Range fractionation

Range fractionation is a term used in biology to describe the way by which a group of sensory neurons are able to encode varying magnitudes of a stimulus.

If the receptors are endowed with distinct transfer functions in such a way that the points of highest sensitivity are scattered along the axis of the quality being measured, the precision of the sense organ as a whole can be increased.

Collectively, the pattern of activity among the sensory neurons is how the organism can identify specific stimulus parameters.

Labeled line theory describes fully segregated channels postsynaptically.

In contrast, sensory neurons that use range fractionation have common synaptic partners, and it is there collective activity that is informative of the stimulus type.

A graph (title: Range Fractionation; x-axis: Stimulus Intensity (low-to-high), y-axis: sensory neuron activity (low-to-high)). 10 bell curves along the graph tile the area, showing different neurons respond to different stimulus intensities.
Graphical representation of range fractionation . In this diagram, 10 sensory neurons respond to fraction of the entire range of intensities of stimulus (blue, bottom). Together, all 10 of these neurons comprise the range of perceived stimuli", which is all of the discernable stimulus intensities to the system. Neuron response is indicated by "Sensory Neuron Activity" (or, Action Potential Firing Rate). The range of a single sensory neuron is indicated in yellow. In this depiction, low-intensity stimuli (light blue, left) would activate a single sensory neuron, whereas high-intensity stimuli (dark blue, right) may activate 3-4 neurons. The collective firing pattern of the sensory neurons will inform the nervous system about the stimulus properties.