Comparison of touch- and laser heat-evoked cortical field potentials in conscious rats

Shaw, Fu-Zen; Chen, Ruei-Feng; Tsao, Hen‐Wai; Yen, Chen‐Tung

doi:10.1016/s0006-8993(99)01185-3

Cited by 39 publications

(37 citation statements)

References 32 publications

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“…These results support that the Vx-SEP and SI-SEP are related to nociception as previously reported [36,38]. Both noxious and tactile responses can be found within the 10-30 ms latency range [5,13,31,33]. However, with -opiate receptor agonists like fentanyl modulating noxious, rather than tactile, processing [6,16,34,41,42], the Vx-SEP and SI-SEP in the present study can be considered to represent processing of noxious stimuli.…”

Section: Discussionsupporting

confidence: 92%

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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Section: Discussionsupporting

confidence: 92%

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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“…At this intensity, consistent with previous studies (Shaw et al 1999(Shaw et al , 2001Tsai et al 2004), short-(LEP1) and long-latency (LEP2) evoked potentials were recorded from the EEG skull electrode in the rostral parietal region. The average LEP1 and LEP2 values of the eight rats were 67 Ϯ 3 and 356 Ϯ 7 ms, respectively (Table 1).…”

Section: Acc and Smi Responses To Laser Irradiation Of The Mid-tailsupporting

confidence: 86%

“…The 10.6-m wavelength infrared radiation of the CO 2 laser selectively activates nociceptive receptors and generates a pure pain sensation, which is conveyed through both myelinated A-␦ and unmyelinated C fibers to the cerebral cortex in humans (Bromm andTreede 1984, 1987). Two cortical laser-evoked potentials (LEP1 and LEP2) have been recorded from the cerebral cortex of the rat (Shaw et al 1999(Shaw et al , 2001). The conduction velocities of the peripheral fibers responsible for the activation of these LEPs have been estimated.…”

Section: Fig 6 Comparison Of Short-(arrowheads)mentioning

confidence: 99%

“…A single longlatency cortical evoked potential was observed, and its peripheral conduction velocity was estimated to be 0.7 m/s. Shaw et al (1999) stimulated different proximo-distal locations of the tail of conscious rats. LEP1 and LEP2 were observed, and their peripheral conduction velocities were estimated to be 22 and 0.7 m/s, respectively.…”

Section: Fig 6 Comparison Of Short-(arrowheads)mentioning

confidence: 99%

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Comparison of Anterior Cingulate and Primary Somatosensory Neuronal Responses to Noxious Laser-Heat Stimuli in Conscious, Behaving Rats

Kuo¹,

Yen²

2005

Journal of Neurophysiology

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Kuo, Chung-Chih and Chen-Tung Yen. Comparison of anterior cingulate and primary somatosensory neuronal responses to noxious laser-heat stimuli in conscious, behaving rats. J Neurophysiol 94: 1825-1836, 2005; 10.1152/jn.00294.2005. In this study, we investigated single-unit responses of the primary sensorimotor cortex (SmI) and anterior cingulate cortex (ACC) to noxious stimulation of the tail of the rat. The influences of morphine on these nociceptive responses were also compared. Multiple single-unit activities were recorded from two eight-channel microwire arrays chronically implanted in the tail region of the SmI and ACC, respectively. CO 2 laser-heat irradiation of the middle part of the tail at an intensity slightly higher than that causing a maximal tail flick response was used as a specific noxious stimulus. Examined individually, ACC neurons were less responsive than SmI neurons to laser-heat stimulus, in that only 51% of the ACC units (n ϭ 125) responded compared with 88% of the SmI units (n ϭ 74). Among these responsive ACC units, many had a very long latency and long-lasting excitatory type of response that was seldom found in the SmI. When ensemble activities were examined, laser heat evoked both short-(60 ϳ 150 ms) and long-latency (151 ϳ 600 ms) responses in the SmI and ACC. Latencies of both responses were longer in the ACC. Furthermore, a single dose of 2.5-10 mg/kg morphine intraperitoneally suppressed only the long latency response in the SmI, but significantly attenuated both responses in the ACC. These effects of morphine were completely blocked by prior treatment with the opiate receptor blocker, naloxone. These results provide further evidence suggesting that the SmI and ACC may play different roles in processing noxious information. I N T R O D U C T I O NRecent neuroimaging studies in human subjects have revealed several key forebrain areas most often activated by noxious stimulations. Among these areas are the primary somatosensory cortex (SI) and anterior cingulate cortex (ACC) (Casey et al. 1994; Coghill et al. 1994 Coghill et al. , 1999 Craig et al. 1996; Davis et al. 1995; Dorbyshire et al. 1997; Hsieh et al. 1995; Talbot et al. 1991; Vogt et al. 1996). Furthermore, studies by Rainville et al. (1997) and Hofbauer et al. (2001) showed that functional MRI (fMRI) intensities in the SI were correlated with the intensity of the noxious heat, whereas those in the ACC were better correlated with subjective unpleasantness, suggesting a differential functional role between SI and ACC.In contrast, the processing of nociceptive information in the forebrain at the cellular level is largely unclear. Neuroanatomical and neurophysiological studies have shown that pain information is processed through a complicated serial and parallel network in the forebrain (Craig 2003; Willis 1985). Electrophysiological studies of the SI have revealed nociceptive neu-

