Mixing Metaphors In The Cerebral Hemispheres: What Happens When Careers Collide?

Are processes of figurative comparison and figurative categorization different? An experiment combining alternative-sense and matched-sense metaphor priming with a divided visual field assessment technique sought to isolate processes of comparison and categorization in the 2 cerebral hemispheres. For target metaphors presented in the right visual field/left cerebral hemisphere (RVF/LH), only matched-sense primes were facilitative. Literal primes and alternative-sense primes had no effect on comprehension time compared to the unprimed baseline. The effects of matched-sense primes were additive with the rated conventionality of the targets. For target metaphors presented to the left visual field/right cerebral hemisphere (LVF/RH), matched-sense primes were again additively facilitative. However, alternative-sense primes, though facilitative overall, seemed to eliminate the preexisting advantages of conventional target metaphor senses in the LVF/RH in favor of metaphoric senses similar to those of the primes. These findings are consistent with tightly controlled categorical coding in the LH and coarse, flexible, context-dependent coding in the RH. (PsycINFO Database Record (c) 2013 APA, all rights reserved)(journal abstract

Hemispheric processing of memory is affected by sleep

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Sleep is known to affect learning and memory, but the extent to which it influences behavioural processing in the left and right hemispheres of the brain is as yet unknown. We tested two hypotheses about lateralised effects of sleep on recognition memory for words: whether sleep reactivated recent experiences of words promoting access to the long-term store in the left hemisphere (LH), and whether sleep enhanced spreading activation differentially in semantic networks in the hemispheres. In Experiment 1, participants viewed lists of semantically related words, then slept or stayed awake for 12 h before being tested on seen, unseen but related, or unrelated words presented to the left or the right hemisphere. Sleep was found to promote word recognition in the LH, and to spread activation equally within semantic networks in both hemispheres. Experiment 2 ensured that the results were not due to time of day effects influencing cognitive performance

Sustained meaning activation for polysemous but not homonymous words: Evidence from EEG

Theoretical linguistic accounts of lexical ambiguity distinguish between homonymy, where words that share a lexical form have unrelated meanings, and polysemy, where the meanings are related. The present study explored the psychological reality of this theoretical assumption by asking whether there is evidence that homonyms and polysemes are represented and processed differently in the brain. We investigated the time-course of meaning activation of different types of ambiguous words using EEG. Homonyms and polysemes were each further subdivided into two: unbalanced homonyms (e.g., ". coach") and balanced homonyms (e.g., ". match"); metaphorical polysemes (e.g., ". mouth") and metonymic polysemes (e.g., ". rabbit"). These four types of ambiguous words were presented as primes in a visual single-word priming delayed lexical decision task employing a long ISI (750. ms). Targets were related to one of the meanings of the primes, or were unrelated. ERPs formed relative to the target onset indicated that the theoretical distinction between homonymy and polysemy was reflected in the N400 brain response. For targets following homonymous primes (both unbalanced and balanced), no effects survived at this long ISI indicating that both meanings of the prime had already decayed. On the other hand, for polysemous primes (both metaphorical and metonymic), activation was observed for both dominant and subordinate senses. The observed processing differences between homonymy and polysemy provide evidence in support of differential neuro-cognitive representations for the two types of ambiguity. We argue that the polysemous senses act collaboratively to strengthen the representation, facilitating maintenance, while the competitive nature of homonymous meanings leads to decay

Cerebral Hemispheric Mechanisms in the Retrieval of Ambiguous Word Meanings

Targets related to ambiguous primes were projected to the left and right visual fields in a lexical priming experiment with stimulus onset asynchronies (SOA) of 35ms and 750ms. Left hemisphere results were similar to earlier results with central projection (Simpson & Burgess, JEP:HPP, 1985). Facilitation across both SOAs for the more frequent meaning and a decrease in facilitation for the less frequent meaning at the longer SOA. In contrast, right hemisphere results indicated a decay of facilitation for the more frequent meaning at the longer SOA, while activation for the subordinate meaning increased. Results suggest that while automatic processing occurs in either hemisphere, only the left hemisphere engages in controlled processing of ambiguous word meanings. In addition, the present results support the idea that the right hemisphere lexicon possesses a richer endowment than earlier thought

