Neuronal tracing

Neuronal tracing, or neuron reconstruction is a technique used in neuroscience to determine the pathway of the neurites or neuronal processes, the axons and dendrites, of a neuron. From a sample preparation point of view, it may refer to some of the following as well as other genetic neuron labeling techniques, Anterograde tracing, for labeling from the cell body to synapse; Retrograde tracing, for labeling from the synapse to cell body; Viral neuronal tracing, for a technique which can be used to label in either direction; Manual tracing of neuronal imagery. In broad sense, neuron tracing is more often related to digital reconstruction of a neuron's morphology from imaging data of above samples. Digital reconstruction or tracing of neuron morphology is a fundamental task in computational neuroscience. It is also critical for mapping neuronal circuits based on advanced microscope images, usually based on light microscopy (e.g. laser scanning microscopy, bright field imaging) or electron microscopy or other methods. Due to the high complexity of neuron morphology and often seen heavy noise in such images, as well as the typically encountered massive amount of image data, it has been widely viewed as one of the most challenging computational tasks for computational neuroscience. Many image analysis based methods have been proposed to trace neuron morphology, usually in 3D, manually, semi-automatically or completely automatically. There are normally two processing steps: generation and proof editing of a reconstruction. The need to describe or reconstruct a neuron's morphology probably began in early days of neuroscience when neurons were labeled or visualized using Golgi's methods. Many of the known neuron types, such as pyramidal neurons and Chandelier cells, were described based on their morphological characterization. The first computer-assisted neuron reconstruction system, now known as Neurolucida, was developed by Dr. Edmund Glaser and Dr. Hendrik Van der Loos in the 1960s.