Perception of the immediate extrapersonal space through proprioceptive inputs

Area of Science:

• Neuroscience
• Cognitive Psychology
• Human Motor Control

Background:

• Internalized spatial representations are crucial for navigation and action.
• The role of visual versus non-visual cues in forming spatial memories is an ongoing area of research.
• Proprioception and abstract spatial constructs are hypothesized to contribute to motor control.

Purpose of the Study:

• To investigate the formation and utilization of spatial representations without visual information.
• To compare the accuracy of reaching movements using trained versus untrained limbs.
• To determine the nature of internal spatial representations (sensory memory vs. abstract construct).

Main Methods:

• Subjects trained to locate points in a horizontal plane using acoustic guidance.
• Reaching accuracy assessed for trained and untrained hands without external cues.
• Analysis of joint contributions to reaching errors to differentiate coordinate systems.

Main Results:

• A memorized sensory image of the limb's position is utilized when available, maximizing accuracy.
• An abstract spatial representation is employed when sensory input is unavailable or unreliable.
• Accuracy decreased by approximately 25% when relying on abstract spatial representations.

Conclusions:

• Humans can form and use internalized spatial representations in the absence of visual input.
• Both sensory memory and abstract spatial constructs contribute to accurate motor control.
• The reliance on different spatial representation types impacts reaching accuracy.