Neural Dynamics of Phonological Processing in the Dorsal Auditory Stream

Neuroanatomical models hypothesize a role for the dorsal auditory pathway in phonological processing as a feedforward efferent system (Davis and Johnsrude, 2007; Rauschecker and Scott, 2009; Hickok et al., 2011). But the functional organization of the pathway, in terms of time course of interactions between auditory, somatosensory, and motor regions, and the hemispheric lateralization pattern is largely unknown. Here, ambiguous duplex syllables, with elements presented dichotically at varying interaural asynchronies, were used to parametrically modulate phonological processing and associated neural activity in the human dorsal auditory stream. Subjects performed syllable and chirp identification tasks, while event-related potentials and functional magnetic resonance images were concurrently collected. Joint independent component analysis was applied to fuse the neuroimaging data and study the neural dynamics of brain regions involved in phonological processing with high spatiotemporal resolution. Results revealed a highly interactive neural network associated with phonological processing, composed of functional fields in posterior temporal gyrus (pSTG), inferior parietal lobule (IPL), and ventral central sulcus (vCS) that were engaged early and almost simultaneously (at 80–100 ms), consistent with a direct influence of articulatory somatomotor areas on phonemic perception. Left hemispheric lateralization was observed 250 ms earlier in IPL and vCS than pSTG, suggesting that functional specialization of somatomotor (and not auditory) areas determined lateralization in the dorsal auditory pathway. The temporal dynamics of the dorsal auditory pathway described here offer a new understanding of its functional organization and demonstrate that temporal information is essential to resolve neural circuits underlying complex behaviors

Predictive inference generation in the cerebral hemispheres: An investigation of time course and reader goals

During reading, individuals activate information that is not explicitly stated to make connections (i.e., inferences) about what is occurring in a text. Readers often make connections between events in a text and their background knowledge by generating expectations about what will occur next (i.e., generating a predictive inference). Although predictive inferences have been shown to improve text comprehension (Magliano et al.,1994), it is currently unclear whether readers routinely generate predictive inferences during reading. Multiple factors have been shown to influence predictive inference generation (e.g., Murray&Burke, 2003); Linderholm, 2002). For example, characteristics of the text (such as the level of textual constraint) and characteristics of the reader (such as an individual\u27s goal during reading) influence how readers process predictive inferences. Specifically, readers generate more predictive inferences when a text is strongly constrained (Virtue, van den Groek, &Linderholm, 2002). In addition, the amount of time (i.e., the can influence how predictive inferences are processed (Till, Mross, & Kintsch, 1988). Specifically, some research does not find evidence of predictive inferences unless readers are given approximately 100 ms to generate an inference (Calvo &Castillo, 1996), whereas other research shows evidence of predictive inference generation after only 500 ms (Klin, Murray, Guzman, & Levine, 1999). Thus conflicting findings exist regarding the generations of predictive inferences. To further examine predictive inference generation, researcher can use a cognitive neuroscience approach to gain a better understanding of how predictive inferences are process in the cerebral hemispheres. Thus, the current study used a divided visual field paradigm to investigate how reading goals, textual constraint, and SOA influence predictive inference generation in the right and left hemisphere. Four experimental studies were conducted in which participants were presented texts that either strongly led to a specific outcome (i.e., were strongly constrained towards a specific predictive inference) or weakly led to a specific outcome (i.e.,were weakly constrained towards a specific predictive inference). Participants then made lexical decision to related target words that were presented to either the right visual field-left hemisphere or the left visual field of right hemisphere. In Experiment 1 and Experiment 2, participants were given an SOA of 500 ms to generate the predictive inference to examine an early time point during inference generation. In Experiment 3 and 4, participants were given an SOA of 1000 ms to generate the predictive inference to examine a later time point during inference generation. Additionally, participants in Experiment 2 and Experiment 4 were instructed to read as if they were preparing for an upcoming exam (i.e, there were given a study goal). Findings showed that reading goals influenced predictive inference generation in the right and left hemisphere at a long SOA, but not at a short SOA. Specifically, when readers were given a reading goal, strongly and weakly constrained predictive inferences were processed similarly in the left hemisphere at a long SOA, whereas strongly constrained predictive inferences showed greater facilitation than weakly constrained predictive inferences in the right hemisphere. In contrast, when readers were not given a specific reading goal, strongly constrained predictive inferences showed a processing advantage in the left hemisphere, whereas strongly and weakly constrained predictive inferences were processed similarly in in the right hemisphere at a long SOA. These findings suggest that reading goals differently influence how predictive inferences are processed in the hemispheres during reading. In addition, findings showed that overall, strongly constrained predictive inferences had a processing advantage over weakly constrained predictive inferences. These findings are consistent with existing theoretical frameworks