Conventional metaphors in longer passages evoke affective brain response

Conventional metaphorical sentences such as She’s a sweet child have been found to elicit greater amygdala activation than matched literal sentences (e.g., She’s a kind child). In the present fMRI study, this finding is strengthened and extended with naturalistic stimuli involving longer passages and a range of conventional metaphors. In particular, a greater number of activation peaks (four) were found in the bilateral amygdala when passages containing conventional metaphors were read than when their matched literal versions were read (a single peak); while the direct contrast between metaphorical and literal passages did not show significant amygdala activation, parametric analysis revealed that BOLD signal changes in the left amygdala correlated with an increase in metaphoricity ratings across all stories. Moreover, while a measure of complexity was positively correlated with an increase in activation of a broad bilateral network mainly involving the temporal lobes, complexity was not predictive of amygdala activity. Thus, the results suggest that amygdala activation is not simply a result of stronger overall activity related to language comprehension, but is more specific to the processing of metaphorical language

Metaphorical language processing and amygdala activation in L1 and L2

The present study aims to investigate the neural correlates of processing conventional figurative language in non-native speakers in a comparison with native speakers. Italian proficient L2 learners of German and German native speakers read conventional metaphorical statements as well as literal paraphrases that were comparable on a range of psycholinguistic variables. Results confirm previous findings that native speakers show increased activity for metaphorical processing, and left amygdala activation increases with increasing Metaphoricity. At the whole-brain level, L2 learners showed the expected overall differences in activation when compared to native speakers (in the fronto-temporal network). But L2 speakers did not show any distinctive activation outside the caudate nucleus as Metaphoricity increased, suggesting that the L2 speakers were less affected by increasing Metaphoricity than native speakers were. With small volume correction, only a single peak in the amygdala reached threshold for L2 speakers as Metaphoricity increased. The findings are consistent with the view that metaphorical language is more engaging for native speakers but not necessarily for L2 speakers

The metaphorical brain [Research topic]

This Frontiers Special Issue will synthesize current findings on the cognitive neuroscience of metaphor, provide a forum for voicing novel perspectives, and promote new insights into the metaphorical brain

Metaphorical sentences are more emotionally engaging than their literal counterparts

Why do people so often use metaphorical expressions when literal paraphrases are readily available? This study focuses on a comparison of metaphorical statements involving the source domain of taste (e.g., She looked at him sweetly) and their literal paraphrases (e.g., She looked at him kindly). Metaphorical and literal sentences differed only in one word and were normed for length, familiarity, imageability, emotional valence, and arousal. Our findings indicate that conventional metaphorical expressions are more emotionally evocative than literal expressions, as the amygdala and the anterior portion of the hippocampus were more active in the metaphorical sentences. They also support the idea that even conventional metaphors can be grounded in sensorimotor and perceptual representations in that primary and secondary gustatory areas (lateral OFC, frontal operculum, anterior insula) were more active as well. A comparison of the individual words that distinguished the metaphorical and literal sentences revealed greater activation in the lateral OFC and the frontal operculum for the taste-related words, supporting the claim that these areas are relevant to taste

Functional and anatomical brain networks : Brain networks during naturalistic auditory stimuli, tactile stimuli and rest : Functional network plasticity in early-blind subjects.

