Pain behavior, chronic or neuropathic pain show a very high incidence and prevalence in humans, the most probably explanation involves pathologic changes in the central nervous system (CNS). Neuronal network of the spinal dorsal horn are the first important pain processing station. Functional connectivity as inferred from firing synchronicity, its discharge patters and modulation by supraspinal structures, the effects of tonic noxious stimulation of primary afferents and sensory processing by small neuronal networks were herein evaluated in the spinal dorsal horn using mathematical tools such as crosscorrelation, autospectral analysis, fractal dimension, Poincare and phase diagrams.