Semantic Attention: Effects of Modality, Lexicality and Semantic Content

Since the discovery of the Stroop Effect in 1935 questions about the role of language vs. non-lexical stimuli in selective attention remain. Early researchers attributed the powerful distracting influence shown in the Stroop task, naming the color in which a spelled word is printed when incongruent with the color name the word spells, to an automaticity of language that gives it privileged access to meaning, but many others since have shown various ways to reduce or even reverse this distracting effect of an incongruent word. This study addresses this by using EEG to record neural activity along with reaction time and accuracy in a temporal flanker selective attention paradigm that uses all combinations of visual and auditory modalities with word and non-word lexicality as both flanking distractors and as targets, manipulating attention using semantically congruent and incongruent trials, thus controlling for the effects of modality, lexicality and semantic congruence on the selective attention task of ignoring the flankers and discriminating the target. We found that in addition to strong main effects of each of these factors, many complex two and three-way interaction effects shifted the effects of each factor depending on the levels of the other factors. We confirmed that the condition of semantic incongruence disrupts attention, shown by reduced performance accuracy and indexed by stronger peak of the N2 ERP between 250 and 310 ms after the target stimulus presentation. We found no support for the hypothesis that words have privileged automaticity, since stimulus lexicality, whether the distractor or target was a word or non-word, did not have a significant main effect on response accuracy. We found that the sensory modality of the distracting and target stimuli , whether auditory or visual, had complex interactions with their word or non-word lexicality that influenced the disrupting effects of semantic incongruence on attention. We propose a model based on 2 well-established frameworks in the neuroscience of attention, that of multiple networks governing 3 stages of attention processing, and parallel multi-modal sensory processing being bottlenecked by sequential language processing, to interpret these interacting effects on attention

Psychologie und Gehirn 2007

Die Fachtagung "Psychologie und Gehirn" ist eine traditionelle Tagung aus dem Bereich psychophysiologischer Grundlagenforschung. 2007 fand diese Veranstaltung, die 33. Jahrestagung der „Deutschen Gesellschaft für Psychophysiologie und ihre Anwendungen (DGPA)“, in Dortmund unter der Schirmherrschaft des Instituts für Arbeitsphysiologie (IfADo) statt. Neben der Grundlagenforschung ist auch die Umsetzung in die Anwendung erklärtes Ziel der DGPA und dieser Tradition folgend wurden Beiträge aus vielen Bereichen moderner Neurowissenschaft (Elektrophysiologie, bildgebende Verfahren, Peripherphysiologie, Neuroendokrinologie, Verhaltensgenetik, u.a.) präsentiert und liegen hier in Kurzform vor

The role of auditory cortices in the retrieval of single-trial auditory-visual object memories.

Single-trial encounters with multisensory stimuli affect both memory performance and early-latency brain responses to visual stimuli. Whether and how auditory cortices support memory processes based on single-trial multisensory learning is unknown and may differ qualitatively and quantitatively from comparable processes within visual cortices due to purported differences in memory capacities across the senses. We recorded event-related potentials (ERPs) as healthy adults (n = 18) performed a continuous recognition task in the auditory modality, discriminating initial (new) from repeated (old) sounds of environmental objects. Initial presentations were either unisensory or multisensory; the latter entailed synchronous presentation of a semantically congruent or a meaningless image. Repeated presentations were exclusively auditory, thus differing only according to the context in which the sound was initially encountered. Discrimination abilities (indexed by d') were increased for repeated sounds that were initially encountered with a semantically congruent image versus sounds initially encountered with either a meaningless or no image. Analyses of ERPs within an electrical neuroimaging framework revealed that early stages of auditory processing of repeated sounds were affected by prior single-trial multisensory contexts. These effects followed from significantly reduced activity within a distributed network, including the right superior temporal cortex, suggesting an inverse relationship between brain activity and behavioural outcome on this task. The present findings demonstrate how auditory cortices contribute to long-term effects of multisensory experiences on auditory object discrimination. We propose a new framework for the efficacy of multisensory processes to impact both current multisensory stimulus processing and unisensory discrimination abilities later in time

Re-evaluating the Time Course of Gender and Phonological Encoding During Silent Monitoring Tasks Estimated by ERP: Serial or Parallel Processing?

