Canonical neurons and their parts

image of a mitral transforming itself into a canonical representation This database stores experimental data for each of the main parts of a neuronal type. Because neurons display a variety of shapes, it makes a logical and universally applicable classification of their parts very difficult. The approach taken here is to use a simplified representation based on the idea of a canonical form, e.g., the simplest form that represents the main neuronal regions. The abbreviations for the canonical parts of a neuron are: D, dendrite; S, soma (cell body); AH, axon hillock-initial segment of the axon; A, axon; T, axon terminal.

Representation of canonical forms of different neurons requires, in addition, a way of representing the diversity of their dendritic trees. The simplest case is a single dendrite, represented as an equivalent cylinder (e) consisting of a chain of three compartments, designated as (p) proximal, (m) middle, and (d) distal with respect to the cell body. More complicated are various multipolar branching patterns. The approach taken here is to follow Rall and Shepherd (1968) in representing these patterns as equivalent dendrites, with corresponding p, m and d compartments. This is appropriate for most experimental data, which are reported in terms of these three critical regions. More complicated still are the dendritic trees of neurons with apical and basal dendritic trees. These are each represented here by apical (a) and basal (b) equivalent dendrites, each with its p, m, and d compartments. Variations on these basic forms may be noted in the annotation boxes.

These categories are the basis for organizing the submission and the viewing of the experimental data relevant to the neurons in this database.