1982; Desmedt et al. 1983; Josiassen et al. 1990; Bolton
and Staines 2011). Overall, attention influences both the P50 and P100 amplitudes, but modulatory changes may be related to differences in experimental paradigms used and/or read more psychological factors (Desmedt and Robertson 1977; Goff et al. 1977). Attentional modulation in Inhibitors,research,lifescience,medical somatosensory cortex Studies investigating the effects of sustained tactile-spatial attention have shown that attention to task-relevant versus irrelevant spatial locations enhances processing of tactile stimuli and modulates somatosensory cortex (SI and SII) (Desmedt and Robertson 1977; Michie 1984; Michie et al. 1987). Several functional neuroimaging studies have found that sustained spatial attention to one hand versus the other during bilateral tactile stimulation enhances hemodynamic responses within contralateral SI and sensorimotor regions (Macaluso et al. 2000; Meador et al. 2002). A positron emission selleck bio tomography study reported that the anticipation Inhibitors,research,lifescience,medical of tactile stimulation can increase activity in contralateral SI even in the absence of any stimuli (Roland 1981). Furthermore, Inhibitors,research,lifescience,medical EEG investigations comparing somatosensory ERPs elicited by tactile stimulation applied to the hands, have reported that attending to the location of tactile stimulation modulates both
early and late somatosensory ERPs (N80, P100, N140) with increased amplitudes for the attended versus unattended tactile location (Desmedt and Robertson 1977; Inhibitors,research,lifescience,medical Michie 1984; Michie et al. 1987; Garcia-Larrea et al. 1995). However, SI responses as early as 45–50 msec post stimulus onset have been reported using an attentional vigilance task (Zopf et al. 2004). Notably, a recent study using simultaneous Inhibitors,research,lifescience,medical EEG and fMRI recordings found that sustained spatial attention during bilateral tactile stimulation (Braille) modulated early somatosensory ERPs (P50, N80, P100, and the long latency potential (LLP)) as well as increased BOLD signals in SI, SII, the inferior parietal lobe and frontal areas.
Correlation results showed that attentional modulation of SI was found to be positively correlated with attentional effects for the P50 and the LLP components (Schubert et al. 2006). The LLP component has multiple neural generators from broadly distributed locations, and is often seen as a sustained positivity Dacomitinib occurring approximately 200–500 msec post stimulus (Hämäläinen et al. 1990; Michie et al. 1987). The precise role of this later positivity remains unclear; however, several attention-based tactile ERP studies have implied that the LLP may share functional similarities to the P300 component, such that increases in the LLP amplitude is thought to reflect the amount of attentional resources devoted to a given task (Desmedt and Robertson 1977; Desmedt and Tomberg 1989; Michie et al. 1987).