The medial pain system: Neural representations of the motivational aspect of pain

Sewards, Terence V.; Sewards, Mark A.

doi:10.1016/s0361-9230(02)00864-x

Cited by 129 publications

(100 citation statements)

References 247 publications

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“…The S1 and striatum are both important regions in the pain network, 22,36,37 in which the S1 is in the lateral pain system discriminating the location and intensity of the stimuli, 38 whereas the striatum receives strong projections from the medial pain system. 39 We did not detect thalamic activation, consistent with a prior study in rats. 36 The absence of thalamic activity could be because of the effect of isoflurane on suppressing thalamic activity 40 and/or regional dependence of neurovascular coupling.…”

Section: Neurovascular Responses In the Striatumsupporting

confidence: 91%

Imaging Neurovascular Function and Functional Recovery after Stroke in the Rat Striatum Using Forepaw Stimulation

Shih

Huang

Lai

et al. 2014

J Cereb Blood Flow Metab

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Negative functional magnetic resonance imaging (fMRI) response in the striatum has been observed in several studies during peripheral sensory stimulation, but its relationship between local field potential (LFP) remains to be elucidated. We performed cerebral blood volume (CBV) fMRI and LFP recordings in normal rats during graded noxious forepaw stimulation at nine stimulus pulse widths. Albeit high LFP-CBV correlation was found in the ipsilateral and contralateral sensory cortices (r ¼ 0.89 and 0.95, respectively), the striatal CBV responses were neither positively, nor negatively correlated with LFP (r ¼ 0.04), demonstrating that the negative striatal CBV response is not originated from net regional inhibition. To further identify whether this negative CBV response can serve as a marker for striatal functional recovery, two groups of rats (n ¼ 5 each) underwent 20-and 45-minute middle cerebral artery occlusion (MCAO) were studied. No CBV response was found in the ipsilateral striatum in both groups immediately after stroke. Improved striatal CBV response was observed on day 28 in the 20-minute MCAO group compared with the 45-minute MCAO group (Po0.05). This study shows that fMRI signals could differ significantly from LFP and that the observed negative CBV response has potential to serve as a marker for striatal functional integrity in rats.

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Section: Neurovascular Responses In the Striatumsupporting

confidence: 91%

Imaging Neurovascular Function and Functional Recovery after Stroke in the Rat Striatum Using Forepaw Stimulation

Shih

Huang

Lai

et al. 2014

J Cereb Blood Flow Metab

View full text Add to dashboard Cite

show abstract

“…In the present study, noxious stimuli of different stimulus intensities were used to modulate the impact of the US. When using different stimulus intensities, the unpleasantness and the sensory discriminative aspects of the noxious stimuli are modulated in parallel [32,34,44]. This explains the absence of dissociation between the Vx-SEP and the SI-SEP with respect to their correlation with the unpleasantness of the noxious stimuli.…”

Section: Discussionmentioning

confidence: 96%

Somatosensory-evoked potentials indicate increased unpleasantness of noxious stimuli in response to increasing stimulus intensities in the rat

Oostrom

Stienen

Bos

et al. 2007

Brain Research Bulletin

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Recently, it has been shown in rats that specific characteristics of somatosensory-evoked potentials (SEPs) recorded from different sites on the scalp correlate differently to the amount of unpleasantness experienced by the animal following noxious stimulation. It was shown that the SEP recorded from vertex (Vx-SEP) did correlate with the unpleasantness, whereas the SEP recorded from the primary somatosensory cortex (SI-SEP) did not. In the present study, we further investigated the relationship between the Vx-SEP, SI-SEP and the unpleasantness of noxious stimuli. Therefore, different groups of rats were subjected to a SEP fear-conditioning paradigm in which the unconditioned stimulus (US), represented by noxious stimuli applied to evoke SEPs, was paired to a conditioned stimulus (CS) represented by a tone. Different stimulus intensities of the US were applied in the different groups. After CS-US presentation, CS-induced fear-conditioned behaviour was analysed in relation to the characteristics of the Vx-and SI-SEP during CS-US presentation. Results showed that increasing stimulus intensities led to increased SEP amplitudes, which were paralleled by an increased amount of CS-induced fear-conditioned behaviour. No differences between Vx-SEP and SI-SEP were found. The increase in the SEPs in parallel with the increased amount of fear-induced behaviour further supports the SEP to be a potentially valuable tool for studying acute pain and analgesia in animals.

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“…The magnitude of the CS-induced fear-response after CS-US pairing, i.e. the strength of the CS-US association represented by the duration of freezing behaviour, is generally accepted as an expression of fear and even considered as an expression of pain experienced from the US [9,32]. Combined, analgesic drug-induced SEP changes during CS-US pairing correlating with a reduced CS-induced fear response, may therefore be assumed to indicate that the US was experienced as less unpleasant by analgesic drug treatment during CS-US pairing ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Vertex-recorded, rather than primary somatosensory cortex-recorded, somatosensory-evoked potentials signal unpleasantness of noxious stimuli in the rat

Stienen

Oostrom

Bos

et al. 2006

Brain Research Bulletin

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In the present study, we investigated in the rat whether vertex-or primary somatosensory cortex-recorded somatosensory-evoked potentials (Vx-SEP/SI-SEP, respectively) signal unpleasantness of noxious stimuli. Therefore, initially we characterised fentanyl effects (0, 20, 40 or 50 g/kg/h) on somatosensory and auditory processing by recording Vx-/SI-SEPs and vertex-and primary auditory cortex-recorded auditory-evoked potentials (Vx-/AI-AEPs, respectively). Subsequently, in a separate experiment, the animals were subjected to a Pavlovian fear-conditioning paradigm. The noxious stimuli applied to evoke Vx-/SI-SEPs (unconditioned stimulus (US)) were paired to a tone (conditioned stimulus (CS)) under 'steady state' conditions of 0, 20, 40 or 50 g/kg/h fentanyl. Vx-/SI-SEPs were recorded simultaneously during these trials. After CS-US presentation, CS-induced fear-conditioned behaviour was analysed in relation to the SEPs recorded during CS-US presentation and the AEPs recorded in the first experiment. While the SI-SEP and AI-AEP were minimally but significantly affected, fentanyl dose-dependently decreased the Vx-SEP and Vx-AEP. The decrease of the Vx-SEP and Vx-AEP was parallelled by the dose-dependent decrease of the amount of CS-induced fear-conditioned behaviour. These results suggest that the dose-dependent decrease of the Vx-SEP amplitude, rather than of the SI-SEP, indicates that the US was experienced as less unpleasant. Next to an altered US processing, altered CS processing contributed to the decrease of the amount of CS-induced fear-conditioned behaviour as indicated by the dose-dependent decrease of the Vx-AEP.

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The medial pain system: Neural representations of the motivational aspect of pain

Cited by 129 publications

References 247 publications

Imaging Neurovascular Function and Functional Recovery after Stroke in the Rat Striatum Using Forepaw Stimulation

Imaging Neurovascular Function and Functional Recovery after Stroke in the Rat Striatum Using Forepaw Stimulation

Somatosensory-evoked potentials indicate increased unpleasantness of noxious stimuli in response to increasing stimulus intensities in the rat

Vertex-recorded, rather than primary somatosensory cortex-recorded, somatosensory-evoked potentials signal unpleasantness of noxious stimuli in the rat

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