Cross-linguistic differences in case marking shape neural power dynamics and gaze behavior during sentence planning

Languages differ in how they mark the dependencies between verbs and arguments, e.g., by case. An eye tracking and EEG picture description study examined the influence of case marking on the time course of sentence planning in Basque and Swiss German. While German assigns an unmarked (nominative) case to subjects, Basque specifically marks agent arguments through ergative case. Fixations to agents and event-related synchronization (ERS) in the theta and alpha frequency bands, as well as desynchronization (ERD) in the alpha and beta bands revealed multiple effects of case marking on the time course of early sentence planning. Speakers decided on case marking under planning early when preparing sentences with ergative-marked agents in Basque, whereas sentences with unmarked agents allowed delaying structural commitment across languages. These findings support hierarchically incremental accounts of sentence planning and highlight how cross-linguistic differences shape the neural dynamics underpinning language use.This work was funded by Swiss National Science Foundation Grant Nr. 100015_160011 (B.B. and M.M.), the NCCR Evolving Language, Swiss National Science Foundation Agreement Nr. #51NF40_180888 (B.B. and M. M.), and the PhD Program in Linguistics and the Graduate Research Campus of the University of Zurich (A.E.). DEB is supported by a grant from the Harvard Data Science Initiative and the Branco Weiss Foundation. I.B.-S. is supported by an Australian Research Council Future Fellowship (FT160100437). I.L. is supported by grants from the Spanish Ministry of Economy and Competitiveness (Grant No. FFI2015-64183-P) and the Basque Government (IT1169-19). The authors thank Anne-Lise Giraud for the suggestion to include beta-band analyses, Vitória Piai for advice on EEG data processing, Giuachin Kreiliger for statistical consultation, Andrina Balsofiore and Edurne Petrirena for help recording the lead-in fragments, Nathalie Rieser and Debora Beuret for help with data collection and processing, and the Phonogram Archives of the University of Zurich for technical support. The authors also thank two anonymous reviewers for their helpful comments on an earlier version of the manuscript

The influence of typeface fluency on simple sentence encoding as measured through spectral power analysis

This item is only available electronically.Previous research has shown that typeface fluency has an impact on the encoding and processing of written texts. Specifically, less fluent letters and words appear to be processed more deeply and remembered more accurately. To date, there is limited research regarding the mechanisms by which typeface fluency impacts on the encoding of full sentences. Therefore, this study aimed to expand on this research by focusing on the way it can be applied to the encoding of full sentences. Participants were asked to memorise simple sentences presented in either a fluent or disfluent typeface. Electroencephalography was used to record the changes in spectral power during the learning phase in order to determine the level of encoding success. Following a period of distraction, an audio-presented recall task was used to assess recall accuracy. Fluency was found to be associated with changes in alpha power at learning. Further, alpha power significantly differed between the parietal and occipital regions of the brain but did not show any reaction with fluency. Due to performance ceiling effects, these findings could not be associated with memory outcomes. This research is especially relevant to education, as much of the information presented in schooling is digitally presented text. Keywords: electroencephalography, spectral power, typeface fluency, language encoding, typographyThesis (B.PsychSc(Hons)) -- University of Adelaide, School of Psychology, 201

Actividad del sistema de neuronas espejo durante la percepción y acción de movimientos de dedos

