Neuroscience Bulletin

, Volume 28, Issue 2, pp 91–99 | Cite as

Population coding of somatic sensations



The somatic sensory system includes a variety of sensory modalities, such as touch, pain, itch, and temperature sensitivity. T The coding of these modalities appears to be best explained by the population-coding theory, which is composed of the following features. First, an individual somatic sensory afferent is connected with a specific neural circuit or network (for simplicity, a sensory-labeled line), whose isolated activation is sufficient to generate one specific sensation under normal conditions. Second, labeled lines are interconnected through local excitatory and inhibitory interneurons. As a result, activation of one labeled line could modulate, or provide gate control of, another labeled line. Third, most sensory fibers are polymodal, such that a given stimulus placed onto the skin often activates two or multiple sensory-labeled lines; crosstalk among them is needed to generate one dominant sensation. Fourth and under pathological conditions, a disruption of the antagonistic interaction among labeled lines could open normally masked neuronal pathways, and allow a given sensory stimulus to evoke a new sensation, such as pain evoked by innocuous mechanical or thermal stimuli and itch evoked by painful stimuli. As a result of this, some sensory fibers operate along distinct labeled lines under normal versus pathological conditions. Thus, a better understanding of the neural network underlying labeled line crosstalk may provide new strategies to treat chronic pain and itch.


developmental neurobiology dorsal root ganglion pain pathways itch spinal dorsal horn 


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© Shanghai Institutes for Biological Sciences, CAS and Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  1. 1.Dana-Farber Cancer Institute and Department of NeurobiologyHarvard Medical SchoolBostonUSA

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