| Title | Coding of stimulus sequences by population responses in visual cortex. | | Author(s) | Benucci A, Ringach DL, Carandini M | | Institution | University College London Institute of Ophthalmology, University College London, London, UK. a.benucci@ucl.ac.uk | | Source | Nat Neurosci 2009 Oct; 12(10):1317-24. | | MeSH | Action Potentials
Animals
Brain Mapping
Cats
Electrodes
Fluorescent Dyes
Membrane Potentials
Models, Neurological
Neurons
Orientation
Photic Stimulation
Predictive Value of Tests
Reaction Time
Time Factors
Visual Cortex
| | Abstract | Neuronal populations in sensory cortex represent time-changing sensory input through a spatiotemporal code. What are the rules that govern this code? We measured membrane potentials and spikes from neuronal populations in cat visual cortex (V1) using voltage-sensitive dyes and electrode arrays. We first characterized the population response to a single orientation. As response amplitude grew, the population tuning width remained constant for membrane potential responses and became progressively sharper for spike responses. We then asked how these single-orientation responses combine to code for successive orientations. We found that they combined through simple linear summation. Linearity, however, was violated after stimulus offset, when responses exhibited an unexplained persistence. As a result of linearity, the interactions between responses to successive stimuli were minimal. Our results indicate that higher cortical areas may reconstruct the stimulus sequence from V1 population responses through a simple instantaneous decoder. Therefore, spatial and temporal codes in area V1 operate largely independently. | | Language | eng | | Pub Type(s) | Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
| | PubMed ID | 19749748 |
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