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Background:The neural mechanisms underlying the modulation of pain perception by hypnosis remain obscure. In this study, we used positron emission tomography in 11 healthy volunteers to identify the brain areas in which hypnosis modulates cerebral responses to a noxious stimulus.Methods: The protocol used a factorial design with two factors: state (hypnotic state, resting state, mental imagery) and stimulation (warm non-noxious vs. hot noxious stimuli applied to right thenar eminence). Two cerebral blood flow scans were obtained with the

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Abstract-We studied a patient in a minimally conscious state using PET and cognitive evoked potentials. Cerebral metabolism was below half of normal values. Auditory stimuli with emotional valence (infant cries and the patient's own name) induced a much more widespread activation than did meaningless noise; the activation pattern was comparable with that previously obtained in controls. Cognitive potentials showed preserved P300 responses to the patient's own name. NEUROLOGY 2004;63:916 -918 Patients in a minimally conscious state (MCS) show some limited evidence of awareness of self or environment. However, caregivers of these patients have difficulties in behaviorally evaluating their level of conscious or emotional perception. By definition, MCS patients show no functional interactive verbal or nonverbal communication. 1 We report a patient in an MCS as documented by extensive and repetitive neuropsychological evaluations. Six months after admission, resting cerebral metabolic rates for glucose (CMRGlu) and regional changes in cerebral blood flow (rCBF) in response to auditory stimuli (with different emotional content and relevance) were studied using PET imaging with simultaneous recording of cognitive event-related potentials (ERPs). Materials and methods. Patient.A 42-year-old man was brought to the hospital after abrupt loss of consciousness. Brain CT showed a left frontal intracerebral hemorrhage. The hematoma was evacuated in emergency. Follow-up MRI showed multifocal bilateral frontal hypodensities, and EEG showed diffuse theta and delta activities. Somatosensory (but not visual) evoked potentials showed preserved cortical potentials. Brainstem auditory evoked potentials were normal.Six months after the insult, CMRGlu-PET, rCBF-PET, and cognitive ERP studies were performed while the patient was in an MCS and free of centrally acting drugs. Videotaped neurologic and neuropsychological assessment included the Wessex Head Injury Matrix 2 and the Western Neuro Sensory Stimulation Profile 3 and Revised Coma Recovery Scale.10 At the time of PET scanning, the patient showed spontaneous eye opening (Ͼ30 minutes), conjugate roving eye movements, and preserved visual and auditory startle reflexes. Brainstem reflexes were normal, and grasp, palmomental, and sucking reflexes were obtained. He showed a spastic quadriparesis with bilateral pyramidal signs, made no spontaneous limb movements, sporadically uttered incomprehensible (apparently meaningless) groans, fixated and tracked family members and a moving mirror, oriented toward new sounds, and inconsistently obeyed simple commands (e.g., showed his tongue when asked by his wife in three of four trials) but failed to make functional communication.Subsequent to PET and ERP studies, the patient could make intelligible vocalizations (e.g., "hello" and "mom") and later showed signs of intentional communication. Unfortunately, the patient died 30 weeks after admission from septic shock. Given that earlier he had been slowly recovering with gradually but consistentl...

We review cerebral processing of auditory and noxious stimuli in minimally conscious state (MCS) and vegetative state (VS) patients. In contrast with limited brain activation found in VS patients, MCS patients show activation similar to controls in response to auditory, emotional and noxious stimuli. Despite an apparent clinical similarity between MCS and VS patients, functional imaging data show striking differences in cortical segregation and integration between these two conditions. However, in the absence of a generally accepted neural correlate of consciousness as measured by functional neuroimaging, clinical assessment remains the gold standard for the evaluation and management of severely brain damaged patients.