EFFICIENT PROCESSING IN THE RETINA

Recent work suggests that visual information can be encoded by the activities of small proportions of many available units [1]. This can be seen as energetically efficient [2] as few outputs are strongly active at any time. An image coding model is presented to examine the effect of an efficient use of synapses rather than outputs. The model has two main parameters, the input:output ratio r, and a total weight energy budget k. It was found that for a given number of output units there is a weight budget that leads to optimal efficiency, balancing network performance and energy expenditure. More outputs can achieve higher efficiency, but this requires a higher budget. The resulting filters have center surround organization with strong quantitative similarities to retinal ganglion cell receptive fields. This work contributes to a common energy efficiency interpretation of sensory and cortical level processing in the visual system.