Resumen: La comprensión de los mecanismos neuronales involucrados en la percepción y acción de movimientos puede contribuir a la formación de músicos y cirujanos. En ese marco, la presente investigación tuvo como objetivo determinar la actividad del sistema de neuronas espejo durante la observación y ejecución de movimientos de dedos. Para ello, se registró la actividad cerebral de seis participantes (tres hombres y tres mujeres) con edades entre 21 y 26 años con un equipo BIOPAC durante tres condiciones experimentales: observación, ejecución y control. La tarea consistió en observar o ejecutar el movimiento de tocar las puntas de los dedos con la punta del dedo pulgar secuencialmente a una frecuencia de 2Hz. Por otra parte, la condición de control consistió en observar una almohada en posición estática. Después de descartar artefactos, se calculó la desincronización relacionada a eventos (DRE) en cada condición experimental y en cuatro bandas de frecuencia. Pruebas de Wilcoxon mostraron que la condición ejecución (Mdn = -41.70) tuvo valores de DRE más pronunciados que la condición de control (Mdn = -8.6) (Z = - 3.58) (r=-.73). Asimismo, indicaron que no hubo diferencias entre la condición de observación (Mdn = -30.95) y las condiciones de ejecución (Z = 2.04) (r=.42) y control (Z = -2.22) (r=-.45). Los resultados aportan evidencia favorable pero no concluyente respecto al rol del sistema de neuronas espejo en la vinculación de la percepción y acción de movimientos de dedos. Mejoras metodológicas son necesarias para generalizar los hallazgos y evaluar sus potenciales aplicaciones en la educación.Abstract: Understanding the neural mechanisms involved in perception and action of movements can contribute to the training of musicians and surgeons. In this context, the present study was aimed to determine the activity of the mirror neuron system during observation and execution of sequential finger movements. To do this, the brain activity of six participants (three males and three females) was recorded with a BIOPAC MP100 in three experimental conditions: observation, execution and control. The experimental task was to observe or execute the movement of touching the fingertips with the tip of the thumb sequentially at a frequency of 2 Hz. Similarly, the control condition was to observe a pillow in a static position. After discarding artifacts, the event-related desynchronization (ERD) was computed in each of the three experimental conditions and in four frequency bands. Wilcoxon tests showed that the execution condition ERD values (Mdn = -41.70) were more pronounced than the control condition ones (Mdn = -8.6) (Z = -3.58) (r=-.73). They also indicated that the observation condition did not have different ERD values than the execution (Z = 2.04) (r=.42) and the control conditions (Z = -2.22) (r=-.45). These results provide supportive but not conclusive evidence regarding the role of the human mirror neuron system in linking perception and action of finger movements. Methodological improvements are required to generalize these findings and assess their potential applications in education.Tesi

Interpreting EEG alpha activity

Exploring EEG alpha oscillations has generated considerable interest, in particular with regards to the role they play in cognitive, psychomotor, psycho-emotional and physiological aspects of human life. However, there is no clearly agreed upon definition of what constitutes ‘alpha activity’ or which of the many indices should be used to characterize it. To address these issues this review attempts to delineate EEG alpha-activity, its physical, molecular and morphological nature, and examine the following indices: (1) the individual alpha peak frequency; (2) activation magnitude, as measured by alpha amplitude suppression across the individual alpha bandwidth in response to eyes opening, and (3) alpha “auto-rhythmicity” indices: which include intra-spindle amplitude variability, spindle length and steepness. Throughout, the article offers a number of suggestions regarding the mechanism(s) of alpha activity related to inter and intra-individual variability. In addition, it provides some insights into the various psychophysiological indices of alpha activity and highlights their role in optimal functioning and behavior

Análisis de la actividad EEG durante una sesión de estimulación multisensorial en una sala Snoezelen

El objetivo de este Trabajo de Fin de Grado es analizar los cambios en la actividad cerebral de sujetos con daño cerebral, durante una sesión de terapia multisensorial Snoezelen®. A pesar de la amplia utilización de la terapia Snoezelen®, pocos estudios han analizado de forma cuantitativa sus efectos. En este estudio, se ha contado con tres grupos de 18 sujetos cada uno: sujetos que sufrían Traumatismo Craneoencefálico, sujetos con Parálisis Cerebral y sujetos de control. La actividad electroencefalográfica (EEG) de cada sujeto se analizó antes, durante y tras la terapia Snoezelen® con parámetros espectrales, métodos no lineales, medidas de conectividad y parámetros derivados de la teoría de grafos. Nuestros resultados muestran cambios estadísticamente significativos entre la actividad cerebral antes de comenzar la terapia, durante y después de la intervención Snoezelen®. Algunos de los cambios más significativos han sido la disminución de los valores medios de la señal, una reducción de la complejidad y de la irregularidad de la señal EEG, así como un mayor equilibrio entre las regiones especializadas del cerebro. Estos cambios podrían ser debidos a la relajación que experimentan los sujetos participando en la terapia.The aim of this Final Work Project is the analysis of the changes in the brain activity of brain-injured subjects during a multisensonry session in a Snoezelen® room. Despite the wide use of the Snoezelen® therapy, just a few studies have analyzed its effects in a quantitative way. In this study, three groups have been analyzed, each one with 18 subjects: Traumatic Brain Injury group, Cerebral Palsy group and control group. The electroencephalographic activity (EEG) of each subject was analyzed before, during and after the Snoezelen® therapy with spectral parameters, non-linear methods, connectivity measures and graph theory parameters. Our results showed statistically significant changes in the cerebral activity before, during and after the Snoezelen® therapy. The most significant changes have been the decreasing of the median values of the signal, the reduction in the complexity and irregularity of the EEG signal, as well as a greater balance in the specialized regions of the brain. These changes could be due to the relaxation of the subjects that participate in the multisensory session.Grado en Ingeniería de Tecnologías Específicas de Telecomunicació

