NMJ-morph reveals principal components of synaptic morphology influencing structure-function relationships at the neuromuscular junction.

The ability to form synapses is one of the fundamental properties required by the mammalian nervous system to generate network connectivity. Structural and functional diversity among synaptic populations is a key hallmark of network diversity, and yet we know comparatively little about the morphological principles that govern variability in the size, shape and strength of synapses. Using the mouse neuromuscular junction (NMJ) as an experimentally accessible model synapse, we report on the development of a robust, standardized methodology to facilitate comparative morphometric analysis of synapses ('NMJ-morph'). We used NMJ-morph to generate baseline morphological reference data for 21 separate pre- and post-synaptic variables from 2160 individual NMJs belonging to nine anatomically distinct populations of synapses, revealing systematic differences in NMJ morphology between defined synaptic populations. Principal components analysis revealed that overall NMJ size and the degree of synaptic fragmentation, alongside pre-synaptic axon diameter, were the most critical parameters in defining synaptic morphology. 'Average' synaptic morphology was remarkably conserved between comparable synapses from the left and right sides of the body. Systematic differences in synaptic morphology predicted corresponding differences in synaptic function that were supported by physiological recordings, confirming the robust relationship between synaptic size and strength.

Development of a supported self-directed learning approach for anatomy education.

The ability to deliver sufficient core anatomical knowledge and understanding to medical students with limited time and resources remains a major challenge for anatomy educators. Here, we report the results of switching from a primarily didactic method of teaching to supported self-directed learning for students studying anatomy as part of undergraduate medicine at the University of Edinburgh. The supported self-directed approach we have developed makes use of an integrated range of resources, including formal lectures and practical sessions (incorporating gross anatomy specimens, medical imaging technologies, anatomical models, clinical scenarios, and surface anatomy workstations). In practical sessions, students are provided with a custom-made workbook that guides them through each session, with academic staff, postgraduate tutors, and near-peer teaching assistants present to deal with misunderstandings and explain more complicated topics. This approach retains many of the best attributes of didactic teaching but blends them with the advantages associated with self-directed learning approaches. The switch to supported self-directed learning-initially introduced in 2005-resulted in a significant improvement in anatomy examination scores over the subsequent period of five years, manifesting as an increase in the average anatomy practical spot examination mark, less students failing to obtain the pass mark and more students passing with distinction. We conclude that the introduction of supported self-directed learning improved students' engagement, leading to deeper learning and better understanding and knowledge of anatomy.