Abstract
Eye-centered (egocentric) and landmark-centered (allocentric) visual signals influence spatial cognition, navigation, and goal-directed action, but the neural mechanisms that integrate these signals for motor control are poorly understood. A likely candidate for egocentric/allocentric integration in the gaze control system is the supplementary eye fields (SEF), a mediofrontal structure with high-level “executive” functions, spatially tuned visual/motor response fields, and reciprocal projections with the frontal eye fields (FEF). To test this hypothesis, we trained two head-unrestrained monkeys (Macaca mulatta) to saccade toward a remembered visual target in the presence of a visual landmark that shifted during the delay, causing gaze end points to shift partially in the same direction. A total of 256 SEF neurons were recorded, including 68 with spatially tuned response fields. Model fits to the latter established that, like the FEF and superior colliculus (SC), spatially tuned SEF responses primarily showed an egocentric (eye-centered) target-to-gaze position transformation. However, the landmark shift influenced this default egocentric transformation: during the delay, motor neurons (with no visual response) showed a transient but unintegrated shift (i.e., not correlated with the target-to-gaze transformation), whereas during the saccade-related burst visuomotor (VM) neurons showed an integrated shift (i.e., correlated with the target-to-gaze transformation). This differed from our simultaneous FEF recordings (Bharmauria et al., 2020), which showed a transient shift in VM neurons, followed by an integrated response in all motor responses. Based on these findings and past literature, we propose that prefrontal cortex incorporates landmark-centered information into a distributed, eye-centered target-to-gaze transformation through a reciprocal prefrontal circuit.
Highlights
The brain integrates egocentric and allocentric visual cues to guide goal-directed behavior (Goodale and Haffenden, 1998; Ball et al, 2009; Chen et al, 2011; Karimpur et al, 2020)
We find that (1) supplementary eye fields (SEF) neurons predominantly possess an eye-centered transformation from target-togaze coding and (2) landmark-centered information is integrated into this transformation, but through somewhat different cellular mechanisms than the frontal eye fields (FEF) (Bharmauria et al, 2020)
If allocentric weight (AW) equals 0, it implies no influence of the shifted landmark, whereas if AW equals 1 it indicates a complete influence of landmark shift on the gaze
Summary
The brain integrates egocentric (eye-centered) and allocentric (landmark-centered) visual cues to guide goal-directed behavior (Goodale and Haffenden, 1998; Ball et al, 2009; Chen et al, 2011; Karimpur et al, 2020). One clue is that humans aim reaches toward some intermediate point between conflicting egocentric/allocentric cues, suggesting Bayesian integration (Bridgeman et al, 1997; Lemay et al, 2004; Neely et al, 2008; Byrne and Crawford, 2010; Fiehler et al, 2014; Klinghammer et al, 2017). Neuroimaging studies suggest this may occur in parietofrontal cortex (Chen et al, 2018) but could not reveal the cellular mechanisms. Similar behavior has been observed in the primate gaze system (Li et al, 2017), suggesting this system can be used to study egocentric/allocentric integration
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
