Abstract
Spatial attention, the ability to select and preferentially process the most important stimulus location in the environment at any instant, is critical for adaptive behavior. To uncover neural circuit mechanisms underlying spatial attention control, the use of a genetically tractable system is critical. As a first step in this endeavor, here, we develop in freely behaving mice, parameterized paradigms for visuospatial attention. Using a touchscreen-based operant set-up, we study, explicitly, endogenous as well as exogenous control of visuospatial attention in mice using, respectively, a spatial expectation task and a flanker task. In the spatial expectation task, a single grating stimulus was presented at one of two possible locations for mice to discriminate its orientation. We manipulated the probability of stimulus occurrence of each location, and found that, compared to blocks in which the stimulus was presented with equal probability at two locations, in blocks when the stimulus was presented with 90% probability at one of the locations, mice exhibited better discrimination sensitivity (d’) and faster reaction time (RT) at that location. We found opposite effects at the low-probability location. In the flanker task, two grating stimuli were presented simultaneously. The target was always at the same location, and mice were rewarded based on their responses to target orientation. The second stimulus (i.e. flanker), was also a grating whose orientation was either congruent (same) or incongruent (orthogonal) to that of the target. We systemically manipulated the contrast of the flanker, and found that mice exhibited deteriorated d’ and slower RT for high-contrast incongruent flankers. Our results reveal systematic changes in d’ as well as RT driven either by learned expectation (endogenous influence) or stimulus salience (exogenous influence), consistent with results from similar human studies. Taken together, we demonstrate that mice exhibit behavioral signatures of visuospatial attention similar to that of humans.
Acknowledgement: JHU Catalyst Award and NIH R03HD093995