Dynamic processing of nociception in cortical network in conscious rats: a laser-evoked field potential study.
(1) Field potential study in conscious rats provides a convenient and effective animal model for pain mechanism and pharmacological research. However, the spatial-temporal character of nociception processing in cortex revealed by field potential technique in conscious rats remains unclear. (2) In the present study, multi-channel field potentials evoked by noxious laser stimulation applied to the hind paw of conscious rats were recorded through 12 chronically implanted skull electrodes. Independent component analysis (ICA) was used to remove possible artifacts and to extract the specific nociception-related component. (3) Two fast sharp responses and one slow blunt response were evoked by noxious laser stimulation. Systemic morphine (5 mg/kg, i.p.) preferentially attenuated the amplitude of the slow blunt response while had no significant effect on the first two sharp responses. ICA revealed that those responses came from activities of contralateral anterior parietal area, medial frontal area and posterior parietal area. A movement artifact was also detected in this study. Partial directed coherence (PDC) analysis showed that there were changes of information flows from medial frontal and posterior parietal area to anterior parietal area after noxious laser stimulation. (4) Characterization of the spatio-temporal responses to noxious laser stimulation may be a valuable model for the study of pain mechanisms and for the assessment of analgesia.
Qiao
Zhi-Mei
ZM
Neuroscience Research Institute, Peking University, Beijing, China.
Wang
Jin-Yan
JY
Han
Ji-Sheng
JS
Luo
Fei
F
D000344:Afferent Pathways / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D003243:Consciousness / Q000502:physiology; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects / Q000502:physiology*; D005625:Frontal Lobe / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D007839:Functional Laterality / Q000187:drug effects / Q000502:physiology; D007834:Lasers; D008297:Male; D009415:Nerve Net / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D010146:Pain / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology*; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D013997:Time Factors
D000701:Analgesics, Opioid