Neural magnetic field dependent fMRI toward direct functional connectivity measurements: A phantom study

Recently, the main issue in neuroscience has been the imaging of the functional connectivity in the brain. No modality that can measure functional connectivity directly, however, has been developed yet. Here, we show the novel MRI sequence, called the partial spinlock sequence toward direct measurements of functional connectivity. This study investigates a probable measurement of phase differences directly associated with functional connectivity. By employing partial spinlock imaging, the neural magnetic field might influence the magnetic resonance signals. Using simulation and phantom studies to model the neural magnetic fields, we showed that magnetic resonance signals vary depending on the phase of an externally applied oscillating magnetic field with non-right flip angles. These results suggest that the partial spinlock sequence is a promising modality for functional connectivity measurements

The Human Auditory System

This book presents the latest findings in clinical audiology with a strong emphasis on new emerging technologies that facilitate and optimize a better assessment of the patient. The book has been edited with a strong educational perspective (all chapters include an introduction to their corresponding topic and a glossary of terms). The book contains material suitable for graduate students in audiology, ENT, hearing science and neuroscience

The influence of external and internal motor processes on human auditory rhythm perception

Musical rhythm is composed of organized temporal patterns, and the processes underlying rhythm perception are found to engage both auditory and motor systems. Despite behavioral and neuroscience evidence converging to this audio-motor interaction, relatively little is known about the effect of specific motor processes on auditory rhythm perception. This doctoral thesis was devoted to investigating the influence of both external and internal motor processes on the way we perceive an auditory rhythm. The first half of the thesis intended to establish whether overt body movement had a facilitatory effect on our ability to perceive the auditory rhythmic structure, and whether this effect was modulated by musical training. To this end, musicians and non-musicians performed a pulse-finding task either using natural body movement or through listening only, and produced their identified pulse by finger tapping. The results showed that overt movement benefited rhythm (pulse) perception especially for non-musicians, confirming the facilitatory role of external motor activities in hearing the rhythm, as well as its interaction with musical training. The second half of the thesis tested the idea that indirect, covert motor input, such as that transformed from the visual stimuli, could influence our perceived structure of an auditory rhythm. Three experiments examined the subjectively perceived tempo of an auditory sequence under different visual motion stimulations, while the auditory and visual streams were presented independently of each other. The results revealed that the perceived auditory tempo was accordingly influenced by the concurrent visual motion conditions, and the effect was related to the increment or decrement of visual motion speed. This supported the hypothesis that the internal motor information extracted from the visuomotor stimulation