The rodent anterior cingulate cortex (ACC) is critical for visceral pain and pain-related aversive response in chronic visceral hypersensitive (VH) state. Long-term potentiation (LTP), induced by theta burst stimulation (TBS) in the medial thalamus (MT)-ACC pathway, is blocked in VH rats. However, the neuronal intrinsic firing characteristics and the MT-ACC connectivity have not been investigated in visceral pain.Using repetitive distension of the colon and rectum (rCRD) as a sensitization paradigm, we have identified that the spontaneous firing rates of ACC neurons and the CRD-stimulated neuronal firings were increased after repetitive visceral noxious stimulation. This correlates with increases in visceral pain responses (visceromotor responses, VMRs).Two multichannel arrays of electrodes were implanted in the MT and ACC. Recordings were performed in free-moving rats before and after repeated CRD treatment. Power spectral density analysis showed that the local field potential (LFP) recorded in the ACC displayed increases in theta band power (4-10. Hz) that were modulated by rCRD. Neural spike activity in the ACC becomes synchronized with ongoing theta oscillations of LFP. Furthermore, cross correlation analysis showed augmented synchronization of thalamo-ACC theta band LFPs, which was consistent with an increase of neuronal communication between the two regions.In conclusion, these results reveal theta oscillations and theta-frequency phase-locking as prominent features of neural activity in the ACC and a candidate neural mechanism underlying acute visceral pain.
|Number of pages||11|
|Publication status||Published - 9 Jul 2015|
Bibliographical noteFunding Information:
This work was supported by the Research Grants Council of Hong Kong [grant number 11100914 and CityU number 160811 , 160812 , and 160713 to Y. Li], the Health and Medical Research Fund of Hong Kong [ 01122006 to Y. Li], the National Science Foundation of China [ 81170353 to Y. Li], and City University of Hong Kong Neuroscience Research Infrastructure Grant [ 9610211 to Y. Li]. City University of Hong Kong Centre for Biosystems, Neuroscience, and Nanotechnology Grant (to S. Pang and Y. Li).
© 2015 The Authors.
- Anterior cingulate cortex
- Thalamocortical synchronization
- Theta oscillation
- Visceral pain
ASJC Scopus subject areas