Visual working memory representations bias attention more when they are the target of an action plan.

Attention has frequently been regarded as an emergent property of linking sensory representations to action plans. It has recently been proposed that similar mechanisms may operate within visual working memory (VWM), such that linking an object in VWM to an action plan strengthens its sensory memory representation, which then expresses as an attentional bias. Here we directly tested this hypothesis by comparing attentional biases induced by VWM representations which were the target of a future action, to those induced by VWM representations that were equally task-relevant, but not the direct target of action. We predicted that the first condition would result in a more prioritized memory state and hence stronger attentional biases. Specifically, participants memorized a geometric shape for a subsequent memory test. At test, in case of a match, participants either had to perform a grip movement on the matching object (action condition), or perform the same movement, but on an unrelated object (control condition). To assess any attentional biases, during the delay period between memorandum and test, participants performed a visual selection task in which either the target was surrounded by the memorized shape (congruent trials) or a distractor (incongruent trials). Eye movements were measured as a proxy for attentional priority. We found a significant interaction for saccade latencies between action condition and shape congruency, reflecting more pronounced VWM-based attentional biases in the action condition. Our results are consistent with the idea that action plans prioritize sensory representations in VWM.

Three-Dimensional Representation of Motor Space in the Mouse Superior Colliculus.

From the act of exploring an environment to that of grasping a cup of tea, animals must put in register their motor acts with their surrounding space. In the motor domain, this is likely to be defined by a register of three-dimensional (3D) displacement vectors, whose recruitment allows motion in the direction of a target. One such spatially targeted action is seen in the head reorientation behavior of mice, yet the neural mechanisms underlying these 3D behaviors remain unknown. Here, by developing a head-mounted inertial sensor for studying 3D head rotations and combining it with electrophysiological recordings, we show that neurons in the mouse superior colliculus are either individually or conjunctively tuned to the three Eulerian components of head rotation. The average displacement vectors associated with motor-tuned colliculus neurons remain stable over time and are unaffected by changes in firing rate or the duration of spike trains. Finally, we show that the motor tuning of collicular neurons is largely independent from visual or landmark cues. By describing the 3D nature of motor tuning in the superior colliculus, we contribute to long-standing debate on the dimensionality of collicular motor decoding; furthermore, by providing an experimental paradigm for the study of the metric of motor tuning in mice, this study also paves the way to the genetic dissection of the circuits underlying spatially targeted motion.