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Author Notes:

Correspondence: Cornelius Schwarz; Email: cornelius.schwarz@uni-tuebingen.de

CW conceived experiments, conducted experiments, analyzed data, wrote the paper.

CW conceived experiments, conducted experiments, analyzed data, wrote the paper.

CJW conceived experiments, analyzed data, wrote the paper.

GS conceived experiments, wrote the paper.

CS conceived experiments, analyzed data, wrote the paper.

We thank Ursula Pascht for excellent technical assistance.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Research Funding:

This work was supported by US-German collaboration grant (German: BMBF CRCNS 01GQ1113; US: NSF CRCNS IOS-1331948) and the Deutsche Forschungsgemeinschaft (DFG SCHW577/10-2).

This work was supported by US-German collaboration grant (German: BMBF CRCNS 01GQ1113; US: NSF CRCNS IOS-1331948) and the Deutsche Forschungsgemeinschaft (DFG SCHW577/10-2).

The open access fee was partly covered by the Deutsche Forschungsgemeinschaft and Open Access Publishing Fund of Tübingen University.

Keywords:

  • behavioral modification
  • head-restraint rat
  • barrel cortex

Support for the slip hypothesis from whisker-related tactile perception of rats in a noisy environment

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Journal Title:

Frontiers in Integrative Neuroscience

Volume:

Volume 9

Publisher:

Type of Work:

Article | Final Publisher PDF

Abstract:

Rodents use active whisker movements to explore their environment. The “slip hypothesis” of whisker-related tactile perception entails that short-lived kinematic events (abrupt whisker movements, called “slips”, due to bioelastic whisker properties that occur during active touch of textures) carry the decisive texture information. Supporting this hypothesis, previous studies have shown that slip amplitude and frequency occur in a texture-dependent way. Further, experiments employing passive pulsatile whisker deflections revealed that perceptual performance based on pulse kinematics (i.e., signatures that resemble slips) is far superior to the one based on time-integrated variables like frequency and intensity. So far, pulsatile stimuli were employed in a noise free environment. However, the realistic scenario involves background noise (e.g., evoked by rubbing across the texture). Therefore, if slips are used for tactile perception, the tactile neuronal system would need to differentiate slip-evoked spikes from those evoked by noise. To test the animals under these more realistic conditions, we presented passive whisker-deflections to head-fixed trained rats, consisting of “slip-like” events (waveforms mimicking slips occurring with touch of real textures) embedded into background noise. Varying the (i) shapes (ramp or pulse); (ii) kinematics (amplitude, velocity, etc.); and (iii) the probabilities of occurrence of slip-like events, we observed that rats could readily detect slip-like events of different shapes against noisy background. Psychophysical curves revealed that the difference of slip event and noise amplitude determined perception, while increased probability of occurrence (frequency) had barely any effect. These results strongly support the notion that encoding of kinematics dominantly determines whisker-related tactile perception while the computation of frequency or intensity plays a minor role.

Copyright information:

© 2015 Waiblinger, Brugger, Whitmire, Stanley and Schwarz.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).

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