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A [14C]iodoantipyrine study of inter-regional correlations of neural substrates following central post-stroke pain in rats.

Lu HC, Chang WJ, Kuan YH, Huang AC, Shyu BC - Mol Pain (2015)

Bottom Line: These results corroborate previous findings that the STT and thalamocingulate pathway are involved in the pathophysiological mechanisms of CPSP symptoms.The mPFC, amygdala, and periaqueductal gray emerged as having important correlations in pain processing in CPSP.The present data provide a basis for a neural correlation hypothesis of CPSP, with implications for CPSP treatment.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan. nhnsc@hotmail.com.

ABSTRACT

Background: Central pain syndrome is characterized by a combination of abnormal pain sensations, and pain medications often provide little or no relief. Accumulating animal and clinical studies have shown that impairments of the spinothalamic tract (STT) and thalamocingulate pathway causes somatosensory dysfunction in central post-stroke pain (CPSP), but the involvement of other neuronal circuitries in CPSP has not yet been systematically examined. The aim of the present study was to evaluate changes in brain activity and neuronal circuitry using [(14)C]iodoantipyrine (IAP) in an animal model of CPSP.

Results: Rats were subjected to lateral thalamic hemorrhage to investigate the characteristics of CPSP. Thermal and mechanical hyperalgesia developed in rats that were subjected to thalamic hemorrhagic lesion. The medial prefrontal cortex (mPFC), anterior cingulate cortex (ACC), striatum, thalamus, hypothalamus, and amygdala were more active in the CPSP group compared with rats that were not subjected to lateral thalamic hemorrhage. The inter-regional correlation analysis showed that regional cerebral blood flow in the mPFC was highly correlated with the amygdala in the right brain, and the right brain showed complex connections among subregions of the ACC. Rats with CPSP exhibited strong activation of the thalamocingulate and mPFC-amygdala pathways.

Conclusions: These results corroborate previous findings that the STT and thalamocingulate pathway are involved in the pathophysiological mechanisms of CPSP symptoms. The mPFC, amygdala, and periaqueductal gray emerged as having important correlations in pain processing in CPSP. The present data provide a basis for a neural correlation hypothesis of CPSP, with implications for CPSP treatment.

No MeSH data available.


Related in: MedlinePlus

Inter-regional rCBF in CPSP rats was analyzed by assessing correlations. Twenty-two ROIs that showed significant increases in radioactivity counts in the CPSP group were included in the correlation analysis. A. Inter-regional correlation matrix of inter-regional rCBF patterns in the CPSP group. Notice the augmented number of significant connections. The thalamus and hypothalamus were much more strongly correlated with the cortex compared with the sham group (see Figure 5A). B. The inter-regional correlation of the mPFC-amygdala pathway in the CPSP group is represented by a graph in which the connections between vertices with significant correlation are shown. The areas of the mPFC were much more positively correlated with the MD and amygdala compared with the sham group (see Figure 5B) C. Graphical representation of inter-regional correlations of the MT-ACC pathway and STT in the CPSP group. The cortex, thalamus, and hypothalamus had more connections with each other.
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Fig6: Inter-regional rCBF in CPSP rats was analyzed by assessing correlations. Twenty-two ROIs that showed significant increases in radioactivity counts in the CPSP group were included in the correlation analysis. A. Inter-regional correlation matrix of inter-regional rCBF patterns in the CPSP group. Notice the augmented number of significant connections. The thalamus and hypothalamus were much more strongly correlated with the cortex compared with the sham group (see Figure 5A). B. The inter-regional correlation of the mPFC-amygdala pathway in the CPSP group is represented by a graph in which the connections between vertices with significant correlation are shown. The areas of the mPFC were much more positively correlated with the MD and amygdala compared with the sham group (see Figure 5B) C. Graphical representation of inter-regional correlations of the MT-ACC pathway and STT in the CPSP group. The cortex, thalamus, and hypothalamus had more connections with each other.

Mentions: The ROI data of the specific brain areas that exhibited significant differences with the SPM and ROI scores in the ANOVA were further analyzed using Pearson correlations. The interregional correlation matrices of the ROIs in the sham and CPSP groups are depicted in Figures 5A and 6A, respectively. Major brain areas, such as the cortex, hippocampus, thalamus, hypothalamus, amygdala, and PAG, were selected for analysis. Significant functional correlations were found between different brain regions in the interregional correlation matrix (p < 0.01). The diagonal line from the lower left to upper right of the matrix is symmetrical, indicating correlations between ROIs and themselves. The analysis identified 154 (33.3%) significant positive correlations in the sham group (p < 0.01). The correlations between distal brain regions, such as the cortex/hippocampus, cortex/thalamus, cortex/hypothalamus, and cortex/amygdala, were low. High correlations were found within different local brain regions, such as within the cortex, thalamus, and hypothalamus (Figure 5A). In contrast, 274 (59.3%) significant positive correlations were found in the CPSP group (p < 0.01). The cortex had a positive correlation with the hippocampus, thalamus (but not VB subarea), hypothalamus, amygdala, and PAG (Figure 6A).Figure 5


A [14C]iodoantipyrine study of inter-regional correlations of neural substrates following central post-stroke pain in rats.

