The neural basis of sign language processing in deaf signers: An activation likelihood estimation meta-analysis

The neurophysiological response during processing of sign language (SL) has been studied since the advent of Positron Emission Tomography (PET) and functional Magnetic Resonance Imaging (fMRI). Nevertheless, the neural substrates of SL remain subject to debate, especially with regard to involvement and relative lateralization of SL processing without production in (left) inferior frontal gyrus (IFG; e.g., Campbell, MacSweeney, & Waters, 2007; Emmorey, 2006, 2015). Our present contribution is the first to address these questions meta-analytically, by exploring functional convergence on the whole-brain level using previous fMRI and PET studies of SL processing in deaf signers. We screened 163 records in PubMed and Web of Science to identify studies of SL processing in deaf signers conducted with fMRI or PET that reported foci data for one of the two whole-brain contrasts: (1) “SL processing vs. control” or (2) “SL processing vs. low-level baseline”. This resulted in a total of 21 studies reporting 23 experiments matching our selection criteria. We manually extracted foci data and performed a coordinate-based Activation Likelihood Estimation (ALE) analysis using GingerALE (Eickhoff et al., 2009). Our selection criteria and the ALE method allow us to identify regions that are consistently involved in processing SL across studies and tasks. Our analysis reveals that processing of SL stimuli of varying linguistic complexity engages widely distributed bilateral fronto-occipito-temporal networks in deaf signers. We find significant clusters in both hemispheres, with the largest cluster (5240 mm3) being located in left IFG, spanning Broca’s region (posterior BA 45 and the dorsal portion of BA 44). Other clusters are located in right middle and inferior temporal gyrus (BA 37), right IFG (BA 45), left middle occipital gyrus (BA 19), right superior temporal gyrus (BA 22), left precentral and middle frontal gyrus (BA 6 and 8), as well as left insula (BA 13). On these clusters, we calculated lateralization indices using hemispheric and anatomical masks: SL comprehension is slightly left-lateralized globally, and strongly left-lateralized in Broca’s region. Sub-regionally, left-lateralization is strongest in BA 44 (Table 1). Next, we performed a contrast analysis between SL and an independent dataset of action observation in hearing non-signers (Papitto, Friederici, & Zaccarella, 2019) to determine which regions are associated with processing of human actions and movements irrespective of the presence of linguistic information. Only studies of observation of non-linguistic manual actions were included in the final set (n = 26), for example, excluding the handling of objects. Significant clusters involved in the linguistic aspects of SL comprehension were found in left Broca’s region (centered in dorsal BA 44), right superior temporal gyrus (BA 22), and left middle frontal and precentral gyrus (BA 6 and 8; Figure 1A, B, D and E). Meta-analytic connectivity modelling for the surviving cluster in Broca’s region using the BrainMap database then revealed that it is co-activated with the classical language network and functionally primarily associated with cognition and language processing (Figure 1C and D). In line with studies of spoken and written language processing (Zaccarella, Schell, & Friederici, 2017; Friederici, Chomsky, Berwick, Moro, & Bolhuis, 2017), our meta-analysis points to Broca’s region and especially left BA 44 as a hub in the language network that is involved in language processing independent of modality. Right IFG activity is not language-specific but may be specific to the visuo-gestural modality (Campbell et al., 2007). References Amunts, K., Schleicher, A., Bürgel, U., Mohlberg, H., Uylings, H. B., & Zilles, K. (1999). Broca’s region revisited: Cytoarchitecture and intersubject variability. The Journal of Comparative Neurology, 412(2), 319-341. Campbell, R., MacSweeney, M., & Waters, D. (2007). Sign language and the brain: A review. Journal of Deaf Studies and Deaf Education, 13(1), 3-20. doi: 10.1093/deafed/enm035 Eickhoff, S. B., Laird, A. R., Grefkes, C., Wang, L. E., Zilles, K., & Fox, P. T. (2009). Coordinate-based activation likelihood estimation meta-analysis of neuroimaging data: A random-effects approach based on empirical estimates of spatial uncertainty. Human Brain Mapping, 30(9), 2907-2926. doi: 10.1002/hbm.20718 Emmorey, K. (2006). The role of Broca’s area in sign language. In Y. Grodzinsky & K. Amunts (Eds.), Broca’s region (p. 169-184). Oxford, England: Oxford UP. Emmorey, K. (2015). The neurobiology of sign language. In A. W. Toga, P. Bandettini, P. Thompson, & K. Friston (Eds.), Brain mapping: An encyclopedic reference (Vol. 3, p. 475-479). London, England: Academic Press. doi: 10.1016/B978-0-12-397025-1.00272-4 Friederici, A. D., Chomsky, N., Berwick, R. C., Moro, A., & Bolhuis, J. J. (2017). Language, mind and brain. Nature Human Behaviour. doi: 10.1038/s41562-017-0184-4 Matsuo, K., Chen, S.-H. A., & Tseng, W.-Y. I. (2012). AveLI: A robust lateralization index in functional magnetic resonance imaging using unbiased threshold-free computation. Journal of Neuroscience Methods, 205(1), 119-129. doi: 10.1016/j.jneumeth.2011.12.020 Papitto, G., Friederici, A. D., & Zaccarella, E. (2019). A neuroanatomical comparison of action domains using Activation Likelihood Estimation meta-analysis [Unpublished Manuscript, Max Planck Institute for Human Cognitive & Brain Sciences]. Leipzig, Germany. Zaccarella, E., Schell, M., & Friederici, A. D. (2017). Reviewing the functional basis of the syntactic Merge mechanism for language: A coordinate-based activation likelihood estimation meta-analysis. Neuroscience & Biobehavioral Reviews, 80, 646-656. doi: 10.1016/j.neubiorev.2017.06.01

