The Faculty


Neural coding and the neural basis of perception


1996-2003 Research Assistant, Department of Psychology, University of North Carolina.
2003-2006 Postdoctoral Fellow, Krieger Mind/Brain Institute, Johns Hopkins University.
2006-2009 Associate Research Scientist, Krieger Mind/Brain Institute, Johns Hopkins University.
2009-Assistant Professor, Department of Organismal Biology and Anatomy, University of Chicago.


2002 Baughman Dissertation Research Award for innovative dissertation projects

Research Interests

Tactile sensation is critical for effective object manipulation, but current prosthetic upper limbs make no provision for delivering haptic feedback to the user. For individuals who require use of prosthetic limbs, this lack of feedback transforms a mundane task into one that requires herculean concentration and effort. Although vibrotactile motors and sensory substitution devices can be used to convey gross sensations, a direct neural interface is required to provide detailed and intuitive sensory feedback. In view of this, the new generation of neuroprostheses will enable electrical stimulation of somatosensory neurons in the peripheral nervous system.  My research background makes me uniquely qualified to address this problem. First, I have published a number of papers in which I characterize how a variety of sensory dimensions are encoded in the responses of neurons in primary somatosensory cortex of primates. Specifically, I have investigated how neurons in the brain encode the shape of an object grasped in the hand and its motion across the skin. I am currently working on how surface texture is represented in the brain. Second, I have published a number of studies in which I characterize the response properties of mechanoreceptive afferents and describe quantitatively how information about various sensory dimensions is conveyed in the responses of populations of afferents. For instance, I have revealed the peripheral neural code for contact force, of critical importance to understanding how this dimension is represented in the brain. Third, I have developed, over the last decade, the state-of-the-art in models of mechanotransduction, with which I can predict with millisecond accuracy the responses of mechanoreceptive afferents to arbitrarily complex spatio-temporal stimuli impinging upon the skin, models that far surpass any other available models, both in the accuracy of their predictions and in their versatility; I have also shown how these models can be used to convey verisimilar percepts through electrical stimulation of the peripheral nerve. Again, understanding how sensory information is represented in the nerve will inform how it is represented in the brain, and ultimately, how to mimic the native neural representations. Fourth, I have been involved with Revolutionizing Prosthetics (Phases 2 and 3), a research program run out of the Johns Hopkins Applied Physics laboratory and funded by the Defense Advanced Research Projects Agency, for which I have been investigating methods to convey sensory information through microstimulation of the somatosensory cortex. The behavioral assays used in my cortical microstimulation studies can readily be applied to test approaches to conveying feedback across a variety of conditions.

Peer-reviewed publications

  1. Bensmaia, S. & Hollins, M. (2000). Complex tactile waveform discrimination, Journal of the Acoustical Society of America, 108, 1236-1245.
  2. Hollins, M., Bensmaia, S., Karlof, K., & Young, F. (2000). Individual Differences in Perceptual Space for Tactile Textures: Evidence from Multidimensional Scaling, Perception & Psychophysics, 62, 1534-1544.
  3. Hollins, M., Bensmaia, S., & Washburn, S. (2001). Vibrotactile adaptation impairs discrimination of fine, but not coarse, textures, Somatosensory and Motor Research, 18, 253-262.
  4. Bensmaia, S. (2002). A transduction model of the Meissner corpuscle, Mathematical Biosciences, 176, 203-217.
  5. Hollins, M., Bensmaia, S. J., & Roy, E. A. (2002). Vibrotaction and texture perception, Behavioural Brain Research, 135, 51-56.
  6. Bensmaia, S.J. & Hollins, M (2003). The vibrations of texture, Somatosensory and motor research, 20, 33-43.
  7. Bensmaia, S.J., Hollins, M., & Yau. J. (2005). Vibrotactile frequency and intensity information in the Pacinian system: a psychophysical model, Perception & Psychophysics, 67, 828-841.
  8. Bensmaia, S.J. & Hollins, M. (2005). Pacinian representation of fine surface texture, Perception & Psychophysics, 67, 842-854.
  9. Bensmaia, S.J., Leung, Y.Y.M., Hsiao, S.S. & Johnson, K.O.  (2005). Vibratory adaptation of cutaneous mechanoreceptive afferents, Journal of Neurophysiology, 94, 3023-3036.
  10. Leung, Y.Y.M., Bensmaia, S.J., Hsiao, S.S. & Johnson, K.O. (2005). Time course of vibratory adaptation and recovery in cutaneous mechanoreceptive afferents, Journal of Neurophysiology, 94, 3037-3045.
  11. Bensmaia, S.J., Craig, J.C., Yoshioka, T., & Johnson, K.O. (2006). SA1 and RA responses to static and vibrating gratings, Journal of Neurophysiology, 95, 1771-1782.
  12. Bensmaia, S.J., Craig, J.C., & Johnson, K.O. (2006). Temporal factors in tactile spatial acuity: Evidence for RA interference in fine spatial processing, Journal of Neurophysiology, 95, 1783-1791.
  13. Sripati, A.P., Bensmaia, S.J., & Johnson, K.O. (2006). A continuum mechanical model for mechanoreceptive afferent responses to indented spatial patterns, Journal of Neurophysiology, 95, 3852-3864.
  14. Bensmaia, S.J., Killebrew, J.H. & Craig, J.C. (2006). Influence of visual motion on tactile motion perception, Journal of Neurophysiology, 96, 1625-1637.
  15. Killebrew, J.H., Bensmaia, S.J., Dammann, J.F., Denchev, P., Hsiao, S.S., Craig, J.C. & Johnson, K.O. (2007). A dense array stimulator to generate arbitrary spatio-temporal tactile stimuli, Journal of Neuroscience Methods, 161, 62-74.
  16. Yoshioka, T., Bensmaia, S.J., Craig, J.C., & Hsiao, S.S. (2007). Texture perception through direct and indirect touch: An analysis of perceptual space for tactile textures in two modes of exploration, Somatosensory and Motor Research, 24, 53-70.
  17. Muniak, M.A., Ray, S., Hsiao, S.S., Dammann, J.F., & Bensmaia, S.J. (2007). The neural coding of stimulus intensity: linking the population response of mechanoreceptive afferents with psychophysical behavior, Journal of Neuroscience, 27, 11687-11699.
  18. Bensmaia, S.J., Hsiao, S.S., Denchev, P.V., Killebrew, J.H., & Craig J.C. (2008). The tactile perception of stimulus orientation, Somatosensory and Motor Research, 25, 49-59.