The spatial relations between stimulus and response determine an absolute visuo-haptic calibration in...

Area of Science:

• Cognitive Neuroscience
• Motor Control
• Human Perception

Background:

• Pantomime-grasps, actions towards absent objects, are thought to rely on visual perception.
• Previous studies suggest pantomime-grasps differ kinematically from real grasps, implying visual mediation.
• These imagined actions lack haptic feedback regarding target size, a key difference from naturalistic grasps.

Purpose of the Study:

• To investigate the influence of experimenter-induced haptic feedback on pantomime-grasps.
• To determine if haptic feedback affects the sensory information used for spatially dissociated and no-target pantomime-grasps.
• To examine adherence to Weber's law in pantomime-grasps under different feedback conditions.

Main Methods:

• Four experiments were conducted to assess the role of haptic feedback.
• Just-noticeable-difference scores were calculated to evaluate psychophysical properties.
• Participants performed spatially dissociated and no-target pantomime-grasps with and without induced haptic feedback.

Main Results:

• Spatially dissociated pantomime-grasps with haptic feedback adhered to Weber's law.
• No-target pantomime-grasps violated Weber's law, even with haptic feedback.
• Haptic feedback differentially impacted the two types of pantomime-grasps.

Conclusions:

• Top-down control in spatially dissociated pantomime-grasping prioritizes visual information, independent of haptic feedback.
• Lower top-down demands in no-target pantomime-grasps allow haptic feedback to aid in absolute visuo-haptic calibration.
• Haptic feedback plays a distinct role in mediating different types of imagined grasping actions.