Attentional sampling between eye channels

Eye channels refer to processing of visual information from each eye before integration in V1 (Hubel & Wiesel, 1977). During development, inputs from both eyes initially overlap in the visual cortex. However, through competitive interactions between neurons with different ocular preferences, the inputs become segregated into distinct columns (Hensch, 2005). This process involves competition between neurons representing the left and right eyes (Tagawa et al., 2005). When the visual system processes several inputs, competitive and suppressive interactions are foundational to the neuronal response. Attention, which is the biasing selection towards relevant parts a scene, was previously found to be implemented through rhythmic brain activity. Similar to brain rhythms, also performance, fluctuates over time. Specifically, when more than one object is attended, objects are selected in alternation. In this study we sought to investigate whether this phenomenon, called attentional sampling, also emerges in the unconscious selection process among eye channels. We presented a display with a single object to both eyes and manipulated the presentation of a cue and a detection target to either both eyes or to the different eyes. We assume that presenting a cue to one eye biases the selection process to content presented to that eye. Target detection fluctuated at 8 Hz under the binocular condition, and at 4 Hz when the dominant eye was cued. This is consistent with findings reporting that competition between receptive fields leads to sampling. The findings also demonstrates that sampling in light of competition does not rely on aware processes.