Atividade eletroencefalográfica de pacientes com acidente vascular cerebral na aprendizagem motora de um jogo baseado em realidade virtual

Stroke is the leading cause of long-term disability among adults and motor relearning is essential in motor sequelae recovery. Therefore, various techniques have been proposed to achieve this end, among them Virtual Reality. The aim of the study was to evaluate electroencephalographic activity of stroke patients in motor learning of a virtual reality-based game. The study included 10 patients with chronic stroke, right-hande; 5 with left brain injury (LP), mean age 48.8 years (± 4.76) and 5 with injury to the right (RP), mean age 52 years (± 10.93). Participants were evaluated for electroencephalographic (EEG) activity and performance while performing 15 repetitions of darts game in XBOX Kinect and also through the NIHSS, MMSE, Fugl-Meyer and the modified Ashworth scale. Patients underwent a trainning with 45 repetitions of virtual darts game, 12 sessions in four weeks. After training, patients underwent reassessment of EEG activity and performance in virtual game of darts (retention). Data were analyzed using ANOVA for repeated measures. According to the results, there were differences between the groups (PD and PE) in frequencies Low Alpha (p = 0.0001), High Alpha (p = 0.0001) and Beta (p = 0.0001). There was an increase in alpha activation powers and a decrease in beta in the phase retention of RP group. In LP group was observed increased alpha activation potency, but without decrease in beta activation. Considering the asymmetry score, RP group increased brain activation in the left hemisphere with the practice in the frontal areas, however, LP group had increased activation of the right hemisphere in fronto-central areas, temporal and parietal. As for performance, it was observed a decrease in absolute error in the game for RP group between assessment and retention (p = 0.015), but this difference was not observed for LP group (p = 0.135). It follows then that the right brain injury patients benefited more from darts game training in the virtual environment with respect to the motor learning process, reducing neural effort in ipsilesionais areas and errors with the practice of the task. In contrast, patients with lesions in left hemisphere decrease neural effort in contralesionais areas important for motor learning and showed no performance improvements with practice of 12 sessions of virtual dart game. Thus, the RV can be used in rehabilitation of stroke patients upper limb, but the laterality of the injury should be considered in programming the motor learning protocol.

Effetti della tDCS sui pattern ERS/ERD indotti da immaginazione motoria: stato dell'arte

I sistemi BCI EEG-based sono un mezzo di comunicazione diretto tra il cervello e un dispositivo esterno il quale riceve comandi direttamente da segnali derivanti dall'attività elettrica cerebrale. Le features più utilizzate per controllare questi dispositivi sono i ritmi sensorimotori, ossia i ritmi mu e beta (8-30 Hz). Questi ritmi hanno la particolare proprietà di essere modulati durante l'immaginazione di un movimento generando così delle desincronizzazioni e delle sincronizzazioni evento correlate, ERD e ERS rispettavamente. Tuttavia i destinatari di tali sistemi BCI sono pazienti con delle compromissioni corticali e non sono sempre in grado di generare dei pattern ERD/ERS stabili. Per questo motivo, negli ultimi anni, è stato proposto l'uso di tecniche di stimolazione cerebrale non invasiva, come la tDCS, da abbinare al training BCI. In questo lavoro ci si è focalizzati sugli effetti della tDCS sugli ERD ed ERS neuronali indotti da immaginazione motoria attraverso un'analisi dei contributi presenti in letteratura. In particolare, sono stati analizzati due aspetti, ossia: i) lo studio delle modificazioni di ERD ed ERS durante (online) o in seguito (offline) a tDCS e ii) eventuali cambiamenti in termini di performance/controllo del sistema BCI da parte del soggetto sottoposto alla seduta di training e tDCS. Le ricerche effettuate tramite studi offline o online o con entrambe le modalità, hanno portato a risultati contrastanti e nuovi studi sarebbero necessari per chiarire meglio i meccanismi cerebrali che sottendono alla modulazione di ERD ed ERS indotta dalla tDCS. Si è infine provato ad ipotizzare un protocollo sperimentale per chiarire alcuni di questi aspetti.

Neuromarketing y nuevas estrategias de la mercadotecnia: análisis de la eficiencia publicitaria en la diferenciación de género y la influencia del marketing sensorial y experiencial en la decisión de compra

La aplicación de las neurociencias en el conocimiento del ser humano ha demostrado cómo el empleo de estímulos sensoriales y experienciales influyen en la atención, el agrado, las emociones, el compromiso –engagement- y la memoria -recuerdo y reconocimiento- de las marcas en entornos publicitarios relacionados con la decisión de compra. El objeto a través del empleo del Neuromarketing es determinar las áreas y funciones de las activaciones cerebrales que modulan la conducta del consumidor relacionadas con la mercadotecnia y el proceso de compra en entornos comerciales. Asimismo identifica el efecto que la publicidad genera en hombres y mujeres al encontrar diferencias de género de cómo les impacta la publicidad como la utilización de personajes célebres a cada uno de ellos, con los que adecuar los mensajes a los segmentos de mercado que tiendan a la excelencia de la eficiencia publicitaria con los que ayudar a los protagonistas clave del sector de la marketing y la publicidad. A través de un estudio propio de Neuromarketing se analiza el comportamiento de hombres y mujeres durante la visualización de los anuncios publicitarios como recurso estratégico para mejorar la eficiencia publicitaria en el diseño y la comunicación de un producto, servicio o campaña publicitaria antes, durante y después del lanzamiento.La medición publicitaria realizada con algunas de las técnicas de Neuroimagen más precisas del mercado, el Electroencefalograma (EEG) y biométricas; el Ritmo Cardíaco (HR) y Respuesta Galvánica de la Piel (GSR), han registrado el aumento del nivel de atención, agrado, emociones o motivación cuando se genera una necesidad o deseo en la demanda de los consumidores mejorando las actuales técnicas de Investigación de Mercado del marketing tradicional. Estas investigaciones permiten presentar la creación del modelo de eficiencia en el diseño y comunicación publicitaria SIADEM (-SENSORY, INTENTION, ATTENTION, DESIRE, EMOTION, MEMORY-) que tiene en cuenta los elementos básicos en los que se debe basar los mensajes publicitarios de cualquier marca para atraer el interés del cerebro consumidor.

Mutant tau knock-in mice display frontotemporal dementia relevant behaviour and histopathology

Peer reviewed

Le ralentissement de l'activité électrique cérébrale dans le trouble comportemental en sommeil paradoxal

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Niveaux de vigilance pendant et après une exposition à la lumière vive durant la nuit

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Hand somatosensory sub-cortical sources arehypoactive in migraine interictally: a functionalsource separation analysis

Background: Recent morpho-functional evidences pointed out that abnormalities in the thalamus could play a major role in the expression of migraine neurophysiological and clinical correlates. Whether this phenomenon is primary or secondary to its functional disconnection from the brain stem remains to be determined.Aim: We used a Functional Source Separation algorithmof EEG signal to extract the activity of the different neuronal pools recruited at different latencies along the somatosensory pathway in interictal migraine without aura(MO) patients. Method: Twenty MO patients and 20 healthy volunteers(HV) underwent EEG recording. Four ad-hoc functional constraints, two sub-cortical (FS14 at brain stem andFS16 at thalamic level) and two cortical (FS20 radial andFS22 tangential parietal sources), were used to extract the activity of successive stages of somatosensory information processing in response to the separate left and right median nerve electric stimulation. A band-pass digital filter (450–750 Hz) was applied offline in order to extract high-frequency oscillatory (HFO) activity from the broadband EEG signal. Results: In both stimulated sides, significant reduced subcortical brain stem (FS14) and thalamic (FS16) HFO activations characterized MO patients when compared with HV. No difference emerged in the two cortical HFO activations between two groups. Conclusion: Present results are the first neurophysiological evidence supporting the hypothesis that a functional disconnection of the thalamus from the subcortical monoaminergicsystem may underline the interictal cortical abnormal information processing in migraine. Further studiesare needed to investigate the precise directional connectivity across the entire primary subcortical and cortical somatosensory pathway in interictal MO.

