Turning attention towards or away from a painful heat stimulus is known to modify both the subjective intensity of pain and cortical evoked potentials noxious stimuli. Using PET, we investigated in 12 volunteers whether pain-related regional cerebral blood flow (rCBF) changes were also modulated by attention. High (mean 46.6°C) low 39°C) thermal stimuli applied hand under three attentional conditions: (i) directed stimuli, (ii) diverted (iii) no task. Only insular/second somatosensory...

Although electrical stimulation of the precentral gyrus (MCS) is emerging as a promising technique for pain control, its mechanisms action remain obscure, and application largely empirical. Using positron emission tomography (PET) we studied regional changes in cerebral flood flow (rCBF) 10 patients undergoing motor cortex seven whom also underwent somatosensory evoked potentials nociceptive spinal reflex recordings. The most significant MCS-related increase rCBF concerned ventral-lateral...

According to most behavioural, electrophysiological, and clinical studies, the cingulate gyrus is widely thought be involved in regulation of emotional life, reactivity painful stimuli, memory processing, attention sensory stimuli. Anatomically cortex composed two distinct areas numbered 24 23 Brodmann's classification. We have investigated connections monkeys, using horseradish peroxydase radioautographic techniques, order verify hypothesis an anatomical complementarity these...

Summary: Purpose: In this study, we report the clinical features of insular lobe seizures based on data from video and stereo‐electroencephalographic (SEEG) ictal recordings direct electric stimulation cortex performed in patients referred for presurgical evaluation temporal epilepsy (TLE). Methods: Since our first seizures, has been included as one targets electrode implantation 50 consecutive with TLE whose were suspected to originate from, or rapidly propagate to, perisylvian cortex. six,...

Detailed clinical sensory and motor signs were correlated case by with somatosensory evoked potentials (SEP) in 22 selected patients a single circumscribed hemisphere lesion. The lesions collectively mapped out variety of cerebral sites from the anterior frontal to posterior parietal regions. SEPs averaged 8 standard scalp an earlobe reference electrode, so that N20-P27-P45 differentiated prerolandic P22-N30 SEP components. wave forms stimulation on unaffected side served as patient's own...

WE investigated the relation between subjective sensation of pain and two different components laser evoked potential, namely vertex response (N220-P350) an earlier lateralized (middle-latency NP160). Brain responses to stimuli were obtained in 15 subjects under attentive distractive conditions. Although stimulus intensity was kept constant, it perceived as significantly higher when attended stimulation. There a positive correlation perception amplitude but no existed with middle-latency...

The clinical, electrophysiological and haemodynamic effects of precentral gyrus stimulation (PGS) as a treatment refractory post-stroke pain were studied in 2 patients. first patient had right hemibody secondary to left parietal infarct sparing the thalamus, while second lower limb developed after mesencephalic infarct. In both cases, spontaneous was associated with hyperpathia, allodynia hypoaesthesia painful territory involving lemniscal extra-lemniscal sensory modalities 1, modality only...

Summary: Purpose : We report the results of 75 intracortical electrical stimulations insular cortex performed in 14 patients during stereo‐electroencephalography (SEEG) investigation drug‐resistant partial epilepsy. The was investigated on electroclinical arguments suggesting possibility a perisylvian spread or rapid multilobar diffusion discharges video EEG. Methods In these patients, 27 stereotactically implanted transopercular electrodes reached (11 right insula, 16 left insula). Square...

Abstract The functional anatomy of perceptual and semantic processings for odors was studied using positron emission tomography (PET). first experiment a pretest in which 71 normal subjects were asked to rate 185 odorants terms intensity, familiarity, hedonicity, comestibility name the odorants. This necessary select most appropriate stimuli different cognitive tasks second experiment. one PET 15 scanned water bolus method measure regional cerebral blood flow (rCBF) during performance three...

The human brain is expert in analyzing rapidly and precisely facial features, especially emotional expressions representing a powerful communication vector. involvement of insula disgust recognition has been reported behavioral functional imaging studies. However, we do not know whether specific insular fields are involved processing nor what the time course is. Using depth electrodes implanted during presurgical evaluation patients with drug-refractory temporal lobe epilepsy, recorded...

Abstract The somatosensory evoked potential negative components in the 100–150‐ms range were studied under conditions where attention was directed either toward or away from probe stimulus. An N120 component, not sensitive to spatial attention, appeared all conditions, including no‐task condition. Its distribution consistent with an origin second somatic area. A later N140 response, recorded neutral highly and reached its maximum stimulation of attended hand; behavior that a processing...

In some candidates for epilepsy surgery in whom the decision to operate is difficult make, invasive presurgical investigations, namely depth electrode recordings, may be needed. The SEEG (StereoElectroEncephaloGraphy) method consists of stereotactic orthogonal implantation electrodes (5 15, 11 on average). object this study clarify indications SEEG, expose its complications, and display usefulness terms surgical strategy results.100 patients, suffering from drug-resistant selected as...

We report the response properties of suprasylvian opercular and insular cortices to a painful stimulation delivered by CO(2) laser recorded depth intracerebral electrodes in epileptic patients. defined two cortical areas activation operculo-insular cortex stimulation: area, where we responses peaking 140-170 ms after (N140-P170), deeper with similar pattern peaked 180-230 stimulus (N180-P230). The average delay 50 measured between may reflect either sequential then insula via corticocortical...

Several observations suggest impaired central sensory integration in dystonia. We studied median and ulnar nerve somatosensory evoked potentials (SEPs) 10 patients who had dystonia involving at least one upper limb (six generalized, two segmental focal dystonia) normal subjects. compared the amplitude of spinal N13, brainstem P14, parietal N20 P27 frontal N30 SEPs obtained by stimulating nerves simultaneously (MU), value being from arithmetic sum elicited same separately (M + U). Throughout...

Thanks to the seminal work of Wilder Graves Penfield (1891-1976) at Montreal Neurological Institute, electrical stimulation is used worldwide localize epileptogenic cortex and map functionally eloquent areas in context epilepsy surgery or lesion resections. In functional elementary experiential responses he described through >20 years careful exploration human via cortical surface, did not identify any 'pain area'. We reinvestigated this issue by analysing subjective videotaped behavioural...

Abstract Event‐related potentials (ERPs) were recorded in 10 adult volunteers, who asked to view pictures of faces with different emotional expressions, i.e. fear, happiness, disgust, surprise and neutral expression [Ekman, P. & Friesen, W.V. (1975). Pictures Facial Affect . Consulting Psychologist Press, Palo Alto, CA]. ERPs during two tasks the same stimuli. Firstly, subjects instructed pay attention gender by counting males or females. Secondly, they had focus on facial expressions...