The Matrix: a new tool for probing the whisker-to-barrel system with natural stimuli.

CNRS, Unité de Neurosciences, Information et Complexité (UNIC), 1 avenue de la Terrasse, 91190 Gif sur Yvette, France.
Journal of neuroscience methods (Impact Factor: 2.3). 03/2010; 189(1):65-74. DOI: 10.1016/j.jneumeth.2010.03.020
Source: PubMed

ABSTRACT The whisker to barrel system in rodents has become one of the major models for the study of sensory processing. Several tens of whiskers (or vibrissae) are distributed in a regular manner on both sides of the snout. Many tactile discrimination tasks using this system need multiple contacts with more than one whisker to be solved. With the aim of mimicking those multi-whisker stimuli during electrophysiological recordings, we developed a novel mechanical stimulator composed of 24 independent multi-directional piezoelectric benders adapted to the five rows and the five caudal arcs of the rat whisker pad. The most widely used technology for producing mechanical deflections of the whiskers is based on piezoelectric benders that display a non-linear behavior when driven with high frequency input commands and, if not compensated, show high unwanted ringing at particular resonance frequencies. If not corrected, this non-linear behavior precludes the application of high frequency deflections and the study of cortical responses to behaviorally relevant stimuli. To cope with the ringing problem, a mechanical and a software based solutions have been developed. With these corrections, the upper bound of the linear range of the bender is increased to 1 kHz. This new device allows the controlled delivery of large scale natural patterns of whisker deflections characterized by rapid high frequency vibrations of multiple whiskers.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The rodent whisker system became one of the main system models for the study of the functional properties of sensory neurons. This is due on one hand to the detailed knowledge that we have on the afferent pathways linking the mechanoreceptors in the follicles to the primary somatosensory cortex and on the other hand to the possibility of controlling the sensory input at a micrometer and millisecond scale. The observation of the natural use of the whiskers by rodents indicates that exploration of objects and textures imply multiple contacts with tens of whiskers simultaneously. We have studied the neural code in the barrel cortex, which receives tactile information from the whiskers. By combining multi-electrode recordings and controlled multiwhisker tactile stimulation with theoretical analysis, we have observed a dependence of neural responses on the statistics of the sensory input. Several classes of neuronal responses, similar to those described in a number of cortical visual areas, were observed in the same cortical volume, indicating that various coding schemes are implemented in the same cortical network and can be put into play differentially to cope with the changing statistics of the peripheral stimuli.
    Medecine sciences: M/S 01/2014; 30(1):93-8. · 0.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Whisking rodents can discriminate finely textured objects using their vibrissae. The biomechanical and neural processes underlying such sensory tasks remain elusive. Here we combine the use of model micropatterned substrates and high-resolution videography of rats' whiskers during tactile exploration to study how texture information is mechanically encoded in the whisker motion. A biomechanical modeling of the whisker is developed, which yields quantitative predictions of the spectral and temporal characteristics of the observed whisker kinetics, for any given topography. These texture-induced whisker vibrations are then replayed via a multiwhisker stimulator while recording neuronal responses in the barrel field of the primary somatosensory cortex (S1bf). These results provide a comprehensive description of the transduction process at play during fine texture sensing in rats. They suggest that the sensory system operates through a vibratory amplitude modulation/demodulation scheme. Fine textural properties are encoded in the time-varying envelope of the whisker-resonant vibrations. This quantity is then recovered by neural demodulation, as it effectively drives the spiking-rate signal of a large fraction of S1 cortical neurons. This encoding/decoding scheme is shown to be robust against variations in exploratory conditions, such as the scanning speed or pad-to-substrate distance, thus allowing for reliable tactile discrimination in realistic conditions.
    Journal of Neuroscience 08/2014; 34(33):10832-10843. · 6.75 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: As in other sensory modalities, one function of the somatosensory system is to detect coherence and contrast in the environment. To investigate the neural bases of these computations, we applied different spatiotemporal patterns of stimuli to rat whiskers while recording multiple neurons in the barrel cortex. Model-based analysis of the responses revealed different coding schemes according to the level of input correlation. With uncorrelated stimuli on 24 whiskers, we identified two distinct functional categories of neurons, analogous in the temporal domain to simple and complex cells of the primary visual cortex. With correlated stimuli, however, a complementary coding scheme emerged: two distinct cell populations, similar to reinforcing and antagonist neurons described in the higher visual area MT, responded specifically to correlations. We suggest that similar context-dependent coexisting coding strategies may be present in other sensory systems to adapt sensory integration to specific stimulus statistics.
    Nature Neuroscience 11/2012; · 14.98 Impact Factor

Full-text (2 Sources)

Available from
May 30, 2014