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We have developed, for the Case 3D Cryo-imaging system, a specialized, multi-scale visualization scheme which provides colorrich volume rendering and multi-planar reformatting enabling one to visualize an entire mouse and zoom in to organ, tissue, and microscopic scales. With this system, we have anatomically characterized, in 3D, from whole animal to tissue level, a transgenic mouse and compared it with its control. The transgenic mouse over-expresses the cytosolic form of phosphoenolpyruvate carboxykinase (PEPCK-C) in its skeletal muscle and is capable of greatly enhanced physical endurance, and has a longer lifespan and reproductive life as compared to control animals. We semi-automatically analyzed selected organs such as kidney, heart, adrenal gland, spleen, and ovaries and found comparatively enlarged heart, much less visceral, subcutaneous and pericardial adipose tissue, and higher tibia-to-femur ratio in the transgenic animal. Microscopically, individual skeletal muscle fibers, fine mesenteric blood vessels, intestinal villi, among others, were clearly seen. [ABSTRACT FROM AUTHOR]

The few studies that compared auditory skill learning between children and adults found variable results, with only some children reaching adult-like thresholds following training. The present study aimed to assess auditory skill learning in children as compared with adults during single- and multisession training. It was of interest to ascertain whether children who do not reach adult-like performance following a single training session simply require additional training, or whether different mechanisms underlying skill learning need to reach maturity in order to become adult-like performers. Forty children (7–9 years) and 45 young adults (18–35 years) trained in a single session. Of them, 20 children and 24 adults continued training for eight additional sessions. Each session included six frequency discrimination thresholds at 1000 Hz using adaptive forced-choice procedure. Retention of the learning-gains was tested 6 to 8 months posttraining. Results showed that (a) over half of the children presented similar performance and time course of learning as the adults. These children had better nonverbal reasoning and working memory abilities than their non-adult-like peers. (b) The best predicting factor for the outcomes of multisession training was a child's performance following one training session. (c) Performance gains were retained for all children with the non-adult-like children further improving, 6 to 8 months posttraining. Results suggest that mature auditory skill learning can emerge before puberty, provided that task-related cognitive mechanisms and task-specific sensory processing are already mature. Short-term training is sufficient, however, to reflect the maturity of these mechanisms, allowing the prediction of the efficiency of a prolonged training for a given child. [ABSTRACT FROM AUTHOR]