title: NEURONAL MODELING. Single-trial spike trains in parietal cortex reveal discrete steps during decision-making.
abstract: Neurons in the macaque lateral intraparietal (LIP) area exhibit firing rates that appear to ramp upward or downward during decision-making. These ramps are commonly assumed to reflect the gradual accumulation of evidence toward a decision threshold. However, the ramping in trial-averaged responses could instead arise from instantaneous jumps at different times on different trials. We examined single-trial responses in LIP using statistical methods for fitting and comparing latent dynamical spike-train models. We compared models with latent spike rates governed by either continuous diffusion-to-bound dynamics or discrete "stepping" dynamics. Roughly three-quarters of the choice-selective neurons we recorded were better described by the stepping model. Moreover, the inferred steps carried more information about the animal's choice than spike counts.
authors.affiliation: Center for Perceptual Systems, The University of Texas at Austin, Austin, TX 78712, USA. Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Latimer
authors.affiliation: Center for Perceptual Systems, The University of Texas at Austin, Austin, TX 78712, USA. Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Jacob L
authors.initials: JL
authors.lastname: Yates
authors.affiliation: Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA. Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA.
authors.forename: Miriam L R
authors.initials: ML
authors.lastname: Meister
authors.affiliation: Center for Perceptual Systems, The University of Texas at Austin, Austin, TX 78712, USA. Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA. Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA. Department of Psychology, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Huk
authors.affiliation: Center for Perceptual Systems, The University of Texas at Austin, Austin, TX 78712, USA. Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA. Department of Psychology, The University of Texas at Austin, Austin, TX 78712, USA. Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, NJ 08544, USA. pillow@princeton.edu.
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Pillow
mesh_terms: D000818:Animals; D002755:Choice Behavior / Q000502:physiology*; D003657:Decision Making / Q000502:physiology*; D008251:Macaca; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology*