This seminar will be held in the Jerome L. Greene Science Center on Columbia's Manhattanville campus (9th floor lecture hall). Columbia University's Intercampus Shuttle Service is the best way to travel between campuses.

In humans, high visual acuity is restricted to a small (~1°) region of the retina: the foveola. Even if the foveola covers less than 1% of the visual field, the stimulus within this region can be complex, particularly when examining natural scenes. What are the contributions of attention and eye movements in foveal vision?

Studying attention at this scale is challenging because small eye movements continuously shift the image on the retina, covering an area as large as the foveola itself. Furthermore, localizing the line of sight within a 1 degree region is challenging and beyond the capabilities of most eye-trackers. Thanks to a combination of techniques allowing for high-resolution recordings of eye position, retinal stabilization, and accurate gaze localization, we circumvented these challenges and examined how attention and visual exploration are controlled at the scale of the foveola.

Here Dr. Poletti and her lab show that fine spatial vision in the foveola is enhanced by means of three different mechanisms: (a) Covert shifts of attention. High-resolution attentional reallocations independent of eye movements improve vision at selected foveal locations. (b) Microsaccade preparation. Planning of microsaccades, saccades smaller than half a degree, enhances fine spatial vision at the microsaccade target location at the expenses of other nearby locations within the foveola. (c) Visual exploration. The visual system possesses not only a coarser priority map of the extrafoveal space to guide saccades, but also a finer grain priority map that is used to guide microsaccades once the region of interest is foveated. The precise repositioning of the preferred retinal locus by means of microsaccades enables visual exploration of foveal stimuli.

Her lab's findings show that, contrary to common intuition, simply placing a stimulus within the foveola is not sufficient for fine spatial vision; vision is the outcome of an orchestrated synergy of motor, cognitive and attentional factors at all levels, from the examination of visual scenes to the examination of detail.

Martina Poletti is an Assistant Professor in the Department of Neuroscience, Brain and Cognitive Sciences and a member of the Center for Visual Science at the University of Rochester. Before joining the University of Rochester she was a Research Assistant Professor in the Department of Psychological and Brain Sciences at Boston University. Dr. Poletti received her MS in Experimental Psychology from the University of Padova in Italy, and then a PhD in Cognitive and Neural Systems from Boston University in 2010. Her research lies at the intersection of perception, action, and attention. Dr. Poletti's work relies on a combination of visual psychophysics, high resolution eyetracking and gaze-contingent technology to investigate how attention and eye movements optimize foveal vision.

Those who wish to meet the speaker during their visit should contact Zikang Zhang (Goldberg Lab). For general inquiries please contact [email protected].

The Columbia Neuroscience Seminar series is a collaborative effort of Columbia's Zuckerman Institute, the Department of Neuroscience, the Doctoral Program in Neurobiology and Behavior and the Columbia Translational Neuroscience Initiative, and with support from the Kavli Institute for Brain Science.