Adaptive Brain-Computer Interface Systems For Communication in People with Severe Neuromuscular Disabilities

Brain-computer interfaces (BCI) have the potential to restore communication or control abilities in individuals with severe neuromuscular limitations, such as those with amyotrophic lateral sclerosis (ALS). The role of a BCI is to extract and decode relevant information that conveys a user's intent directly from brain electro-physiological signals and translate this information into executable commands to control external devices. However, the BCI decision-making process is error-prone due to noisy electro-physiological data, representing the classic problem of efficiently transmitting and receiving information via a noisy communication channel.

This research focuses on P300-based BCIs which rely predominantly on event-related potentials (ERP) that are elicited as a function of a user's uncertainty regarding stimulus events, in either an acoustic or a visual oddball recognition task. The P300-based BCI system enables users to communicate messages from a set of choices by selecting a target character or icon that conveys a desired intent or action. P300-based BCIs have been widely researched as a communication alternative, especially in individuals with ALS who represent a target BCI user population. For the P300-based BCI, repeated data measurements are required to enhance the low signal-to-noise ratio of the elicited ERPs embedded in electroencephalography (EEG) data, in order to improve the accuracy of the target character estimation process. As a result, BCIs have relatively slower speeds when compared to other commercial assistive communication devices, and this limits BCI adoption by their target user population. The goal of this research is to develop algorithms that take into account the physical limitations of the target BCI population to improve the efficiency of ERP-based spellers for real-world communication.

In this work, it is hypothesised that building adaptive capabilities into the BCI framework can potentially give the BCI system the flexibility to improve performance by adjusting system parameters in response to changing user inputs. The research in this work addresses three potential areas for improvement within the P300 speller framework: information optimisation, target character estimation and error correction. The visual interface and its operation control the method by which the ERPs are elicited through the presentation of stimulus events. The parameters of the stimulus presentation paradigm can be modified to modulate and enhance the elicited ERPs. A new stimulus presentation paradigm is developed in order to maximise the information content that is presented to the user by tuning stimulus paradigm parameters to positively affect performance. Internally, the BCI system determines the amount of data to collect and the method by which these data are processed to estimate the user's target character. Algorithms that exploit language information are developed to enhance the target character estimation process and to correct erroneous BCI selections. In addition, a new model-based method to predict BCI performance is developed, an approach which is independent of stimulus presentation paradigm and accounts for dynamic data collection. The studies presented in this work provide evidence that the proposed methods for incorporating adaptive strategies in the three areas have the potential to significantly improve BCI communication rates, and the proposed method for predicting BCI performance provides a reliable means to pre-assess BCI performance without extensive online testing.