Hearing is a versatile sense allowing us, among other things, to avoid danger and engage in pleasurable discussions. The ease with which we follow a conversation in a noisy environment is astonishing. Study I in this thesis used functional magnetic resonance imaging to explore the large-scale organization of speech and non-speech sound processing during a naturalistic stimulus comprised of an audio drama. Two large-scale functional networks processed the audio drama; one processed only speech, the other processed both speech and non-speech sounds. Hearing is essential for blind subjects. Anatomical and functional changes in the brains of blind people allow them to experience a detailed auditory world, compensating for the lack of vision. Therefore, comparing early-blind subjects brains to those of sighted people during naturalistic stimuli reveals fundamental differences in brain organization. In Study II, naturalistic stimuli were employed to explore whether one of the most distinguishing traits of the auditory system the left-lateralized responses to speech changes following blindness. As expected, in sighted subjects, speech processing was left-hemisphere dominant. Curiously, the left-hemisphere dominance for speech was absent or even reversed in blind subjects. In early-blind people, the senses beyond vision are strained as they try to compensate for the loss of sight; on the other hand, the occipital cortices are devoid of normal visual information flow. Interestingly, in blind people, senses other than vision recruit the occipital cortex. Additional to changes in the occipital cortex, the sensory cortices devoted to touch and hearing change. Data presented here suggested more inter-subject variability in auditory and parietal areas in blind subjects compared with sighted subjects. The study suggested that the greater the inter-subject variability of the network, the greater the experience-dependent plasticity of that network. As the prefrontal areas display large inter-subject spatial variability, the activation of the prefrontal cortex varies greatly. The variable activation might partly explain why the top-down influences of the prefrontal cortex on tactile discrimination are not well understood. In the fourth study, anatomical variability was assessed on an individual level, and transcranial magnetic stimulation was targeted at individually-chosen prefrontal locations indicated in tactile processing. Stimulation of one out of two prefrontal cortex locations impaired the subjects ability to distinguish a single tactile pulse from paired pulses. Thus, the study suggested that tactile information is regulated by functionally specialized prefrontal subareas.Anatomiska och funktionella hjärnnätverk hos seende och synskadade Hörseln är möjligen vårt viktigaste sinne. Med hjälp av hörseln kan vi bl.a. undvika faror och enkelt skilja mellan tal och oljud. I den första delen av avhandlingen fick försökspersonerna lyssna till en radiopjäs medan de undergick funktionell magnetresonanstomografi. Vi fann två olika hjärnnätverk som behandlade pjäsen. Det ena reagerade på både tal och andra ljud, medan det andra registrerade enbart tal. Synskadade klarar sig väl i vardagslivet, detta anses påvisa hjärnans förmåga att anpassa sig till begränsningar i dess normala funktion. I andra delen av avhandlingen jämfördes sedan ungdomen synskadade med seende. Det framgick att seende reagerade starkare på tal med den vänstra hjärnhalvan. Tidigt synskadade visade inga skillnader mellan hjärnhalvorna i reaktivitet till tal. Hos blinda rör det sig naturligtvis inte synintryck i syncortex. Detta medför att tidigt i livet synskadade brukar syncortex för att bearbeta hörsel- och känselintryck. Funktionell magnetresonanstomografi har möjliggjort att undersöka hur synskadade