Manganese-enhanced magnetic resonance imaging depicts brain activity in models of acute and chronic pain: A new window to study experimental spontaneous pain?

Application of functional imaging techniques to animal models is vital to understand pain mechanisms, but is often confounded by the need to limit movement artefacts with anaesthesia, and a focus on evoked responses rather than clinically relevant spontaneous pain and related hyperalgesia. The aim of the present study was to investigate the potential of manganese-enhanced magnetic resonance imaging (MEMRI) to measure neural responses during on-going pain that underpins hyperalgesia in pre-clinical models of nociception. As a proof of concept that MEMRI is sensitive to the neural activity of spontaneous, intermittent behaviour, we studied a separate positive control group undergoing a voluntary running wheel experiment. In the pain models, pain behaviour (weight bearing asymmetry and hindpaw withdrawal thresholds (PWTs)) was measured at baseline and following either intra-articular injection of nerve growth factor (NGF, 10µg/50µl; acute pain model, n=4 rats per group), or the chondrocyte toxin monosodium iodoacetate (MIA, 1mg/50µl; chronic model, n=8 rats per group), or control injection. Separate groups of rats underwent a voluntary wheel running protocol (n=8 rats per group). Rats were administered with paramagnetic ion Mn2+ as soluble MnCl2 over seven days (subcutaneous osmotic pump) to allow cumulative activity-dependent neural accumulation in the models of pain, or over a period of running. T1-weighted MR imaging at 7T was performed under isoflurane anaesthesia using a receive-only rat head coil in combination with a 72mm volume coil for excitation. The pain models resulted in weight bearing asymmetry (NGF: 20.0 ± 5.2%, MIA: 15 ± 3%), and a reduction in PWT in the MIA model (8.3 ± 1.5g) on the final day of assessment before undergoing MR imaging. Voxel-wise and region-based analysis of MEMRI data did not identify group differences in T1 signal. However, MnCl2 accumulation in the VTA, right Ce amygdala, and left cingulate was negatively correlated with pain responses (greater differences in weight bearing), similarly MnCl2 accumulation was reduced in the VTA in line with hyperalgesia (lower PWTs), which suggests reduced regional activation as a result of the intensity and duration of pain experienced during the 7 days of MnCl2 exposure. Motor cortex T1-weighted signal increase was associated with the distance ran in the wheel running study, while no between group difference was seen. Our data suggest that on-going pain related signal changes identified using MEMRI offers a new window to study the neural underpinnings of spontaneous pain in rats.

'What vision?': experiences of Team members in a community service for adults with intellectual disabilities.

BACKGROUND: In the UK, the closure of 'long-stay' hospitals was accompanied by the development of community teams (CTs) to support people with intellectual disabilities (IDs) to live in community settings. The self-reported experiences of staff working in such teams have been neglected. METHODS: Focusing on a single county-wide service, comprising five multi-disciplinary and inter-agency CTs, we measured perceptions among the health care and care management Team members of (1) their personal well-being; (2) the functioning of their team; and (3) the organisation's commitment to quality, and culture. RESULTS: Almost three-quarters of the questionnaires were returned (73/101; 72%). The scores of health care practitioners and care managers were very similar: (1) the MBI scores of more than half the respondents were 'of concern'; (2) similarly, almost four in ten respondents' scores on the Vision scale of the TCI were 'of concern'; (3) the perceived commitment to quality (QIIS-II Part 2) was uncertain; and (4) the organisational culture (QIIS-II, Part 1) was viewed as primarily hierarchical. DISCUSSION: The perceived absence of a vision for the service, combined with a dominant culture viewed by its members as strongly focussed on bureaucracy and process, potentially compromises the ability of these CTs to respond proactively to the needs of people with IDs. Given the changes in legislation, policy and practice that have taken place since CTs were established, it would be timely to revisit their role and purpose.

Cognitive processing in post-traumatic stress disorder.

Recent research has suggested an abnormal attentional bias to threat in anxiety disorders. We have assessed the processing of thoughts of trauma, panic attacks, general fear and positive affect in a cohort of 15 war veterans with post-traumatic stress disorder (PTSD) and an age- and sex-matched normal control group. Subjects with PTSD showed delayed processing of self-referential sentences when the themes of the sentences were traumatic experiences or positive affect, compared with controls. However, they were more efficient than control subjects in the processing of sentences describing situations of panic attacks and general fear. It would therefore appear that in patients with PTSD, cognitive processing is hindered by personally relevant themes of past traumatic experiences, whereas it may be facilitated by information related to general threat or internal body sensations of panic.

Successful treatment of night terrors and somnambulism with paroxetine.

A patient with a 30-year history of somnambulism and night terrors is described. The use of a home ambulatory sleep electroencephalogram (EEG) recording in clarifying the diagnosis and in monitoring the results of treatment is illustrated and successful treatment using a selective serotonin re-uptake inhibitor is reported.