could be incorporated into the percept of an auditory rhythm. Taken together, the present thesis concludes that, rather than as a mere reaction to the given auditory input, our motor system plays an important role in contributing to the perceptual process of the auditory rhythm. This can occur via both external and internal motor activities, and may not only influence how we hear a rhythm but also under some circumstances improve our ability to hear the rhythm.Musikalische Rhythmen bestehen aus zeitlich strukturierten Mustern akustischer Stimuli. Es konnte gezeigt werden, dass die Prozesse, welche der Rhythmuswahrnehmung zugrunde liegen, sowohl motorische als auch auditive Systeme nutzen. Obwohl sich für diese auditiv-motorischen Interaktionen sowohl in den Verhaltenswissenschaften als auch Neurowissenschaften übereinstimmende Belege finden, weiß man bislang relativ wenig über die Auswirkungen spezifischer motorischer Prozesse auf die auditive Rhythmuswahrnehmung. Diese Doktorarbeit untersucht den Einfluss externaler und internaler motorischer Prozesse auf die Art und Weise, wie auditive Rhythmen wahrgenommen werden. Der erste Teil der Arbeit diente dem Ziel herauszufinden, ob körperliche Bewegungen es dem Gehirn erleichtern können, die Struktur von auditiven Rhythmen zu erkennen, und, wenn ja, ob dieser Effekt durch ein musikalisches Training beeinflusst wird. Um dies herauszufinden wurde Musikern und Nichtmusikern die Aufgabe gegeben, innerhalb von präsentierten auditiven Stimuli den Puls zu finden, wobei ein Teil der Probanden währenddessen Körperbewegungen ausführen sollte und der andere Teil nur zuhören sollte. Anschließend sollten die Probanden den gefundenen Puls durch Finger-Tapping ausführen, wobei die Reizgaben sowie die Reaktionen mittels eines computerisierten Systems kontrolliert wurden. Die Ergebnisse zeigen, dass offen ausgeführte Bewegungen die Wahrnehmung des Pulses vor allem bei Nichtmusikern verbesserten. Diese Ergebnisse bestätigen, dass Bewegungen beim Hören von Rhythmen unterstützend wirken. Außerdem zeigte sich, dass hier eine Wechselwirkung mit dem musikalischen Training besteht. Der zweite Teil der Doktorarbeit überprüfte die Idee, dass indirekte, verdeckte Bewegungsinformationen, wie sie z.B. in visuellen Stimuli enthalten sind, die wahrgenommene Struktur von auditiven Rhythmen beeinflussen können. Drei Experimente untersuchten, inwiefern das subjektiv wahrgenommene Tempo einer akustischen Sequenz durch die Präsentation unterschiedlicher visueller Bewegungsreize beeinflusst wird, wobei die akustischen und optischen Stimuli unabhängig voneinander präsentiert wurden. Die Ergebnisse zeigten, dass das wahrgenommene auditive Tempo durch die visuellen Bewegungsinformationen beeinflusst wird, und dass der Effekt in Verbindung mit der Zunahme oder Abnahme der visuellen Geschwindigkeit steht. Dies unterstützt die Hypothese, dass internale Bewegungsinformationen, welche aus visuomotorischen Reizen extrahiert werden, in die Wahrnehmung eines auditiven Rhythmus integriert werden können. Zusammen genommen, 5 zeigt die vorgestellte Arbeit, dass unser motorisches System eine wichtige Rolle im Wahrnehmungsprozess von auditiven Rhythmen spielt. Dies kann sowohl durch äußere als auch durch internale motorische Aktivitäten geschehen, und beeinflusst nicht nur die Art, wie wir Rhythmen hören, sondern verbessert unter bestimmten Bedingungen auch unsere Fähigkeit Rhythmen zu identifizieren

