| 1. |
- Arvidsson, Caroline, et al.
(författare)
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Conversational production and comprehension: fMRI-evidence reminiscent of but deviant from the classical Broca–Wernicke model
- 2024
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Ingår i: Cerebral Cortex. - : Oxford University Press (OUP). - 1047-3211 .- 1460-2199. ; 34:3
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Tidskriftsartikel (refereegranskat)abstract
- A key question in research on the neurobiology of language is to which extent the language production and comprehension systems share neural infrastructure, but this question has not been addressed in the context of conversation. We utilized a public fMRI dataset where 24 participants engaged in unscripted conversations with a confederate outside the scanner, via an audio-video link. We provide evidence indicating that the two systems share neural infrastructure in the left-lateralized perisylvian language network, but diverge regarding the level of activation in regions within the network. Activity in the left inferior frontal gyrus was stronger in production compared to comprehension, while comprehension showed stronger recruitment of the left anterior middle temporal gyrus and superior temporal sulcus, compared to production. Although our results are reminiscent of the classical Broca–Wernicke model, the anterior (rather than posterior) temporal activation is a notable difference from that model. This is one of the findings that may be a consequence of the conversational setting, another being that conversational production activated what we interpret as higher-level socio-pragmatic processes. In conclusion, we present evidence for partial overlap and functional asymmetry of the neural infrastructure of production and comprehension, in the above-mentioned frontal vs temporal regions during conversation.
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| 2. |
- Norrman, Gunnar, et al.
(författare)
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Irreversible specialization for speech perception in early international adoptees compensated by inhibitory control in adulthood
- 2022
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Ingår i: Cerebral Cortex. - : Oxford University Press (OUP). - 1047-3211 .- 1460-2199. ; 32:17, s. 3777-3785
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Tidskriftsartikel (refereegranskat)abstract
- In early childhood, the human brain goes through a period of tuning to native speech sounds but retains remarkable flexibility, allowing the learning of new languages throughout life. However, little is known about the stability over time of early neural specialization for speech and its influence on the formation of novel language representations. Here, we provide evidence that early international adoptees, who lose contact with their native language environment after adoption, retain enhanced sensitivity to a native lexical tone contrast more than 15 years after being adopted to Sweden from China, in the absence of any pretest familiarization with the stimuli. Changes in oscillatory brain activity showed how adoptees resort to inhibiting the processing of defunct phonological representations, rather than forgetting or replacing them with new ones. Furthermore, neurophysiological responses to native and nonnative contrasts were not negatively correlated, suggesting that native language retention does not interfere with the acquisition of adoptive phonology acquisition. These results suggest that early language experience provides strikingly resilient specialization for speech which is compensated for through inhibitory control mechanisms as learning conditions change later in life.
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| 3. |
- Ylinen, Sari, et al.
(författare)
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Two Distinct Auditory-Motor Circuits for Monitoring Speech Production as Revealed by Content-Specific Suppression of Auditory Cortex
- 2015
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Ingår i: Cerebral Cortex. - : Oxford University Press (OUP). - 1460-2199 .- 1047-3211. ; 25:6, s. 1576-1586
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Tidskriftsartikel (refereegranskat)abstract
- Speech production, both overt and covert, down-regulates the activation of auditory cortex. This is thought to be due to forward prediction of the sensory consequences of speech, contributing to a feedback control mechanism for speech production. Critically, however, these regulatory effects should be specific to speech content to enable accurate speech monitoring. To determine the extent to which such forward prediction is content-specific, we recorded the brain's neuromagnetic responses to heard multisyllabic pseudowords during covert rehearsal in working memory, contrasted with a control task. The cortical auditory processing of target syllables was significantly suppressed during rehearsal compared with control, but only when they matched the rehearsed items. This critical specificity to speech content enables accurate speech monitoring by forward prediction, as proposed by current models of speech production. The one-to-one phonological motor-to-auditory mappings also appear to serve the maintenance of information in phonological working memory. Further findings of right-hemispheric suppression in the case of whole-item matches and left-hemispheric enhancement for last-syllable mismatches suggest that speech production is monitored by 2 auditory-motor circuits operating on different timescales: Finer grain in the left versus coarser grain in the right hemisphere. Taken together, our findings provide hemisphere-specific evidence of the interface between inner and heard speech.
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| 4. |
- Geber, Jonny, et al.
(författare)
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King Olaf's men? : Contextualizing Viking burials at S:t Olofsholm, Gotland, Sweden
- 2023
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Ingår i: International journal of osteoarchaeology. - : John Wiley & Sons. - 1047-482X .- 1099-1212. ; 33:5, s. 802-815
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Tidskriftsartikel (refereegranskat)abstract
- The discovery of burials at S:t Olofsholm, a site associated with the Saint Olaf cult on Gotland in Sweden, has enabled a bioarchaeological contextualization of medieval legends and sagas in conjunction with the archaelogical record. This study seeks to illuminate who were buried at S:t Olofsholm, through a biocultural lens, and whether these burials can be linked to folklore and sagas associated with the site. Five burials of possibly six individuals (cal. AD 980-1270) were assessed macroscopically and through stable isotope analysis (delta C-13, delta N-15, delta S-34, Sr-87/Sr-86, and delta O-18) of incremental dentine, bulk enamel, and bone samples. Sagas and legends associated with S:t Olofsholm mention episodes of conflict and contact involving King Olaf Haraldsson of Norway (later canonized as Saint Olaf), Gutes and Icelanders, and travels between Norway and Kyiv Rus. Two (or three) burials show signs of violent deaths, including evidence of sharp force trauma and burning. Isotope analyses indicate local and non-local signals, with possible links to southern Scandinavia, Britain, Iceland, the Baltics, and Kyiv Rus. In general, the evidence neither challenges nor confirms the legends and sagas associated with S:t Olofsholm. Instead, the findings illustrate the site's function as an early Christian place of worship within a wider Viking world that was characterized by travel and contact across the Baltic Sea, Scandinavia, and beyond. The burials at S:t Olofsholm are likely to be non-normative as indicated by their place of interment and the violent cause of death of most individuals.
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