TY - JOUR

T1 - tDCS Facilitation of Picture Naming

T2 - Item-specific, task general, or neither?

AU - Payne, Joshua

AU - Tainturier, Marie-Josephe

PY - 2018/8/10

Y1 - 2018/8/10

N2 - The aim of the present study was to clarify the conditions under which anodal tDCS applied to left hemisphere language sites mayfacilitate picture naming latencies in healthy young adults. We built upon previous studies by directly testing for item-specific andgeneralised effects of tDCS through manipulation of item-familiarisation and through testing for both online and offline effects ofstimulation, in the same paradigm. In addition, we tested for the robustness of these effects by comparing two left hemispheresites critical for lexical retrieval. Twenty-eight healthy young adults completed two testing sessions receiving either anodal(1.5mA, 20mins) or sham stimulation (1.5mA, 30s) in each session. Half of the participants received tDCS over the left inferiorfrontal region and the other half over the left posterior superior temporal region. All participants were asked to a name a set ofpictures and their response latencies were compared at three time points (before, during and after the end of stimulation). Thestimulus set was constructed so that some items were presented at all time points, some before and after stimulation, and someduring stimulation only. A parsimonious linear mixed effects model revealed robust repetition priming effects as latencies werereliably faster for previously named items in all conditions. However, active tDCS did not produce any additional facilitation inrelation to sham, and even led to slower performance in the IFG group when the stimulated items differed from those tested atbaseline and post-test. Our findings add to the present debate about the efficacy of single-session tDCS for modulation of lexicalretrieval in healthy young adults. We conclude that future research should take a more systematic, step-wise approach to theapplication of tDCS to the study of language and that more sensitive experimental paradigms, which include a training element,are more adapted to the study of cognitive processes in populations with optimal levels of cortical excitability.

AB - The aim of the present study was to clarify the conditions under which anodal tDCS applied to left hemisphere language sites mayfacilitate picture naming latencies in healthy young adults. We built upon previous studies by directly testing for item-specific andgeneralised effects of tDCS through manipulation of item-familiarisation and through testing for both online and offline effects ofstimulation, in the same paradigm. In addition, we tested for the robustness of these effects by comparing two left hemispheresites critical for lexical retrieval. Twenty-eight healthy young adults completed two testing sessions receiving either anodal(1.5mA, 20mins) or sham stimulation (1.5mA, 30s) in each session. Half of the participants received tDCS over the left inferiorfrontal region and the other half over the left posterior superior temporal region. All participants were asked to a name a set ofpictures and their response latencies were compared at three time points (before, during and after the end of stimulation). Thestimulus set was constructed so that some items were presented at all time points, some before and after stimulation, and someduring stimulation only. A parsimonious linear mixed effects model revealed robust repetition priming effects as latencies werereliably faster for previously named items in all conditions. However, active tDCS did not produce any additional facilitation inrelation to sham, and even led to slower performance in the IFG group when the stimulated items differed from those tested atbaseline and post-test. Our findings add to the present debate about the efficacy of single-session tDCS for modulation of lexicalretrieval in healthy young adults. We conclude that future research should take a more systematic, step-wise approach to theapplication of tDCS to the study of language and that more sensitive experimental paradigms, which include a training element,are more adapted to the study of cognitive processes in populations with optimal levels of cortical excitability.

KW - transcranial direct current stimulation, lexical retrieval, picture naming, Repetition Priming, generalisation, inferior frontal gyrus, superior temporal gyrus

U2 - 10.3389/fnins.2018.00549

DO - 10.3389/fnins.2018.00549

M3 - Article

VL - 12

JO - Frontiers in Neuroscience

JF - Frontiers in Neuroscience

SN - 1662-453X

M1 - 549

ER -