title: Vibrotactile discrimination in the rat whisker system is based on neuronal coding of instantaneous kinematic cues.
abstract: Which physical parameter of vibrissa deflections is extracted by the rodent tactile system for discrimination? Particularly, it remains unclear whether perception has access to instantaneous kinematic parameters (i.e., the details of the trajectory) or relies on temporally integration of the movement trajectory such as frequency (e.g., spectral information) and intensity (e.g., mean speed). Here, we use a novel detection of change paradigm in head-fixed rats, which presents pulsatile vibrissa stimuli in seamless sequence for discrimination. This procedure ensures that processes of decision making can directly tap into sensory signals (no memory functions involved). We find that discrimination performance based on instantaneous kinematic cues far exceeds the ones provided by frequency and intensity. Neuronal modeling based on barrel cortex single units shows that small populations of sensitive neurons provide a transient signal that optimally fits the characteristic of the subject's perception. The present study is the first to show that perceptual read-out is superior in situations allowing the subject to base perception on detailed trajectory cues, that is, instantaneous kinematic variables. A possible impact of this finding on tactile systems of other species is suggested by evidence for instantaneous coding also in primates.
authors.affiliation: Werner Reichardt Center for Integrative Neuroscience, Systems Neuroscience, Hertie Institute for Clinical Brain Research, Department of Cognitive Neurology, Eberhard Karls University, Tübingen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Waiblinger
authors.affiliation: Werner Reichardt Center for Integrative Neuroscience, Systems Neuroscience, Hertie Institute for Clinical Brain Research, Department of Cognitive Neurology, Eberhard Karls University, Tübingen, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Brugger
authors.affiliation: Werner Reichardt Center for Integrative Neuroscience, Systems Neuroscience, Hertie Institute for Clinical Brain Research, Department of Cognitive Neurology, Eberhard Karls University, Tübingen, Germany.
authors.forename: Cornelius
authors.initials: C
authors.lastname: Schwarz
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003463:Cues; D004192:Discrimination, Psychological / Q000502:physiology*; D004567:Electrodes, Implanted; D005260:Female; D008839:Microelectrodes; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology; D011594:Psychometrics; D011601:Psychophysics; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000502:physiology*; D055698:Touch Perception / Q000502:physiology*; D014732:Vibration; D014738:Vibrissae / Q000502:physiology*
keywords: head-fixed rat; neuronal coding; primary somatosensory cortex; psychophysics; tactile perception