[The rubber hand illusion in patients with complex regional pain syndrome. Successful illusion induction shows multisensory integration]. / Die Gummihandillusion bei CRPS-Patienten. Erfolgreiche Illusionsinduktion zeigt intakte multisensorische Integration.

Next to neurogenic inflammation and pathological sympathetic-afferent coupling, functional imaging studies have shown the crucial role of maladaptive cortical reorgansation in the pathophysiology of CRPS. Bilateral neuroplastic alterations in the somatosensory cortex seem to play a substantial role in the dysfunctional sensory processing of stimuli. The aim was to investigate the multimodal integration of sensory and visual stimuli into the body scheme and the influence of higher cognitive body representation in the integration of multimodal schema, body relevant stimuli in patients with CRPS. The investigated sample included 24 patients suffering from CRPS of the upper extremities, 21 patients with chronic hand pain of other origins and 24 healthy probands. The rubber hand illusion was carried out for the first time in patients with complex regional pain syndrome (CRPS). The reprentations show that the patients can integrate a rubber hand in their body representation to the same degree as healthy patients. The intact experience of the rubber hand illusion by CRPS patients indicates that the integration of congruent visual and tactile stimuli in CRPS is intact.

[Comparable disorder of the body schema in patients with complex regional pain syndrome (CRPS) and phantom pain]. / Vergleichbare Störung des Körperschemas bei Patienten mit komplexem regionalem Schmerzsyndrom (CRPS) oder Phantomschmerz.

In patients with complex regional pain syndrome (CRPS) a disruption of the body schema has been shown in an altered cortical representation of the hand and in delayed reaction times (RT) in the hand laterality recognition task. However, the role of attentional processes or the effect of isolated limb laterality training has not yet been clarified. The performance of healthy subjects (n = 38), CRPS patients (n = 12) and phantom limb pain (PLP) patients (n = 12) in a test battery of attentional performance (TAP) and in a limb laterality recognition task was compared and the effect of limb laterality training in CRPS patients and healthy subjects evaluated. The RTs of both CRPS and PLP patients were significantly slower than those of healthy subjects despite normal TAP values. The CRPS and PLP patients showed bilaterally delayed RTs. Through training RTs improved significantly but the RTs of CRPS patients remained slower than those of healthy subjects. In this study an equal disruption of the body schema was found in both CRPS and PLP patients which cannot be accounted for by attentional processes. For CRPS patients this disorder cannot be fully reversed by isolated limb laterality recognition training.

Consequences of different housing conditions on brain morphology in laying hens.

The aim of this study was to analyze the impact of physical and social stress on the avian forebrain morphology. Therefore, we used laying hens kept in different housing systems from puberty (approximately 16 weeks old) until the age of 48 weeks: battery cages, small littered ground pen, and free range system. Cell body sizes and catecholaminergic and serotonergic innervation patterns were investigated in brain areas expected to be sensitive to differences in environmental stimulation: hippocampal substructures and the nidopallium caudolaterale (NCL), a functional analogue of the prefrontal cortex. Our analysis shows both structures differing in the affected morphological parameters. Compared to battery cage hens, hens in the free range system developed larger cells in the dorsomedial hippocampus. Only these animals exhibited an asymmetry in the tyrosine hydroxylase density with more fibres in the left dorsomedial hippocampus. We assume that the higher spatial complexity of the free range system is the driving force of these changes. In contrast, in the NCL the housing systems affected only the serotonergic innervation pattern with highest fibre densities in free range hens. Moreover hens of the free range system displayed the worst plumage condition, which most likely is caused by feather pecking causing an altered serotonergic innervation pattern. Considering the remarkable differences between the three housing conditions, their effects on hippocampal structures and the NCL were surprisingly mild. This observation suggests that the adult brain of laying hens displays limited sensitivity to differences in social and physical environment induced post-puberty, which warrants further studies.