When analyzing complex scenes, humans often focus their attention on an object at a particular spatial location in the presence of background noises and irrelevant visual objects. The ability to decode the attended spatial location would facilitate brain computer interfaces (BCI) for complex scene analysis. Here, we tested two different neuroimaging technologies and investigated their capability to decode audio-visual spatial attention in the presence of competing stimuli from multiple locations. For functional near-infrared spectroscopy (fNIRS), we targeted dorsal frontoparietal network including frontal eye field (FEF) and intra-parietal sulcus (IPS) as well as superior temporal gyrus/planum temporal (STG/PT). They all were shown in previous functional magnetic resonance imaging (fMRI) studies to be activated by auditory, visual, or audio-visual spatial tasks. We found that fNIRS provides robust decoding of attended spatial locations for most participants and correlates with behavioral performance. Moreover, we found that FEF makes a large contribution to decoding performance. Surprisingly, the performance was significantly above chance level 1s after cue onset, which is well before the peak of the fNIRS response. For electroencephalography (EEG), while there are several successful EEG-based algorithms, to date, all of them focused exclusively on auditory modality where eye-related artifacts are minimized or controlled. Successful integration into a more ecological typical usage requires careful consideration for eye-related artifacts which are inevitable. We showed that fast and reliable decoding can be done with or without ocular-removal algorithm. Our results show that EEG and fNIRS are promising platforms for compact, wearable technologies that could be applied to decode attended spatial location and reveal contributions of specific brain regions during complex scene analysis.

Pain perception can be drastically affected by external factors in the surrounding environment. Previous studies relying on subjective ratings of pain have shown that guided meditations supplemented by virtual reality (VR) can reduce the perception of pain more successfully than the audio alone. The research question for this study was: How does the efficacy of meditation as a means of pain mitigation differ with and without the application of VR? To answer this question, we used fNIRS to visualize changes in the dorsolateral prefrontal cortex (DLPFC), which has been shown to play a role in the larger pain matrix in the brain. To induce discomfort, we used a Cold Pressor Arm Wrap (CPAW), which is a variation of the more common Cold Pressor Task (CPT). This study was a within-subjects design where in each of the three conditions participants experienced CPAW. The three conditions were: (1) control (no VR & no audio), (2) audio (audio only), and (3) VR (audio + VR). We hypothesized that there would be a decrease in cortical activity in the DLPFC during CPAW when supplemented by VR meditation compared to audio-led meditation and no meditation, due to a decrease in perceived pain in the VR condition. Our results showed that VR meditation did significantly reduce perceived pain, according to the subjective pain ratings. Participants rated their discomfort the lowest in the VR condition, slightly higher in the audio condition, and highest for the control condition (in the absence of meditation). However, there were no significant differences in activity in the DLPFC between the conditions. The lack of any significant findings with the fNIRS data could be the result of many issues, including not having a large enough sample, physiological noise, improper localization of the pain ROIs, and not having a strong enough discomfort stimulus. The future directions for this study would seek to remedy these issues in order to obtain more informative fNIRS results. Overall, this study did show that VR meditation does effectively reduce pain perception and is therefore a promising tool for nonpharmacological pain management.

No description available.

Frequency domain functional near infrared spectroscopy (FD-fNIRS) is a tissue optical measurement technique used to measure absolute haemoglobin concentrations in brain tissue. This work is intended to be the first step in the development of a wearable, low-cost FD-fNIRS device for neurofeedback applications. The system requirements were generated from a review of relevant literature. A simplified system architecturewas developed based on the various instrumentation methodologies proposed by various authors. The functional blocks of this system were prototyped and their performance was evaluated. The developed vertical-cavity surface-emitting laser (VCSEL) current source was found to have a span of 10uA which meets the design specifications. Challenges exist in optimally biasing silicon photomultiplier (SiPM), which is susceptible to optical and electronic noise sources.

