Pain
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This study aimed to investigate whether the differences in pain perception between patients with borderline personality disorder (BPD) and healthy subjects (HCs) can be explained by differences in the glutamate/GABA ratio in the posterior insula. In total, 29 BPD patients and 31 HCs were included in the statistical analysis. Mechanical pain sensitivity was experimentally assessed with pinprick stimuli between 32 and 512 mN on a numeric rating scale. ⋯ In the BPD patient group, the correlations between the glutamate/GABA ratio and the pain intensity ratings to 256- and 512-mN pinpricks did not reach significance. In conclusion, the study showed that individual differences in pain perception may in part be explained by the individual glutamate/GABA ratio in the posterior insula. However, this possible mechanism does not explain the differences in pain perception between BPD patients and HCs.
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Nociceptive trigeminal afferents innervating craniofacial area, eg, facial skin and cranial meninges, project to a broad region in the medullary and upper cervical dorsal horn designated as the trigeminocervical complex. Lamina I neurons in the trigeminocervical complex integrate and relay peripheral inputs, thus playing a key role in both cranial nociception and primary headache syndromes. Because of the technically challenging nature of recording, the long-range trigeminal afferent inputs to the medullary and cervical lamina I neurons were not intensively studied so far. ⋯ This pattern of supply was consistent with our labelling experiments showing extensive cervical projections of trigeminal afferents. Excitatory inputs were mediated, although not exclusively, through AMPA/kainate and NMDA receptors, whereas inhibitory inputs through both GABA and glycine receptors. In conclusion, the trigeminocervical lamina I neurons receive a complex pattern of long-range monosynaptic and polysynaptic inputs from a variety of the trigeminal nociceptive afferents.
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Three clinical scales (the Nociception Coma Scale adapted for Intubated patients [NCS-I], its Revised version [NCS-R-I], and the Behavioral Pain Scale [BPS]) and videopupillometry were compared for measuring pain in intubated, noncommunicating, critically ill, brain-injured patients. Pain assessment was performed before, during, just after, and 5 minutes after 3 procedures: the reference non-nociceptive procedure (assessment of the Richmond Agitation Sedation Scale) and 2 nociceptive procedures (turning and tracheal suctioning). The primary endpoint was construct validity (discriminant and criterion validation), determined by comparing pain measurements between different times/procedures. ⋯ Scale feasibility was better for the NCS-I and NCS-R-I than for the BPS. In conclusion, the BPS, NCS-I, and NCS-R-I are valid, reliable, and acceptable pain scales for use in intubated critically ill, brain-injured patients, unlike videopupillometry. Future research requires tool design centered on domains of observation adapted to this very specific population.