The Impact of Neurofeedback on Women Diagnosed with PTSD: A Multiple Case Study

The purpose of this study was to examine how women diagnosed with PTSD experienced neurofeedback (NFB) using quantitative and qualitative data. The quantitative data included pre- and post-test scores on the quantitative electroencephalogram (QEEG), the Davidson Trauma Scale, and the Inventory of Altered Self-capacities. The qualitative data illuminated participants’ experiences with NFB and their observations about the changes that occurred during and after NFB. The participants in this study included three women who received at least 20 sessions of NFB to treat their PTSD. The results indicated that two participants achieved a significant reduction in their PTSD symptoms and improvements in their concentration, sustained attention, and ability to calm themselves down. The third participant observed limited reductions in her depression and anxiety symptoms and improvement in her concentration and sustained attention. Participants also shared that understanding NFB before beginning treatment would have helped them to acquire self-regulation skills. Results also implicated that negative effects could occur from overtraining and standardized NFB protocols. Recommendations were made for the use of individualized NFB protocols to address clients’ unique symptoms and EEG patterns. Future studies should utilize mixed-method or qualitative methods to investigate the impact of NFB combined with bottom-up approaches such as somatic experiencing therapy, trauma-sensitive yoga, and eye movement desensitization and reprocessing (EMDR). Recommendations were also made to investigate treating PTSD new NFB protocols based on the triple network model. تهدف الدراسة إلى الكشف عن تأثير العلاج بالتغذية الراجعة العصبية على النساء المشخصات باضطراب كرب ما بعد الصدمة باستخدام البيانات الكمية والنوعية. تضمنت البيانات الكمية الدرجات القبلية والبعدية للتخطيط الكمي الكهربائي للدماغ ومقياس ديفيدسون للصدمات وقائمة جرد القدرات الذاتية المتغيرة. وقد أظهرت البيانات النوعية تجربة المشاركات للعلاج بالتغذية الراجعة العصبية وملاحظاتهن حول التغيرات التي حدثت أثناء وبعد العلاج. كانت عينة الدراسة ثلاث سيدات تلقيّن على الأقل عشرين جلسة تغذية راجعة عصبية لعلاج اضطراب كرب ما بعد الصدمة. أشارت النتائج إلى انخفاض كبير في أعراض اضطراب كرب ما بعد الصدمة لدى مشاركتين ، بالإضافة إلى تحسن التركيز واستمراية الانتباه والقدرة على التهدئة عند الاستثارة. و كان انخفاض أعراض الاكتئاب والقلق لدى المشاركة الثالثة محدودًا في حين تحسّن مستوى التركيز واستمرار الانتباه لديها. أوضحت المشاركات أن فهم إجراءات العلاج بالتغذية الراجعة العصبية قبل بدء العلاج يساعد على اكتسابهن لمهارات الضبط الذاتي. كما أشارت النتائج إلى أن الآثار السلبية يمكن أن تحدث من الإفراط في التدريب أواستخدام بروتوكولات علاجية موحدة. تم تقديم توصيات لاستخدام بروتوكولات فردية وفقا لأعراض كل فرد وأنماط تخطيط الدماغ لديه. وقد أوصت الدراسة بإجراء دراسات مستقبلية تجمع بين المنهج الكمي والنوعي لاكتشاف تأثير الجمع بين العلاج بالتغذية الراجعة العصبية ومناهج (من أسفل إلى أعلى) مثل علاج الخبرة الجسية ، والعلااج بإزالة التحسس وإعادة المعالجة باستخدام حركة العين. كما أوصت الدراسة بإجراء دراسات مستقبلية لاختبار بروتوكولات جديد في العلاج بالتغذية الراجعة العصبية لعلاج اضطراب مابعد الصدمة استنادا على نموذج شبكة الدماغ الثلاثية

Examining the relationship between sensory processing and attention in individuals with autism spectrum disorders

