ИСТИНА

Word-specific memory traces in the brain are supposed to be formed in the process of mutual connection strengthening between different brain areas; this happens as actions, objects or concepts are learnt when they are experienced in conjunction with the words used to describe them (Pulvermuller, 2005). The ability to quickly acquire word-picture associations was shown to depend on the reorganization in neocortical networks including the left temporal area, especially the left temporal pole (Sharon et al., 2011), as well as temporoparietal, premotor, and prefrontal regions (Majerus et al., 2005; Mestres-Misse et al., 2008; Paulesu et al., 2009; Sharon et al., 2011). Yet, very little is known about the localization of the earliest stages of this process. We designed a behavioral paradigm that involves rapid word meaning acquisition. This procedure mimics important aspects of natural word learning and is most relevant to associative biological interpretation of word meaning acquisition. We attempted to find time and location of significant events in the brain linked to acquisition of word meaning. Our findings imply that long-term effects of natural language usage may involve multiple consolidation/reconsolidation phases, and rooting the word meaning into one's sensory-motor experience is a necessary but not a sufficient prerequisite for its embedding into the associative structure of semantic memory. Taken together, our findings show that learning of novel word meaning through word-action association selectively increased neural specificity for these words in the auditory parabelt areas responsible for spectrotemporal analysis, as well as in articulatory areas, located in the left hemisphere. Importantly, this effect was detected in passive conditions after active learning, evidencing formation of a robust memory trace. The extent of neural changes was linked to the degree of language learning, specifically implicating the physiological contribution of the left perisylvian cortex in the learning success.