Reward Signals Sweep the Entire Mouse Visual Cortex

When a mouse gets a drop of water for noticing a change on a screen, its entire visual cortex reacts — not just the primary visual area where reward-related activity had been studied before, but every one of the six cortical areas that process sight. That is the central finding of a new study posted in Frontiers in Behavioral Neuroscience, which mined the Allen Visual Behavior Neuropixels dataset to ask whether the visual cortex as a whole carries a dedicated reward signal. Across 103 recording sessions in which head-fixed mice performed a visual change-detection task, the researchers aligned the activity of 54,039 neurons to the moment of reward delivery and found that reward modulation is a cortex-wide phenomenon, not a specialty of a single area.

The team was deliberately strict about what counted as reward coding. A neuron’s peri-reward response had to be reproducible, verified with a split-half test against an inter-spike-interval null distribution, and it had to be reward-specific in two separate contrasts: active behavior versus passive replay of the same stimuli, and hit trials versus miss trials. Only units passing both filters were retained. This double screen matters because visual cortex activity can reflect images, movement, or arousal rather than reward itself; requiring the modulation to survive both contrasts isolates a signal tied to the reward event. Even under this conservative criterion, a substantial cohort of reward-modulated neurons emerged in all six visual areas.

The dominant sign of that modulation was surprising: suppression. Most reward-modulated units reduced their firing around reward delivery rather than increasing it, and the strength of this suppressive predominance fell off systematically along the functional hierarchy of the visual system — strongest in primary visual cortex and progressively weaker in higher-order areas. The effect was also concentrated in layer 4 and in narrow-spiking neurons. Together these patterns suggest that reward arrives in the visual cortex largely as a dampening of activity, anchored early in the cortical hierarchy, rather than as the excitatory burst one might naively expect from a positive event.

At the population level, the reward-modulated neurons behaved differently from their neighbors in a measurable way: in every visual area, this cohort operated in a lower-variability regime than the surrounding population. The researchers then decomposed the individual peri-reward response profiles and found that they did not sort into discrete categories. Instead, the temporal shapes formed a shared continuum, common across areas, within which one feature stood out geographically: an anticipatory ramp of activity building up before reward delivery was most prevalent in primary visual cortex.

The authors conclude that the mouse visual cortex carries a distributed, predominantly suppressive and anticipatory reward signal — hierarchically graded across areas, yet built from a shared temporal repertoire. The work is a correlative analysis of an existing dataset in head-fixed mice performing a trained change-detection task, so it establishes how reward-related activity is organized across the visual cortical hierarchy rather than testing any intervention, and the findings apply to the mouse visual system under these task conditions. Even so, the study broadens the map considerably: reward-related signaling, previously documented almost entirely in primary visual cortex under trained associative paradigms, now appears to be a system-wide feature of the visual cortex, with suppression as its dominant mode and a graded structure that mirrors the cortex’s own hierarchy.

Subject of Research: Reward-related neural signaling across the six areas of the mouse visual cortex during a change-detection task

Article Title: Reward coding across mouse visual cortical areas

Article References: Souza, J. P. G., Vieira, A. B., Ventura, V., de Lima, J. C., Arcanjo, G., de Paula, E. V., Sales, M., Souza, A. B. A., Alvarez-Jácobo, J. E., Fontenele, A. J., Aguiar, L. A. A., de Santana, M. A., Sousa, N., & de Vasconcelos, N. A. P. (2026). Reward coding across mouse visual cortical areas. Frontiers in Behavioral Neuroscience, 20, 1944695. https://doi.org/10.3389/fnbeh.2026.1944695

Image Credits: AI Generated

DOI: 10.3389/fnbeh.2026.1944695

Keywords: visual cortex, reward coding, Neuropixels, mouse neuroscience, cortical hierarchy, neural suppression, primary visual cortex, change-detection task, Allen Brain Observatory, layer 4, anticipatory activity, spike train analysis