Since I recently posted on directional tuning in the rodent whisker system I want to point out that it’s been shown that when human finger tips touch objects they elicit directionally tuned responses in nerve cells carrying the signals to the brain.
Nearly a decade ago Ingvars Birznieks and colleagues showed that nerve cells carrying signals from human fingertips responded with the maximum number of impulses to a force applied in a particular direction (“Encoding of Direction of Fingertip Forces by Human Tactile Afferents” published in the October 15, 2001 issue of the Journal for Neuroscience).
A few years later Roland Johansson and Ingvars Birznieks showed that the relative timing of the first nerve impulses traveling to the brain carry reliable information about the direction of force and the shape of the surface contacting the fingertip (“First spikes in ensembles of human tactile afferents code complex spatial fingertip events” published in the February 2004 issue of Nature Neuroscience).