Automatic Segmentation of the Corpus Callosum Using a Cell-Competition Algorithm: Diffusion Tensor Imaging-Based Evaluation of Callosal Atrophy and Tissue Alterations in Patients With Systemic Lupus Erythematosus.

OBJECTIVE: Patients with neuropsychiatric systemic lupus erythematosus (NPSLE) may exhibit corpus callosal atrophy and tissue alterations. Measuring the callosal volume and tissue integrity using diffusion tensor imaging (DTI) could help to differentiate patients with NPSLE from patients without NPSLE. Hence, this study aimed to use an automatic cell-competition algorithm to segment the corpus callosum and to investigate the effects of central nervous system (CNS) involvement on the callosal volume and tissue integrity in patients with SLE. METHODS: Twenty-two SLE patients with (N = 10, NPSLE) and without (N = 12, non-NPSLE) CNS involvement and 22 control subjects were enrolled in this study. For volumetric measurement, a cell-competition algorithm was used to automatically delineate corpus callosal boundaries based on a midsagittal fractional anisotropy (FA) map. After obtaining corpus callosal boundaries for all subjects, the volume, FA, and mean diffusivity (MD) of the corpus callosum were calculated. A post hoc Tamhane's T2 analysis was performed to statistically compare differences among NPSLE, non-NPSLE, and control subjects. A receiver operating characteristic curve analysis was also performed to compare the performance of the volume, FA, and MD of the corpus callosum in differentiating NPSLE from other subjects. RESULTS: Patients with NPSLE had significant decreases in volume and FA but an increase in MD in the corpus callosum compared with control subjects, whereas no significant difference was noted between patients without NPSLE and control subjects. The FA was found to have better performance in differentiating NPSLE from other subjects. CONCLUSIONS: A cell-competition algorithm could be used to automatically evaluate callosal atrophy and tissue alterations. Assessments of the corpus callosal volume and tissue integrity helped to demonstrate the effects of CNS involvement in patients with SLE.

The modification by systemic morphine of the responses of serotonergic and non-serotonergic neurons in nucleus raphe magnus to heating the tail.

In anaesthetised rats, 63 raphe-spinal units in nucleus raphe magnus (NRM) have been identified by means of electrophysiological methods and further classified into serotonergic (5-HT) and non-5-HT units according to their conduction velocity and spontaneous discharge rate. All units, except one, showed either excitatory (n = 39) or inhibitory (n = 23) responses to noxious heating of the tail with hot water at 52 degrees C. The threshold temperature was around 44 degrees C and both types of responses increased with stepwise increases in temperature. The excitatory or inhibitory responses of raphe-spinal units induced by noxious heating of the tail correlated well with those elicited by noxious pinching, but did not correlate with the different transmitter populations (5-HT or non-5-HT) of the NRM unit. The effects of morphine or Fentanyl administration on the heat-induced responses of NRM units was observed. The possible involvement of NRM raphe-spinal units in 'diffuse noxious inhibitory controls' (DNICs) was discussed, particularly in relation to the 'lifting of DNICs' produced by morphine.