Adaptation of neuromagnetic N1 without shifts in dipolar orientation.
306-channel magnetoencephalography, coregistered with high-resolution volumetric magnetic resonance imaging, was used with 10 healthy participants to test if repetition adapts subsequent processing of sounds in a sequence and whether this adaptation influenced the orientation of the dipolar sources in the auditory cortex. Auditory N1m responses to 1 kHz pure tones were indexed by clusters of sensors situated bilaterally over the temporal lobes. N1m was augmented in amplitude at an interstimulus interval of 16 s relative to 1 s. This neuromagnetic amplitude augment occurred in dipoles in the vicinity of the auditory cortex, without significant shifts in the dipolar orientation. Recent repetition thus adapts auditory cortical neurons, in a manner subject to recovery after a period of silence.
Campbell
Tom
T
Helsinki Collegium for Advanced Studies, University of Helsinki, Finland. tom.campbell@helsinki.fi
Neuvonen
Tuomas
T
D000161:Acoustic Stimulation / Q000379:methods; D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D001931:Brain Mapping; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D015225:Magnetoencephalography; D008297:Male; D009949:Orientation / Q000502:physiology*