Biomedical subjects

Deborah E Bentley

Publications and source records attributed to Deborah E Bentley.

4 recordsLinked to original sources

PubMed2007

'Prior entry' for pain: attention speeds the perceptual processing of painful stimuli.

We investigated whether the perception of simultaneity for pairs of nociceptive and visual stimuli was dependent upon the focus of participants' attention to a particular sensory modality (either pain or vision). Two stimuli (one painful and the other visual) were presented randomly at different stimulus onset asynchronies (SOAs) using the method of constant stimuli. Participants made unspeeded verbal responses as to which stimulus they perceived as having been presented first, or else responded that the two stimuli were presented simultaneously. This temporal discrimination task was repeated under three different attention conditions (blocks): divided attention, attend pain, and attend vision. The results showed that under conditions of divided attention, nociceptive stimuli had to be presented before visual stimuli in order for the two to be perceived as simultaneous. A comparison of the two focused attention conditions revealed that the painful stimulus was perceived as occurring earlier in time (relative to the visual stimulus) when attention was directed toward pain than when it was directed toward vision. These results provide the first empirical demonstration that attention can modulate the temporal perception of painful stimuli.

Adult↗

PubMed2004

Lateralisation of nociceptive processing in the human brain: a functional magnetic resonance imaging study.

Nociceptive processing within the human brain takes place within two distinct and parallel systems: the lateral and medial pain systems. Current knowledge indicates that the lateral system is involved in processing the sensory-discriminative aspects of pain, and that the medial system is involved in processing the affective-motivational aspects of pain. Hemispheric differences in brain activation (lateralisation) during nociceptive processing were studied to further clarify the division of function between the lateral and medial pain systems. Hemispheric lateralisation was studied by applying painful CO(2) laser stimuli of 3-s duration sequentially to the left and right medial lower calves of five normal right-handed human subjects. The resultant brain activity was measured using 3-T functional magnetic resonance imaging, by determining significant changes in blood oxygen level dependent (BOLD) signal and applying a general linear modelling approach. Volumes of interest were defined for the primary and secondary somatosensory cortices (SI and SII), the insular cortex, and the thalamus, on individual subjects' high-resolution structural scans. Hemispheric lateralisation was quantified by comparing the level of activation between brain hemispheres within each volume of interest. In SII, no significant hemispheric difference in activation was detected. In the insula, activation was significantly greater in the left hemisphere than the right. In both SI and the thalamus, activation in response to painful stimulation was significantly greater in the hemisphere contralateral to the stimulus, which is consistent with these areas being involved in processing the sensory-discriminative aspects of pain.

Adult↗

PubMed2003

Caudal cingulate cortex involvement in pain processing: an inter-individual laser evoked potential source localisation study using realistic head models.

Electrophysiological studies have revealed a source of laser pain evoked potentials (LEPs) in cingulate cortex. However, few studies have used realistically shaped head models in the source analysis, which account for individual differences in anatomy and allow detailed anatomical localisation of sources. The aim of the current study was to accurately localise the cingulate source of LEPs in a group of healthy volunteers, using realistic head models, and to assess the inter-individual variability in anatomical location. LEPs, elicited by painful CO(2) laser stimulation of the right forearm, were recorded from 62 electrodes in five healthy subjects. Dipole source localisation (CURRY 4.0) was performed on the most prominent (P2) peak of each LEP data set, using head models derived from each subject's structural magnetic resonance image (MRI).For all subjects, the P2 LEP peak was best explained by a dipole whose origin was in cingulate cortex (mean residual variance was 3.9+/-2.4 %). For four out of five subjects, it was located at the border of the caudal division of left anterior cingulate cortex (area 24/32') with left posterior cingulate cortex (area 23/31). For the fifth subject the dipole was centred in right posterior cingulate cortex (area 31). This study demonstrates that the location of the cingulate source of LEPs is highly consistent across subjects, when analysed in this way, and supports the involvement of caudal cingulate regions in pain processing.

Adult↗

PubMed2002

Selective attention to pain: a psychophysical investigation.

Laboratory research suggests that the processing of painful stimuli can be modulated by selective attention to a particular sensory modality. However, alternative accounts for previous findings remain possible in terms of task-switching and spatial attention effects. In the present study, we examined whether attention can be selectively directed to the pain modality in order to facilitate the processing of the sensory-discriminative aspects of painful laser heat stimuli when these alternatives were ruled out. Participants made speeded spatial discrimination responses to an unpredictable sequence of painful laser heat and visual stimuli presented on the left forearm. On each trial, a symbolic cue predicted the likely modality for the upcoming target on the majority of trials. Participants responded more rapidly when the target was presented in the expected as opposed to the unexpected modality, demonstrating that selective attention can modulate the processing of painful stimuli. These findings are discussed in relation to contemporary theories of crossmodal attention and multisensory information-processing.

Attention↗