Effect of gaze direction on neck muscle activity during cervical rotation

Abstract

Control of the neck muscles is coordinated with the sensory organs of vision, hearing and balance. For instance, activity of splenius capitis (SC) is modified with gaze shift. This interaction between eye movement and neck muscle activity is likely to influence the control of neck movement. The aim of this study was to investigate the effect of eye position on neck muscle activity during cervical rotation. In eleven subjects we recorded electromyographic activity (EMG) of muscles that rotate the neck to the right [right obliquus capitis inferior (OI), multifides (MF), and SC, and left sternocleidomastoid (SCM)] with intramuscular or surface electrodes. In sitting, subjects rotated the neck in each direction to specific points in range that were held statically with gaze either fixed to a guide (at three different positions) that moved with the head to maintain a constant intra-orbit eye position or to a panel in front of the subject. Although right SC and left SCM EMG increased with rotation to the right, contrary to anatomical texts, OI EMG increased with both directions and MF EMG did not change from the activity recorded at rest. During neck rotation SCM and MF EMG was less when the eyes were maintained with a constant intra-orbit position that was opposite to the direction of rotation compared to trials in which the eyes were maintained in the same direction as the head movement. The inter-relationship between eye position and neck muscle activity may affect the control of neck posture and movement.

Motor cortex representation of deep and superficial neck flexor muscles in individuals with and without neck pain

“…Evaluation of M1 maps of the extensor muscles would require separate trials with a different task to control preactivation [because erector spinae muscles have shown to have high stimulation threshold (Ferbert, Caramia, Priori, Bertolasi, & Rothwell, ; O'Connell, Maskill, Cossar, & Nowicky, ; Strutton, Theodorou, Catley, McGregor, & Davey, ; Tsao, Danneels, & Hodges, )] and a different coil orientation. Further, the anatomical configuration of the neck extensors muscles means that intramuscular electrodes are required to record from separate muscle layers (Bexander, Mellor, & Hodges, ), and this would not be feasible in an already invasive study. Future work should investigate the extensor muscles in people with and without NP.…”

Ultrasound-guided insertion of intramuscular electrodes into suboccipital muscles in the non-human primate

“…The value of this approach is that it increases the options for accessing this region, and hence would be suitable for experiments for which the invasive surgery or fixed electrode placement inherent to a chronic implant are not appropriate. Moreover, this technique could be extended to other muscles in the primate neck, potentially providing a comparative dataset to similar recordings made from deep muscles in humans (Bexander et al, 2005;Blouin et al, 2007;Falla et al, 2003Falla et al, , 2006 that are inaccessible to surface recording techniques (Mayoux-Benhamou et al, 1995). Primate neck muscles display a high degree of structural and histochemical complexity (Richmond et al, 2001b), and the distribution of different fibre types throughout a muscle is far from homogenous, even within a small muscle such as OCI (Richmond et al, 1999b).…”

“…Insertion of homonymous muscles in humans can be done without sedation (Bexander et al, 2005;Blouin et al, 2007), although this requires subject compliance. The use of an experimental animal necessitates sedation to avoid undue distress and strain on the implant, but the level of sedation may well depend on both experimental and idiosyncratic factors.…”

“…Although intramuscular recordings have been described (Bexander et al, 2005;Blouin et al, 2007), such an approach is likely limited to healthy and cooperative subjects. Animal models potentiate the pairing of intramuscular approaches with neurophysiological or neuroanatomical techniques that cannot be used in humans.…”

Real Time Acquisition of EMG Signal and Head Movement Recognition

“…Various studies [4,5,6,7,8,9] show that electromyography (EMG) activity of sternocleidomastoid (SCM) muscle and head rotation is interdependent. The EMG value of right SCM increased when the head turns to left hand side and for left SCM muscle, the EMG value increased when the head turn to right hand side [8].…”