Search for: All records

Sub-additivity and variability are ubiquitous response motifs in primary visual cortex (V1). Response sub-additivity provides a sign of the brain processes that enable us to construct useful interpretations of the visual environment (i.e., nonlinear input transformations), while response variability provides a sign of the brain processes that limit the precision with which we can do this (i.e., neural information loss). Historically, these two motifs have been studied independently of each other. Yet, there is increasing evidence that experimen- tal manipulations that elicit response sub-additivity often also quench response variability. Here we provide a unifying review of these phenomena, suggesting that response sub-additivity and variability quenching may have a common origin. We review empirical findings as well as recent model-based insights into the functional operations, computational objectives, and circuit mechanisms underlying V1 activity. Although these model- ing approaches address different aspects of cortical activity, they all predict that response sub-additivity and variability quenching will often co-occur. Response sub-additivity and variability quenching are not limited to V1 but are widespread cortical phenomena. Many of the insights we review generalize to other cortical areas, suggesting that the connection between response sub-additivity and variability quenching may be a canonical motif across cortex.