Probability distributions of whisker-surface contact: Quantifying elements of the rat vibrissotactile natural scene

Jennifer A. Hobbs, R. Blythe Towal, Mitra J Z Hartmann*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Analysis of natural scene statistics has been a powerful approach for understanding neural coding in the auditory and visual systems. In the field of somatosensation, it has been more challenging to quantify the natural tactile scene, in part because somatosensory signals are so tightly linked to the animal's movements. The present work takes a step towards quantifying the natural tactile scene for the rat vibrissal system by simulating rat whisking motions to systematically investigate the probabilities of whisker-object contact in naturalistic environments. The simulations permit an exhaustive search through the complete space of possible contact patterns, thereby allowing for the characterization of the patterns that would most likely occur during long sequences of natural exploratory behavior. We specifically quantified the probabilities of 'concomitant contact', that is, given that a particular whisker makes contact with a surface during a whisk, what is the probability that each of the other whiskers will also make contact with the surface during that whisk? Probabilities of concomitant contact were quantified in simulations that assumed increasingly naturalistic conditions: first, the space of all possible head poses; second, the space of behaviorally preferred head poses as measured experimentally; and third, common head poses in environments such as cages and burrows. As environments became more naturalistic, the probability distributions shifted from exhibiting a 'row-wise' structure to a more diagonal structure. Results also reveal that the rat appears to use motor strategies (e.g. head pitches) that generate contact patterns that are particularly well suited to extract information in the presence of uncertainty.

Original languageEnglish (US)
Pages (from-to)2551-2562
Number of pages12
JournalJournal of Experimental Biology
Issue number16
StatePublished - Aug 1 2015


  • Active touch
  • Exploration
  • Mechanics
  • Natural scene statistics
  • Tactile
  • Trigeminal
  • Vibrissotactile
  • Whisker

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Insect Science

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