Biology subjects

Aagten-Murphy, D.

Publications and source records attributed to Aagten-Murphy, D..

3 recordsLinked to original sources

bioRxiv2021

Transsaccadic integration operates independently in different feature dimensions

Our knowledge about objects in our environment reflects an integration of current visual input with information from preceding gaze fixations. Such a mechanism may reduce uncertainty, but requires the visual system to determine which information obtained in different fixations should be combined or kept separate. To investigate the basis of this decision, we conducted three experiments. Participants viewed a stimulus in their peripheral vision, then made a saccade that shifted the object into the opposite hemifield. During the saccade, the object underwent changes of varying magnitude in two feature dimensions (Experiment 1: color and location, Experiments 2 and 3: color and orientation). Participants reported whether they detected any change and estimated one of the post-saccadic features. Integration of pre-saccadic with post-saccadic input was observed as a bias in estimates towards the pre-saccadic feature value. In all experiments, pre-saccadic bias weakened as the magnitude of the transsaccadic change in the estimated feature increased. Changes in the other feature, despite having a similar probability of detection, had no effect on integration. Results were quantitatively captured by an observer model where the decision whether to integrate information from sequential fixations is made independently for each feature and coupled to awareness of a feature change.

neuroscience↗

bioRxiv2019

Visual landmarks calibrate auditory space across eye movements

Visual objects that are present both before and after eye movements can act as landmarks, aiding localization of other visual stimuli. We investigated whether visual landmarks would also influence auditory localization - despite participants head position remaining unchanged. Participants made eye-movements from central fixation to a peripheral visual landmark, which either remained stationary or was covertly displaced. Following the movement, participants judged whether a stimulus (auditory or visual) was shifted in location relative to before the movement. Visual localization estimates shifted along with the landmark, although the landmark displacement itself went unnoticed. Interestingly, auditory localization estimates were also displaced. Thus, despite identical auditory input reaching the ears, two auditory stimuli originating from the same position were perceived as spatially distinct when the visual landmark moved. These results are consistent with the idea that auditory spatial information is encoded within an eye-centered reference frame and subject to spatial recalibration by visual landmarks. HighlightsO_LIVisual landmarks affect stimulus localization across eye movements C_LIO_LIWe show this also for auditory stimuli, even when the head remains stable C_LIO_LIDue to a visual landmark displacement, identical auditory stimuli are perceived as shifted C_LIO_LIThis suggests that auditory space is calibrated on eye-centered maps across saccades C_LI

neuroscience↗

bioRxiv2019

Sounds are remapped across saccades

To achieve visual space constancy, our brain remaps eye-centered projections of visual objects across saccades. Here, we measured saccade trajectory curvature following the presentation of visual, auditory, and audiovisual distractors in a double-step saccade task to investigate if this stability mechanism also accounts for localized sounds. We found that saccade trajectories systematically curved away from the position at which either a light or a sound was presented, suggesting that both modalities are represented in eye-centered oculomotor centers. Importantly, the same effect was observed when the distractor preceded the execution of the first saccade. These results suggest that oculomotor centers keep track of visual, auditory and audiovisual objects by remapping their eye-centered representations across saccades. Furthermore, they argue for the existence of a supra-modal map which keeps track of multi-sensory object locations across our movements to create an impression of space constancy.

neuroscience↗