Temporal regularity and metrical organisation are important factors in beat and metre perception. The current thesis aims to investigate neural correlates of beat and metre perception in healthy non-musician volunteers, using functional magnetic resonance imaging (fMRI). In particular, the thesis focuses on determining the role of the Inferior Frontal Gyrus (IFG, in particular BA44/45) in beat and metre perception. The IFG has been proposed to be involved in higher order cognitive processes during various temporal sequencing, such as speech, movement, and music. Previous studies have shown that the temporal processing of rhythm activates auditory and sensorimotor areas, but the role of the IFG in rhythm perception has not yet been fully understood. Study 1 investigated beat perception in complex rhythms, in which the addition of volume accents either enhanced or weakened the beat perception, resulting in Unaccented, Beat Accented or Non-Beat Accented rhythms. Participants (N=14; 6 males) listened to rhythm pairs across all three conditions, and judged whether each rhythm pair was the same or different. Results showed that left IFG activation (BA44) was significantly greater during the Non-Beat Accented condition compared to Beat Accented condition, whereas the right IFG activation showed no significant difference between the two conditions. Study 2 investigated metre perception of a series of isochronous sequences, of which metrical organisation was grouped by 2/4 (C2), 3/4 (C3), or 4/4 (C4) using pitch accents, or remained without metrical grouping (or 1/4, C1). The same participants (N=15; 6 males) listened to the stimuli and indicated the perceived metrical grouping level. Results showed that the activation of bilateral IFG parametrically increased from C2 to C3 to C4. Interestingly, the activation was found to be significantly greater in C1 relative to C2, suggesting that involuntary subjective in C1 may increase the brain response. Converging results from both Study 1 and Study 2 demonstrated, firstly, that the bilateral IFG is involved in rhythm perception in addition to the auditory and sensorimotor areas, including primary and secondary auditory areas, supplementary motor areas, premotor areas, insula, and basal ganglia. Secondly, the left IFG (BA44) in particular was significantly modulated by the rhythmic complexity relating to both temporal regularity and metrical organisation, while showing the suppression during the Beat Accented rhythm condition of Study 1 and the binary pattern (C2) of Study 2. This thesis argues that the left IFG (BA44) may have the role the higher order cognitive processing, such as attention and prediction, in the perception of hierarchical structures in metric rhythms.

There is a rich literature demonstrating that adults who stutter (AWS) demonstrate atypical functional brain activity during speech production. These differences can be characterized by increased activity in the right inferior frontal gyrus and premotor regions and decreased activity in the left inferior frontal gyrus, premotor area, and bilaterally in the superior temporal gyrus. The process of speech production requires motor movements first be planned and then executed. However, few studies have examined activity related to speech-motor planning independently from speech-motor execution. Additionally, due to methodological limitations, few investigations have examined functional brain activity in children who stutter (CWS). We hypothesized that AWS and CWS would demonstrate atypical brain activity related to both speech-motor planning and execution. Using Near Infrared Spectroscopy (fNIRS), we measured the change in oxygenated hemoglobin concentration (HbO) during speech-motor planning (repetition of nonwords with three repeated or different syllables) and speech-motor execution (covert/overt naming). Results indicated that both AWS and CWS demonstrated cortical activity that was atypical during speech-motor planning processes in the right inferior frontal gyrus and atypical speech-motor execution processes in the left inferior frontal gyrus. Deactivations in the left inferior frontal gyrus may reflect inefficient feedforward mechanisms for speech production. Inefficient feedforward mechanisms will likely result in more variable movements, for which larger feedback correction signals will be necessary. Overactivations in the right inferior frontal gyrus may reflect this increased correction. Additionally, AWS demonstrated atypical speech-motor planning activity in the right middle frontal gyrus, potentially related to the production of prosody. These results are presented within a theoretical framework of two competing theories of stuttering.

This review has examined the spatial and temporal neural activation of speech comprehension. Six theories on speech comprehension were selected and reviewed. The most fundamental structures for speech comprehension are the superior temporal gyrus, the fusiform gyrus, the temporal pole, the temporoparietal junction, and the inferior frontal gyrus. Considering temporal aspects of processes, the N400 ERP effect indicates semantic violations, and the P600 indicates re-evaluation of a word due to ambiguity or syntax error. The dual-route processing model provides the most accurate account of neural correlates and streams of activation necessary for speech comprehension, while also being compatible with both the reviewed studies and the reviewed theories. The integrated theory of language production and comprehension provides a contemporary theory of speech production and comprehension with roots in computational neuroscience, which in conjunction with the dual-route processing model could drive the fields of language and neuroscience even further forward.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20664号 / 医博第4274号 / 新制||医||1024(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 髙橋 良輔, 教授 伊佐 正, 教授 井上 治久 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

The main aim of this dissertation was to investigate the difference in neural language patternsrelated to language ability in healthy adults. The focus lies on unraveling the contributions of theright‐hemispheric homologues to Broca’s area in the inferior frontal gyrus (IFG) and Wernicke’s areain the posterior temporal and inferior parietal lobes. The functions of these regions are far from fullyunderstood at present. Two study populations consisting of healthy adults and a small group ofpeople with generalized epilepsy were investigated. Individual performance scores in tests oflanguage ability were correlated with brain activation obtained with functional magnetic resonanceimaging during semantic and word fluency tasks. Performance‐dependent differences were expectedin the left‐hemispheric Broca’s and Wernicke’s area and in their right‐hemispheric counterparts. PAPER I revealed a shift in laterality towards right‐hemispheric IFG and posterior temporal lobeactivation, related to high semantic performance. The whole‐brain analysis results of PAPER IIrevealed numerous candidate regions for language ability modulation. PAPER II also confirmed thefinding of PAPER I, by showing several performance‐dependent regions in the right‐hemispheric IFGand the posterior temporal lobe. In PAPER III, a new study population of healthy adults was tested.Again, the right posterior temporal lobe was related to high semantic performance. A decrease in lefthemisphericIFG activation could be linked to high word fluency ability. In addition, task difficultywas modulated. Increased task complexity showed to correlate positively with bilateral IFGactivation. Lastly, PAPER IV investigated anti‐correlated regions. These regions are commonly knownas the default mode network (DMN) and are normally suppressed during cognitive tasks. It wasfound that people with generalized epilepsy had an inadequate suppression of regions in the DMN,and showed poorer performance in a complex language test. The results point to neural adaptabilityin the IFG and temporal lobe. Decreased left‐lateralization of the IFG and increased rightlateralizationof the posterior temporal lobe are proposed as characteristics of individuals with highlanguage ability.

The aim of this study is to investigate the neural mechanisms underlying the drawing of inferences based on a reader s knowledge during reading. Previous research studies have investigated this topic by using different types of text materials varying in coherence (e.g. Kuperberg et al., 2006), complexity (e.g. Xu et al., 2005), comprehensibility (e.g. Vandenberghe et al., 2002) or acceptability (e.g. Hagoort et al., 2004). Instead of using different types of text materials, we used a less explored method that manipulated the reader s reading goals to vary the level of engagement of inference processes. Cognitive psychologists have shown that the reader s reading goals have considerable influence on the cognitive processes of comprehension and on the content of the resulting representation of the text (Graesser et al., 1994). Here, two functional magnetic resonance imaging (fMRI) experiments were conducted to investigate the neural mechanisms of drawing strategic and routine inferences. The experimental data were analysed using two complementary approaches, namely conventional fMRI data analysis and effective connectivity analysis. Combined with an anatomical model developed in this study, the latter approach enabled us to quantify the interregional interactions modulated by the experimental conditions and to discriminate between several plausible hypotheses regarding how inferences are drawn. The results of both fMRI experiments show that the left inferior frontal gyrus (IFG) in Brodmann area (BA) 45/47 is involved in inference processes, regardless of whether inferences are drawn strategically or routinely, while the left anterior prefrontal cortex in BA 9/10 is only involved in retrieving strategic inferences. The effective connectivity analyses show that the retrieval of strategic and routine inferences consistently enhances the connectivity between the left posterior superior temporal sulcus and the left dorsal lateral IFG.