2017 Fall.Includes bibliographical references.Attention is a crucial element of our goal-directed, purposeful response to sensory information in our social and physical environments. Individuals with autism spectrum disorders (ASD) have significant deficits in sensory processing and attention. However, there is limited research examining the relationship between attention and sensory processing in individuals with autism spectrum disorders (ASD). The purpose of this dissertation was to examine the relationship between attention and sensory processing in individuals with autism spectrum disorders (ASD) and neurotypical individuals. Specifically, the objective was to examine if consciously directing attention to incoming information would result in more typical neural processing in individuals with ASD. To answer this question, study 1 was designed to understand how attention and distraction impacted sensory processing in neurotypical individuals. Studies 2 and 3 examined neural measures of sensory processing in individuals with ASD as compared to age-matched neurotypical controls during passive and active attentional states. In Study 1, electroencephalography (EEG) data were recorded while 60 adults (18-35 years) heard random presentations of 4 auditory stimuli at 2 frequencies (1 and 3 kHz) each at 2 intensities (50 and 70 dB). Participants were randomly divided into 2 viewing conditions; one group watched a silent movie and the other viewed a fixation point during the recording. All participants completed 2 attention conditions, the passive condition involved only listening to the stimuli, followed by the active condition, wherein participants were instructed to press a button to the 1 kHz 50 dB tone. Amplitude and latency measures were obtained for the N1, P2, N2, and P3 components for each of the auditory stimuli. The ANOVAs revealed a significant main effect of attention condition for the N1, P2, N2, and P3 amplitudes. There were also significant attention-by-viewing condition interaction effects at the P3 component. Results indicated that actively directing attention to the tones impacts auditory processing at all components. Additionally, manipulation of attention by changing the viewing environment significantly interacted with sensory processing, such that movie viewing resulted in larger P3 amplitudes compared with fixation viewing. Thus, viewing environment or distraction impacts sensory processing. In study 2, we examined the effect of attention on auditory filtering using the sensory gating paradigm in individuals with ASD. EEG data were recorded during 2 attention conditions from 24 adults with ASD and 24 neurotypical individuals during the sensory gating paradigm. During the passive condition, participants were presented with single and paired clicks. For the active condition, participants made a motor response following the single click but not the paired click. Attending to the clicks resulted in larger P50 and N1 amplitudes, and reduced gating for all participants. Although, the ASD group had P50 and N1 gating during both attention conditions, they had significantly longer N1 latencies to the Click 1 during both the attention conditions, suggesting a delayed orienting response. However, click 2 latencies were delayed only in the passive condition and not the active condition for the ASD group compared to the neurotypical group. This finding suggests of attention-based amelioration of processing speed in individuals with ASD. Individuals with ASD also had significantly more deficits on behavioral measures of social responsivity, attention, sensory and perceptual processing. Additionally, neural measures of gating were associated with several behavioral measures of sensory processing as measured by self-report questionnaires and a performance-based measure of attention, such that efficient neural processing was associated with more typical sensory processing and attention. In study 3, we examined the effect of attention on auditory discrimination in individuals with ASD. EEG data were recorded from 24 individuals with ASD and 24 neurotypical individuals, while they heard random presentations of 4 auditory stimuli at 2 different frequencies (1 and 3 kHz) each at 2 different intensities (50 and 70 dB). All participants completed two attention conditions; the passive condition involved only listening to the stimuli, followed by the active condition, wherein participants were instructed to press a button to the 1 kHz 50 dB tone. Attention impacted N2, and P3 amplitudes, and P2 and N2 latencies. The ASD group had significantly longer N1, N2, and P3 latencies, suggesting delayed processing. N2 and P3 latency delays in the ASD group were present during the passive but not active condition, implying an attention-based amelioration of processing delay. Behavioral measures of sensory processing and attention correlated with neural measures of auditory processing. Thus, through the series of studies, we found that actively directing attention to the tones impacts auditory processing, and may result in more typical processing in ASD. The study findings also suggest that sensory processing deficits observed in ASD may be associated with underlying deficits of attention. Study findings have significant implications related to understanding auditory discrimination in individuals with ASD and examining the impact of attention on sensory processing. Additionally, these results can help practitioners understand the neural basis of behavioral manifestations of ASD, especially those atypical behaviors that occur in response to sensory experiences in everyday activities

Functional connectivity of EEG is subject-specific, associated with phenotype, and different from fMRI

A variety of psychiatric, behavioral and cognitive phenotypes have been linked to brain ‘’functional connectivity’’ -- the pattern of correlation observed between different brain regions. Most commonly assessed using functional magnetic resonance imaging (fMRI), here, we investigate the connectivity-phenotype associations with functional connectivity measured with electroencephalography (EEG), using phase-coupling. We analyzed data from the publicly available Healthy Brain Network Biobank. This database compiles a growing sample of children and adolescents, currently encompassing 1657 individuals. Among a variety of assessment instruments we focus on ten phenotypic and additional demographic measures that capture most of the variance in this sample. The largest effect sizes are found for age and sex for both fMRI and EEG. We replicate previous findings of an association of Intelligence Quotient (IQ) and Attention Deficit Hyperactivity Disorder (ADHD) with the pattern of fMRI functional connectivity. We also find an association with socioeconomic status, anxiety and the Child Behavior Checklist Score. For EEG we find a significant connectivity-phenotype relationship with IQ. The actual spatial patterns of functional connectivity are quite different between fMRI and source-space EEG. However, within EEG we observe clusters of functional connectivity that are consistent across frequency bands. Additionally we analyzed reproducibility of functional connectivity. We compare connectivity obtained with different tasks, including resting state, a video and a visual flicker task. For both EEG and fMRI the variation between tasks was smaller than the variability observed between subjects. We also found an increase of reliability with increasing frequency of the EEG, and increased sampling duration. We conclude that, while the patterns of functional connectivity are distinct between fMRI and phase-coupling of EEG, they are nonetheless similar in their robustness to the task, and similar in that idiosyncratic patterns of connectivity predict individual phenotypes