Role of early visual cortex in trans-saccadic memory of object features

Area of Science:

• Neuroscience
• Cognitive Science
• Visual Perception

Background:

• Early visual cortex (EVC) is known to participate in visual feature memory and location updating across saccades.
• The specific role of EVC in the trans-saccadic integration of object features, however, remains unclear.

Purpose of the Study:

• To investigate the causal role of EVC in updating object features relative to gaze during trans-saccadic perception.
• To test the hypothesis that EVC involvement in updating object features is disrupted when saccades remap object representations into perturbed EVC sites.

Main Methods:

• Applied transcranial magnetic stimulation (TMS) to EVC clusters localized by fMRI, corresponding to specific visual quadrants (VQs).
• Subjects performed a visual memory task involving object orientation change detection, either maintaining fixation or making horizontal saccades.
• TMS pulses were delivered during pre-, peri-, and postsaccade intervals while participants fixated or executed saccades.

Main Results:

• TMS over EVC significantly reduced performance when saccades remapped a remembered object into the stimulated VQ, particularly for leftward saccades.
• No performance effects were observed when fixation was maintained, saccades kept the object within the same VQ, or the unstimulated EVC quadrant was targeted.
• Larger saccades showed a more pronounced suppression effect, suggesting a role in gaze-centered updating of object features.

Conclusions:

• These findings provide causal evidence that EVC is involved in the gaze-centered updating of object features for trans-saccadic memory.
• The results support the notion that EVC contributes to integrating object information across saccadic eye movements, influencing perception.