title: Primary somatosensory contextual modulation is encoded by oscillation frequency change.
abstract: OBJECTIVE
  This study characterized thalamo-cortical communication by assessing the effect of context-dependent modulation on the very early somatosensory evoked high-frequency oscillations (HF oscillations).
  
  
  METHODS
  We applied electrical stimuli to the median nerve together with an auditory oddball paradigm, presenting standard and deviant target tones representing differential cognitive contexts to the constantly repeated electrical stimulation. Median nerve stimulation without auditory stimulation served as unimodal control.
  
  
  RESULTS
  A model consisting of one subcortical (near thalamus) and two cortical (Brodmann areas 1 and 3b) dipolar sources explained the measured HF oscillations. Both at subcortical and the cortical levels HF oscillations were significantly smaller during bimodal (somatosensory plus auditory) than unimodal (somatosensory only) stimulation. A delay differential equation model was developed to investigate interactions within the 3-node thalamo-cortical network. Importantly, a significant change in the eigenfrequency of Brodmann area 3b was related to the context-dependent modulation, while there was no change in the network coupling.
  
  
  CONCLUSIONS
  This model strongly suggests cortico-thalamic feedback from both cortical Brodmann areas 1 and 3b to the thalamus. With the 3-node network model, thalamo-cortical feedback could be described.
  
  
  CONCLUSIONS
  Frequency encoding plays an important role in contextual modulation in the somatosensory thalamo-cortical network.
authors: Biomagnetic Center, Hans Berger Department of Neurology, Jena University Hospital, Erlanger Allee 101, 07747 Jena, Germany; Center for Sepsis Control and Care, Jena University Hospital, Erlanger Allee 101, 07747 Jena, Germany.
authors: T
authors: T
authors: Götz
authors: Institute of Medical Statistics, Computer Sciences and Documentation, Jena University Hospital, Bachstrasse 18, 07740 Jena, Germany.
authors: T
authors: T
authors: Milde
authors: Neurophysics Group, Department of Neurology, Campus Benjamin Franklin, Charité - University Medicine Berlin, Hindenburgdamm 30, 12200 Berlin, Germany.
authors: G
authors: G
authors: Curio
authors: Faculty VI, Department of Psychology, Neuropsychology Lab, University of Oldenburg, 26111 Oldenburg, Germany.
authors: S
authors: S
authors: Debener
authors: Institute of Medical Statistics, Computer Sciences and Documentation, Jena University Hospital, Bachstrasse 18, 07740 Jena, Germany.
authors: T
authors: T
authors: Lehmann
authors: Institute of Medical Statistics, Computer Sciences and Documentation, Jena University Hospital, Bachstrasse 18, 07740 Jena, Germany.
authors: L
authors: L
authors: Leistritz
authors: Hans Berger Department of Neurology, Jena University Hospital, Erlanger Allee 101, 07747 Jena, Germany; Center for Sepsis Control and Care, Jena University Hospital, Erlanger Allee 101, 07747 Jena, Germany.
authors: O W
authors: OW
authors: Witte
authors: Institute of Medical Statistics, Computer Sciences and Documentation, Jena University Hospital, Bachstrasse 18, 07740 Jena, Germany.
authors: H
authors: H
authors: Witte
authors: Biomagnetic Center, Hans Berger Department of Neurology, Jena University Hospital, Erlanger Allee 101, 07747 Jena, Germany; Institute of Biomedical Engineering and Informatics, Faculty of Computer Science and Automation, Technical University Ilmenau, Gustav-Kirchhoff-Straße 2, 98693 Ilmenau, Germany. Electronic address: jens.haueisen@tu-ilmenau.de.
authors: J
authors: J
authors: Haueisen
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology; D004558:Electric Stimulation / Q000379:methods; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology; D009415:Nerve Net / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*; D013788:Thalamus / Q000502:physiology*
keywords: 600Hz wavelets; Auditory oddball; Electroencephalography; Magnetoencephalography; Median nerve; Primary somatosensory cortex