The role of the right hemisphere in semantic control: A case-series comparison of right and left hemisphere stroke.

TY - JOUR

T1 - The role of the right hemisphere in semantic control: A case-series comparison of right and left hemisphere stroke.

AU - Thompson, Hannah Elizabeth

AU - Lauren, Henshall,

AU - Jefferies, Elizabeth Alice

N1 - Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

PY - 2016/5/1

Y1 - 2016/5/1

N2 - Semantic control processes guide conceptual retrieval so that we are able to focus on non-dominant associations and features when these are required for the task or context, yet the neural basis of semantic control is not fully understood. Neuroimaging studies have emphasised the role of left inferior frontal gyrus (IFG) in controlled retrieval, while neuropsychological investigations of semantic control deficits have almost exclusively focussed on patients with left-sided damage (e.g., patients with semantic aphasia, SA). Nevertheless, activation in fMRI during demanding semantic tasks typically extends to right IFG. To investigate the role of the right hemisphere (RH) in semantic control, we compared nine RH stroke patients with 21 left-hemisphere SA patients, 11 mild SA cases and 12 healthy, aged-matched controls on semantic and executive tasks, plus experimental tasks that manipulated semantic control in paradigms particularly sensitive to RH damage. RH patients had executive deficits to parallel SA patients but they performed well on standard semantic tests. Nevertheless, multimodal semantic control deficits were found in experimental tasks involving facial emotions and the 'summation' of meaning across multiple items. On these tasks, RH patients showed effects similar to those in SA cases - multimodal deficits that were sensitive to distractor strength and cues and miscues, plus increasingly poor performance in cyclical matching tasks which repeatedly probed the same set of concepts. Thus, despite striking differences in single-item comprehension, evidence presented here suggests semantic control is bilateral, and disruption of this component of semantic cognition can be seen following damage to either hemisphere.

AB - Semantic control processes guide conceptual retrieval so that we are able to focus on non-dominant associations and features when these are required for the task or context, yet the neural basis of semantic control is not fully understood. Neuroimaging studies have emphasised the role of left inferior frontal gyrus (IFG) in controlled retrieval, while neuropsychological investigations of semantic control deficits have almost exclusively focussed on patients with left-sided damage (e.g., patients with semantic aphasia, SA). Nevertheless, activation in fMRI during demanding semantic tasks typically extends to right IFG. To investigate the role of the right hemisphere (RH) in semantic control, we compared nine RH stroke patients with 21 left-hemisphere SA patients, 11 mild SA cases and 12 healthy, aged-matched controls on semantic and executive tasks, plus experimental tasks that manipulated semantic control in paradigms particularly sensitive to RH damage. RH patients had executive deficits to parallel SA patients but they performed well on standard semantic tests. Nevertheless, multimodal semantic control deficits were found in experimental tasks involving facial emotions and the 'summation' of meaning across multiple items. On these tasks, RH patients showed effects similar to those in SA cases - multimodal deficits that were sensitive to distractor strength and cues and miscues, plus increasingly poor performance in cyclical matching tasks which repeatedly probed the same set of concepts. Thus, despite striking differences in single-item comprehension, evidence presented here suggests semantic control is bilateral, and disruption of this component of semantic cognition can be seen following damage to either hemisphere.

KW - Aged

KW - Aged, 80 and over

KW - Brain/diagnostic imaging

KW - Case-Control Studies

KW - Executive Function

KW - Female

KW - Functional Laterality/physiology

KW - Humans

KW - Language Disorders/etiology

KW - Magnetic Resonance Imaging

KW - Male

KW - Middle Aged

KW - Neuropsychological Tests

KW - Semantics

KW - Stroke/complications

KW - Tomography Scanners, X-Ray Computed

KW - Vision Disorders/diagnosis

UR - http://www.scopus.com/inward/record.url?scp=84960388717&partnerID=8YFLogxK

U2 - 10.1016/j.neuropsychologia.2016.02.030

DO - 10.1016/j.neuropsychologia.2016.02.030

M3 - Article

C2 - 26945505

SN - 0028-3932

VL - 85

SP - 44

EP - 61

JO - Neuropsychologia

JF - Neuropsychologia

ER -