title: The Development of Nociceptive Network Activity in the Somatosensory Cortex of Freely Moving Rat Pups.
abstract: Cortical perception of noxious stimulation is an essential component of pain experience but it is not known how cortical nociceptive activity emerges during brain development. Here we use continuous telemetric electrocorticogram (ECoG) recording from the primary somatosensory cortex (S1) of awake active rat pups to map functional nociceptive processing in the developing brain over the first 4 weeks of life. Cross-sectional and longitudinal recordings show that baseline S1 ECoG energy increases steadily with age, with a distinctive beta component replaced by a distinctive theta component in week 3. Event-related potentials were evoked by brief noxious hindpaw skin stimulation at all ages tested, confirming the presence of functional nociceptive spinothalamic inputs in S1. However, hindpaw incision, which increases pain sensitivity at all ages, did not increase S1 ECoG energy until week 3. A significant increase in gamma (20-50 Hz) energy occurred in the presence of skin incision at week 3 accompanied by a longer-lasting increase in theta (4-8 Hz) energy at week 4. Continuous ECoG recording demonstrates specific postnatal functional stages in the maturation of S1 cortical nociception. Somatosensory cortical coding of an ongoing pain "state" in awake rat pups becomes apparent between 2 and 4 weeks of age.
authors: Department of Neuroscience, Physiology & Pharmacology, University College London, London WC1E6BT, UK.|Current address: Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London WC1N 3BG, UK.
authors: P
authors: P
authors: Chang
authors: Department of Neuroscience, Physiology & Pharmacology, University College London, London WC1E6BT, UK.
authors: L
authors: L
authors: Fabrizi
authors: Department of Statistical Science, University College London, London WC1E6BT, UK.
authors: S
authors: S
authors: Olhede
authors: Department of Neuroscience, Physiology & Pharmacology, University College London, London WC1E6BT, UK m.fitzgerald@ucl.ac.uk.
authors: M
authors: M
authors: Fitzgerald
mesh_terms: D000818:Animals; D003430:Cross-Sectional Studies; D000069280:Electrocorticography; D004567:Electrodes, Implanted; D005071:Evoked Potentials / Q000502:physiology; D065818:Gamma Rhythm / Q000502:physiology; D006614:Hindlimb / Q000293:injuries; D008137:Longitudinal Studies; D008297:Male; D009434:Neural Pathways / Q000254:growth & development / Q000502:physiology; D059225:Nociception / Q000502:physiology*; D010812:Physical Stimulation; D017207:Rats, Sprague-Dawley; D012815:Signal Processing, Computer-Assisted; D012867:Skin / Q000293:injuries; D013003:Somatosensory Cortex / Q000254:growth & development* / Q000502:physiology*; D013686:Telemetry; D013826:Theta Rhythm / Q000502:physiology; D055698:Touch Perception / Q000502:physiology
keywords: EEG; development; neonatal; nociceptive networks; pain