OHBM 2022 | 2634 | Talk | Brigitte Kaufmann | The superior colliculus & its role in visual attenti…
Title: The superior colliculus & its role in visual attention: isolated SC lesion leads to neglect.
Session: Talk
Speaker: Brigitte Kaufmann
Animal models of visual attention, suggest that in humans the final downstream neural substrate in the visuo-motor pathway, directing visual attention and the eyes to our surrounding, is the midbrain superior colliculus (SC). In humans, studies with large lesions of the midbrain involving the SC exist but do not provide direct evidence of the importance of the SC in attention an whether or not an isolated SC lesion produces contralateral visual neglect. Here, we report the case of a single patient with a small abscess confined to the right SC, aiming to further investigate and precise the model. Video-oculography during Free Visual Exploration (FVE) demonstrates that in humans an isolated SC lesion results in contralesional neglect. More precisely, 3 months after diagnosis and therapy, the mean gaze position was shifted 2.14° towards the right, indicating a neglect towards the left. Compared to 15 age-matched healthy controls, the patient showed a significant leftward neglect with fewer fixations and less time spent in the contralesional , as well as more fixations and more time spent in the ipsilesional space. Additionally, neglect-typical significant rightward bias of early orientation, was found.A follow-up measure at 9 months revealed neglect remission in the mean gaze position. However, other parameters showed the persistence of neglect; less time spent left and more time spent on the right. Furthermore, the patient showed a persistence of rightward early orientation.The present case study, is the first of it's kind to provide direct evidence for the important role of the SC in visual attention, by showing that a lesion of the SC leads to neglect. Indeed, our results support the view that the SC is not only a node in the descending pathway of visual attention, but also an important neural substrate of the human visual attention control itself.
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