Without an accurate knowledge of the rotation of one's own eyes in the orbit, it would be virtually impossible to reach to a cup, to match a voice to a face in a crowd based on their common location or to recognize large visual scenes from multiple retinal snapshots. Retinal information is insufficient for an accurate perception of object location.
The same retinal projection can correspond to different locations in the visual space, depending on the direction of gaze.
Gaze direction helps align vision with the motor space and with the other sensory modalities, such as touch or audition.
How do we attend? How do we reach? How do we piece together visual information from multiple retinal snapshots into a written sentence when reading a book or into a map of the environment when navigating an unfamiliar city? Research in my lab aims to answer these questions by focusing on basic sensory and motor signals that lie at the foundation of spatial cognition.
A former PhD student, Barthel Odoj, and I reported that an eye position signal in the somatosensory cortex (eye proprioception or oculoproprioception) is specific for spatial attention. This signal is less important for locating external objects (where to reach) and more important for allocating internal priorities for perception (where to attend).
This discovery is exciting not only because it shows that a basic sensorimotor signal can play a selective role in cognition rather than in movement control, but also because it indicates a potential disease mechanism in spatial neglect. Spatial neglect is a common disorder in stroke survivors characterized by a lateral displacement in the focus of attention, often to the right of the body midline. We found that when patients with spatial neglect are given an attention cue, they do not attend to its exact location, but rather, slightly to the right of it. This error is present even in their right, "normal", hemispace. Could a disease mechanism in spatial neglect be an error in the cortical gaze direction signal? Our research predicts that such an error could selectively impact the brain's attentional priority map. Could one treat spatial neglect by targetting the oculoproprioceptive signal using repetitive transcranial magnetic stimulation?
University of St Andrews
School of Psychology and Neuroscience
St Mary's College
last updated by Daniela on 29.06.2023, 11:35
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