Left posterior inferior frontal gyrus is causally involved in complex sentence comprehension

INTRODUCTION Storage and reordering of words are two core processes required for successful sentence comprehension. Storage is necessary whenever the verb and its arguments (i.e., subject and object) are separated over a long distance, while reordering is necessary whenever the argument order is atypical (e.g., object-first order in German, where subject-first order is typical). Previous neuroimaging work (Meyer et al., 2012) has associated storage with the left planum temporale (PT), and reordering with the left posterior inferior frontal gyrus (pIFG). However, it is unclear whether left PT and pIFG are indeed causally relevant for storage and reordering, respectively. Here, we tested the necessity of the PT and pIFG for storage and reordering using repetitive transcranial magnetic stimulation (rTMS). METHODS We applied either effective online rTMS (5 pulses at 10 Hz) over PT or pIFG, or sham rTMS, while subjects listened to sentences that independently manipulated storage demands (short vs. long argument–verb distance) and reordering demands (subject– vs. object-first argument order). We employed behavioral modeling, using a drift diffusion model, to assess rTMS-induced disruption of sentence comprehension. RESULTS We found that rTMS over pIFG, but not PT, selectively impaired reordering during the processing of sentences with a long argument–verb distance. Specifically, relative to sham rTMS, rTMS over pIFG significantly increased the performance decline for object– vs. subject-first long-distance sentences (t23 = 2.86; p = 0.009). This effect was anatomically specific as the same comparison for PT stimulation was far from significant (t23 = −0.11; p = 0.9), and a direct across-sites comparison showed that the pIFG effect was significantly stronger (t23 = −2.62; p = 0.015). CONCLUSION Our results provide the first causal evidence that the left pIFG supports the reordering of arguments in long-distance sentences. We thereby substantially extend previous neuroimaging studies that showed a correlation between pIFG activation and reordering demands. Together with previous evidence (Lauro et al., 2010), our findings indicate that the left pIFG crucially supports the comprehension of syntactically complex sentences. These results might extend to other domains, such as music (Maess et al., 2001) and action (Clerget et al., 2009), indicating a domain-general role of left pIFG in the processing of hierarchically-structured sequences

történeti dráma 5 felvonásban - irta: Sardou Viktor - francziából forditotta: Paulay Ede és Szerdahelyi Kálmán

Debreczeni Szinház. Kedd, 1881. évi november hó 15-kán. Krecsányi Ignácz igazgatása alatti dráma-, vigjáték-, népszinmű- és operette-szintársulat által, Abonyi Gyula jutalomjátékaul.Debreceni Egyetem Egyetemi és Nemzeti Könyvtá

‘Mining the materials’: A framework for student-led self-study task creation

Meaningful independent learning is rightly viewed as a central component of successful study in L2. Given that the considerable majority of learners’ time is spent outside the classroom, the self-study space has become a source of great intrigue for English language teachers (Benson and Reinders, 2011). However, precisely because self-directed learning lies beyond the typical boundaries of the teacher’s gaze, it is influenced by a variety of factors, not least learners’ familiarity with effective independent learning practices. This summary article traces and evaluates the implementation of a framework for student-led self-study task creation with a group of 14 foundation pre-sessional students making the transition from secondary to tertiary study at the University of Glasgow with little or no existing concept of effective self-study practices. The trial aimed to provide a space for students to evaluate their strengths and weaknesses in English and establish independent learning priorities, as well as a more critical awareness (‘mining’) of regular classroom tasks as potential models for independent learning activities. Obtaining feedback at regular intervals, coupled with data from weekly reflection cycles, the investigation tracked developments in self-study practices while highlighting obstacles to enhanced independent learning. The trial also presented plentiful opportunities to reflect on the definition of effectiveness with regard to independent learning