personers hjärnor förändrat sig. I tredje delen av avhandlingen påvisades att synskadade hade en större individuella skillnader i tal- och hörselcortex. Syncortex däremot hade större individuella skillnader hos seende. Det kan tyda på att ökningen av de individuella skillnaderna speglar hjärnans adaptionsmekanismer. En orsak till vår bristfälliga kunskap on frontallobens sammansättning kan ligga i de stora individuella variationerna. Vätskediffusions-MR kan påvisa anatomiska nervbanor på en individuell nivå. I avhandlingens fjärde del utvärderades anatomiska kontakter på individnivå. Sedan användes transkraniell magnetstimulering för att aktivera utvalda nervbanor mellan frontalloben och känslocortex medan vi observerade försökspersonernas förmåga att särskilja antalet känslostötar. Försökspersoner kunde inte urskilja mängden känslostötar ifall ett visst område av frontalloben stimulerades.Sokeiden ja näkevien aivoverkot Tämän väitöskirjatyön tavoitteena oli selvittää aivoverkkojen ominaisuuksia levossa, sekä tunto- ja ääniärsykkeiden aikana. Tarkemmat tavoitteet olivat seuraavat: 1) Tutkia, miten luonnonmukainen ääniärsyke käsitellään näkevien ja sokeiden koehenkilöiden aivoverkoissa. 2) Tutkia toiminnallisten aivoverkkojen yksilöllisiä eroja sokeilla ja näkevillä. 3) Selvittää miten etuaivolohkon ja tuntoaivokuoren välisen hermorata-yhteyden ärsyttäminen vaikuttaa tuntoärsykkeen käsittelyyn. Kuulo on mahdollisesti tärkein aistimme. Kuuloaistin avulla mm. vältämme vaaroja ja erotamme vaivattomasti puheen ympäröivästä melusta. Tämän väitöksen ensimmäisessä osatyössä tutkittavat kuuntelivat ääninäytelmää aivojen toiminnallisen magneettikuvauksen aikana. Tutkimuksessa havaittiin kaksi erillistä ääninäytelmää käsittelevää toiminnallista aivoverkkoa. Toinen käsitteli puheääniä ja ympäristöääniä, toinen pelkästään puheääniä. Sokeat pärjäävät hyvin arkielämässä. Tätä pidetään osoituksena aivojen kyvystä paikata puuttuvaa näköaistia muovautumalla. Toisessa osatyössä tutkittiin, miten varhain sokeutuneiden aivot käsittelevät ääninäytelmää. Kun varhain sokeutuneiden koehenkilöiden aivojen toimintaa verrattiin näkevien aivojen toimintaan, paljastui, että näkevillä vasen aivopuolisko reagoi puheeseen oikeata aivopuoliskoa vahvemmin, kun taas sokeilla tämä aivopuoliskojen välinen ero ei tullut esille. Sokeilla kuuloaivokuori korvaa näköaistin puutetta, toisaalta näköaivokuorelle ei tule näköaistin tuottamia viestejä. Tästä seuraa, että varhain sokeutuneilla muut aistit valtaavat näköaivokuoren. Aivojen toiminnallinen magneettikuvaus sekä uudet analyysimenetelmät ovat mahdollistaneet sokeiden aivojen muovautumisen tutkimisen. Tässä väitöskirjatyössä käytettiin uusia analyysimenetelmiä sokeiden ja näkevien aivokuoren toiminnan muovautumisen tutkimiseen. Osoitimme, että sokeilla oli näkeviä enemmän yksilöllistä vaihtelua puhe- ja kuuloaivokuoren toiminnassa. Näköaivokuoren toiminnassa sokeilla oli vähemmän yksilöllistä vaihtelua kuin näkevillä. Päättelimme, että yksilöllisen vaihtelevuuden lisääntyminen oli osoitus sokeuden seurauksena tapahtuneesta aivojen muovautumisesta. Yhtenä syynä etuaivolohkon järjestäytymisen puutteelliseen tuntemiseen voi olla etuaivolohkon toiminnan suuri yksilöllinen vaihtelevuus. Diffuusiopainotteinen aivokuvantaminen yhdistettynä traktografiaan paljastaa anatomisia hermoratayhteyksiä yksilötasolla. Neljännessä osatyössä arvioimme näitä menetelmiä käyttäen tuntoaivokuoren ja etuaivolohkon anatomisia yhteyksiä yksilötasolla, ja ärsytimme näitä kohteita käyttäen nk. transkraniaalista magneettistimulaatiota (TMS). Kun otsalohkon toimintaa näin häirittiin yksilöllisesti tarkasti suunnatulla TMS pulssilla, tutkittavien kyky eritellä tuntopulssien määrää häiriintyi. Työ osoitti, että otsalohkon etuosa säätelee tuntoaivokuoren toimintaa

