Getting completely turned around: how disorientation impacts subjective straight ahead

Area of Science:

• Neuroscience
• Human sensorimotor control
• Spatial cognition

Background:

• The egocentric reference frame is crucial for spatial orientation and navigation.
• Previous research suggests a stable egocentric frame, but its susceptibility to conflicting sensory information is not fully understood.

Purpose of the Study:

• To investigate the stability of the egocentric reference frame under conditions of combined sensory blockade and physical motion.
• To determine if physical motion, in addition to sensory blockade, impacts the variability of subjective straight ahead (SSA) perception.

Main Methods:

• Participants performed a task to indicate subjective straight ahead (SSA).
• Experimental conditions included external sensory blockade alone versus combined sensory blockade with whole-body rotations.
• A temporal delay control condition was also implemented.

Main Results:

• Increased variability in reporting SSA was observed when whole-body rotations were combined with external sensory blockade, compared to sensory blockade alone.
• This increased variability was not observed when a temporal delay matched to the rotation duration was used instead of actual rotation.
• These findings indicate that physical motion significantly disrupts the egocentric reference frame.

Conclusions:

• The observer's egocentric reference frame is more complex and less stable than previously assumed.
• Combined vestibular and proprioceptive disruption, alongside sensory blockade, significantly impacts spatial orientation.
• Future research should explore the neural mechanisms underlying egocentric reference frame instability.