Simultaneous intracerebral EEG recordings of early auditory thalamic and cortical activity in human.
We describe documented simultaneous intracerebral auditory evoked potentials from the auditory cortex and medial geniculate body (MGB) of a human patient. The MGB response lasted > 300 ms, with an initial negativity at 13.5 ms (N13), two positive peaks P21 and P29, and two broader negativities N50 and N200. P21 and N50 amplitudes were strongest for lowest tone frequencies, suggesting possible MGB tonotopic organization. Thalamic peaks were strongly interlaced with cortical activities recorded in Heschl's gyri before 30 ms: N13 preceded the first cortical component by 3.5 ms, then P21 and P29 preceded and lagged, respectively, the following two cortical polarity reversals by 1.5-2 ms. This study provides new functional data on the human MGB, and supports a more complex than simply relay-like role of the thalamus in sound perception.
Yvert
Blaise
B
Inserm Unité 280, 151 cours Albert Thomas, F-69424 Lyon cedex 03, France. b.yvert@Inr.u-bordeaux.fr
Fischer
Catherine
C
Guénot
Marc
M
Krolak-Salmon
Pierre
P
Isnard
Jean
J
Pernier
Jacques
J
D000161:Acoustic Stimulation; D000328:Adult; D001303:Auditory Cortex / Q000473:pathology / Q000503:physiopathology*; D001307:Auditory Perception / Q000502:physiology; D001309:Auditory Threshold / Q000502:physiology; D004569:Electroencephalography; D004827:Epilepsy / Q000473:pathology / Q000503:physiopathology*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D005829:Geniculate Bodies / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D010897:Pitch Discrimination / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013997:Time Factors