Children's syntax is supported by the maturation of BA44 at 4 years, but of the posterior STS at 3 years of age

Within the first years of life, children learn major aspects of their native language. However, the ability to process complex sentence structures, a core faculty in human language called syntax, emerges only slowly. A milestone in syntax acquisition is reached around the age of 4 years, when children learn a variety of syntactic concepts. Here, we ask which maturational changes in the child's brain underlie the emergence of syntactically complex sentence processing around this critical age. We relate markers of cortical brain maturation to 3- and 4-year-olds' sentence processing in contrast to other language abilities. Our results show that distinct cortical brain areas support sentence processing in the two age groups. Sentence production abilities at 3 years were associated with increased surface area in the most posterior part of the left superior temporal sulcus, whereas 4-year-olds showed an association with cortical thickness in the left posterior part of Broca's area, i.e. BA44. The present findings suggest that sentence processing abilities rely on the maturation of distinct cortical regions in 3- compared to 4-year-olds. The observed shift to more mature regions involved in processing syntactically complex sentences may underlie behavioral milestones in syntax acquisition at around 4 years

Language processing within the human medial temporal lobe

Although the hippocampal formation is essential for verbal memory, it is not fully understood how it contributes to language comprehension. We recorded event-related potentials (ERPs) directly from two substructures of the medial temporal lobe (MTL), the rhinal cortex and the hippocampus proper, while epilepsy patients listened to sentences that either were correct or contained semantic or syntactic violations. Semantic violations elicited a large negative ERP response peaking at approximately 400 ms in the rhinal cortex. In contrast, syntactically incorrect sentences elicited a negative deflection of 500-800 ms in the hippocampus proper. The results suggest that functionally distinct aspects of integration in language comprehension are supported by different MTL structures: the rhinal cortex is involved in semantic integration, whereas the hippocampus proper subserves processes of syntactic integration. An analysis of phase synchronization within the gamma band between rhinal and hippocampal recording sites showed that both of the above-mentioned ERP components were preceded by an increase of phase synchronization. In contrast to these short phasic increases of phase synchronization in both violation conditions, correct sentences were associated with a long-lasting synchronization in a late time window, possibly reflecting the integration of semantic and syntactic information as required for normal comprehension

Functional brain plasticity during L1 training on complex sentences: Changes in gamma‐band oscillatory activity

The adult human brain remains plastic even after puberty. However, whether first language (L1) training in adults can alter the language network is yet largely unknown. Thus, we conducted a longitudinal training experiment on syntactically complex German sentence comprehension. Sentence complexity was varied by the depth of the center embedded relative clauses (i.e., single or double embedded). Comprehension was tested after each sentence with a question on the thematic role assignment. Thirty adult, native German speakers were recruited for 4 days of training. Magnetoencephalography (MEG) data were recorded and subjected to spectral power analysis covering the classical frequency bands (i.e., theta, alpha, beta, low gamma, and gamma). Normalized spectral power, time-locked to the final closure of the relative clause, was subjected to a two-factor analysis (“sentence complexity” and “training days”). Results showed that for the more complex sentences, the interaction of sentence complexity and training days was observed in Brodmann area 44 (BA 44) as a decrease of gamma power with training. Moreover, in the gamma band (55–95 Hz) functional connectivity between BA 44 and other brain regions such as the inferior frontal sulcus and the inferior parietal cortex were correlated with behavioral performance increase due to training. These results show that even for native speakers, complex L1 sentence training improves language performance and alters neural activities of the left hemispheric language network. Training strengthens the use of the dorsal processing stream with working-memory-related brain regions for syntactically complex sentences, thereby demonstrating the brain's functional plasticity for L1 training

Psycholinguistic norms for more than 300 lexical manual signs in German Sign Language (DGS)

