Two different features of a vibrotactile stimulus are encoded by rate and temporal codes in primary sensory cortex.  The amplitude was reflected in the overall firing rate of neurons whereas the frequency was reflected in the oscillatory phase-locking of spikes.
Harvey et al, 2013 PLOS Biology

The two coding schemes, rate vs temporal codes, are often debated as if they are in opposition and mutually exclusive.  They are not and this paper elegantly demonstrates this important point.  And this is not just limited to vibratory tactile stimuli.  Schroeder and colleagues have argued that all sensory processing involves periodic sampling and rhythmic entrainment of cortical neurons.  (We, for example, periodically sample vision via periodic eye movements and shifts of attention.)

Plus, rhythmic synchrony allows multiplexing, not only by adding another coding dimension as shown here, but also by allowing neurons to communicate different messages to different targets depending on whom they are synchronized with (and how, e.g., phase, frequency).  That way, the same neurons can participate in different functions yet still convey unambiguous messages.  For a brief discussion of this latter point and why we need multiplexing in the cortex see: Miller, E.K. and Fusi, S. (2013) Limber neurons for a nimble mind. Neuron. 78:211-213. View PDF

About the Author


The Miller Lab uses experimental and theoretical approaches to study the neural basis of the high-level cognitive functions that underlie complex goal-directed behavior. ekmillerlab.mit.edu