Neuropsychologia
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Placebo has been shown to be a powerful analgesic with corresponding reduction in the activation of the pain matrix in the brain. However, the response to placebo treatment is highly variable. It is unclear how anticipatory and pain-evoked potentials are affected by the treatment and how reproducible the response is. ⋯ A significant correlation was found between the reduction in state anxiety in the repeat session relative to the first and the reduction in the anticipatory response in the sham-treatment group. Receiving a placebo treatment appears to cause a lasting change in the cognitive processing of pain for at least 6 weeks. This cognitive change may be facilitated by a change in state anxiety.
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To contribute to the identification of brain regions involved in déjà-vu, we studied the metabolic pattern of cortical involvement in patients with seizures of temporal lobe origin presenting with or without déjà-vu. Using voxel-based analysis of 18FDG-PET brain scans, we compared glucose metabolic rate of 8 patients with déjà-vu, 8 patients without déjà-vu, and 20 age-matched healthy subjects. Patients were selected after comprehensive non-invasive presurgical evaluation, including normal brain MRI and surface electroclinical features compatible with unilateral temporal lobe epilepsy (TLE). ⋯ Hippocampal metabolism was spared in 3 of these 7 patients. These findings argue for metabolic dysfunction of a medial-lateral temporal network in patients with déjà-vu and normal brain MRI. Within the medial temporal lobe, specific involvement of the parahippocampal region, often in the absence of hippocampal impairment, suggests that the feeling of familiarity during seizures greatly depends on alteration of the recognition memory system.
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In a previous study, we demonstrated that the mirror neuron system is involved in watching competitive games performed by multiple players [Shimada, S., & Abe, R. (2009). Modulation of the motor area activity during observation of a competitive game. NeuroReport, 20, 979-983]. ⋯ It was also greater when the player was presented with an incongruent view than with a congruent view, regardless of the outcome. In contrast, the dorsal posterior region of the motor area was activated only when the supported player won and was observed with a congruent view. We suggest that mirror neuron system activity during observation of a competitive game reflects the subject's internal assimilation of the actions of the observed player.