Publications (10) View all
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Article: Long-term phonological learning begins at the level of word form.
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ABSTRACT: Incidental learning of phonological structures through repeated exposure is an important component of native and foreign-language vocabulary acquisition that is not well understood at the neurophysiological level. It is also not settled when this type of learning occurs at the level of word forms as opposed to phoneme sequences. Here, participants listened to and repeated back foreign phonological forms (Korean words) and new native-language word forms (Finnish pseudowords) on two days. Recognition performance was improved, repetition latency became shorter and repetition accuracy increased when phonological forms were encountered multiple times. Cortical magnetoencephalography responses occurred bilaterally but the experimental effects only in the left hemisphere. Superior temporal activity at 300-600ms, probably reflecting acoustic-phonetic processing, lasted longer for foreign phonology than for native phonology. Formation of longer-term auditory-motor representations was evidenced by a decrease of a spatiotemporally separate left temporal response and correlated increase of left frontal activity at 600-1200ms on both days. The results point to item-level learning of novel whole-word representations.NeuroImage 07/2012; 63(2):789-99. · 5.89 Impact Factor -
Article: Differences in word recognition between early bilinguals and monolinguals: behavioral and ERP evidence.
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ABSTRACT: We investigated the behavioral and brain responses (ERPs) of bilingual word recognition to three fundamental psycholinguistic factors, frequency, morphology, and lexicality, in early bilinguals vs. monolinguals. Earlier behavioral studies have reported larger frequency effects in bilinguals' nondominant vs. dominant language and in some studies also when compared to corresponding monolinguals. In ERPs, language processing differences between bilinguals vs. monolinguals have typically been found in the N400 component. In the present study, highly proficient Finnish-Swedish bilinguals who had acquired both languages during childhood were compared to Finnish monolinguals during a visual lexical decision task and simultaneous ERP recordings. Behaviorally, we found that the response latencies were overall longer in bilinguals than monolinguals, and that the effects for all three factors, frequency, morphology, and lexicality were also larger in bilinguals even though they had acquired both languages early and were highly proficient in them. In line with this, the N400 effects induced by frequency, morphology, and lexicality were larger for bilinguals than monolinguals. Furthermore, the ERP results also suggest that while most inflected Finnish words are decomposed into stem and suffix, only monolinguals have encountered high frequency inflected word forms often enough to develop full-form representations for them. Larger behavioral and neural effects in bilinguals in these factors likely reflect lower amount of exposure to words compared to monolinguals, as the language input of bilinguals is divided between two languages.Neuropsychologia 02/2012; 50(7):1362-71. · 3.64 Impact Factor -
Article: MEG evoked responses and rhythmic activity provide spatiotemporally complementary measures of neural activity in language production.
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ABSTRACT: Phase-locked evoked responses and event-related modulations of spontaneous rhythmic activity are the two main approaches used to quantify stimulus- or task-related changes in electrophysiological measures. The relationship between the two has been widely theorized upon but empirical research has been limited to the primary visual and sensorimotor cortex. However, both evoked responses and rhythms have been used as markers of neural activity in paradigms ranging from simple sensory to complex cognitive tasks. While some spatial agreement between the two phenomena has been observed, typically only one of the measures has been used in any given study, thus disallowing a direct evaluation of their exact spatiotemporal relationship. In this study, we sought to systematically clarify the connection between evoked responses and rhythmic activity. Using both measures, we identified the spatiotemporal patterns of task effects in three magnetoencephalography (MEG) data sets, all variants of a picture naming task. Evoked responses and rhythmic modulation yielded largely separate networks, with spatial overlap mainly in the sensorimotor and primary visual areas. Moreover, in the cortical regions that were identified with both measures the experimental effects they conveyed differed in terms of timing and function. Our results suggest that the two phenomena are largely detached and that both measures are needed for an accurate portrayal of brain activity.NeuroImage 12/2011; 60(1):29-36. · 5.89 Impact Factor -
Conference Proceeding: Predicting Reaction Times in Word Recognition by Unsupervised Learning of Morphology.
Artificial Neural Networks and Machine Learning - ICANN 2011 - 21st International Conference on Artificial Neural Networks, Espoo, Finland, June 14-17, 2011, Proceedings, Part I; 01/2011 -
Article: Modulation of brain activity after learning predicts long-term memory for words.
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ABSTRACT: The acquisition and maintenance of new language information, such as picking up new words, is a critical human ability that is needed throughout the life span. Most likely you learned the word "blog" quite recently as an adult, whereas the word "kipe," which in the 1970s denoted stealing, now seems unfamiliar. Brain mechanisms underlying the long-term maintenance of new words have remained unknown, albeit they could provide important clues to the considerable individual differences in the ability to remember words. After successful training of a set of novel object names we tracked, over a period of 10 months, the maintenance of this new vocabulary in 10 human participants by repeated behavioral tests and magnetoencephalography measurements of overt picture naming. When naming-related activation in the left frontal and temporal cortex was enhanced 1 week after training, compared with the level at the end of training, the individual retained a good command of the new vocabulary at 10 months; vice versa, individuals with reduced activation at 1 week posttraining were less successful in recalling the names at 10 months. This finding suggests an individual neural marker for memory, in the context of language. Learning is not over when the acquisition phase has been successfully completed: neural events during the access to recently established word representations appear to be important for the long-term outcome of learning.Journal of Neuroscience 11/2010; 30(45):15160-4. · 7.11 Impact Factor
