be processed in competition to the excitatory input of white noise via the direct contralateral pathway.
This article has been cited by other articles:
![]() |
A. Brechmann, B. Gaschler-Markefski, M. Sohr, K. Yoneda, T. Kaulisch, and H. Scheich Working Memory Specific Activity in Auditory Cortex: Potential Correlates of Sequential Processing and Maintenance Cereb Cortex, November 1, 2007; 17(11): 2544 - 2552. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Behne, B. Wendt, H. Scheich, and A. Brechmann Contralateral White Noise Selectively Changes Left Human Auditory Cortex Activity in a Lexical Decision Task J Neurophysiol, April 1, 2006; 95(4): 2630 - 2637. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |