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This dissertation aims to understand how attention can be used to improve sensory integration for postural control. Decades of research have been done using visual manipulations to study how healthy and clinical populations resolve multisensory (vision, vestibular, and somatosensory) mismatches to maintain postural stability. Postural control is a complex motor skill that requires accurate integration of multiple senses to maintain body alignment and orientation with respect to the environment. Age-related decline in visual, vestibular, and somatosensory acuity increases the risk for falls, and these sensory declines can be identified by assessing sensory reweighting. Sensory reweighting is the process in which the nervous redistributes the reliance, or "weight," on the sensory inputs to achieve postural stability. While the literature on sensory manipulation on postural control and fall risk has uncovered a wealth of knowledge on sensory reweighting for balance, it has neglected to identify how sensory reweighting can be improved. At the same time, motor learning literature has demonstrated the importance of focus attention during balance training to improve postural control. However, rudimentary analyses such as duration of balance and sway variability in this literature have limited deeper examination of the underlying neural mechanisms affected by focus of attention. This dissertation aims to bridge the gap between the two works of literature by implementing sensory manipulation techniques on posture using the latest technologies in virtual reality (VR) head-mount display (HMD) with motion capture and electroencephalography (EEG) recordings to study how different focuses of attention help resolve multisensory conflicts. In aim one, forty-two healthy adults participated in the study that used VR manipulation to induce a multisensory conflict. Participants were tasked to maintain upright stability on a rocker board while given different instructions on where to focus their attention. Instructions included focusing on keeping the rocker board leveled (external focus), focusing on keeping feet leveled to each other (internal focus), and focusing on staying as still as possible (control). This study revealed an immediate improvement in postural stability when instructed with external focus compared to control. This improvement was also associated with a significant decrease in visual weighting. Additionally, this aim revealed an immediate change in cortical activity within the frontal and occipital regions of the brain as identified by EEG recordings when participants are instructed to use external focus and internal focus. In aim two, twenty-eight healthy adults participated in the crossover study that demonstrated order effects when multiple instructions of attentional focus were given to the same participant for postural stability and visual reweighting. This study showed that the effects of external focus on postural stability and visual reweighting are greater when external focus is used before internal focus. However, the effects of external focus were nullified when used after using internal focus. Furthermore, the order of the instructions may have corresponded with a recency bias regarding how the participant perceived the effectiveness depending on when they received the attentional focus instruction. Guided by the findings from aims one and two, aim three recruited twenty-seven older adults to participate in a single-session balance training using repeated exposure to VR manipulation that challenged their balance on a rocker board. The older adults were randomized into one of the three groups: external focus, internal focus, and control group. The external focus group did not demonstrate an immediate reduction in visual weighting as found in aim 1. However, the external focus group did demonstrate better immediate postural stability when compared to the internal focus groups. Both external and internal focus groups revealed a significant improvement in visual weighting and postural stability across training blocks, suggesting a potential role of attentional focus on postural control adaption to repeated VR exposure. This dissertation was one of the first studies to investigate how the attentional focus impacts sensory reweighting and postural control in young and older adults using VR HMD. This project also established a VR experimental paradigm that can be used to study the focus of attention and the resolution of multisensory mismatch. With the increased use of VR for balance training and rehabilitation, this project is at the forefront of utilizing VR HMD technology to expose underlying sensory mechanisms for postural control. Results from this study can guide future rehabilitation and balance training interventions by identifying how attention should be directed during training. / Public Health

Nós realizamos três experimentos para estudar a distribuição da atenção pelo campo visual e a possibilidade dos recursos atentivos serem mais concentrados no interior de uma área delimitada por uma figura geométrica de aparecimento abrupto. Os participantes realizaram uma tarefa de julgamento de ordem temporal (JOT), na qual julgaram a ordem de duas letras apresentadas em seqüência. Uma letra foi apresentada dentro e a outra fora de uma moldura, que não foi relacionada com a tarefa. A percepção de ordem temporal foi influenciada pela moldura nos três experimentos. A variação da distância entre as duas letras e o tempo de exposição da moldura foram manipulados, alterando o julgamento dos participantes. Os resultados demonstraram uma variação na concentração dos recursos atentivos em função da distância entre as duas letras e em função do tempo de exposição da moldura. Os resultados sugerem que a forma de uma figura geométrica pode produzir uma reorganização dos recursos atentivos, que parecem estar mais concentrados dentro do que fora das suas bordas. / We conducted three experiments to examine the distribution of visual attention and the possibility of the attentional resources to be concentrated along an area delimited by a frame of abrupt onset. The participants performed a temporal order judgment (TOJ) task, in which judged the order of two letters presented in sequence. One letter was showed inside and other outside a frame that was not related to the task. Perception of temporal order was influenced by the frame in all experimental conditions. The judgement of participants was affected by the distance between the two letters and the cue lead time. The findings suggest that the form of a geometric figure can reallocate the resources of attention that should be more concentrated inside than outside of its borders.