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“…Six stainless steel screws were driven bilaterally into the skull overlaying the frontal (A ϩ2.0, L 2.0 with reference to the Bregma), parietal (A Ϫ2.0, L 2.0), and occipital (A Ϫ6.0, L 2.0) regions of the cortex to record cortical activities. The parietal lead was placed over the tail and hindlimb representative area of the primary somatosensory cortex (Shaw et al 1999a). A ground electrode was implanted 2 mm caudal to lambda.…”

Section: E T H O D Smentioning

confidence: 99%

Is Spontaneous High-Voltage Rhythmic Spike Discharge in Long Evans Rats an Absence-Like Seizure Activity?

Shaw

2004

Journal of Neurophysiology

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111

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Shaw, Fu-Zen. Is spontaneous high-voltage rhythmic spike discharge in Long Evans rats an absence-like seizure activity? J Neurophysiol 91: 63-77, 2004. First published June 25, 2003 10.1152/jn.00487.2003. A distinct high-voltage rhythmic spike (HVRS) discharge characterized by a barrage of negative spikes oscillating at 5-12 Hz was observed in chronically implanted Long Evans rats. Spontaneous HVRS discharges were exhibited in 90% of 40 Long Evans rats and occurred during sudden arrest of ongoing behavior (immobility) with occasional facial/whisker twitching. However, the function of HVRS discharges in Long Evans rats remains inconclusive to date and has been associated with alpha tremor/mu rhythm, attentive mu wave, and absence seizure. To elucidate the function of HVRS discharges in Long Evans rats, several experiments were performed. In a 6-h recording session (12:00 -18:00), HVRS activities primarily occurred in several specific vigilance states, being particularly abundant in a short-lasting period before vigilance changes. Several characteristics, such as durations, oscillatory frequencies, and interspike intervals (ISIs) of HVRS discharges, were altered during wake-sleep states. Oscillatory frequencies were negatively correlated with durations of HVRS segments. In addition, ISIs of a HVRS episode exhibited a crescendo-decrescendo pattern. These variable ISIs could explain why a negative correlation was found between oscillatory frequencies and durations of HVRS episodes. Moreover, HVRS discharges were demonstrated to have widespread and near-synchronous distribution to bilateral cortical areas. In addition, innocuous electrical stimuli were unable to stop ongoing HVRS discharges. By contrast, noxious stimuli elicited behavioral arousal and immediately terminated most HVRS discharges. Cortical-evoked potentials in response to mild electrical stimulation under HVRS discharges were different from those under waking state but resemble those under slow-wave sleep with a smaller magnitude. Moreover, the temporal and spectral characteristics of spontaneous HVRS activities were analogous to those of seizure activities induced by penicillin and pentylenetetrazol. The incidence of spontaneous HVRS discharges was significantly decreased by ethosuximide administration. Based on these results, HVRS discharge might not be associated with a voluntary mu-rhythm behavior, instead it behaves as an absence-like seizure activity. These results were also collaborated using other genetic absence-seizure rats, such as WAG/Rij and GAERS rats. Possible mechanisms for the generation and termination of paroxysmal HVRS discharges are also discussed.

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Comparison of touch- and laser heat-evoked cortical field potentials in conscious rats

Cited by 39 publications

References 32 publications

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

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

Comparison of Anterior Cingulate and Primary Somatosensory Neuronal Responses to Noxious Laser-Heat Stimuli in Conscious, Behaving Rats

Is Spontaneous High-Voltage Rhythmic Spike Discharge in Long Evans Rats an Absence-Like Seizure Activity?

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