Artifact Analysis and Removal of Electroencephalographic (EEG) Recordings

Electroencephalography (EEG) technique has been widely used in continuous monitoring the brain activities in academic research and clinical applications. In cognitive neuroscience research, the electrical brain signals can be used to measure mental effort of subjects. However, the presence of artifacts is a constant problem when recording brain activities, which will obscure the underlying neural dynamics and therefore make it difficult to interpret EEG signals accurately. These unwanted signals or artifacts have different effects depending on their sources of generation. Among them, the motion of the subject is one of the major contributors to physiological artifacts that causes most of the contaminations to the underlying brain activities. It is quite challenging to correct the myogenic activity from EEG background potentials due to its wide spectral distribution overlapped with typical bands of brain waves related to cognitive activities, and the spatial distribution over the entire scalp of human. As such, this thesis focuses on the analysis and removal of motion artifacts from EEG signals. The preliminary investigations include the movement-triggered artifact identification and the analysis of the characteristics of the motion artifact. According to the recorded video, the contaminated epochs are extracted from the original EEG signals. A set of features of the movement-triggered artifacts are proposed based on power spectral density and wavelet transform. Statistical analysis is performed to distinguish the segments that contain motions. Two typical methods of artifact removal are then studied, and the efficiency to correct this type of artifact is validated by comparing the extracted features of non-movement segments and the contaminated segments. The result shows that the tested artifact removal methods cannot completely remove movement artifacts, which also infers the potential relation between motion and mental activities

Development and applications of a smartphone-based mobile electroencephalography (EEG) system

Electroencephalography (EEG) is a clinical and research technique used to non-invasively acquire brain activity. EEG is performed using static systems in specialist laboratories where participant mobility is constrained. It is desirable to have EEG systems which enable acquisition of brain activity outside such settings. Mobile systems seek to reduce the constraining factors of EEG device and participant mobility to enable recordings in various environments but have had limited success due to various factors including low system specification. The main aim of this thesis was to design, build, test and validate a novel smartphone-based mobile EEG system.A literature review found that the term ‘mobile EEG’ has an ambiguous meaning as researchers have used it to describe many differing degrees of participant and device mobility. A novel categorisation of mobile EEG (CoME) scheme was derived from thirty published EEG studies which defined scores for participant and device mobilities, and system specifications. The CoME scheme was subsequently applied to generate a specification for the proposed mobile EEG system which had 24 channels, sampled at 24 bit at a rate of 250 Hz. Unique aspects of the EEG system were the introduction of a smartphone into the specification, along with the use of Wi-Fi for communications. The smartphone’s processing power was used to remotely control the EEG device so as to enable EEG data capture and storage as well as electrode impedance checking via the app. This was achieved by using the Unity game engine to code an app which provided the flexibility for future development possibilities with its multi-platform support.The prototype smartphone-based waist-mounted mobile EEG system (termed ‘io:bio’) was validated against a commercial FDA clinically approved mobile system (Micromed). The power spectral frequency, amplitude and area of alpha frequency waves were determined in participants with their eyes closed in various postures: lying, sitting, standing and standing with arms raised. Since a correlation analysis to compare two systems has interpretability problems, Bland and Altman plots were utilised with a priori justified limits of agreement to statistically assess the agreement between the two EEG systems. Overall, the results found similar agreements between the io:bio and Micromed systems indicating that the systems could be used interchangeably. Utilising the io:bio and Micromed systems in a walking configuration, led to contamination of EEG channels with artifacts thought to arise from movement and muscle-related sources, and electrode displacement.To enable an event related potential (ERP) capability of the EEG system, additional coding of the smartphone app was undertaken to provide stimulus delivery and associated data marking. Using the waist-mounted io:bio system, an auditory oddball paradigm was also coded into the app, and delivery of auditory tones (standard and deviant) to the participant (sitting posture) achieved via headphones connected to the smartphone. N100, N200 and P300 ERP components were recorded in participants sitting, and larger amplitudes were found for the deviant tones compared to the standard ones. In addition, when the paradigm was tested in individual participants during walking, movement-related artifacts impacted negatively upon the quality of the ERP components, although components were discernible in the grand mean ERP.The io:bio system was redesigned into a head-mounted configuration in an attempt to reduce EEG artifacts during participant walking. The initial approach taken to redesign the system involved using electronic components populated onto a flexible PCB proved to be non-robust. Instead, the rigid PCB form of the circuitry was taken from the io:bio waist-mounted system and placed onto the rear head section of the electrode cap via a bespoke cradle. Using this head-mounted system, in a preliminary auditory oddball paradigm study, ERP responses were obtained in participants whilst walking. Initial results indicate that artifacts are reduced in this head-mounted configuration, and N100, N200 and P300 components are clearly identifiable in some channels