L'objectif de cette thèse a été d'investiguer la question de la généralité et de l'automatisation des processus de contrôle inhibiteur au fil du développement cognitif. Cette question a été approchée par différentes études expérimentales menées chez l'enfant, chez l'adolescent et chez l'adulte. Trois études ont porté sur la généralité des processus de contrôle inhibiteur agissant dans des tâches appartenant à des domaines cognitifs différents. Dans la première, nous avons voulu répondre à deux problématiques liées aux divergences présentes dans la littérature sur le développement du contrôle inhibiteur dans des contextes émotionnels. Le but de cette étude était de déterminer (a) si le contrôle inhibiteur froid (dans des contextes affectivement neutres) et le contrôle inhibiteur chaud (dans des contextes émotionnellement chargés) suivent un pattern développemental identique, particulièrement à l'adolescence et (b) le degré de spécificité de ces deux types de contrôle inhibiteur au fil du développement. Pour cela, nous avons comparé les performances d'enfants de 10 ans, d'adolescents de 13 ans et de jeunes adultes de 21 ans à une tâche de Stroop couleur-mot affectivement neutre et une tâche de Stroop émotionnel. Dans une deuxième étude, nous avons testé auprès d'un groupe d'enfants de 9 ans si les processus inhibiteurs impliqués dans une tâche classique piagétienne de conservation du nombre (i.e., domaine logico-mathématique) étaient identiques ou partiellement identiques à ceux impliqués dans la résolution de la tâche neuropsychologique classique de Stroop couleur-mot (i.e., domaine verbal). Dans une troisième étude, nous avons testé auprès d'un groupe d'enfants de 10 ans et d'un groupe de jeunes adultes de 20 ans la transférabilité des processus inhibiteurs entre une tâche de discrimination de lettres en miroir (dont il a récemment été démontré qu'elle nécessite l'inhibition) et une tâche classique de Stroop couleur-mot, afin de déterminer (a) si la mise en place de mécanismes inhibiteurs impliqués dans la résolution d'un conflit à un niveau perceptif très précoce (la reconnaissance visuelle de symboles) peut faciliter la résolution d'un conflit à un niveau de traitement beaucoup plus tardif (niveau sémantique et moteur), et (b) si l'âge affecte cette transférabilité. Ensuite nous nous sommes intéressés à l'automaticité des processus de contrôle inhibiteur, testant si le contrôle inhibiteur peut fonctionner de manière totalement inconsciente sur des conflits provoqués par deux stimuli subliminaux interférents. Pour cela, nous avons conçu un paradigme d'amorçage composé d'essais dans lesquels un item de Stroop inversé subliminal précédait un item de Stroop visible. Le but de ce paradigme était de vérifier la présence d'un effet d'adaptation de conflit et d'un effet d'amorçage négatif du stimulus subliminal sur le stimulus visible, deux effets rapportés dans les études utilisant des stimuli visibles et suggérant un transfert des processus de contrôle de l'amorce à la cible. Enfin dans une cinquième étude nous avons cherché à savoir si les différences interindividuelles en termes de contrôle inhibiteur découlent en partie des processus prénataux, sur base de l'analyse de la forme sulcale du cortex, considérée comme une caractéristique qualitative de l'anatomie cérébrale déterminée pendant la vie fœtale et stable au cours du développement. En utilisant l'imagerie par résonance magnétique anatomique, nous avons analysé les corrélations entre les performances à une tâche de Stroop couleur-mot et la forme sulcale de deux régions clefs du réseau neuronal du contrôle inhibiteur, le cortex cingulaire antérieur dorsal et le sillon frontal inférieur (qui limite le gyrus frontal inférieur), chez un groupe d'enfants de 10 ans et un groupe d'adultes de 22 ans. En conclusion, cette thèse apporte un nouvel éclairage à la question de la généralité et de l'automatisation des processus d'inhibition exécutive dans une perspective développementale / The objective of this thesis was to investigate the question of the domain-generality of inhibitory control and its automatization throughout development. This question has been approached by various experimental studies in children, adolescents and adults. Three studies have focused on the generality of control processes operating in tasks belonging to different cognitive domains. In the first study, we wanted to answer two questions related to the discrepancies found in the literature on the development of inhibitory control in affectively charged contexts. The aim of this study was to determine (a) whether cool inhibition (control processes in emotionally neutral contexts) and hot inhibition (control processes in emotionally charged contexts) follow the same developmental pattern, and (b) the degree of specificity of these two types of inhibitory control throughout development. We thus compared the performance of 10-year-olds, 13-year-olds and 21-year-olds to an emotionally neutral color-word Stroop task and an emotional Stroop task. In a second study on 9-year-old children, we tested whether the inhibitory processes involved in a classical Piagetian conservation task (i.e., logico-mathematical domain) were identical or partially identical to those involved in the resolution of the classical neuropsychological color-word Stroop task (i.e., verbal domain). In a third study, we tested on a group of 10-year-old children and a group of 20-year-old young adults the transferability of inhibitory processes between a mirror letters discrimination task (that has recently been shown to require inhibition) and a color-word Stroop task, to determine (a) whether the resolution of a conflict at an early perceptual stage of the processing stream (recognition of visual symbols) can facilitate the resolution of a conflict arising at a much later stage (semantic and motor levels), and (b) if age affects this transferability. Then we looked at the automaticity of the inhibition processes by testing whether inhibitory control can operate completely unconsciously on conflicts arising between two subliminal interfering stimuli. To this end, we designed a priming paradigm consisting of trials in which a subliminal reverse Stroop item preceded a visible Stroop item. The aim of this paradigm was to verify the presence of a conflict adaptation effect and a negative priming effect produced by the subliminal items on the visible items. These two effects are commonly reported in studies using visible stimuli and suggest a transfer of control processes from the prime to the probe. Finally, in a fifth study, we investigated whether inter-individual differences in inhibitory control are in part due to prenatal processes, based on the analysis of the sulcal pattern, considered as a qualitative feature of the cerebral anatomy that is determined during fetal life and is stable during development. Using anatomical magnetic resonance imaging, we analyzed the correlations between the performance on a color-word Stroop task and the sulcal pattern of two key regions of the inhibitory control neural network, the dorsal anterior cingulate cortex and the inferior frontal sulcus (which limits the lower frontal gyrus) in a group of 10-year-old children and in a group of 22-year-old adults. In conclusion, this thesis sheds new light on the question of the generality and the automatization of the inhibitory control processes from a developmental perspective.

