HealthInsights

The Neuroscience of Spatial Neglect: Ignoring Half the World

By Elena Rostova•
NeuroscienceBrain HealthPsychology

Spatial neglect, or hemispatial neglect, is one of the most striking disorders in clinical neuroscience. Typically following a stroke or injury to the right parietal lobe, patients with this condition do not simply lose vision on their left side—they lose the very concept of the left side of space.

More Than a Visual Deficit

Unlike hemianopia, where a patient is aware of their blind spot and compensates by turning their head, patients with spatial neglect are often completely unaware of their deficit (a condition called anosognosia). They might eat only from the right side of their plate, apply makeup to only the right side of their face, or fail to notice people standing to their left, even if their eyes are perfectly functional.

The Role of the Parietal Lobe

The right posterior parietal cortex is responsible for mapping our internal and external space. It integrates sensory information with our attention systems. When this area is damaged, the brain's ability to "attend" to the contralateral (opposite) side is severely impaired. The "winner-take-all" nature of the brain's attentional circuits means the intact left hemisphere dominates, pulling all attention toward the right side of the world.

Varieties of Neglect

Neglect can manifest in different "frames" of space:

  1. Personal Space: Ignoring the left side of one's own body.
  2. Peripersonal Space: Ignoring items within arm's reach.
  3. Extrapersonal Space: Ignoring distant objects or environments.
  4. Representational Neglect: Even in the "mind's eye," patients may fail to describe the left side of a familiar town square when imagining it.

Rehabilitation and Hope

Rehabilitation for spatial neglect often involves "prismatic adaptation," where patients wear glasses that shift their visual field to the right. When they take the glasses off, their brain overcompensates by looking to the left. Other techniques include limb activation therapy and vestibular stimulation. Understanding the neural basis of neglect not only helps in patient care but also reveals how our brains construct the reality we take for granted.