Charting the effects of TMS with fMRI

Modulation of cortical recruitment within the distributed network supporting semantic control

Glyn P. Hallam, Carin Whitney, Mark Hymers, Andre D. Gouws, Elizabeth Jefferies

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Semantic memory comprises our knowledge of the meanings of words and objects but only some of this knowledge is relevant at any given time. Thus, semantic control processes are needed to focus retrieval on relevant information. Research on the neural basis of semantic control has strongly implicated left inferior frontal gyrus (LIFG) but recent work suggests that a wider network supports semantic control, including left posterior middle temporal gyrus (pMTG), right inferior frontal gyrus (RIFG) and pre-supplementary motor area (pre-SMA). In the current study, we used repetitive transcranial magnetic stimulation (1 Hz offline TMS) over LIFG, immediately followed by fMRI, to examine modulation of the semantic network. We compared the effect of stimulation on judgements about strongly-associated words (dog-bone) and weaker associations (dog-beach), since previous studies have found that dominant links can be recovered largely automatically with little engagement of LIFG, while more distant connections require greater control. Even though behavioural performance was maintained in response to TMS, LIFG stimulation increased the effect of semantic control demands in pMTG and pre-SMA, relative to stimulation of a control site (occipital pole). These changes were accompanied by reduced recruitment of both the stimulated region (LIFG) and its right hemisphere homologue (RIFG), particularly for strong associations with low control requirements. Thus repetitive TMS to LIFG modulated the contribution of distributed regions to semantic judgements in two distinct ways.

Original languageEnglish
Pages (from-to)40-52
Number of pages13
JournalNeuropsychologia
Volume93
Issue numberA
Early online date17 Sep 2016
DOIs
Publication statusPublished - Dec 2016
Externally publishedYes

Fingerprint

Prefrontal Cortex
Semantics
Magnetic Resonance Imaging
Motor Cortex
Temporal Lobe
Dogs
Transcranial Magnetic Stimulation
Bone and Bones
Research

Cite this

Hallam, Glyn P. ; Whitney, Carin ; Hymers, Mark ; Gouws, Andre D. ; Jefferies, Elizabeth. / Charting the effects of TMS with fMRI : Modulation of cortical recruitment within the distributed network supporting semantic control. In: Neuropsychologia. 2016 ; Vol. 93, No. A. pp. 40-52.
@article{5fa785c058f945cc80eda50f14ed8677,
title = "Charting the effects of TMS with fMRI: Modulation of cortical recruitment within the distributed network supporting semantic control",
abstract = "Semantic memory comprises our knowledge of the meanings of words and objects but only some of this knowledge is relevant at any given time. Thus, semantic control processes are needed to focus retrieval on relevant information. Research on the neural basis of semantic control has strongly implicated left inferior frontal gyrus (LIFG) but recent work suggests that a wider network supports semantic control, including left posterior middle temporal gyrus (pMTG), right inferior frontal gyrus (RIFG) and pre-supplementary motor area (pre-SMA). In the current study, we used repetitive transcranial magnetic stimulation (1 Hz offline TMS) over LIFG, immediately followed by fMRI, to examine modulation of the semantic network. We compared the effect of stimulation on judgements about strongly-associated words (dog-bone) and weaker associations (dog-beach), since previous studies have found that dominant links can be recovered largely automatically with little engagement of LIFG, while more distant connections require greater control. Even though behavioural performance was maintained in response to TMS, LIFG stimulation increased the effect of semantic control demands in pMTG and pre-SMA, relative to stimulation of a control site (occipital pole). These changes were accompanied by reduced recruitment of both the stimulated region (LIFG) and its right hemisphere homologue (RIFG), particularly for strong associations with low control requirements. Thus repetitive TMS to LIFG modulated the contribution of distributed regions to semantic judgements in two distinct ways.",
keywords = "Executive function, Inferior frontal gyrus, Posterior middle temporal gyrus, Semantic cognition, Transcranial magnetic stimulation",
author = "Hallam, {Glyn P.} and Carin Whitney and Mark Hymers and Gouws, {Andre D.} and Elizabeth Jefferies",
year = "2016",
month = "12",
doi = "10.1016/j.neuropsychologia.2016.09.012",
language = "English",
volume = "93",
pages = "40--52",
journal = "Neuropsychologia",
issn = "0028-3932",
publisher = "Elsevier Limited",
number = "A",

}

Charting the effects of TMS with fMRI : Modulation of cortical recruitment within the distributed network supporting semantic control. / Hallam, Glyn P.; Whitney, Carin; Hymers, Mark; Gouws, Andre D.; Jefferies, Elizabeth.

