Painful Stimuli Evoke Potentials Recorded From the Parasylvian Cortex in Humans

Self Cite

Kobayashi K, Winberry J, Liu CC, Treede RD, Lenz FA. A painful cutaneous laser stimulus evokes responses from single neurons in the human thalamic principal somatic sensory nucleus ventral caudal (Vc). J Neurophysiol 101: 2210 -2217, 2009. First published February 25, 2009 doi:10.1152/jn.91347.2008. Cutaneous application of painful radiant heat laser pulses evokes potentials (laserevoked potentials) that can be recorded from scalp or intracranial electrodes. We have now tested the hypothesis that the response of thalamic neurons to a cutaneous laser stimulus occurs at latencies predicted by the conduction delay between the periphery and the thalamus. We have carried out recordings from human thalamic neurons in the principal sensory nucleus (ventral caudal) in patients undergoing awake surgery for the treatment of tremor. The results demonstrate that many neurons respond to the laser with early and/or late latency peaks of activity, consistent with conduction of the response to the laser stimulus through pathways from A␦ and C fibers to the thalamus. These peaks were of short duration, perhaps due to the somatotopic-and modality-specific arrangements of afferent pathways to the thalamus. The responses of these thalamic neurons to the laser stimulus sometimes included low-threshold spike (LTS) bursts of action potentials, consistent with previous studies of different painful stimuli. A prior study has demonstrated that spike trains characterized by common LTS bursts such as the intermediate (I) category spontaneously change their category more commonly than do those without LTS bursts (NG: nongrouped category) during changes in the cognitive task. Spike trains of laser-responsive neurons were more common in the I category, whereas those of laser nonresponsive neurons were more common in the NG category. Therefore neuronal spike trains in the I category may mediate shifts in endogenous or cognitive pain-related behavior.

Section: Discussionsupporting

confidence: 81%

Section: Discussionsupporting

confidence: 43%

A Painful Cutaneous Laser Stimulus Evokes Responses From Single Neurons in the Human Thalamic Principal Somatic Sensory Nucleus Ventral Caudal (Vc)

Kobayashi¹,

Winberry²,

Liu³

et al. 2009

Self Cite

“…6). However, subdural recordings in patients showed that the negative component in the ACC occurred later in time (211-242 ms; Lenz et al 1998a), i.e., at a time where our model showed a small local extreme (240 ms). Another hypothesis is that the source at CP1 represents an activation of the thalamus as the driving place for all other cortical regions.…”

Section: Discussionmentioning

confidence: 63%

“…With reference to earlier results of intracortical recordings of LEPs (e.g., Lenz et al 1998aLenz et al ,b, 2000, and to keep the number of statistical comparisons reasonable, we defined five intervals for GCI analysis of LEP activities that reflect activations of different brain areas of cortical stimulus processing: The first time window started at stimulus onset and covered the first 80 ms poststimulus. This time window is considered as one where the cortex does not yet receive laser-heat induced afferent input, thus serving as a precortical activity interval.…”

Section: E T H O D Smentioning

confidence: 99%

How Do Brain Areas Communicate During the Processing of Noxious Stimuli? An Analysis of Laser-Evoked Event-Related Potentials Using the Granger Causality Index

Weiß

Hesse²,

Ungureanu³

et al. 2008

Several imaging techniques have identified different brain areas involved in the processing of noxious stimulation and thus in the constitution of pain. However, only little is known how these brain areas communicate with one another after activation by stimulus processing and which areas directionally affect or modulate the activity of succeeding areas. One measure for the analysis of such interactions is represented by the Granger Causality Index (GCI). In applying time-varying bivariate and partial variants of this concept (tvGCI), the aim of the present study was to investigate the interaction of neural activities between a set of scalp electrodes that best represent the brain electrical neural activity of major cortical areas involved in the processing of noxious laser-heat stimuli and their variation in time. Bivariate and partial tvGCIs were calculated within four different intervals of laser-evoked event-related potentials (LEPs) including a baseline period prior to stimulus application and three intervals immediately following stimulus application, i.e., between 170 and 200 ms (at the N2 component), between 260 and 320 ms (P2 component), and between 320 and 400 ms (P3 component of LEPs). Results show some similarities, but also some striking differences between bivariate and partial tvGCIs. These differences might be explained by the nature of bivariate and partial tvGCIs. However, both tvGCI approaches revealed a directed interaction between medial and lateral electrodes of the centroparietal region. This result was interpreted as a directed interaction between the anterior cingulate cortex and the secondary somatosensory cortex and the insula, structures that are significantly involved in the constitution of pain.

“…In most reports, LEP are recorded from the scalp, where they are limited by muscle and blink artifacts, by low-pass and spatial filtering at the scalp, skull, and CSF (Cooper et al 1965;Gevins et al 1994;Lenz et al 1998Lenz et al , 2000Ohara et al 2004aOhara et al , 2004bOhara et al , 2004cPfurtscheller and Cooper, 1975;Valeriani et al 2000;Vogel et al 2003;Wang et al 2007), and by large interelectrode distances (Garcia-Larrea et al 2003). We have applied subdural recordings, a technique that brings increased resolution and clarity to the study of human S1 cortical pain mechanisms (Ohara et al 2004b;Scherg 1992).…”

Section: Discussionmentioning

confidence: 99%

Dipole source analyses of laser evoked potentials obtained from subdural grid recordings from primary somatic sensory cortex

Baumgärtner

Vogel

Ohara

et al. 2011

The cortical potentials evoked by cutaneous application of a laser stimulus (laser evoked potentials, LEP) often include potentials in the primary somatic sensory cortex (S1), which may be located within the subdivisions of S1 including Brodmann areas 3A, 3B, 1, and 2. The precise location of the LEP generator may clarify the pattern of activation of human S1 by painful stimuli. We now test the hypothesis that the generators of the LEP are located in human Brodmann area 1 or 3A within S1. Local field potential (LFP) source analysis of the LEP was obtained from subdural grids over sensorimotor cortex in two patients undergoing epilepsy surgery. The relationship of LEP dipoles was compared with dipoles for somatic sensory potentials evoked by median nerve stimulation (SEP) and recorded in area 3B (see Baumgärtner U, Vogel H, Ohara S, Treede RD, Lenz FA. J Neurophysiol 104: 3029–3041, 2010). Both patients had an early radial dipole in S1. The LEP dipole was located medial, anterior, and deep to the SEP dipole, which suggests a nociceptive dipole in area 3A. One patient had a later tangential dipole with positivity posterior, which is opposite to the orientation of the SEP dipole in area 3B. The reversal of orientations between modalities is consistent with the cortical surface negative orientation resulting from superficial termination of thalamocortical neurons that receive inputs from the spinothalamic tract. Therefore, the present results suggest that the LEP may result in a radial dipole consistent with a generator in area 3A and a putative later tangential generator in area 3B.