2D vs. 3D pain visualization: User preferences in a spinal cord injury cohort

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 Springer VerlagResearch on pain experienced after Spinal Cord Injury (SCI) has revealed that not only are there several types of pain present in the same individual with this kind of trauma, but also that people who suffer such an injury can describe the characteristics of the same type of pain in different ways. Making it possible, therefore, to more precisely describe pain experience could prove to be vital for an increased quality of life. Accordingly, fifteen individuals with pain after SCI were asked to describe their pain experience using a 3 Dimensional (3D) model of the human body that could be used as an aid in communicating their pain. The results of this study suggest that the consensus of the participants approved the ability of the 3D model to more accurately describe their pain, an encouraging outcome towards the use of 3D technology in support of post SCI pain rehabilitation

Uncertainties in the modelled CO2 threshold for Antarctic glaciation

A frequently cited atmospheric CO2 threshold for the onset of Antarctic glaciation of ∼780 ppmv is based on the study of DeConto and Pollard (2003) using an ice sheet model and the GENESIS climate model. Proxy records suggest that atmospheric CO2 concentrations passed through this threshold across the Eocene-Oligocene transition ∼34 Ma. However, atmospheric CO2 concentrations may have been close to this threshold earlier than this transition, which is used by some to suggest the possibility of Antarctic ice sheets during the Eocene. Here we investigate the climate model dependency of the threshold for Antarctic glaciation by performing offline ice sheet model simulations using the climate from 7 different climate models with Eocene boundary conditions (HadCM3L, CCSM3, CESM1.0, GENESIS, FAMOUS, ECHAM5 and GISS-ER). These climate simulations are sourced from a number of independent studies, and as such the boundary conditions, which are poorly constrained during the Eocene, are not identical between simulations. The results of this study suggest that the atmospheric CO2 threshold for Antarctic glaciation is highly dependent on the climate model used and the climate model configuration. A large discrepancy between the climate model and ice sheet model grids for some simulations leads to a strong sensitivity to the lapse rate parameter

Sensory Stimulation Prior to Spinal Cord Injury Induces Post-Injury Dysesthesia in Mice

Chronic pain and dysesthesias are debilitating conditions that can arise following spinal cord injury (SCI). Research studies frequently employ rodent models of SCI to better understand the underlying mechanisms and develop better treatments for these phenomena. While evoked withdrawal tests can assess hypersensitivity in these SCI models, there is little consensus over how to evaluate spontaneous sensory abnormalities that are seen in clinical SCI subjects. Overgrooming (OG) and biting after peripheral nerve injury or spinal cord excitotoxic lesions are thought to be one behavioral demonstration of spontaneous neuropathic pain or dysesthesia. However, reports of OG after contusion SCI are largely anecdotal and conditions causing this response are poorly understood. The present study investigated whether repeated application of sensory stimuli to the trunk prior to mid-thoracic contusion SCI would induce OG after SCI in mice. One week prior to SCI or laminectomy, mice were subjected either to nociceptive and mechanical stimulation, mechanical stimulation only, the testing situation without stimulation, or no treatment. They were then examined for 14 days after surgery and the sizes and locations of OG sites were recorded on anatomical maps. Mice subjected to either stimulus paradigm showed increased OG compared with unstimulated or uninjured mice. Histological analysis showed no difference in spinal cord lesion size due to sensory stimulation, or between mice that overgroomed or did not overgroom. The relationship between prior stimulation and contusion injury in mice that display OG indicates a critical interaction that may underlie one facet of spontaneous neuropathic symptoms after SCI

Decreased Spinothalamic and Dorsal Column Medial Lemniscus-Mediated Function Is Associated with Neuropathic Pain after Spinal Cord Injury

Neuropathic pain (NP) after spinal cord injury (SCI) can significantly and negatively affect quality of life and is often refractory to currently available treatments. In order to find more effective therapeutic avenues, it would be helpful to identify the primary underlying pathophysiological mechanisms in each individual. The aim of the present study was to assess the relationship between the presence and severity of NP after SCI and measures of somatosensory function mediated via the dorsal column medial lemniscal (DCML) pathway and the spinothalamic tract (STT). Vibratory, mechanical, thermal, and pain thresholds measured in areas at and below the neurological level of injury (LOI) in persons with SCI and NP (SCI-NP, n=47) and in persons with SCI without NP (SCI-noNP, n=18) were normalized to data obtained from able-bodied pain-free control subjects (A-B, n=30). STT-mediated function at and below the LOI was significantly impaired in both SCI groups compared with A-B controls (p<0.001), but not significantly different between the two SCI groups (NP vs. no-NP). In contrast, the SCI-NP group had significantly greater impairment of DCML-mediated function at the LOI, as reflected by greater vibratory detection deficits (z=−3.89±0.5), compared with the SCI-noNP group (z=−1.95±0.7, p=0.034). Within the SCI-NP group, NP severity was significantly associated with increased thermal sensitivity below the LOI (r=0.50, p=0.038). Our results suggest that both impaired STT and DCML-mediated function are necessary for the development of NP after SCI. However, within the SCI-NP group, greater NP severity was associated with greater sensitivity to thermal stimuli below the LOI. This finding concurs with other studies suggesting that STT damage with some sparing is associated with NP