Visual Orientation and Directional Selectivity through Thalamic Synchrony

• Authors: Garrett Stanley, Emory University; Jianzhong Jin, State University of New York; Yushi Wang, State University of New York; Gaëlle Desbordes, Georgia Institute of Technology; Qi Wang, Georgia Institute of Technology; Michael J. Black, Max Planck Institute for Intelligent Systems; Jose-Manuel Alonso, State University of New York
• Journal Title: Journal of Neuroscience Nursing
• Volume: Volume 32, Number 26
• Publisher: Lippincott, Williams & Wilkins | 2012-06-27, Pages 9073-9088
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1523/JNEUROSCI.4968-11.2012
• Subjects: Engineering, Biomedical; Biology, General
• Keywords: Science & Technology; Life Sciences & Biomedicine; Neurosciences; Neurosciences & Neurology; NEUROSCIENCES; LATERAL GENICULATE-NUCLEUS; CATS STRIATE CORTEX; RECEPTIVE-FIELD PROPERTIES; NEURONS IN-VIVO; SIMPLE CELLS; NATURAL SCENES; FEEDFORWARD INHIBITION; COINCIDENCE DETECTION; SOMATOSENSORY CORTEX; STIMULUS SELECTIVITY

Abstract

Thalamic neurons respond to visual scenes by generating synchronous spike trains on the timescale of 10-20 ms that are very effective at driving cortical targets. Here we demonstrate that this synchronous activity contains unexpectedly rich information about fundamental properties of visual stimuli. We report that the occurrence of synchronous firing of cat thalamic cells with highly overlapping receptive fields is strongly sensitive to the orientation and the direction of motion of the visual stimulus. We show that this stimulus selectivity is robust, remaining relatively unchanged under different contrasts and temporal frequencies (stimulus velocities). A computational analysis based on an integrate-and-fire model of the direct thalamic input to a layer 4 cortical cell reveals a strong correlation between the degree of thalamic synchrony and the nonlinear relationship between cortical membrane potential and the resultant firing rate. Together, these findings suggest a novel population code in the synchronous firing of neurons in the early visual pathway that could serve as the substrate for establishing cortical representations of the visual scene.