The purpose of this study was to examine the effects of internal and external focus feedback and their preference on skill learning at age of 12-13 years. Internal focus feedback related with body movements, whereas external focus feedbacks related with movement effects. As a task &ldquo / tennis&rdquo / service in volleyball was used for both acquisition and retention measurements. The subjects (N=78) were randomly assigned to three groups which were internal focus feedback group (IFF), external focus feedback group (EFF) and preference groups (PF). To promote learning three practice days and to assess learning one retention day was applied. Also, during these days, both technique of the skill and targeting was tried to measure. In technique measure the IFF group performed better than EFF group in acquisition and retention phases. PF group had similar scores with IFF group in acquisition phase whereas it did not show better performance than IFF group in retention phase. PF group performed better than EFF group in both phases. In product measure, significant differences between attentional focus feedback groups in acquisition and retention phases. This study indicated that for young children with limited amount of knowledge about a skill internal focus feedback is more appropriate compared to external focus feedback in terms of retention. Being able to choose among internal and external focus of attention also seems to make a difference in retention performance of novice children indicating that active participation on the learning variables is an important concept.

Submitted by JULIANA LAHR null (ju_lahr@hotmail.com) on 2016-01-08T17:34:37Z No. of bitstreams: 1 Lahr, Juliana_dissertação.pdf: 4300978 bytes, checksum: c8f51cad4332528f3754c1d768464c48 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-01-11T18:03:07Z (GMT) No. of bitstreams: 1 lahr_j_me_rcla.pdf: 4300978 bytes, checksum: c8f51cad4332528f3754c1d768464c48 (MD5) / Made available in DSpace on 2016-01-11T18:03:07Z (GMT). No. of bitstreams: 1 lahr_j_me_rcla.pdf: 4300978 bytes, checksum: c8f51cad4332528f3754c1d768464c48 (MD5) Previous issue date: 2015-12-17 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Background: Parkinson’s disease (PD) presents asymmetric early motor symptoms, and those symptoms affect the processing and the integration of proprioceptive information. Due to that, the upper limb motor control is impaired even on single task (isolated manual task) and dual task (manual task and posture control). Because these sort of tasks are performed during activities of daily living, the role of asymmetry on those task must be clarified to elucidate the effects of disease on PD functionality and thus guide the therapists choose more effective interventions. Among strategies of intervention on PD motor impairments, two strategies that deserve special attention are the instruction of external focus of attention and mirror therapy (MT). Both interventions might be potentially effective to facilitate motor learning. Aims: to assess the role of PD asymmetry on upper limbs motor control and postural control in conditions of single versus dual task; and tasks with attentional focus with instructions versus external focus as well as to verify the effect of MT on upper limbs motor control more affected on postural control of PD patients. Methods: Twenty PD patients were submitted to assessments on: Upper Limb motor control (kinematic analysis) and postural control (kinetics analysis), in single and dual task conditions, with and without external focus of attention. Posteriorly, the subjects were distributed in two different groups: GI1 and GI2. The MT protocol consisted in a unilateral home therapy on less affected upper limb, performed 30 minutes a day, five days a week, during 6 consecutives weeks. To assist the subjects of GI1, they performed this protocol using a visual feedback (mirror therapy). Both groups were assessed before and after therapy protocol. Results: performance was not different between upper limbs and single and dual tasks, both in single and in dual task. After protocol period, both groups showed improvements on kinematic outcomes (manual dexterity, movement frequency of the hand, hesitation and task performance time improvements, independent of the sort of focus of attention that was used). Conclusion: Manual task is not affected by PD asymmetry on single and dual task. The external focus of attention was not effective to improve the task performance in PD patients, and it is not recommended to be performed during dynamic tasks. The therapy protocol with or without visual feedback promotes extended benefits on execution and planning of manual task of more affected upper limb independently of focus of attention, but it is not able to decrease the functional and motor impairments neither improve postural control. Therefore MT seems to be equally effective on manual tasks benefits, however more studies are necessary to confirm this efficacy. / Introdução: a doença de Parkinson (DP) tem o início assimétrico dos sintomas motores e afeta o processamento e a integração das informações proprioceptivas, comprometendo o controle motor dos membros superiores tanto em tarefa singular (tarefa manual isolada) quanto em tarefa dupla (tarefa manual e controle postural). Por estas tarefas serem frequentemente exigidas nas atividades de vida diária, esclarecimentos quanto ao papel da assimetria da doença nessas tarefas podem elucidar sobre os efeitos da doença na funcionalidade dos pacientes e nortear a decisão sobre estratégias de intervenção mais pertinentes. Dentre as estratégias de intervenção para esses comprometimentos encontram-se a instrução de foco de ação externo e a terapia do espelho (TE). Ambas as intervenções podem ser potencialmente eficazes na DP por facilitar a aprendizagem motora. Objetivos: avaliar o papel da assimetria da doença no controle dos membros superiores e do controle postural nas condições de tarefa singular versus dupla e de tarefa com instrução de foco de atenção livre versus foco externo, assim como verificar o efeito da TE no controle motor do membro superior afetado e no controle postural de pacientes com DP. Método: 20 pacientes foram avaliados quanto ao controle dos membros superiores (análise cinemática) e ao controle postural (análise cinética), nas condições de tarefa singular e dupla, foco de atenção livre e externo. Posteriormente, os pacientes foram distribuídos nos grupos GI1 e GI2 e realizaram a intervenção que consistiu de treino unilateral do membro superior menos afetado, com duração de 30 minutos diários, 5 dias consecutivos na semana, durante 6 semanas, em domicílio. Na intervenção somente o GI1 utilizou o feedback visual - TE. Os grupos foram avaliados pré- e pós-intervenção. Resultados: o desempenho não diferiu entre os membros superiores e entre as condições de tarefa singular e dupla. O foco de atenção externo reduziu o desempenho da tarefa manual, tanto na tarefa singular quanto na dupla. Após o período de intervenção, ambos os grupos melhoraram o desempenho nas variáveis cinemáticas – aumentaram a destreza manual e a frequência de movimento da mão, diminuíram a hesitação na realização do movimento e o tempo para realizar a tarefa, independente do foco de atenção empregado. Conclusão: a assimetria da doença não interfere no desempenho da tarefa manual nas condições de tarefa singular e dupla. O foco de atenção externo não foi eficaz em melhorar o desempenho da tarefa manual em pacientes com DP, não devendo ser utilizado em tarefas dinâmicas. A intervenção, com ou sem feedback visual, melhora a execução e o planejamento da tarefa manual do membro superior afetado independente do foco atencional empregado, mas não é capaz de reduzir o comprometimento funcional e motor, nem de melhorar o desempenho do controle postural. Portanto, a TE parece ser igualmente eficaz na melhora do desempenho da tarefa manual, porém, mais estudos são necessários para afirmar sua efetividade. / CNPq: 157894/2013-4

Nós realizamos três experimentos para estudar a distribuição da atenção pelo campo visual e a possibilidade dos recursos atentivos serem mais concentrados no interior de uma área delimitada por uma figura geométrica de aparecimento abrupto. Os participantes realizaram uma tarefa de julgamento de ordem temporal (JOT), na qual julgaram a ordem de duas letras apresentadas em seqüência. Uma letra foi apresentada dentro e a outra fora de uma moldura, que não foi relacionada com a tarefa. A percepção de ordem temporal foi influenciada pela moldura nos três experimentos. A variação da distância entre as duas letras e o tempo de exposição da moldura foram manipulados, alterando o julgamento dos participantes. Os resultados demonstraram uma variação na concentração dos recursos atentivos em função da distância entre as duas letras e em função do tempo de exposição da moldura. Os resultados sugerem que a forma de uma figura geométrica pode produzir uma reorganização dos recursos atentivos, que parecem estar mais concentrados dentro do que fora das suas bordas. / We conducted three experiments to examine the distribution of visual attention and the possibility of the attentional resources to be concentrated along an area delimited by a frame of abrupt onset. The participants performed a temporal order judgment (TOJ) task, in which judged the order of two letters presented in sequence. One letter was showed inside and other outside a frame that was not related to the task. Perception of temporal order was influenced by the frame in all experimental conditions. The judgement of participants was affected by the distance between the two letters and the cue lead time. The findings suggest that the form of a geometric figure can reallocate the resources of attention that should be more concentrated inside than outside of its borders.

For over two decades, research has shown that providing instructions and feedback to promote an external focus (i.e., mentally focusing on movement effects or outcome) leads to enhanced motor performance and learning, compared to an internal focus (i.e., mentally focusing on the muscles and joints, or movement kinematics). Notably, while a majority of the research has been on healthy young adults, the external focus benefit has also been found to extend to individuals recovering from musculoskeletal dysfunction. Despite the potential benefit of an external focus for rehabilitation, observational studies have revealed that physiotherapists provide their clients with more internal, than external, focus statements and have little awareness of the focus of attention literature. Consequently, the end goal of this doctoral research was to translate the focus of attention research findings into Canadian physiotherapy practice through the design, delivery and assessment of an educational workshop for practicing physiotherapists. With this in mind, the first step became to determine whether such a workshop was warranted by assessing the self-reported focus of attention provision by Canadian physiotherapists. Thus, in Study 1 a study-specific questionnaire, titled the "Therapists' Perceptions of Motor Learning Principles Questionnaire" (TPMLPQ), was designed and completed by 121 Canadian physiotherapists. Results showed an overall low relative frequency of self-reported external focus promotion (M = 31.3%, SD = 14.9), across six hypothetical rehabilitation scenarios. Markedly, descriptions of a functional reaching (M = 55.5 %, SD = 37.0) and pelvic floor task (M = 65.6%, SD = 32.9) resulted in a greater self-reported promotion of external, than internal, focus of attention. These results suggested that Canadian physiotherapists could benefit from an educational workshop on focus of attention, and that there was a potential task dependency for their focus of attention promotion. Study 2 employed virtual one-on-one interviews with eight Southern Ontario-based physiotherapists, all whom completed the TPMLPQ just prior to the interview. The first few questions gathered participants' perceptions on factors that influence physiotherapists' focus of attention use, as well as barriers to promoting an external focus and potential solutions to them. Coding of the interview data generated four themes related to factors that influenced focus of attention use: (1) physiotherapist experiences and characteristics, (2) client experiences and characteristics, (3) task characteristics and (4) focus of attention statement provision strategies. Moreover, the barriers to external focus promotion were organized into three themes: (1) educational experiences, (2) reinforcement of internal focus encouragement once in practice and (3) research aspects. All interviewed physiotherapists proposed continuing education on focus of attention as a solution to these barriers. Questions in the second half of the interview garnered input on how to get physiotherapists to attend a focus of attention workshop, and what activities to include before, during or after the workshop to promote physiotherapists to use more externally focusing statements in their practice. This information was used to inform the workshop design and delivery. In addition to the physiotherapists' input, I also considered previous research that has emphasized the importance of evidence-based training programs to be based on theoretical frameworks. In this regard, Bandura's social cognitive theory was selected as a theoretical foundation. Further, knowing that the target population for the workshop consisted of adults with higher education, Knowles' adult learning theory was also selected as a complimentary theoretical foundation. Additionally, the Kirkpatrick model for training evaluation was selected to guide the assessment of the workshop, due to its strong overlap with constructs from both theoretical frameworks adopted. A final contribution to the workshop design process was holding a virtual group session with four focus of attention researchers in order to gain input on workshop content. The final workshop product consisted of two parts: seven self-directed asynchronous website modules and a synchronous virtual group session. Ultimately, in Study 3, the workshop was delivered to fifteen Canadian physiotherapists. In addition to completing the two workshop components (asynchronous and synchronous), participants completed assessment packages at three time points: (1) one-week pre-synchronous workshop, (2) immediately post-synchronous workshop, and (3) one-week post-synchronous workshop. Analysis of the data revealed a chain of evidence supporting the merits of the workshop. Explicitly, physiotherapists reported high satisfaction (Mdn = 4.60), perceived relevance (Mdn = 4.83), and engagement in the workshop (Mdn = 4.83). Comparing one-week pre- to immediately post-workshop, analyses revealed significant improvements to physiotherapists' (1) scores on the knowledge assessment (pre M = 51.30%, SD = 22.30; post M = 84.30%, SD = 11.50; p < .001, d = 2.06) with an accompanying decrease in the uncertainty in their responses (pre M = 23.19%, SD = 18.05; post M = 1.16%, SD = 1.99; p < .001, d = 1.28), (2) relative frequency of externally focusing to total focus of attention statements created on the skill assessment (pre M = 18.23%, SD = 13.17; post M = 67.95%, SD = 25.13; p < .001, d = 2.11), (3) self-reported attitudes towards learning and practice of external focus promotion (pre M = 88.25, SD = 11.00; post M = 92.83, SD = 6.59; p = .024, d = 0.56) and self-efficacy (pre M = 59.50, SD = 22.36; post M = 85.72, SD = 7.95, p < .001, r = 0.86). Using descriptive statistics, physiotherapists reported that participating in the workshop allowed them to increase their encouragement of external focus adoption (M = 79.00, SD = 15.14). Thirteen of the physiotherapists reported that they believed that their use of externally focusing statements led to improvements in their clients' rehabilitation outcomes (n = 13; M = 68.08, SD = 22.13), while the other two physiotherapists noticed no difference. Finally, those 13 physiotherapists also reported a high intention to continue to provide external focus statements in their practice (M = 87.31, SD = 15.09). In the context of social cognitive theory, these findings suggest that the workshop was successful in strengthening the physiotherapists' behavioral capabilities, self-efficacy, and outcome expectations, suggesting that the behavior change self-reported by the physiotherapists (i.e., more external focus promotion) could extend beyond the short-term assessment period used here. The whole of this doctoral research acts as a powerful step on the pathway to translate focus of attention research into Canadian physiotherapy, and also provides a useful framework for future studies aiming to translate motor learning research into the field - in Canada or globally.

Within the last decade, the influence of focus of attention (FOA) instruction on postural control has been an increased interest among researchers (Yeh et al., 2016; McNevin et al., 2013). The general agreement when it comes to the role of FOA has been that adopting an external (EXT) FOA enhances the efficiency of motor programming by strengthening the relationship between movement planning and outcome, when compared to an internal (INT) FOA (see Wulf, 2013). However, increasing evidence suggests that the benefits from an EXT FOA can be mitigated by certain factors (e.g., age, skill level, novelty of the task and task complexity; Becker & Smith, 2013; Emanuel et al., 2008). As such, questions remain as to what form of FOA instruction is best suited for young learners, as FOA research has been criticized for being studied almost exclusively among adults (Agar et al., 2016). Research in this area is particularly sparse as it pertains to FOA in combination with postural control among this younger age group. This is particularly problematic as significant changes in postural control, stability and balance occur during one’s first decade in life (Haas, et al., 1989; Hay & Redon, 1999; Barela et al., 2003). Moreover, there exists some methodological concerns with regard to the lack of consistency of FOA instructions being used during experimentation. This directly influences where participants are guiding their attention and their interpretation of FOA cues (Davids, 2007; Petranek, et al., 2019). Further, the lack of replicability of traditional FOA studies and the increasing number of non-statistically significant findings in this research, calls into question the overall validity, both internal and external, regarding FOA instruction (Becker & Smith, 2013; Lawrence et al., 2011). Therefore, as a series of four complementary studies, the overall aim of this thesis is to further investigate these theoretical as well as procedural gaps. The first study examines which type of FOA instruction is best suited for two groups of young learners (typically developing children between 4-6 and 7-10 years of age) performing a postural control task. Participants will be randomized into either an INT, EXT or CTRL condition, where they will perform a postural control task with different respective visual displays. A force platform will be used to assess participants’ mediolateral centre of pressure (COP) performance, and electromyography (EMG) will be used to assess muscular activation of the participants’ major ankle stabilizers. The primary goal of study one is to investigate the influence of FOA in children by following the most common and traditional of FOA instruction. The second study serves as an extension for the first study. The aim of this study is to specifically investigate the validity and reliability of using FOA instructions, and whether or not the different attentional cues can drive their intended mental focus states. The method of this study is identical to those is Study 1 with a few major exceptions. In this case, two manipulation checks will be added to the procedure in order to assess how participants perceived, comprehended, and acted to their assigned FOA instructional condition. The first manipulation check is embedded in the structure of the trial itself: the comparison of postural control performance with and without visual information, modeled after the technique used in Yeh and colleagues (2016). The second manipulation check will be a retrospective verbal interview inspired by Perreault & French (2016). Finally, the third and fourth studies look to expand the research question from study one and two to different populations of atypically developing young learners who are known to struggle with both attention and postural control. Individuals with ADHD and individuals with DCD have been shown to interpret attentional and postural information differently when compared to age-matched controls. Therefore, the aim of these studies is to compare the differing effects of FOA across neurodiverse populations. Specifically, study three will use a group of young learners (from 4 – 10 years of age) with ADHD and study four will use a group of young learners (from 4 – 10 years of age) with DCD. The only differences in these studies compared to study one will be the lack of an age split and the use of EMG assessment. / Thesis / Master of Science in Kinesiology

