[Audiology] Recent paper on auditory processing

[Peter]

Hi there,

I would like to draw your attention to my recent publication:

http://www.biomedcentral.com/1741-7007/4/25/abstract
http://www.biomedcentral.com/content/pdf/1741-7007-4-25.pdf

The neurochemical basis of human cortical auditory processing: 
combining proton magnetic resonance spectroscopy and 
magnetoencephalography

Peter Soros, Nikolaus Michael, Melanie Tollkotter  and Bettina Pfleiderer

BMC Biology 2006, 4:25     doi:10.1186/1741-7007-4-25

Background
A combination of magnetoencephalography and proton magnetic resonance 
spectroscopy was used to correlate the electrophysiology of rapid 
auditory processing and the neurochemistry of the auditory cortex in 15 
healthy adults. To assess rapid auditory processing in the left 
auditory cortex, the amplitude and decrement of the N1m peak, the major 
component of the late auditory evoked response, were measured during 
rapidly successive presentation of acoustic stimuli. We tested the 
hypothesis that: (i) the amplitude of the N1m response and (ii) its 
decrement during rapid stimulation are associated with the cortical 
neurochemistry as determined by proton magnetic resonance spectroscopy.

Results
Our results demonstrated a significant association between the 
concentrations of N-acetylaspartate, a marker of neuronal integrity, 
and the amplitudes of individual N1m responses. In addition, the 
concentrations of choline-containing compounds, representing the 
functional integrity of membranes, were significantly associated with 
N1m amplitudes. No significant association was found between the 
concentrations of the glutamate/glutamine pool and the amplitudes of 
the first N1m. No significant associations were seen between the 
decrement of the N1m (the relative amplitude of the second N1m peak) 
and the concentrations of N-acetylaspartate, choline-containing 
compounds, or the glutamate/glutamine pool. However, there was a trend 
for higher glutamate/glutamine concentrations in individuals with 
higher relative N1m amplitude.

Conclusions
These results suggest that neuronal and membrane functions are 
important for rapid auditory processing. This investigation provides a 
first link between the electrophysiology, as recorded by 
magnetoencephalography, and the neurochemistry, as assessed by proton 
magnetic resonance spectroscopy, of the auditory cortex.