The presence of semantic content in a visual recognition memory task reduces the severity of neglect

Elior Moreh; Ehud Zohary; Tanya Orlov

doi:10.1016/j.neuropsychologia.2021.107860

The presence of semantic content in a visual recognition memory task reduces the severity of neglect

Neuropsychologia. 2021 Jul 16:157:107860. doi: 10.1016/j.neuropsychologia.2021.107860. Epub 2021 Apr 24.

Authors

Elior Moreh¹, Ehud Zohary², Tanya Orlov²

Affiliations

¹ Physical Medicine and Rehabilitation Department, Hadassah Medical Center and Faculty of Medicine, Jerusalem, Israel; Neurobiology Department, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel. Electronic address: elior@hadassah.org.il.
² Neurobiology Department, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.

PMID: 33901565
DOI: 10.1016/j.neuropsychologia.2021.107860

Abstract

Patients with right hemisphere damage often show a lateral bias when asked to report the left side of mental images held in visual working memory (i.e. representational neglect). The neural basis of representational neglect is not well understood. One hypothesis suggests that it reflects a deficit in attentional-exploratory mechanisms, i.e. an inability to direct attention to the left side of the image. Another proposition states that intact visual working memory (VWM) is necessary for correctly creating a mental image. Here we examined two components of VWM in patients with unilateral spatial neglect (USN): memory for identity, and memory for spatial position. We manipulated the strength of memory representations by presenting two distinct categories of objects, in separate blocks. These were familiar namable objects (fruits, etc.), and unfamiliar abstract objects. The former category elicits stronger working-memory traces, thanks to preexisting visual and semantic representations in long-term memory. We hypothesized that if USN patients show a lateralized deficit in VWM, it should be more pronounced for abstract objects, due to their weaker working-memory traces. Importantly, to isolate a spatially lateralized deficit in memory from a failure to fully perceive the object-arrays, we ensured that all included patients perceived every item during the encoding phase. We used a working-memory task: participants viewed object arrays and had to memorize items' identities and spatial positions. Then, single objects were presented requiring 'old/new' recognition, and retrieval of 'old' items' original positions. Our results show a lateral bias in patients' recognition-memory performance. Remarkably, it was threefold milder for namable objects compared to abstract objects. We conclude that VWM lateralized deficit is substantial in USN patients and could play a role in representational neglect.

Keywords: Attention; Recognition memory; Representational neglect; Spatial position; Unilateral spatial neglect.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Humans
Memory, Short-Term
Perceptual Disorders* / etiology
Recognition, Psychology
Semantics*
Visual Perception