Enhancement and suppression in a lexical interference fMRI‐paradigm

Abstract

Previous picture-word interference (PWI) fMRI-paradigms revealed ambiguous mechanisms underlying facilitation and inhibition in healthy subjects. Lexical distractors revealed increased (enhancement) or decreased (suppression) activation in language and monitoring/control areas. Performing a secondary examination and data analysis, we aimed to illuminate the relation between behavioral and neural interference effects comparing target-related distractors (REL) with unrelated distractors (UNREL). We hypothesized that interference involves both (A) suppression due to priming and (B) enhancement due to simultaneous distractor and target processing. Comparisons to UNREL should remain distractor unspecific even at a low threshold. (C) Distractor types with common characteristics should reveal overlapping brain areas. In a 3T MRI scanner, participants were asked to name pictures while auditory words were presented (stimulus onset asynchrony [SOA] = –200 msec). Associatively and phonologically related distractors speeded responses (facilitation), while categorically related distractors slowed them down (inhibition) compared to UNREL. As a result, (A) reduced brain activations indeed resembled previously reported patterns of neural priming. Each target-related distractor yielded suppressions at least in areas associated with vision and conflict/competition monitoring (anterior cingulate cortex [ACC]), revealing least priming for inhibitors. (B) Enhancements concerned language-related but distractor-unspecific regions. (C) Some wider brain regions were commonly suppressed for combinations of distractor types. Overlapping areas associated with conceptual priming were found for facilitatory distractors (inferior frontal gyri), and areas related to phonetic/articulatory processing (precentral gyri and left parietal operculum/insula) for distractors sharing feature overlap. Each distractor with semantic relatedness revealed nonoverlapping suppressions in lexical-phonological areas (superior temporal regions). To conclude, interference combines suppression of areas well known from neural priming and enhancement of language-related areas caused by dual activation from target and distractor. Differences between interference and priming need to be taken into account. The present interference paradigm has the potential to reveal the functioning of word-processing stages, cognitive control, and responsiveness to priming at the same time.

Neural evidence for phonologically based language production deficits in older adults: An fMRI investigation of age‐related differences in picture‐word interference

“…Moreover, neither age group demonstrated priming‐related reductions in activation, which others have reported as decreases in activation in the superior temporal gyrus during the processing of phonological distractors relative to unrelated distractors (de Zubicaray & McMahon, ; de Zubicaray et al., ). Our results are more consistent with other recent studies (e.g., Abel et al., , ; Diaz, Hogstrom, et al., ), as younger adults showed increased activation in regions including the middle temporal gyrus, superior temporal gyrus, and supramarginal gyrus, many of these regions have been previously associated with phonological processing (e.g., Vigneau et al., ). Additionally, portions of these activations extend to the ventral portion of the precentral gyrus, which has previously been associated with articulatory processes (Brown, Ngan, & Liotti, ; Brown et al., ; Takai, Brown, & Liotti, ).…”

“…However, other studies have reported an opposite pattern of activation, reporting that the presence of a phonological distractor results in increased activation. Increased activation has been observed in the left STG and SMG when compared to both semantic distractors (Diaz, Hogstrom, et al., ) and unrelated distractors (Abel et al., ), while activation of the bilateral middle temporal gyrus (MTG) has also been reported for phonological compared to unrelated distractors (Abel, Dressel, Weiller, & Huber, ). Overall, it appears as though target repetition may strongly influence whether phonological processing is associated with increased or decreased activation.…”

Gestörter Wortabruf im kognitiven Modell und im Gehirn - eine Therapiestudie mit 3 Einzelfällen

“…Ein erh ö hter Bedarf an Sprachkontrolle zeigte sich bei den Nebengeordneten in einer -verglichen mit der phonologischen Bedingung -st ä rkeren Aktivierung eines Areals, das f ü r die Ü berwachung von Konfl ikten verantwortlich ist (anteriorer Cortex cinguli (ACC) links): Eine unbeabsichtigte Produktion des st ö renden Konkurrenten musste verhindert werden. Bei den Unrelationierten war der Kontrollbedarf aber am st ä rksten, besonders deutlich wieder im Vergleich mit den Phonologischen [14] . Letztere ben ö tig ten nicht nur weniger Ressourcen in pr ä frontalen und cingul ä ren Arealen zur kognitiven Kontrolle, sondern auch in jenen Arealen, die f ü r neuronales Priming bei wiederholter visueller Objektvorgabe vorbeschrieben sind, darunter visuelle und konzeptuell-semantische Netzwerke.…”

Embedded word priming elicits enhanced fMRI responses in the visual word form area

“…We hypothesized three possible outcomes of our fMRI experiments: repetition enhancement [25–27], repetition suppression [10, 28–30], or both. Findings of mutual interference between the embedded words and their carriers in behavioral priming studies indicate a co-activation of the embedded words and their carriers [22, 23].…”

“…In either case, canceling out could occur, because although the latency of repetition suppression voxels is typically faster than the latency of repetition enhancement voxels (~3 s); due to poor temporal resolution of fMRI and the limitation of the current study, it would be impossible to detect such a difference [35]. Additionally, or alternatively, concurrent enhancement and suppression for the embedded words could co-occur in different brain regions based on sensitivity to visual versus language-related characteristics of stimuli (e.g., [27]).…”