No description available.

We investigated age-related differences in neural activation associated with recognition of familiar melodies, a process that requires retrieval from musical semantic memory and leads to a feeling of familiarity. We used sparse sampling fMRI to determine the neural correlates of melody processing and familiarity by comparing activation when listening to melodies versus signal-correlated noise, and to familiar versus unfamiliar melodies, respectively. Overall, activity in the bilateral superior temporal gyrus correlated well with melody processing. Familiarity was associated with several frontal regions (bilateral inferior frontal gyrus, superior frontal gyrus, and precentral gyrus; left insular cortex), right superior temporal gyrus; left supramarginal gyrus and cingulate gyrus; bilateral putamen and thalamus; cerebellum and brainstem. No significant differences were found between younger and older adults for either melody processing or familiarity based activation. Assessment of familiarity-related group differences using less stringent criteria identified plausible areas; greater activation was seen bilaterally in the superior temporal gyrus in younger adults and in some left parietal regions in older adults. This study adds to the knowledge of musical semantic memory with results based on a large sample (N = 40) that includes older adults. Our findings for activation associated with melody processing and familiarity support some, but not all, previous results of related studies. We were unable to find conclusive evidence of age-related differences in neural correlates of musical semantic memory, while also being the first study (to the best of our knowledge) to search for these differences. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2013-09-16 12:38:10.757

We investigated age-related differences in neural activation associated with recognition of familiar melodies, a process that requires retrieval from musical semantic memory and leads to a feeling of familiarity. We used sparse sampling fMRI to determine the neural correlates of melody processing and familiarity by comparing activation when listening to melodies versus signal-correlated noise, and to familiar versus unfamiliar melodies, respectively. Overall, activity in the bilateral superior temporal gyrus correlated well with melody processing. Familiarity was associated with several frontal regions (bilateral inferior frontal gyrus, superior frontal gyrus, and precentral gyrus; left insular cortex), right superior temporal gyrus; left supramarginal gyrus and cingulate gyrus; bilateral putamen and thalamus; cerebellum and brainstem. No significant differences were found between younger and older adults for either melody processing or familiarity based activation. Assessment of familiarity-related group differences using less stringent criteria identified plausible areas; greater activation was seen bilaterally in the superior temporal gyrus in younger adults and in some left parietal regions in older adults. This study adds to the knowledge of musical semantic memory with results based on a large sample (N = 40) that includes older adults. Our findings for activation associated with melody processing and familiarity support some, but not all, previous results of related studies. We were unable to find conclusive evidence of age-related differences in neural correlates of musical semantic memory, while also being the first study (to the best of our knowledge) to search for these differences. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2013-09-16 12:38:10.757