In: Neuropsychologia, Vol. 93, No. A, 12.2016, p. 40-52.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Charting the effects of TMS with fMRI

T2 - Modulation of cortical recruitment within the distributed network supporting semantic control

AU - Hallam, Glyn P.

AU - Whitney, Carin

AU - Hymers, Mark

AU - Gouws, Andre D.

AU - Jefferies, Elizabeth

PY - 2016/12

Y1 - 2016/12

N2 - Semantic memory comprises our knowledge of the meanings of words and objects but only some of this knowledge is relevant at any given time. Thus, semantic control processes are needed to focus retrieval on relevant information. Research on the neural basis of semantic control has strongly implicated left inferior frontal gyrus (LIFG) but recent work suggests that a wider network supports semantic control, including left posterior middle temporal gyrus (pMTG), right inferior frontal gyrus (RIFG) and pre-supplementary motor area (pre-SMA). In the current study, we used repetitive transcranial magnetic stimulation (1 Hz offline TMS) over LIFG, immediately followed by fMRI, to examine modulation of the semantic network. We compared the effect of stimulation on judgements about strongly-associated words (dog-bone) and weaker associations (dog-beach), since previous studies have found that dominant links can be recovered largely automatically with little engagement of LIFG, while more distant connections require greater control. Even though behavioural performance was maintained in response to TMS, LIFG stimulation increased the effect of semantic control demands in pMTG and pre-SMA, relative to stimulation of a control site (occipital pole). These changes were accompanied by reduced recruitment of both the stimulated region (LIFG) and its right hemisphere homologue (RIFG), particularly for strong associations with low control requirements. Thus repetitive TMS to LIFG modulated the contribution of distributed regions to semantic judgements in two distinct ways.

AB - Semantic memory comprises our knowledge of the meanings of words and objects but only some of this knowledge is relevant at any given time. Thus, semantic control processes are needed to focus retrieval on relevant information. Research on the neural basis of semantic control has strongly implicated left inferior frontal gyrus (LIFG) but recent work suggests that a wider network supports semantic control, including left posterior middle temporal gyrus (pMTG), right inferior frontal gyrus (RIFG) and pre-supplementary motor area (pre-SMA). In the current study, we used repetitive transcranial magnetic stimulation (1 Hz offline TMS) over LIFG, immediately followed by fMRI, to examine modulation of the semantic network. We compared the effect of stimulation on judgements about strongly-associated words (dog-bone) and weaker associations (dog-beach), since previous studies have found that dominant links can be recovered largely automatically with little engagement of LIFG, while more distant connections require greater control. Even though behavioural performance was maintained in response to TMS, LIFG stimulation increased the effect of semantic control demands in pMTG and pre-SMA, relative to stimulation of a control site (occipital pole). These changes were accompanied by reduced recruitment of both the stimulated region (LIFG) and its right hemisphere homologue (RIFG), particularly for strong associations with low control requirements. Thus repetitive TMS to LIFG modulated the contribution of distributed regions to semantic judgements in two distinct ways.

KW - Executive function

KW - Inferior frontal gyrus

KW - Posterior middle temporal gyrus

KW - Semantic cognition

KW - Transcranial magnetic stimulation

UR - http://www.scopus.com/inward/record.url?scp=84991608371&partnerID=8YFLogxK

UR - https://www.journals.elsevier.com/neuropsychologia

U2 - 10.1016/j.neuropsychologia.2016.09.012

DO - 10.1016/j.neuropsychologia.2016.09.012

M3 - Article

VL - 93

SP - 40

EP - 52

JO - Neuropsychologia

JF - Neuropsychologia

SN - 0028-3932

IS - A

ER -