Submitted by PPG Medicina e Ci?ncias da Sa?de (medicina-pg@pucrs.br) on 2018-02-23T19:15:10Z No. of bitstreams: 1 JULIANA_ANTOLA_PORTO_TES.pdf: 4776720 bytes, checksum: 1995f76f1de8d24f63bbbf990ed7083c (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2018-02-26T19:46:38Z (GMT) No. of bitstreams: 1 JULIANA_ANTOLA_PORTO_TES.pdf: 4776720 bytes, checksum: 1995f76f1de8d24f63bbbf990ed7083c (MD5) / Made available in DSpace on 2018-02-26T19:51:08Z (GMT). No. of bitstreams: 1 JULIANA_ANTOLA_PORTO_TES.pdf: 4776720 bytes, checksum: 1995f76f1de8d24f63bbbf990ed7083c (MD5) Previous issue date: 2017-10-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / As bases neurais do processamento da emo??o facial na inf?ncia s?o amplamente desconhecidas. Os fatores ambientais que podem afetar o processamento facial e o reconhecimento emocional ao longo do curso de desenvolvimento tamb?m s?o pouco compreendidos. No entanto, acredita-se que as experi?ncias iniciais, particularmente envolvendo exposi??o repetida a faces emocionais dos cuidadores, influenciem esse curso. O objetivo deste estudo foi investigar os correlatos neurais do processamento de faces emocionais em lactentes usando a espectroscopia funcional no infravermelho pr?ximo (fNIRS), e examinar a poss?vel influ?ncia das experi?ncias emocionais iniciais dos lactentes, indiretamente medida pela investiga??o de sintomas de ansiedade materna. Foram avaliadas 29 crian?as de 5 meses de idade e suas m?es, recrutadas de uma amostra da comunidade de Boston, EUA. A ansiedade materna foi avaliada usando o componente tra?o do Invent?rio de Ansiedade Tra?o-Estado (STAI-T). Os lactentes observaram imagens visuais est?ticas de faces femininas retratando express?es de alegria e medo, enquanto as respostas hemodin?micas corticais foram medidas usando fNIRS. As respostas de oxihemoglobina (oxiHb) e deoxihemoglobina (deoxiHb) nas ?reas frontais, parietais e temporais foram comparadas entre as faces emocionais, e entre filhos de m?es com n?veis altos e baixos de sintomas de ansiedade. Os resultados demonstraram efeito principal significativo da emo??o (p=0,022), evidenciado pelo aumento na concentra??o de oxiHb para faces de alegria em compara??o a faces de medo. Ademais, observou-se efeito principal significativo da regi?o (p=0,013), induzido por maior concentra??o de oxiHb nas regi?es corticais temporais em rela??o ?s regi?es corticais frontais (p=0,031). Al?m disso, houve uma intera??o significativa entre emo??o, hemisf?rio e ansiedade (p=0,037). As an?lises revelaram que filhos de m?es com alta ansiedade demonstraram uma resposta hemodin?mica significativamente elevada no hemisf?rio esquerdo para faces de alegria, em compara??o com faces de medo no hemisf?rio direito (p=0,040) e esquerdo (p=0,033). Os resultados indicam que lactentes de 5 meses discriminaram faces de alegria em compara??o com faces de medo, evidenciado pela maior ativa??o para a primeira. A maior ativa??o nas regi?es temporais em rela??o ?s ?reas frontais foi discutida em rela??o ? ontog?nese do processamento facial e ?s redes neurais de reconhecimento emocional. A resposta mais acentuada, comparando faces de alegria e medo observada nos filhos de m?es com alta ansiedade, pode estar relacionada a altera??es no ambiente emocional dessas crian?as em compara??o com os filhos de m?es com baixa ansiedade. Assim, os n?veis de ansiedade materna parecem moderar as respostas cerebrais hemodin?micas das crian?as ?s faces emocionais. / The neural bases of facial emotion processing in infancy are largely unknown. The environmental factors that may impact facial processing and emotion recognition along the developmental course are also not clearly understood. However, early experiences, particularly involving consistent exposure to familiar caregiver faces, are believed to influence this course. The aim of this study was to investigate the neural correlates of infants? emotional face processing using functional near-infrared spectroscopy (fNIRS), and examine the potential influence of infants? early emotional experiences, indirectly measured by investigating maternal anxiety symptoms. Participants were 29 typically developing 5-monthold infants and their mothers, recruited from a community sample from the Boston greater area, MA, USA. Maternal anxiety was assessed using the trait component of the State-Trait Anxiety Inventory. Infants observed static visual images of a female model portraying happy and fearful expressions, while hemodynamic brain responses were measured using fNIRS. The oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb) responses over frontal, parietal and temporal areas were compared for the emotional expressions in infants of mothers reporting low and high levels of anxiety symptoms. Results revealed a significant main effect of emotion (p=.022), driven by greater oxyHb concentration responses for happy compared to fearful faces. There was also a main effect of region (p=.013) induced by a significantly greater oxyHb concentration in temporal compared to frontal cortical regions (p=.031). Additionally, a significant three-way interaction between emotion, hemisphere and anxiety was observed (p=.037). Planned comparisons revealed that infants of high-anxious mothers showed significantly greater left hemispheric activation of oxyHb to happy faces when compared with right (p=.040) and left (p=.033) hemispheric activation of oxyHb to fearful faces. These findings possibly indicate that 5-month-olds can discriminate happy from fearful faces, evinced by the greater activation for the former. The greater activation in temporal as compared to frontal areas was discussed in relation to the ontogenesis of face processing and emotion recognition neural networks. The enhanced response to happy versus fearful faces observed in infants of high-anxious mothers can be related to the presumed altered emotional environment experienced by these infants, compared to that of infants of low-anxious mothers. Therefore, maternal anxiety levels appeared to moderate infants? hemodynamic brain responses to emotional faces.