Lu HC, Chang WJ, Kuan YH, Huang AC, Shyu BC - Mol Pain (2015)

Inter-regional rCBF in CPSP rats was analyzed by assessing correlations. Twenty-two ROIs that showed significant increases in radioactivity counts in the CPSP group were included in the correlation analysis. A. Inter-regional correlation matrix of inter-regional rCBF patterns in the CPSP group. Notice the augmented number of significant connections. The thalamus and hypothalamus were much more strongly correlated with the cortex compared with the sham group (see Figure 5A). B. The inter-regional correlation of the mPFC-amygdala pathway in the CPSP group is represented by a graph in which the connections between vertices with significant correlation are shown. The areas of the mPFC were much more positively correlated with the MD and amygdala compared with the sham group (see Figure 5B) C. Graphical representation of inter-regional correlations of the MT-ACC pathway and STT in the CPSP group. The cortex, thalamus, and hypothalamus had more connections with each other.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4358859&req=5

Fig6: Inter-regional rCBF in CPSP rats was analyzed by assessing correlations. Twenty-two ROIs that showed significant increases in radioactivity counts in the CPSP group were included in the correlation analysis. A. Inter-regional correlation matrix of inter-regional rCBF patterns in the CPSP group. Notice the augmented number of significant connections. The thalamus and hypothalamus were much more strongly correlated with the cortex compared with the sham group (see Figure 5A). B. The inter-regional correlation of the mPFC-amygdala pathway in the CPSP group is represented by a graph in which the connections between vertices with significant correlation are shown. The areas of the mPFC were much more positively correlated with the MD and amygdala compared with the sham group (see Figure 5B) C. Graphical representation of inter-regional correlations of the MT-ACC pathway and STT in the CPSP group. The cortex, thalamus, and hypothalamus had more connections with each other.
Mentions: The ROI data of the specific brain areas that exhibited significant differences with the SPM and ROI scores in the ANOVA were further analyzed using Pearson correlations. The interregional correlation matrices of the ROIs in the sham and CPSP groups are depicted in Figures 5A and 6A, respectively. Major brain areas, such as the cortex, hippocampus, thalamus, hypothalamus, amygdala, and PAG, were selected for analysis. Significant functional correlations were found between different brain regions in the interregional correlation matrix (p < 0.01). The diagonal line from the lower left to upper right of the matrix is symmetrical, indicating correlations between ROIs and themselves. The analysis identified 154 (33.3%) significant positive correlations in the sham group (p < 0.01). The correlations between distal brain regions, such as the cortex/hippocampus, cortex/thalamus, cortex/hypothalamus, and cortex/amygdala, were low. High correlations were found within different local brain regions, such as within the cortex, thalamus, and hypothalamus (Figure 5A). In contrast, 274 (59.3%) significant positive correlations were found in the CPSP group (p < 0.01). The cortex had a positive correlation with the hippocampus, thalamus (but not VB subarea), hypothalamus, amygdala, and PAG (Figure 6A).Figure 5

Bottom Line: These results corroborate previous findings that the STT and thalamocingulate pathway are involved in the pathophysiological mechanisms of CPSP symptoms.The mPFC, amygdala, and periaqueductal gray emerged as having important correlations in pain processing in CPSP.The present data provide a basis for a neural correlation hypothesis of CPSP, with implications for CPSP treatment.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan. nhnsc@hotmail.com.

ABSTRACT

Background: Central pain syndrome is characterized by a combination of abnormal pain sensations, and pain medications often provide little or no relief. Accumulating animal and clinical studies have shown that impairments of the spinothalamic tract (STT) and thalamocingulate pathway causes somatosensory dysfunction in central post-stroke pain (CPSP), but the involvement of other neuronal circuitries in CPSP has not yet been systematically examined. The aim of the present study was to evaluate changes in brain activity and neuronal circuitry using [(14)C]iodoantipyrine (IAP) in an animal model of CPSP.

Results: Rats were subjected to lateral thalamic hemorrhage to investigate the characteristics of CPSP. Thermal and mechanical hyperalgesia developed in rats that were subjected to thalamic hemorrhagic lesion. The medial prefrontal cortex (mPFC), anterior cingulate cortex (ACC), striatum, thalamus, hypothalamus, and amygdala were more active in the CPSP group compared with rats that were not subjected to lateral thalamic hemorrhage. The inter-regional correlation analysis showed that regional cerebral blood flow in the mPFC was highly correlated with the amygdala in the right brain, and the right brain showed complex connections among subregions of the ACC. Rats with CPSP exhibited strong activation of the thalamocingulate and mPFC-amygdala pathways.

Conclusions: These results corroborate previous findings that the STT and thalamocingulate pathway are involved in the pathophysiological mechanisms of CPSP symptoms. The mPFC, amygdala, and periaqueductal gray emerged as having important correlations in pain processing in CPSP. The present data provide a basis for a neural correlation hypothesis of CPSP, with implications for CPSP treatment.

No MeSH data available.


Related in: MedlinePlus