Motor‐related cortical dynamics to intact movements in tetraplegics as revealed by high‐resolution EEG

Abstract

We explored the cortical dynamics during movements of an unaffected body part in tetraplegic subjects with chronic spinal cord injury (SCI). The aims were to find out whether the intact movements were associated with a physiological time-varying pattern of activity in the motor-related cortical areas and whether the primary motor area (MI) activation followed a somatotopic distribution. Event-related potentials to self-initiated lip movements were analyzed by means of cortical source imaging of EEG recorded from seven tetraplegic subjects and seven control subjects. Regions of interest (ROIs) were selected on individual MRI and the time-varying electrophysiologic activity (cortical current density, CCD) was estimated on these ROIs and subjected to across-subject analysis. A significant, bilateral movement-related pattern of MI activation was detected during motor task execution in SCI patients as well as in controls. The site of local maxima activation displayed a symmetrical discrete distribution within MI, consistently with a putative somatotopic lip representation, in all the subjects. The supplementary motor area proper (SMAp) was always coactivated with MI and coactivation was characterized by a time course with typical premotion and motion phases over both motor areas. A clear-cut temporal delay between the SMAp and MI activation did not occur either in SCI patients or in controls. These findings obtained with noninvasive neuroelectrical source imaging document that in chronic SCI subjects "executive" motor areas are engaged with a preserved temporal and spatial pattern during preparation and execution of intact movements.

High-resolution EEG techniques for brain–computer interface applications

“…In this respect, cortical source estimation is likely to provide a better signal conditioning in preparation of BCI processing. In fact, it is well know that the estimation of the cortical activity from scalp EEG data by solving the linear inverse problem with realistic head models greatly enhances the spatial details available when compared to the Surface Laplacian methods (Babiloni et al, 2000;Cincotti et al, 2004a;He et al, 2006;Mattia et al, 2006;Nunez, 1995;Urbano et al, 1998).…”

“…This region should plausibly include the foot representation site within the MI according to its somatotopic organization. To define the primary motor hand and lip representational area, we followed an anatomical-functional procedure previously reported (Mattia et al, 2006). The anatomical localization of other EEG sources were related to the major sulci and gyri distinguishable on the individual MRIs, and named according to Brodmann nomenclature BA6, BA5, BA7, BA8 and BA9/46).…”

Reorganization and Preservation of Motor Control of the Brain in Spinal Cord Injury: A Systematic Review

“…Lower limb motor tasks included foot movement (Alkadhi et al, 2005;Astolfi et al, 2007;Cramer et al, 2005Cramer et al, , 2007Fallani et al, 2007;Halder et al, 2006;Hotz-Boendermaker et al, 2008;Lacourse et al, 1999;Lotze et al, 1999;Turner et al, 2001;Winchester et al, 2005) and toe movement (Castro et al, 2007;Green et al, 1998Green et al, , 1999Sabbah et al, 2002;Shoham et al, 2001;Winchester et al, 2005). Facial motor tasks included lip movement Fallani et al, 2007;Green et al, 1998;Lotze et al, 1999;Mattia et al, 2006;Shoham et al, 2001) and tongue movement (Curt et al, 2002a;Mikulis et al, 2002;Turner et al, 2001). Imagined movement was also investigated in some studies and included lower limb movement (Alkadhi et al, 2005;Cramer et al, 2005;Hotz-Boendermaker et al, 2008;Lacourse et al, 1999;Lotze et al, 1999;Sabbah et al, 2002) and upper limb movement (Lacourse et al, 1999;Sabbah et al, 2002).…”

“…In the present review, a number of imaging modalities were used in the included articles, with the primary modality being fMRI (14 articles) (Alkadhi et al, 2005;Cramer et al, 2005Cramer et al, , 2007Curt et al, 2002a;Hotz-Boendermaker et al, 2008;Jurkiewicz et al, 2007;Lotze et al, 1999Lotze et al, , 2006Mikulis et al, 2002;Sabbah et al, 2002;Shoham et al, 2001;Turner et al, 2001Turner et al, , 2003Winchester et al, 2005) and the others including EEG (eight articles) Castro et al, 2007;Fallani et al, 2007;Green et al, 1998Green et al, , 1999Halder et al, 2006;Lacourse et al, 1999;Mattia et al, 2006) and PET (two articles) (Bruehlmeier et al, 1998;Curt et al, 2002b). The imaging and mapping modalities cited in the studies measure plasticity of the brain differently.…”

“…For those studies specifying gender of subjects, one third of studies used only males, while just less than one half used a combination of males and females, with males comprising 70% of the subjects. Among studies, the level and extent of SCI lesions were also variable, with seven articles involving exclusively cervical lesions Fallani et al, 2007;Jurkiewicz et al, 2007;Mattia et al, 2006;Mikulis et al, 2002;Shoham et al, 2001;Winchester et al, 2005), five articles involving lesions in the cervical to thoracic range (Cramer et al, 2005(Cramer et al, , 2007Green et al, 1998Green et al, , 1999Turner et al, 2001), eight articles involving lesions in the thoracic to lumbar range (Alkadhi et al, 2005;Curt et al, 2002a;Halder et al, 2006;Hotz-Boendermaker et al, 2008;Lotze et al, 1999Lotze et al, , 2006Sabbah et al, 2002;Turner et al, 2003), three articles involving lesions in the cervical to lumbar range (Bruehlmeier et al, 1998;Curt et al, 2002b;Lacourse et al, 1999), and one article did not specify lesion location (Castro et al, 2007). In terms of completeness of injury, five articles included exclusively complete injuries (Alkadhi et al, 2005;Castro et al, 2007;Cramer et al, 2005;Curt et al, 2002b;Turner et al, 2003), one article involved exclusively incomplete injuries (Winchester et al, 2005), 13 articles included both complete and incomplete injuries (Cramer et al, 2005(Cramer et al, , 2007Green et al, 1998Green et al, , 1998Halder et al, 2006;HotzBoendermaker...…”