Purchase this article with an account.
Kevin DeSimone, Kartik Sreenivasan, Clayton Curtis; Spatially specific delay period activity in the human superior colliculus.. Journal of Vision 2018;18(10):245. doi: 10.1167/18.10.245.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The superior colliculus (SC) is a key node in a distributed oculomotor network and mediates orienting behaviors such as saccadic eye-movements and gaze shifts. The SC is a laminar structure sitting atop the brainstem and contains two tightly registered retinotopic maps: a visual map in the superficial layer, and a motor map in the intermediate and deep layers representing the angle and amplitude of saccades (Wurtz & Albano, 1980; Sparks, 1986). However, this classical view of the response properties of the SC has been challenged by pharmacological inactivation of the deep layers of the SC in the macaque (McPeek & Keller, 2004; Lovejoy & Krauzlis, 2010). We sought to examine the extent to which the human SC is able to maintain representations of behavioral goals beyond simpler visual and/or motor responses. We hypothesized that the SC acts as a topographic map of spatial priority (Fecteau & Munoz, 2006), and predicted that we should find spatially specific representations of behavioral goals in human SC during a delay period between visual stimulation and motor execution. To test this, we used fMRI to measure SC activity while participants performed memory-guided saccades. We used an inverted encoding model (Sprague & Serences, 2013) to characterize the spatial tuning of SC activity during the task. First, we found robust and spatially specific univariate persistent activity during the delay period following presentation of the visual cue but prior to execution of the saccade. Second, we found that the multivariate delay period activity in the SC was tuned for the location of the memory-guided saccade but not the location of the visual cue or visually-guided saccade. These findings suggest that the human SC maintains a representation of task-relevant behavior and thus plays a role in cognition.
Meeting abstract presented at VSS 2018
This PDF is available to Subscribers Only