Neurolinguistic and psycholinguistic studies suggest that grammatical (gender) and phonological information are retrieved independently and that gender can be accessed before phonological information. This study investigated the relative time courses of gender and phonological encoding using topographic evoked potentials mapping methods. Event-related brain potentials (ERPs) were recorded using a high resolution electroencephalogram (EEG) system (128 channels) during gender and phoneme monitoring in silent picture naming. Behavioural results showed similar reaction times (RT) between gender and word onset (first phoneme) monitoring, and longer RT when monitoring the second syllable onset. Temporal segmentation analysis (defining dominant map topographies using cluster analysis) revealed no timing difference between gender monitoring and word onset monitoring: both effects fall within the same time window at about 270-290ms after picture presentation. Monitoring a second syllable onset generated a later effect at about 480ms. Direct comparison between gender and first phoneme monitoring revealed a difference of only 10ms between tasks at approximately 200ms. Taken together, these results suggest that lemma retrieval and phonological encoding may proceed in parallel or overlap. Word onset is retrieved simultaneously with gender, while the longer RT and the later ERP effect for second syllable onset reflect that segmental encoding continues incrementally to the following phoneme

The role of phonology in visual word recognition: evidence from Chinese

Posters - Letter/Word Processing V: abstract no. 5024The hypothesis of bidirectional coupling of orthography and phonology predicts that phonology plays a role in visual word recognition, as observed in the effects of feedforward and feedback spelling to sound consistency on lexical decision. However, because orthography and phonology are closely related in alphabetic languages (homophones in alphabetic languages are usually orthographically similar), it is difficult to exclude an influence of orthography on phonological effects in visual word recognition. Chinese languages contain many written homophones that are orthographically dissimilar, allowing a test of the claim that phonological effects can be independent of orthographic similarity. We report a study of visual word recognition in Chinese based on a mega-analysis of lexical decision performance with 500 characters. The results from multiple regression analyses, after controlling for orthographic frequency, stroke number, and radical frequency, showed main effects of feedforward and feedback consistency, as well as interactions between these variables and phonological frequency and number of homophones. Implications of these results for resonance models of visual word recognition are discussed.postprin

Verbal short-term memory and vocabulary learning

This thesis addressed two key issues. The first was the extent to which verbal short-term memory (STM) for item and order information can be differentiated in terms of their underlying neural mechanisms. The second was to analyze the relative contributions of item and order STM to vocabulary learning in bilingual (BL) and monolingual (ML) children and ML adults. The first issue was addressed with four studies. Three used electroencephalography (EEG) with ML adults, BL adults and ML children. The aim was to determine whether there is any evidence that the two types of verbal STM have different neural signatures. The fourth study used transcranial magnetic stimulation (TMS) in ML adults to test the hypothesis that the right intraparietal sulcus (IPS) is involved in order STM but not item STM. The second issue was addressed by two behavioural studies. The first was a large-scale longitudinal study testing item and order STM in relation to natural vocabulary acquisition in 7 to 10 year old BL and ML children. The children were tested once in the beginning and once in the end of the school year. In addition, ML children learning a second language were examined in the end of the school year. The second behavioural study explored therelationship of item and order STM with new-word-learning in ML adults using artificially-created nonwords. Some evidence was found to support the view that the distinction of item and order STM is a useful one. Results of the EEG data suggested differences in patterns of neuro-electrical activity for ML and BL adults and ML children when they are performing item STM and order STM tasks. The results suggest that order STM is important for new word learning in one´s native language learning, where there has already been some exposure to this language, but not in complete novice language learners