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The spinal cord is endogenously capable of several forms of adaptive plasticity and learning, including functional re-training, instrumental, and Pavlovian learning. Understanding the mechanisms of spinal plasticity could lead to improved therapies for spinal cord injury and other neuromotor disorders. We describe and demonstrate techniques for eliciting spinal learning in the adult mouse using the Horridge paradigm. In the Horridge paradigm, instrumental learning occurs when a nociceptive leg stimulus is made to be contingent on leg position and the spinal cord learns to maintain the ankle in a flexed position. Using fine-wire intramuscular stimulating electrodes, an inexpensive real-time video tracking system, and DC current stimulation, we were able to elicit instrumental spinal learning from mouse lumbrosacral spinal cords that were functionally isolated from the brain. This technique makes it more feasible to use the powerful genetic manipulations available in mice to better understand the processes of spinal learning, memory, and plasticity.

Background:The facial region has traditionally been quantified using linear anthropometrics. These are well established in dentistry, but require expertise to be used effectively. The aim of this study was to augment the utility of linear anthropometrics by applying them in conjunction with modern 3-D morphometrics. Methods: Facial images of 75 males and 94 females aged 18-25 years with self-reported Caucasian ancestry were used. An anthropometric mask was applied to establish corresponding quasi-landmarks on the images in the dataset. A statistical face-space, encoding shape covariation, was established. The facial median plane was extracted facilitating both manual and automated indication of commonly used midline landmarks. From both indications, facial convexity angles were calculated and compared. The angles were related to the face-space using a regression based pathway enabling the visualization of facial form associated with convexity variation. Results: Good agreement between the manual and automated angles was found (Pearson correlation: 0.9478-0.9474, Dahlberg root mean squared error: 1.15°-1.24°). The population mean angle was 166.59°-166.29°(SD 5.09°-5.2°) for males-females. The angle-pathway provided valuable feedback. Conclusions: Linear facial anthropometrics can be extended when used in combination with a face-space derived from 3-D scans and the exploration of property pathways inferred in a statistically verifiable way.

Background: A functional appliance is commonly used to optimize the development of the facial skeleton in the treatment of Class II malocclusion. Recent three-dimensional(3D) image-based analysis offers numerous advantages in quantitative measurement and visualization in orthodontics. The aim of this study was to localize in 3D the skeletal effect produced by the Herbst appliance on the mandible using the geometric morphometric technique. Methods: Twenty patients treated with a Herbst appliance and subsequent fixed appliances were included. Conebeam computed tomography (CBCT) images were taken before treatment (T1), 8 weeks after Herbst appliance removal (T2), and after subsequent fixed appliance treatment (T3). Spatially dense morphometric techniques were used to establish the corresponding points of the mandible. The mandibular morphological changes from T1-T2, T2-T3, and T1-T3 were calculated for each patient by superimposing two mandibular models at two time points with robust Procrustes superimposition. These changes were then compared to the morphological changes estimated from normative mandibular growth curves over the same period. The proportion of cases exceeding the growth expression for controls was compared to a normal population using a one tailed binomial test. Results: Approximately 1.5-2 mm greater condylar changes and 0.5 mm greater changes in the chin occurred from Tl to T2. This effect lasted until the completion of treatment (T1-T3), but there was no obvious skeletal effect during the orthodontic phase (T2-T3). Approximately 40-50% of the patient sample exceeded condylar growth by > 1.5 mm compared to untreated controls (p < .05). However, changes at the chin were not statistically significant. Conclusions: The principal skeletal effect of Herbst appliance treatment was additional increase in condylar length for about half of the sample. This inconsistency may relate to the degree of mandibular growth suppression associated with a specific malocclusion.