George W Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, United States
Mercedes M Gonzalez
George W Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, United States
Colby F Lewallen
Ocular and Stem Cell Translational Research Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institute of Health, Bethesda, United States
Corey R Landry
Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, United States
Ilya Kolb
GENIE Project Team, Janelia Research Campus Howard Hughes Medical Institute, Ashburn, United States
Bo Yang
George W Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, United States
William M Stoy
Department of Electrical Engineering, Columbia University, New York, United States
Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, United States; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, United States; Howard Hughes Medical Institute, Cambridge, United States
Significant technical challenges exist when measuring synaptic connections between neurons in living brain tissue. The patch clamping technique, when used to probe for synaptic connections, is manually laborious and time-consuming. To improve its efficiency, we pursued another approach: instead of retracting all patch clamping electrodes after each recording attempt, we cleaned just one of them and reused it to obtain another recording while maintaining the others. With one new patch clamp recording attempt, many new connections can be probed. By placing one pipette in front of the others in this way, one can ‘walk’ across the mouse brain slice, termed ‘patch-walking.’ We performed 136 patch clamp attempts for two pipettes, achieving 71 successful whole cell recordings (52.2%). Of these, we probed 29 pairs (i.e. 58 bidirectional probed connections) averaging 91 μm intersomatic distance, finding three connections. Patch-walking yields 80–92% more probed connections, for experiments with 10–100 cells than the traditional synaptic connection searching method.
