Attention to Painful Stimulation Enhances γ-Band Activity and Synchronization in Human Sensorimotor Cortex

Abstract

A number of cortical regions are involved in processing pain-related information. The SI and SII somatosensory cortices process mainly sensory discriminative attributes but also play an important role in recognition and memory of painful events. Regions such as SII and the posterior insula appear to be the first stations that house processes by which attention profoundly shapes both behavioral responses and subjective pain experience. We investigated the influence of directed attention on pain-induced oscillations and synchronization processes using magnetoencephalogram in combination with an oddball paradigm in 20 healthy subjects. The subject's task was to count rare painful electrical stimuli applied to one finger, while ignoring frequent stimuli at a different finger. A high detection ratio was observed for all blocks and subjects. Early evoked oscillations in the ␦-band increased with higher stimulus intensity and directed attention, most prominently at contralateral sensorimotor sites. Furthermore, suppression and rebound of ␤ activity were observed after painful stimulation. Moreover, induced oscillatory activity in the high ␥-band increased with directed attention, an effect being significantly stronger for high compared with low stimulus intensity. Coupling analysis performed for this high ␥ response revealed stronger functional interactions between ipsilateral and contralateral sites during attention. We conclude that pain-induced high-frequency activity in sensorimotor areas may reflect an attentional augmentation of processing, leading to enhanced saliency of pain-related signals and thus to more efficient processing of this information by downstream cortical centers.

Emotional Facial Expressions Modulate Pain-Induced Beta and Gamma Oscillations in Sensorimotor Cortex

“…In line with the activity pattern of paininduced total oscillatory responses (Figs. 2, 3), which are to a large extent comparable with our previous study (Hauck et al, 2007), the focus of the statistical analysis of oscillatory responses was on the examination of BBA (13-23 Hz) and GBA (70 -90 Hz) in the hand region of the sensorimotor cortex. An early time interval centered at 170 ms was subjected to the statistical analysis.…”

“…Recently, neural synchronization mechanisms were also linked to pain processing and pain perception (Hauck et al, 2008). Specifically, the GBA in primary somatosensory (Gross et al, 2007;Tiemann et al, 2010) and sensorimotor cortex (Hauck et al, 2007) was positively correlated to pain perception. Furthermore, it has been shown that painful inputs suppress oscillatory activity in the alpha-band (7-15 Hz) and beta-band (Ploner et al, 2006a).…”

The Neural Basis of Self-Touch in a Pain-Free Situation

“…This suggests that the bodily self is specifically important for the effects observed, together with VMPFC involvement. In addition, synchronous SII activity is shown to bias the routing of signals towards the ACC [61]. In our study, stronger bilateral SII activity coherence was associated with more RVM deactivation.…”

Intersubject variability and induced gamma in the visual cortex: DCM with empirical Bayes and neural fields

“…Local field potential or MEG recordings often show oscillatory responses that reflect summed activity from excitatory and inhibitory pools of neurons under various input stimuli and in several cortical regions [Hauck et al, 2007; Katzner et al, 2009; Xing et al, 2009]. Our focus is on visually induced responses and individual differences in cortical oscillations in the gamma band.…”