Visual attention mitigates information loss in small- and large-scale neural codes

• Brains are capacity-limited due to a finite number of neurons and stochastic synapses.
• Attention enhances relevant information at the expense of irrelevant information.
• Multiple attentional modulations are seen at the single-neuron or -voxel levels.
• Population-based stimulus reconstructions index net attention effects on neural codes.

The visual system transforms complex inputs into robust and parsimonious neural codes that efficiently guide behavior. Because neural communication is stochastic, the amount of encoded visual information necessarily decreases with each synapse. This constraint requires that sensory signals are processed in a manner that protects information about relevant stimuli from degradation. Such selective processing – or selective attention – is implemented via several mechanisms, including neural gain and changes in tuning properties. However, examining each of these effects in isolation obscures their joint impact on the fidelity of stimulus feature representations by large-scale population codes. Instead, large-scale activity patterns can be used to reconstruct representations of relevant and irrelevant stimuli, thereby providing a holistic understanding about how neuron-level modulations collectively impact stimulus encoding.