Investigating attentional function and cognitive fluctuations in Lewy body dementia

PhD ThesisLewy body dementias (LBD), which include dementia with Lewy bodies (DLB) and Parkinson’s disease with dementia (PDD), are characterised by attentional dysfunction and fluctuating cognition. The underlying aetiology of these clinical features is poorly understood, yet such knowledge is essential for developing effective management strategies. The aim of this project was to determine the specific facets of attention affected in LBD patients, and to use high-density electroencephalography (EEG) to delineate the underlying pathophysiology and how this relates to cognitive fluctuations. Methods: Attentional network efficiency was investigated in LBD patients (n = 32), Alzheimer’s disease (AD) patients (n = 27), and age-matched healthy controls (n = 21) by using a modified version of the Attention Network Test (ANT). The ANT, a visual attention task, probes the efficiency of three anatomically defined attentional networks: alerting, orienting and executive conflict. Participants completed the ANT whilst undergoing EEG recordings (128 channels). In a subsample of the participants (22 DLB, 24 AD, 19 controls), time-frequency wavelet analyses were conducted to investigate event-related spectral perturbations (ERSP), between 4-90 Hz, in the 500 ms post-stimuli presentation. Attentional network ERSP was calculated by contrasting the oscillatory reactivity following relevant stimuli. Results: Overall mean reaction time was slower in the dementia groups (AD and LBD) relative to the controls, and the LBD group were slower than the AD group. Behaviourally, there were no group differences regarding the orienting effect. However, both dementia groups exhibited reduced executive conflict processing efficiency, and a lack of an alerting effect. Electrophysiologically, the DLB group exhibited a profound lack of post-stimulus oscillatory reactivity below 30 Hz, irrespective of stimulus condition. For the alerting network, the DLB group exhibited attenuated reactivity in the lower frequencies (< 30 Hz); in the theta range (4-7 Hz) the controls and AD group showed global synchronisation (across all regions), peaking at approximately 300 ms, which was absent in the DLB group. Lack of DLB theta synchronisation between 200-450 ms over the right parietal cortex was associated with a ii higher total score on the Clinical Assessment of Fluctuation scale. Orienting and executive conflict network reactivity was comparable across all groups; primarily intermittent synchronisation, of reduced power relative to the alerting network, diffuse across the time and frequency domains in all regions. Conclusions: Attenuated global oscillatory reactivity in the DLB group specific to the alerting network (the network associated with the ability to maintain an alert state) is indicative of this fractionated aspect of attention being differentially affected in the DLB patients relative to the AD and control groups. Lack of theta reactivity in the parietal regions may contribute to the underlying pathophysiology of cognitive fluctuations in DLB.Alzheimer’s Research U