L. Garcia-larrea - Academia.edu (original) (raw)

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Papers by L. Garcia-larrea

Electroencephalography and clinical neurophysiology, 1998

Localization of hippocampal paroxysmal activities in temporal lobe epilepsy (TLE) by means of dip... more Localization of hippocampal paroxysmal activities in temporal lobe epilepsy (TLE) by means of dipole modeling has often been criticized because of the supposed inaccuracy of this technique in localizing deep sources of EEG signals. This study aimed at assessing the relevance of mesio-temporal dipoles, as identified by modeling of scalp recorded spikes in TLE. Surface and depth EEG activities were simultaneously recorded using scalp and intracranial electrodes implanted through the foramen ovale (FO) in 3 patients with refractory TLE seizures. Intracranial FO spikes were used as triggers for scalp EEG averaging. The averaged signals were modeled by current dipoles, the localization of which were fused with patients' 3D-MRI. Individual FO spikes were undetectable on visual analysis of raw scalp EEG but were reflected by low-amplitude scalp EEG transients on averaged signal. Dipole modeling of this EEG deflection consistently identified a mesio-limbic source in a position close to ...

Pain, 1995

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

Neurophysiologie Clinique/Clinical Neurophysiology, 1999

Neurophysiologie Clinique/Clinical Neurophysiology, 1997

Neurophysiologie Clinique/Clinical Neurophysiology, 2011

European Journal of Pain, 2011

The autonomic nervous system (ANS) reacts to nociceptive stimulation during sleep, but whether th... more The autonomic nervous system (ANS) reacts to nociceptive stimulation during sleep, but whether this reaction is contingent to cortical arousal, and whether one of the autonomic arms (sympathetic/parasympathetic) predominates over the other remains unknown. We assessed ANS reactivity to nociceptive stimulation during all sleep stages through heart rate variability, and correlated the results with the presence of cortical arousal measured in concomitant 32channel EEG. Fourteen healthy volunteers underwent whole-night polysomnography during which nociceptive laser stimuli were applied over the hand. RR intervals (RR) and spectral analysis by wavelet transform were performed to assess parasympathetic (HF WV ) and sympathetic (LF WV and LF WV /HF WV ratio) reactivity. During all sleep stages, RR significantly decreased in reaction to nociceptive stimulations, reaching a level similar to that of wakefulness, at the 3 rd beat post-stimulus and returning to baseline after 7 beats. This RR decrease was associated with an increase in sympathetic LF WV and LF WV /HF WV ratio without any parasympathetic HF WV change. Albeit RR decrease existed even in the absence of arousals, it was significantly higher when an arousal followed the noxious stimulus. These results suggest that the sympathetic-dependent cardiac activation induced by nociceptive stimuli is modulated by a sleep dependent phenomenon related to cortical activation and not by sleep itself, since it reaches a same intensity whatever the state of vigilance.

European Journal of Pain, 2007

Epilepsy Research, 1994

Effects of GABA, receptors activation on brain glucose metabolism in normal subjects and temporal... more Effects of GABA, receptors activation on brain glucose metabolism in normal subjects and temporal lobe epilepsy (TLE) patients. A positron emission tomography (PET) study

Clinical Neurophysiology, 2011

Pain, 1989

Nociceptive flexion reflexes of the lower limbs (RIII responses) have been studied in 21 patients... more Nociceptive flexion reflexes of the lower limbs (RIII responses) have been studied in 21 patients undergoing either epidural (DCS, n = 16) or transcutaneous (TENS, n = 5) analgesic neurostimulation (AN) for chronic intractable pain. Flexion reflex RIII was depressed or suppressed by AN in 11 patients (52.4%), while no modification was observed in 9 cases and a paradoxical increase during AN was evidenced in 1 case. In all but 2 patients, RIII changes were rapidly reversible after AN interruption. RIII depression was significantly associated with subjective pain relief, as assessed by conventional self-rating; moreover, in 2 patients it was possible to ameliorate the pain-suppressing effects of AN by selecting those stimulation parameters (intensity and frequency) that maximally depressed nociceptive reflex RIII. We recorded 2 cases of RIII attenuation after contralateral neurostimulation. AN appeared to affect nociceptive reflexes rather selectively, with no or very little effect on other cutaneous, non-nociceptive responses. Recording of RIII reflexes is relatively simple to implement as a routine paraclinical procedure. It facilitates the objective assessment of AN efficacy and may help to choose the most appropriate parameters of neurostimulation. In addition, RIII behavior in patients could be relevant to the understanding of some of the mechanisms involved in AN-induced pain relief.