Submitted on May 25, 2006
Accepted on November 13, 2006
The cortical response to auditory motion suggests an asymmetry in the reliance on inter-hemispheric connections between the left and right auditory cortices
Katrin Krumbholz1*, Nicola Hewson-Stoate1, and Marc Schönwiesner2
1 MRC Institute of Hearing Research, Nottingham, United Kingdom
2 Department of Neuropsychology, Montreal Neurological Institute, Montréal, Canada
* To whom correspondence should be addressed. E-mail: katrin{at}ihr.mrc.ac.uk.
The aim of the current study was to measure the brain's response to auditory motion using electroencephalography (EEG) in order to gain insight into the mechanisms by which hemispheric lateralisation for auditory spatial processing is established in the human brain. The onset of leftward or rightward motion in an otherwise continuous sound was found to elicit a large response, which appeared to arise from higher-level, non-primary auditory areas. This motion onset response was strongly lateralised to the hemisphere contralateral to the direction of motion. The response latencies suggest that the ipsilateral response to the leftward motion was produced by indirect, callosal projections from the opposite hemisphere, whereas the ipsilateral response to the rightward motion seemed to receive contributions from direct, thalamocortical projections. These results suggest an asymmetry in the reliance on inter-hemispheric projections between the left and right auditory cortices for auditory spatial processing.