Investigating metabolomic biomarkers of hypoxic ischaemic encephalopathy

Background An early objective biomarker to predict the severity of hypoxic-ischaemic encephalopathy (HIE) and identify infants suitable for intervention remains elusive. This thesis aims to progress metabolomic markers of HIE through a pipeline of biomarker discovery and validation by employing a novel untargeted mass spectrometry metabolomic method. Methodology Term infants with perinatal asphyxia were recruited, all having umbilical cord blood (UCB) drawn and biobanked within three hours of birth. HIE was defined by Sarnat score at 24hours and continuous multichannel-EEG. Infant neurodevelopment was assessed at 36-42 months using the Bayley Scales of Infant and Toddler Development Ed. III (BSID-III). Untargeted metabolomic analysis of UCB was performed using direct injection FT-ICR mass spectrometry (DI FT-ICR MS). Putative metabolite annotations and lipid classes were assigned and pathway analysis was performed. Results Untargeted metabolomic analysis: Thirty enrolled infants were diagnosed with HIE, including 17 mild, 8 moderate, and 5 severe cases. Pathway analysis revealed that ΔHIE was associated with a 50% and 75% perturbation of tryptophan and pyrimidine metabolism respectively, alongside alterations in amino acid pathways. Significant metabolite alterations were detected from six putatively identified lipid classes including fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterol lipids and prenol lipids. Outcome prediction: Metabolite model scores significantly correlated with outcome R=0.429 (model A) and R=0.549 (model B) respectively. Model B demonstrates the potential to predict both severe outcome (AUROC of 0.915) and intact survival (AUROC of 0.800). The effect of haemolysis: On average 5% of polar and 1.5% of non-polar features were altered between paired haemolysed and clean samples. However unsupervised multivariate analysis concluded that the preanalytical variability introduced by haemolysis was negligible compared with the inherent biological inter-individual variability. Conclusion This research has employed untargeted metabolomics to identify potential early cord blood biomarkers of HIE and has performed the technical validation of previously proposed markers.

Dynamic classifiers for neonatal brain monitoring

Brain injury due to lack of oxygen or impaired blood flow around the time of birth, may cause long term neurological dysfunction or death in severe cases. The treatments need to be initiated as soon as possible and tailored according to the nature of the injury to achieve best outcomes. The Electroencephalogram (EEG) currently provides the best insight into neurological activities. However, its interpretation presents formidable challenge for the neurophsiologists. Moreover, such expertise is not widely available particularly around the clock in a typical busy Neonatal Intensive Care Unit (NICU). Therefore, an automated computerized system for detecting and grading the severity of brain injuries could be of great help for medical staff to diagnose and then initiate on-time treatments. In this study, automated systems for detection of neonatal seizures and grading the severity of Hypoxic-Ischemic Encephalopathy (HIE) using EEG and Heart Rate (HR) signals are presented. It is well known that there is a lot of contextual and temporal information present in the EEG and HR signals if examined at longer time scale. The systems developed in the past, exploited this information either at very early stage of the system without any intelligent block or at very later stage where presence of such information is much reduced. This work has particularly focused on the development of a system that can incorporate the contextual information at the middle (classifier) level. This is achieved by using dynamic classifiers that are able to process the sequences of feature vectors rather than only one feature vector at a time.

Le ralentissement de l'activité électrique cérébrale dans le trouble comportemental en sommeil paradoxal

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Niveaux de vigilance pendant et après une exposition à la lumière vive durant la nuit

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

La música en el desarrollo de la espiritualidad y la religiosidad. Una aproximación al Cristianismo y al Budismo

La música puede afectar al individuo en todos sus niveles –físico, mental y espiritual–. El presente artículo se centra en el papel que ésta desempeña en el desarrollo de la vida espiritual y trascendental. Para ello, realizaremos un repaso histórico de su evolución estética y social, abordaremos dicho fenómeno a nivel fisiológico y presentaremos sus aplicaciones clínicas y sociales. Seguidamente y a modo de ejemplo de las concepciones de pensamiento occidental y oriental, trataremos la forma en que el cristianismo y el budismo conciben la música dentro de su doctrina. Finalizaremos con algunas reflexiones sobre el tema.

My mind, my self, my identity: a task-independent neural signature for biometric identification

Programa de doctorado: Sistemas Inteligentes y Aplicaciones Numéricas en Ingeniería

Global slowing of network oscillations in mouse neocortex by diazepam

SCHEFFZUK, C. , KUKUSHKA, V. , VYSSOTSKI, A. L. , DRAGUHN, A. , TORT, A. B. L. , BRANKACK, J. . Global slowing of network oscillations in mouse neocortex by diazepam. Neuropharmacology , v. 65, p. 123-133, 2013.