Subject: paper on the neurochemistry of cortical auditory processing From: Peter Soros <peter.soros@xxxxxxxx> Date: Wed, 23 Aug 2006 14:08:47 -0400I 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 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. -- Dr. Peter Soros Postdoctoral Fellow Imaging Research Sunnybrook Health Sciences Centre 2075 Bayview Avenue Room SG 28 Toronto Ontario M4N 3M5 Canada Phone: 416.480.6100 ext 3843 e-mail: peter.soros@xxxxxxxx http://neuroactivity.org/