The different association of allocentric and egocentric neglect with dorsal and ventral pathways

Abstract

Rationale:Egocentric neglect is characterized by responses missing on the contralateral side with respect to the viewer, while allocentric neglect is characterized in responses missing on the contralateral side with respect to the object . However, little has been reported about the neural tracts associated with egocentric and allocentric neglect. We investigated which neural tracts were involved in two types of neglect (egocentric and allocentric) in a stroke patient who showed allocentric neglect by using the Apple Cancellation test, a specialized test to distinguish between egocentric and allocentric neglect.Patient concerns:He showed good cognitive function but presented with severe neglect on the left side (A 42-year-old, right-handed male patient). He was unable to undergo even the pencil and paper test for evaluation of the severity of neglect.Diagnoses:He was diagnosed as spontaneous intracerebral hemorrhage at the right basal ganglia and underwent conservative management at the neurosurgery department of a university hospital.Interventions:Two weeks after onset, he began rehabilitation at the rehabilitation department of the same university hospital. During a seven month rehabilitation, the patient showed significant improvement of his severe left neglect.Outcomes:We used the Apple Cancellation test to distinguish between egocentric and allocentric neglect; the results failed to reveal egocentric neglect, however, they did reveal severe allocentric neglect. In addition, on diffusion tensor tractography (DTT) at 2 weeks after onset, the right superior longitudinal fasciculus (SLF) showed partial injury and narrowing in the parietal lobe compared to that of the left SLF. In addition, the right inferior fronto-occipital fasciculus (IFOF) was not reconstructed. By contrast, on 7-month post-onset DTT, the right SLF revealed elongation and thickening in the parietal lobe that approached similarity to that for the left SLF. However, the right IFOF was still not reconstructed.Lessons:The associations of egocentric neglect with the dorsal pathway (SLF) and the association of allocentric neglect with the ventral pathway (IFOF) in the right hemisphere were demonstrated in a stroke patient. It appears that DTT can be helpful in demonstrating both the affected pathway and the neglect type in patients with neglect.

Vision for Perception and Vision for Action in Space Travelers

“…The ventral visual subsystem's primary function is the recognition and identification of visual objects and events; it is believed to incorporate visual memory representations of object categories, individual objects, and features such as color and shape, and to utilize an allocentric frame of reference (Norman, 2002 ; Jang and Jang, 2018 ). The ventral stream is recruited in tasks that require verbal judgments on visual stimuli (Milner, 2017 ).…”