La thèse porte sur le statut sémantico-pragmatique des propositions relatives appositives (PRA), étudié à travers l’examen du fonctionnement discursif des phrases complexes de la forme ‘Matrice, qui PRA’ du français. Dans beaucoup de langues, les PRA n’interagissent pas sémantiquement avec les opérateurs présents dans leurs propositions enchâssantes et tendent à s’interpréter pragmatiquement comme porteuses d’informations non-centrales ou secondaires pour la question en discussion (QUD) du discours en cours. Plusieurs analyses (Holler 2005, Arnold 2007, Koev 2012) dissocient ces deux propriétés en dérivant la projection des PRA de leur statut d’assertions indépendantes et en expliquant leur lecture pragmatique à l’aide de principes généraux de gestion du flot discursif. En effet, lorsque les PRA apparaissent en fin de phrase, elles sont susceptibles d’interagir avec la QUD tout en ayant une portée large vis-à-vis du reste de la phrase. Certains phénomènes discursifs semblent néanmoins contredire l’idée que les PRA constituent des assertions indépendantes. D’abord, les PRA peuvent interagir avec la QUD seulement si leurs matrices véhiculent également des informations pertinentes pour le sujet en discussion. Ensuite, contrairement à ce que l’on peut observer dans une séquence de deux propositions indépendantes, dans une séquence formée d’une proposition matrice et d’une PRA, quel que soit l’ordre de leur linéarisation, la matrice s’interprète toujours comme centrale pour le discours, alors que le statut pragmatique de la PRA dépend fortement du degré d’informativité du reste de la phrase vis-à-vis de la QUD. Enfin, les résultats de deux études comportementales conduites pour la thèse montrent que, suite au traitement de phrases complexes comme ‘Matrice, qui PRA’, les référents du type ‘individu’ mentionnés par la matrice restent hautement saillants pour le discours subséquent contrairement à ceux dont il est question dans la PRA, qui jouissent d’un degré d’accessibilité assez faible. Partant de ces données, nous concluons que la lecture pragmatique centrale des PRA n’est pas une conséquence de leur statut d’assertions indépendantes mais résulte de l’intégration de leur contenu dans le domaine focal de leurs matrices. Plus généralement, en nous appuyant sur les travaux d’Ander Bois & al. (2010) et Schlenker (2013, ms), nous défendons l’idée que le manque d’interaction entre les PRA et le reste de leurs phrases d’accueil ainsi que leur prédisposition à une interprétation non-centrale pour le discours proviennent du fait, qu’à la différence de leurs matrices, dont l’énonciation s’accompagne de l’introduction d’un référent propositionnel nouveau, les PRA sont des anaphores propositionnelles, dont la portée sémantique et l’interprétation pragmatique dépendent de la position discursive de l’expression important dans l’univers du discours le référent auquel s’applique le contenu qu’elles expriment. / The thesis focuses on the semantic-pragmatic status of appositive relative clauses (ARC). We address this question by examining discourse functioning of complex sentences of the form ‘Matrix, qui ARC’ in French. Crosslinguistically, ARC fail to interact semantically with scope taking operators contained in their embedding clauses and tend to be interpreted pragmatically as carrying non-central or secondary information for the question under discussion (QUD) in the ongoing discourse. Several analysis (Holler 2005, Arnold 2007, Koev 2012) dissociate these two properties, deriving the ARC projection from their status of independent assertions and explaining their pragmatic reading with independent principles of the discourse flow management. Indeed, when an ARC follows linearly its embedding clause, it can interact with the QUD while still receiving a wide scope relatively to the rest of the host sentence. Some discursive phenomena seem nevertheless contradict the idea that ARC constitute independent assertions. First, an ARC can interact with a QUD only if its matrix clause also conveys information relevant to the subject under discussion. Second, contrary to what we observe examining sequences of two independent clauses, in sequences formed of a matrix clause and an ARC, regardless of the order of their linearization, the matrix clause is always interpreted as being at-issue for the discourse, while the pragmatic status of the ARC depends to a great extent on the degree of informativeness of the rest of the sentence relatively to the QUD. And, third, the results of two psycholinguistic experiments conducted as part of this study show that after processing a sentence such as ‘Matrix, qui ARC’, the entity-type referents realized by the matrix clause are highly salient for the subsequent discourse unlike those realized by the ARC, which have a rather low accessibility degree. Based on these data, we conclude that at-issue pragmatic reading of ARC is not a consequence of their functioning as independent assertions but results from integration of their content into the focal domain of the embedding clause. More generally, building on the works of AnderBois & al. (2010) and Schlenker (2013, ms), we defend the idea that the lack of interaction between ARC and the host sentences as well as their tendency to receive a not at-issue reading in discourse arise from the fact that unlike their matrix clauses, whose utterance has the effect of introducing a new propositional referent, ARC are propositional anaphora, the semantic and pragmatic interpretation of which depends thus on the discourse position of their antecedent expression, importing into the discourse the propositional referent the ARC’s content applies to.