Modelling of cortical and thalamic 600 Hz activity by means of oscillatory networks

Head models and dynamic causal modeling of subcortical activity using magnetoencephalographic/electroencephalographic data

“…Several studies have used these techniques to report the ability of M/EEG to detect signals from deep structures, such as the amygdala, hippocampus or thalamus, with a strong increase of interest during the last decade Ribary et al , 1991 ;Rogers et al , 1993 ;Ioannides et al , 1995Ioannides et al , , 2000Tesche , 1996bTesche , , 1997Kikuchi et al , 1997 ;Simos et al , 1997 ;Nishitani et al , 1998 ;Baumgartner et al , 2000 ;Tesche and Karhu , 2000a,b ;Gross et al , 2002 ;Ikeda et al , 2002 ;Hanlon et al , 2003 ;Bish et al , 2004 ;Kessler et al , 2006 ;Jerbi et al , 2007 ;Luo et al , 2007 ;Martin et al , 2007 ;Moses et al , 2007Moses et al , , 2009Cornwell et al , 2008 ;Kujala et al , 2008 ;Attal et al , 2009Attal et al , , 2010Milde et al , 2009 ;Riggs et al , 2009 ;Dumas et al , 2010bDumas et al , , 2011Poch et al , 2011 ;Quraan et al , 2011 ). We review some of these below.…”

Primary somatosensory contextual modulation is encoded by oscillation frequency change

“…Further details of this model, especially the justification of the input term u(t), can be found in Milde et al (2009). The difference between the former (Milde et al, 2009) and the present model is the occurrence of both feedback terms e 32 y(t À d 5 ) and e 33 x(t À d 6 ) which represent the influence of the cortical activity (HFcr and HFct, respectively) on the subcortical activity (HFp). Thus, two analysis steps were carried out (see below): the cortico-thalamic feedback analysis and the complete network coupling parameter analysis.…”

“…With the help of oscillatory network modelling, Haueisen et al (2007) recently introduced a method to analyze information processing in the primary somatosensory system by means of a set of coupled oscillators to model source activation time courses. Milde et al (2009) were able to additionally verify significant feedback from the Brodmann area 3b to the thalamus. Despite this verifiable feedback from cortex to the thalamus, context-related paradigms have been rarely investigated in conjunction with somatosensory high frequency oscillations.…”

“…For the source localization a fixed dipole approach was chosen. Specifically, a cortical radial source (HFcr), a cortical tangential source (HFct), and a subcortical radial source (HFp) were fitted (Scherg and Buchner, 1993;Buchner et al, 1994Buchner et al, , 1995Haueisen et al, 2007;Jaros et al, 2008;Milde et al, 2009). The unexplained variance after the dipole fit for combined EEG and MEG dipoles was 39.4% (±4.6) for HF dipoles in a time range of 16-25 ms (average over all volunteers).…”

“…Functional connectivity between subcortical and cortical structures in the somatosensory pathway have been investigated using partial directed coherence (Porcaro et al, 2013). Moreover, information flow between thalamus and cortex is bidirectional (Milde et al, 2009;Sherman, 2010, 2011). We speculate that the described enhanced feedback from cortex to thalamus in the condition Std lessens the signal transfer from thalamus to the cortex during the standard condition in the sense of a gating effect (Ermutlu et al, 2007).…”