QTIP: Quantifier for Topographic Index of Presynaptic-terminal using 3D Confocal Imaging

Topography mapping is an important and general strategy for the nervous system to encode the locations of sensory stimuli. It has been difficult to analyze the relative spatial position between adjacent neurons in the same nervous system because of complex fine branches of axon terminals, especially at single-cell resolution. This paper describes an automatic image analysis tool QTIP (Quantifier for Topographic Index of Presynaptic-terminal), which quantifies fine-scale 3D structures’ spatial relative topography. Using confocal microscopic imaging assisted with advanced immunostaining, the presented image quantification tool enables automatic analysis of fine scale topography mapping in a 3D context, exemplified by the axon terminal topography analysis in Drosophila larva somatosensory system. The tool QTIP is developed as an ImageJ plugin and available at http://faculty.cs.niu.edu/~zhou/tool/qtip/.