Modulating the interhemispheric balance in healthy participants with transcranial direct current stimulation: No significant effects on word or sentence processing
Patient studies and brain stimulation evidence suggest that language processing can be enhanced by altering the interhemispheric balance: namely, preferentially enhancing left-hemisphere activity while suppressing right-hemisphere activity. To our knowledge, no study has yet compared the effects of such bilateral brain stimulation to both logically necessary control conditions (separate left- and right-hemisphere stimulation). This study did so in a between-group sham-controlled design, applying transcranial direct current stimulation over Broca’s area and/or its homologue in 72 healthy participants. The effects were measured not only in a single-word-level task but also in a sentence-level task, rarely tested previously. We did not find either any significant overall effects of stimulation or greater stimulation effects in the bilateral compared to control groups. This null result, obtained in a large sample, contributes to the debate on whether tDCS can modulate language processing in healthy individuals.
The purpose of the present study was to identify general and syndrome-specific deficits in the lexical processing of individuals with non-fluent and fluent aphasia compared to individuals without cognitive, neurological or language impairments. The time course of lexical access, as well as lexical selection and integration was studied using a visual-world paradigm in three groups of Russian speakers: 36 individuals in the control group, 15 individuals with non-fluent aphasia and eight individuals with fluent aphasia. Participants listened to temporarily ambiguous sentences wherein the context biased the interpretation of an ambiguous word toward one of its two meanings. In half of the experimental sentences, a reanalysis was needed upon encountering the disambiguating phrase. The effect of the length of the intervening material between the ambiguous word and the disambiguation point was additionally monitored. All groups of participants showed intact lexical access under slowed speech rate, but non-fluent participants experienced difficulties with timely activation of multiple referents. At later stages of lexical processing, they additionally demonstrated a specific impairment of reanalysis. The deficit in participants with fluent aphasia was not focalized at any specific stage of lexical processing. Rather, the breakdown of lexical processes in fluent aphasia was likely related to difficulties with the inhibition of irrelevant lexical activation, which is further supported by the finding that increased phonological distance between the ambiguous word and ambiguity resolution was influential to the offline performance in this group.
Background: Agrammatic speakers have problems with grammatical encoding and decoding. However, not all syntactic processes are equally problematic: present time reference, who questions, and reflexives can be processed by narrow syntax alone and are relatively spared compared to past time reference, which questions, and personal pronouns, respectively. The latter need additional access to discourse and information structures to link to their referent outside the clause (Avrutin, 2006). Linguistic processing that requires discourse linking is difficult for agrammatic individuals: verb morphology with reference to the past is more difficult than with reference to the present (Bastiaanse et al., 2011). The same holds for which questions compared to who questions and for pronouns compared to reflexives (Avrutin, 2006). These results have been reported independently for different populations in different languages. The current study, for the first time, tested all conditions within the same population.
Aims: We had two aims with the current study. Firstly, we wanted to investigate whether discourse linking is the common denominator of the deficits in time reference, wh-questions, and object pronouns. Secondly, we aimed to compare the comprehension of discourse-linked elements in people with agrammatic and fluent aphasia, to define the degree of the discourse linking deficit specificity.
Methods & Procedures: Three sentence-picture-matching tasks were administered to 10 agrammatic, 10 fluent aphasic, and 10 non-brain-damaged Russian speakers (NBDs): (1) the Test for Assessing Reference of Time (TART) for present imperfect (reference to present) and past perfect (reference to past), (2) the Wh-Extraction Assessment Tool (WHEAT) for which and who subject questions, and (3) the Reflexive-Pronoun Test (RePro) for reflexive and pronominal reference.
Outcomes & Results: NBDs scored at ceiling and significantly higher than the aphasic participants. We found an overall effect of discourse linking in the TART and WHEAT for the agrammatic speakers, and in all three tests for the fluent speakers. Scores on the RePro were at ceiling.
Conclusions: The problems that individuals with agrammatic and fluent aphasia experience when comprehending sentences that contain verbs with past time reference, which question words and pronouns are caused by the fact that these elements need to involve operations at the discourse level. The effect is not specific to agrammatism, although might result from different underlying disorders in agrammatic and fluent aphasia.
Human societies crucially depend on social norms that specify appropriate actions in various situation. The effect of norms on collective behavior can break down if norm violations are not sanctioned. Social punishment is a form of behavior to enforce social norm compliance that relies on two key brain region: the “mentalizing network” (right temporo-parietal junction – rTPJ) evaluating individual responsibility and the “central-executive network” (right dorsolateral prefrontal cortex – rDLPFC) determining the final decision to punish norm violators. Here we further investigate the role of the brain network – rDLPFC-rTPJ – in third-party punishment. We used transcranial direct-current stimulation (tDCS) to disrupt the rDLPFC-rTPJ network of healthy subjects while they performed the Dictator Game. Our results suggests that the frequency of third-party punishment increased after the tDCS of the rDLPFC-rTPJ. To the best of our knowledge, this is the first study demonstrating the effect of simultaneous tDCS of the rDLPFC and rTPJ on the third-party punishment. We also show that personality traits modulate the effect of tDCS on the third-party punishment.
Psycholinguistic research demonstrates that representational distance between meanings influences recognition of ambiguous words. Our goal was to investigate whether the neural correlates of ambiguity are also modulated by representational distance as a function of syntactic similarity (i.e., grammatical class) and meaning dominance. In an event-related fMRI experiment, participants completed a visual lexical decision task that included balanced and unbalanced noun-noun and noun-verb homonyms, unambiguous words, and nonwords. Syntactic similarity effects were observed in left inferior frontal regions, with greater activation for noun-verb than noun-noun homonyms. Meaning dominance effects were observed in left middle and superior temporal regions, with greater activation for balanced than unbalanced homonyms. These findings indicate that the behavioral cost associated with processing ambiguous word meanings, modulated by syntactic similarity and meaning dominance, is reflected in the neural systems underlying ambiguity processing, as frontal and temporal regions are recruited by increased competition as a function of representational distance.
This book presents an interdisciplinary approach to the problem of mental lexicon organization. Several models of visual word recognition as well as brain mechanisms of reading are discussed. Also, such basic neurolinguistic topics are reviewed here as brain structure and functioning, memory organization, models of the mental lexicon and lexical access, electrophysiological approach to speech and language research, aphasia’s types and developmental language disorders (SLI, developmental dyslexia), genetics of language impairments, and so on. Finally, this monograph gives the results of four eye tracking experiments on visual word recognition during reading.
The present book is address to a wide range of researchers (linguists, neurophysiologists, psychologists, artificial intelligence specialists, philosophers) who works are associated with cognitive brain research.
The book describes theinterdependent relations between the multilingualism and literary creativity.
The paper is focused on the study of reaction of italian literature critics on the publication of the Boris Pasternak's novel "Doctor Jivago". The analysys of the book ""Doctor Jivago", Pasternak, 1958, Italy" (published in Russian language in "Reka vremen", 2012, in Moscow) is given. The papers of italian writers, critics and historians of literature, who reacted immediately upon the publication of the novel (A. Moravia, I. Calvino, F.Fortini, C. Cassola, C. Salinari ecc.) are studied and analised.
In the article the patterns of the realization of emotional utterances in dialogic and monologic speech are described. The author pays special attention to the characteristic features of the speech of a speaker feeling psychic tension and to the compositional-pragmatic peculiarities of dialogic and monologic text.