Sign languages provide researchers with an opportunity to ask empirical questions about the human language faculty that go beyond considerations specific to speech and writing. Whereas psycholinguists working with spoken and written language stimuli routinely control their materials for parameters such as lexical frequency and age of acquisition (AoA), no such information or normed stimulus sets are currently available to researchers working with German Sign Language (DGS). Our contribution presents the first norms for iconicity, familiarity, AoA, and transparency for DGS. The normed stimulus set consists of more than 300 clips of manual DGS signs accom- panied by mouthings and non-manual components. Norms for the signs in the clips are derived from ratings by a total of 30 deaf signers in Leipzig, Göttingen, and Hamburg, as well as 30 hearing non-signers and native speakers of German in Leipzig. The rating procedure was implemented in a browser to ensure functionality and a similar procedure across locations and participants (Figure 1a), yet all participants performed the ratings on site in the presence of an experimenter. Deaf signers performed a total of three tasks in which they rated stimulus clips for iconicity, AoA, and familiarity. Such subjective measures of AoA and familiarity have been shown to be good proxies for corpus measures in studies of other spoken and sign languages (Vinson, Cormier, Denmark, Schembri, & Vigliocco, 2008). Hearing non-signers performed two tasks in which they first guessed the meaning of the signs in the clips to determine transparency and in the second task rated iconicity given the meaning. In addition to empirical norming data (e.g., Figure 1b), we provide information about German and English correspondences of signs. The stimulus set has been annotated in machine-readable form with regard to lexico-semantic as well as phonological properties of signs: one-handed vs. two-handed, place of articulation, path movement, symmetry, most likely lexical class, animacy, verb type, (potential) homonymy, and potential dialectal variation. Information about sign on- and offset for all stimulus clips and a number of quantitative measures of movement are also available. These were derived from automated motion tracking by fitting a pose-estimation model (Figure 1c) to the clips using OpenPose (Wei, Ramakrishna, Kanade, & Sheikh, 2016) which allows us to quantify and automatically track movement (velocity and acceleration) beyond annotation (Figure 1d). In this presentation, we will focus on providing an overview of the derived norms and attempt to put them in perspective of published empirical norms for other sign languages, for example, ASL and BSL (Vinson et al., 2008; Caselli, Sehyr, Cohen-Goldberg, & Emmorey, 2017), as well as comparable information for spoken languages. This includes a comparison of our subjective rating data with regard to frequency and AoA obtained using DGS signs with norms for other sign languages as well as with similar measures for German and English. We also discuss the relationship of mean iconicity ratings between deaf signers and hearing non-signers, as well as the relation of iconicity and transparency. Our norms and stimulus set are intended to control for psychologically relevant param- eters in future psycho- and neurolinguistic studies of DGS beyond the work of our own labs. Consequently, the norms, stimulus clips, cleaned raw data, and the R scripts used for analysis will be made available for download through the Open Science Framework. References Caselli, N. K., Sehyr, Z. S., Cohen-Goldberg, A. M., & Emmorey, K. (2017). ASL-LEX: A lexical database of American Sign Language. Behavior Research Methods, 49(2), 784-801. doi: 10.3758/ s13428-016-0742-0 Vinson, D. P., Cormier, K., Denmark, T., Schembri, A., & Vigliocco, G. (2008). The British Sign Language (BSL) norms for age of acquisition, familiarity, and iconicity. Behavior Research Methods, 40(4), 1079-1087. doi: 10.3758/BRM.40.4.1079 Wei, S.-E., Ramakrishna, V., Kanade, T., & Sheikh, Y. (2016). Convolutional pose machines. arXiv:1602.00134 [cs]

Alpha power during task performance predicts individual language comprehension

Alpha power attenuation during cognitive task performing has been suggested to reflect a process of release of inhibition, increase of excitability, and thereby benefit the improvement of performance. Here, we hypothesized that changes in individual alpha power during the execution of a complex language comprehension task may correlate with the individual performance in that task. We tested this using magnetoencephalography (MEG) recorded during comprehension of German sentences of different syntactic complexity. Results showed that neither the frequency nor the power of the spontaneous oscillatory activity at rest were associated with the individual performance. However, during the execution of a sentences processing task, the individual alpha power attenuation did correlate with individual language comprehension performance. Source reconstruction localized effects in temporal-parietal regions of both hemispheres. While the effect of increased task difficulty is localized in both hemispheres, the difference in power attenuation between tasks of different complexity exhibiting a correlation with performance was localized in left temporal-parietal brain regions known to be associated with language processing. Our results support the notion that in-task attenuation of individual alpha power is related to the essential mechanisms of the underlying cognitive processes, rather than merely to general phenomena like attention or vigilance