京都大学 / 新制・課程博士 / 博士(教育学) / 甲第24353号 / 教博第283号 / 新制||教||214(附属図書館) / 京都大学大学院教育学研究科教育科学専攻 / (主査)教授 MANALO Emmanuel, 教授 楠見 孝, 准教授 野村 理朗 / 学位規則第4条第1項該当 / Doctor of Philosophy (Education) / Kyoto University / DGAM

There is considerable evidence to suggest that object affordances (see Gibson, 1966) can serve to moderate volitional responses by “priming” the visuomotor system toward certain actions (e.g., Tucker & Ellis, 1998). Typically, these studies assume that shorter voluntary reaction time latencies reflect more efficient movement planning. Questions remain however, as to whether object affordances offer the same motor priming benefits in situations where the temporal window to initiate motor action precludes volitional movements (e.g., during an unexpected balance perturbation). The efficiency of balance reactions to a perturbation is dependent upon the ability for the motor system to generate short latency actions at the onset of instability. Due to the rapid nature of these actions, they are suggested to be regulated by information received prior to the perturbation. In this study, participants sat in a custom-built chair that delivered posterior perturbations and, on each trial, were presented with two of three types of stimuli within their reach (two graspable poles that varied in orientation and a flat non-graspable control). They were instructed to reach and grasp one of the poles at the moment of perturbation so as to mitigate the tilt. To assess cortical activity that may be indicative of motor planning in response to the perception of object affordances, changes in oxyhemoglobin (oxy-Hb) in the right and left premotor cortices were measured using a continuous wave fNIRS system. Results revealed a significant increase (F= 4.62, p= .043) in oxy-Hb in the right and left hemisphere (M = .023 µM) in response to objects that afford an optimal form of grasping action (mitigating excessive supination or pronation of the hand), compared to when no grasping opportunity was present (M = -.051 µM). These results suggest that affordances may be used to prime the system in the event of a balance threat. / Thesis / Master of Science (MSc)

False memories happen when someone mis-remembers a past event that occurred. The study of false memories is commonly done using the DRM paradigm which can form false memories through semantic list learning. The current study is evaluating false memory, deception, and truth-telling using the DRM paradigm while measuring cortical activation with fNIRS. Results indicated no interactions between specific condition responses and brain regions in the prefrontal cortex. A main effect of condition was found indicating that correct responses have the lowest level of activation. Additionally, there were no significant differences found between deception and false memory responses. Further research needs to be conducted to help further analyze possible differences between these conditions as well as in more subcortical regions of the prefrontal cortex.

No description available.

In everyday life, the ability to perform two tasks simultaneously, dual task, is an omnipresent issue. There are several factors that can limit an individual’s ability to dual task, such as neurological pathologies, or physical disabilities. A reduced ability to perform dual task activities can result in decreased gait performance, higher risk of falls, a high probability of reduced participation, as well as contributing to a number of deterioration processes in the body. There are numerous situations in which dual tasking is used in therapy, however, there is no consensus regarding what kind of dual task to train in order to have the most effective outcomes. The aim of this systematic review is to investigate the relative effect of motor versus cognitive dual task on brain activity patterns and gait performance. Ten studies were identified in a systematic literature review in order to provide insight into the current status concerning the topic. The results showed high variations of analysed parameters and a very small amount of studies examining motor dual tasks. However, results indicated that cognitive dual tasks had a greater impact on brain activity. In regard to gait performance, no definite answer was found. Given the importance of dual tasks in everyday life and the numerous groups of people experiencing difficulties while dual tasking, the possibilities of adapting dual tasks in therapy should be a topic of future research. / Die Fähigkeit, zwei Aufgaben gleichzeitig auszuführen, auch dual tasking genannt, ist im Alltag ein allgegenwärtiges Thema. Es gibt verschiedene Faktoren, die die Fähigkeit eines Menschen, dual tasks auszuführen, einschränken, wie beispielsweise neurologische Pathologien oder körperliche Behinderungen. Die Verminderung dieser Fähigkeit kann zu abnehmender Gangleistung, erhöhtem Fallrisiko und einer hohen Wahrscheinlichkeit für reduzierte Partizipation führen, sowie folglich zu einer Anzahl an Abnützungserscheinungen des Körpers beitragen. Obwohl es zahlreiche Situationen gibt, in denen dual tasking als Intervention in Verwendung kommt, gibt es keinen Konsens bezüglich der Frage welche Art von Doppelaufgabe trainiert werden soll, um möglichst wirksame Resultate zu erzielen. Das Ziel dieser Arbeit ist es, die relativen Effekte von motorischen dual tasks im Vergleich zu kognitiven dual tasks auf die Hirnaktivität und die Gangleistung zu untersuchen. Zehn Studien wurden in der systematischen Übersichtsarbeit ermittelt, um einen Einblick in den aktuellen Stand der Forschung in diesem Thema zu gewährleisten. Die Ergebnisse zeigten eine Vielzahl an verwendeten Analyseparametern und eine kleine Anzahl an Studien zur Untersuchung von motorischen dual tasks. Trotzdem zeigte sich eine größere Auswirkung von kognitiven dual tasks auf die Hirnaktivität. In Bezug auf die Gangleistung konnte keine eindeutige Antwort gefunden werden. Aufgrund der Wichtigkeit von dual tasks im Alltag und der Vielzahl an betroffenen Personengruppen, die Schwierigkeiten bei der Ausführung jener erleben, sollte die Möglichkeiten der Anpassung von dual tasks auf verschiedene Therapieziele und Patientengruppen Thema für zukünftige Forschung sein.