A two-dimensional force sensor in the millinewton range for measuring vibrissal contacts

The rat vibrissal (whisker) array is a common model system in neuroscience used to study sensorimotor integration. Recent work has suggested that during object contact, the forces and moments at the whisker base may serve as important perceptual cues to the rat. To date, however, the force/moment profile that results from a whisker sweeping against an object has yet to be characterized, because it requires the simultaneous measurement of two-dimensional forces on the order of millinewtons. Current technology for these measurements typically involves prohibitively bulky, expensive equipment with complicated fabrication techniques. We have developed a simple, yet effective two-dimensional force sensor with +/-0.02 mN resolution; it is extremely compact, has a highly linear static response with low-noise output, and is inexpensive to build. We demonstrate the advantages and limitations of the sensor in three different experimental protocols, ranging from the precise quantification of forces on isolated (plucked) whiskers, to the detection of whisker-contact times in the awake behaving animal. Given the high fidelity of the sensor, it could have utility in a broad range of applications in which measuring contact/detach occurrence and/or small magnitude forces are important.

[1]  D. Kleinfeld,et al.  Active Spatial Perception in the Vibrissa Scanning Sensorimotor System , 2007, PLoS biology.

[2]  L. Wineski Facial morphology and vibrissal movement in the golden hamster , 1985, Journal of morphology.

[3]  R Bermejo,et al.  Optoelectronic monitoring of individual whisker movements in rats , 1998, Journal of Neuroscience Methods.

[4]  Takashi R Sato,et al.  Divergent movement of adjacent whiskers. , 2002, Journal of neurophysiology.

[5]  B. Munger,et al.  A comparative light microscopic analysis of the sensory innervation of the mystacial pad. I. Innervation of vibrissal follicle‐sinus complexes , 1986, The Journal of comparative neurology.

[6]  Joseph H. Solomon,et al.  Biomechanics: Robotic whiskers used to sense features , 2006, Nature.

[7]  J. M. Gibson,et al.  Quantitative studies of stimulus coding in first-order vibrissa afferents of rats. 2. Adaptation and coding of stimulus parameters. , 1983, Somatosensory research.

[8]  R. Frostig,et al.  Whisker-based discrimination of object orientation determined with a rapid training paradigm , 2005, Neurobiology of Learning and Memory.

[9]  Rune W. Berg,et al.  Rhythmic whisking by rat: retraction as well as protraction of the vibrissae is under active muscular control. , 2003, Journal of neurophysiology.

[10]  M. Hartmann,et al.  Mechanical Characteristics of Rat Vibrissae: Resonant Frequencies and Damping in Isolated Whiskers and in the Awake Behaving Animal , 2003, The Journal of Neuroscience.

[11]  R Bermejo,et al.  Topography of whisking II: Interaction of whisker and pad , 2005, Somatosensory & motor research.

[12]  A. Iggo,et al.  Functional characteristics of mechanoreceptors in sinus hair follicles of the cat , 1973, The Journal of physiology.

[13]  E. Ahissar,et al.  Responses of trigeminal ganglion neurons to the radial distance of contact during active vibrissal touch. , 2006, Journal of neurophysiology.

[14]  Tae-Eun Jin,et al.  Fiber Types of the Intrinsic Whisker Muscle and Whisking Behavior , 2004, The Journal of Neuroscience.

[15]  A. Keller,et al.  Response properties of whisker-related neurons in rat second somatosensory cortex. , 2004, Journal of neurophysiology.

[16]  Joseph H. Solomon,et al.  Biomechanical models for radial distance determination by the rat vibrissal system. , 2007, Journal of neurophysiology.

[17]  D. Simons,et al.  Task- and subject-related differences in sensorimotor behavior during active touch. , 1995, Somatosensory & motor research.

[18]  Ben Mitchinson,et al.  Feedback control in active sensing: rat exploratory whisking is modulated by environmental contact , 2007, Proceedings of the Royal Society B: Biological Sciences.

[19]  Ford F. Ebner,et al.  Cortical Modulation of Spatial and Angular Tuning Maps in the Rat Thalamus , 2007, The Journal of Neuroscience.

[20]  D. H. Mellor,et al.  Real time , 1981 .

[21]  M. Brecht,et al.  Functional architecture of the mystacial vibrissae , 1997, Behavioural Brain Research.

[22]  F. Ebner,et al.  Temporal organization of multi-whisker contact in rats. , 2001, Somatosensory & motor research.

[23]  James F. Wilson,et al.  A Whisker Probe System for Shape Perception of Solids , 1995 .

[24]  F. Barth,et al.  Arthropod touch reception: spider hair sensilla as rapid touch detectors , 2001, Journal of Comparative Physiology A.

[25]  Daniel J Simons,et al.  Response properties of whisker-associated trigeminothalamic neurons in rat nucleus principalis. , 2003, Journal of neurophysiology.

[26]  D. Simons,et al.  Biometric analyses of vibrissal tactile discrimination in the rat , 1990, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[27]  H. Zeigler,et al.  Topography of rodent whisking--I. Two-dimensional monitoring of whisker movements , 2002, Somatosensory & motor research.

[28]  M. Castro-Alamancos,et al.  Spatiotemporal Gating of Sensory Inputs in Thalamus during Quiescent and Activated States , 2005, The Journal of Neuroscience.

[29]  E. Ahissar,et al.  Encoding of Vibrissal Active Touch , 2003, Neuron.

[30]  Russell H. Taylor,et al.  A miniature microsurgical instrument tip force sensor for enhanced force feedback during robot-assisted manipulation , 2003, IEEE Trans. Robotics Autom..

[31]  R. Bermejo, H. Philip Zeigler,et al.  “Real-time” monitoring of vibrissa contacts during rodent whisking , 2000, Somatosensory & motor research.