Activity Correlations between Direction-Selective Retinal Ganglion Cells Synergistically Enhance Motion Decoding from Complex Visual Scenes

Neurons in sensory systems are often tuned to particular stimulus features. During complex naturalistic stimulation, however, multiple features may simultaneously affect neuronal responses, which complicates the readout of individual features. To investigate feature representation under complex stimulation, we studied how direction-selective ganglion cells in salamander retina respond to texture motion where direction, velocity, and spatial pattern inside the receptive field continuously change. We found that the cells preserve their direction preference under this stimulation, yet their direction encoding becomes ambiguous due to simultaneous activation by luminance changes. The ambiguities can be resolved by considering populations of direction-selective cells with different preferred directions. This gives rise to synergistic motion decoding, yielding more information from the population than the summed information from single-cell responses. Strong positive response correlations between cells with different preferred directions amplify this synergy. Our results show how correlated population activity can enhance feature extraction in complex visual scenes. [Display omitted] •Direction-selective ganglion cells respond to motion as well as luminance changes•This obscures the readout of direction from single cells under complex texture motion•Population decoding improves direction readout supralinearly over individual cells•Strong spike correlations further enhance readout through increased synergy Direction-selective retinal ganglion cells encode visual motion but also respond to luminance changes. Kühn and Gollisch report that this dual-feature sensitivity creates ambiguities for decoding complex motion stimuli. Population decoding resolves these ambiguities and provides a synergistic motion readout.