The Metaphor Interpretation Test: Cognitive Processes Involved and Age Group Differences in Performance

It is well known that aging affects fluid cognitive processes while leaving crystallized processes largely intact. When it comes to language abilities, figurative language tends to be more associated with fluid abilities and literal language with more crystallized abilities. Fluid abilities involve short-term storage of information and mental manipulation, which are associated with metaphor interpretation. Eighty participants (40 adults over fifty years old, and 40 young adults) completed the Metaphor Interpretation Test (Iskandar & Baird, 2013). The test includes 17 items chosen from a list of metaphors by Katz et al. (1988). Answers were coded as abstract complete (AC), abstract partial (AP), concrete (CT), or other/unrelated (OT) response. On a multiple choice version of the test, each option represented one of these categories. Participants also completed cognitive tests measuring estimated verbal IQ, short-term memory, working memory, processing speed, mental flexibility, verbal abstraction, and visual abstraction. Overall, younger adults produced a greater number of and chose more AC responses on free and multiple-choice formats of the test, respectively, than older adults. Conversely, older adults produced a greater number of and chose more CT responses on free and multiple-choice formats, respectively, than younger adults. Several measures were associated with aspects of performance on the Metaphor Interpretation Test Verbal short-term memory span most often emerged as a predictor in these analyses. Co-varying on verbal short-term memory span eliminated age-group effects, while co-varying on estimated verbal IQ increased age group differences. Results suggest that aging adversely affects novel metaphor interpretation through age-related limitations in the ability to hold information in mind long enough to search for and link similar cognitive networks

An integrated theory of language production and comprehension

Currently, production and comprehension are regarded as quite distinct in accounts of language processing. In rejecting this dichotomy, we instead assert that producing and understanding are interwoven, and that this interweaving is what enables people to predict themselves and each other. We start by noting that production and comprehension are forms of action and action perception. We then consider the evidence for interweaving in action, action perception, and joint action, and explain such evidence in terms of prediction. Specifically, we assume that actors construct forward models of their actions before they execute those actions, and that perceivers of others' actions covertly imitate those actions, then construct forward models of those actions. We use these accounts of action, action perception, and joint action to develop accounts of production, comprehension, and interactive language. Importantly, they incorporate well-defined levels of linguistic representation (such as semantics, syntax, and phonology). We show (a) how speakers and comprehenders use covert imitation and forward modeling to make predictions at these levels of representation, (b) how they interweave production and comprehension processes, and (c) how they use these predictions to monitor the upcoming utterances. We show how these accounts explain a range of behavioral and neuroscientific data on language processing and discuss some of the implications of our proposal

Towards a complete multiple-mechanism account of predictive language processing [Commentary on Pickering & Garrod]

Although we agree with Pickering & Garrod (P&G) that prediction-by-simulation and prediction-by-association are important mechanisms of anticipatory language processing, this commentary suggests that they: (1) overlook other potential mechanisms that might underlie prediction in language processing, (2) overestimate the importance of prediction-by-association in early childhood, and (3) underestimate the complexity and significance of several factors that might mediate prediction during language processing

Native and Non-native Idiom Processing: Same Difference

This dissertation looks at idiom processing in native (L1) and non-native (L2) speakers. The duality of meaning represented by idioms (e.g., the idiom piece of cake means figuratively very easy but literally describes dessert) poses issues for theories of language processing and composition. While L1 speakers can easily comprehend idioms, L2 speakers have more difficulty in doing so. However, it is still unclear whether these difficulties are evidence of differential processing in L1 and L2 listeners. This work looks at idiom processing in both speaker groups via a collection of experimental studies in order to answer the overarching question: How do L1 and L2 idiom processing compare? In doing so, a number of issues are considered, such as: the timeline of meaning activation for figurative (idiomatic) meaning as well as literal constituent and phrasal meaning; the flexibility in this process during comprehension; the impact of idiomatic properties on processing; recognition memory for equal figurative and literal phrases after learning; and brain activation during comprehension. The work includes a database of American English idioms with L1 and L2 (German L1) norming values as well as experimental methods in L1 and L2 speakers such as cross-modal priming, eye-tracking, self-paced reading, training and recognition, and fMRI. The evidence presented suggests that L1 and L2 idiom processing differ based on general L1 and L2 differences, however, a single idiomatic processing method which considers both figurative and literal meaning is responsible for both speaker groups