Tesi sul tema "FMRI"
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1
Turkay, Kemal Dogus. "Simulated Fmri Toolbox". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611465/index.pdf.
Testo completoAbstract (sommario):
In this thesis a simulated fMRI toolbox is developed in order to generate simulated data to compare and benchmark different functional magnetic resonance image analysis methods. This toolbox is capable of loading a high resolution anatomic brain volume, generating 4D fMRI data in the same data space with the anatomic image, and allowing the user to create block and event-related design paradigms. Common fMRI artifacts such as scanner drift, cardiac pulsation, habituation and task related or spontaneous head movement can be incorporated into the 4D fMRI data. Input to the toolbox is possible through MINC 2.0 file format, and output is provided in ANALYZE format. The major contribution of this toolbox is its facilitation of comparison of fMRI analysis methods by generating several different fMRI data under varying noise and experiment parameters.
2
Allan, Thomas. "Novel fMRI analysis". Thesis, University of Nottingham, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.659287.
Testo completoAbstract (sommario):
Functional Magnetic Resonance Imaging using the Blood Oxygenation Level Dependent (BOLD) contrast allows the brain's neural activity to be measured indirectly. This BOLD signal contains a wealth of information including changes in brain activity and functional connectivity (FC). FC is a measure of how correlated spatially separate brain regions are with each other. The work in this thesis is primarily concerned with novel methods of analysing the BOLD signal, in particular to give new measures of FC. A particular problem with typical measures of FC is that they assume that the networks are large scale and distributed, and that they originate from low frequency, static oscillations. It is clear from the way that we interact with the world that these assumptions are wrong, requiring a dynamic approach to investigate FC and the origins of what might be driving this. Here, a method combining short window correlation analysis and paradigm free mapping, a technique to detect spontaneous BOLD events without prior knowledge of their timings, is used to study the dynamic nature of these networks. It is further shown that these networks are at least in part driven by spontaneous activity, and that the rate of this spontaneous activity can be modulated by a task. These spontaneous events are then combined with network masks and temporal Independent Component Analysis to decompose these large scale networks into smaller sub-networks. Finally, the effects of spontaneous BOLD events on attention and task performance during a visual task is evaluated, highlighting how different brain regions that are not associated with a task can distract the subject's attention. It is shown that BOLD events that relate to a specific task use highly focal specific regions of the brain, confirming the spatial specificity of brain regions to a particular function.
3
Pavlicova, Martina. "Thresholding FMRI images". The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1097769474.
Testo completo
4
Pavlicová, Martina. "Thresholding FMRI images". Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1097769474.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xvii, 109 p.; also includes graphics (some col.) Includes bibliographical references (p. 107-109). Available online via OhioLINK's ETD Center
5
Barreto, Felipe Rodrigues. "O acoplamento neurovascular e metabólico do córtex visual ativado de sujeitos jovens saudáveis durante a disponibilidade reduzida de oxigênio". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-29092016-142720/.
Testo completoAbstract (sommario):
O tecido cerebral é altamente dependente de uma complexa rede vascular e um suprimento adequado de oxigênio, uma vez que o metabolismo oxidativo é a principal via de produção de ATP. Entretanto, durante o aumento da atividade neuronal existe uma relação não linear entre fluxo sanguíneo cerebral e consumo de oxigênio, verificado por tomografia de emissão de pósitrons e posteriormente por técnicas quantitativas de ressonância magnética nuclear. O aumento mais pronunciado do fluxo sanguíneo em comparação com o consumo de oxigênio levanta questões sobre a possibilidade de o oxigênio atuar como um fator limitante. Apesar dos efeitos devastadores da privação completa de oxigênio ao tecido cerebral dentro de minutos, a redução da disponibilidade de oxigênio por curtos períodos de tempo é comum em pacientes com apneia do sono e está associada como fator de risco à hipertensão e acidentes vasculares. Acreditamos que a obtenção de novas informações sobre o efeito da disponibilidade de oxigênio na regulação da resposta vascular e do metabolismo energético no cérebro humano in vivo é crucial para um melhor entendimento de aspectos básicos do metabolismo energético cerebral e sua relação com o sistema neurovascular. Nesta tese foi avaliado o impacto da redução da disponibilidade de oxigênio no acoplamento neurovascular e metabólico do cérebro humano saudável. Dois estudos foram realizados na presença de hipóxia moderada, com saturação sanguínea entre 80 a 85%, e normóxia como condição de controle. O primeiro utilizou técnicas quantitativas de ressonância magnética funcional (fMRI) em 3T para caracterizar a resposta vascular evocada de 9 sujeitos saudáveis perante a estimulação visual. O segundo visou caracterizar as concentrações metabólicas em repouso e também as alterações induzidas pela estimulação visual em 11 sujeitos, utilizando a técnica de espectroscopia de ressonância magnética funcional (fMRS) em 7T. Os dados de fMRI mostraram reduções significativas das áreas corticais recrutadas durante a hipóxia moderada, embora as áreas comuns às três técnicas que continuaram ativas demonstraram respostas com amplitude de fluxo e volume sanguíneos similares a normoxia. Além disto, a variação de consumo de oxigênio devido à estimulação visual foi menor durante a hipóxia. Tais achados potencialmente poderiam indicar diminuição da extensão do recrutamento neuronal, porém um novo desacoplamento entre atividade neuronal e a resposta vascular, ou seja, aumento da atividade neuronal sem uma mesma resposta vascular durante a hipóxia moderada não poderia ser descartado. O estudo de fMRS demonstrou alterações metabólicas (glutamato e lactato) induzidas pela estimulação similares em ambas as condições gasosas. Entretanto, alterações significativas nas concentrações de aspartato, glutamato e glutamina foram observadas entre as condições no repouso. A combinação dos achados de ambos os estudos aqui apresentados sugere que a hipóxia moderada não resulta na diminuição do recrutamento neuronal, pois variações similares de glutamato e lactato, considerados fortes marcadores do aumento de atividade neuronal, foram observadas durante hipóxia moderada. Entretanto, há evidências de que a disponibilidade reduzida de oxigênio leva a alterações no mecanismo do acoplamento vascular e também no metabolismo basal. Análises futuras serão necessárias para verificar se existe um mecanismo fisiológico que explica as alterações vasculares e metabólicas aqui observadas.The cerebral tissue is highly dependent on a complex vascular network and a tight regulated supply of oxygen, since oxidative metabolism is the primary source of ATP synthesis. Increased neuronal activity leads to a well-established mismatch between CBF and CMRO2, measured by PET and nuclear magnetic resonance techniques. The much larger CBF evoked response as compared to CMRO2 response raises questions about the role played by oxygen as a potential limiting factor. Despite the devastating effects of intense hypoxia to cerebral tissue, moderate oxygen deprivation through short periods of time is frequent in chronic disorders such as obstructive sleep apnea and has been suggested to be a risk factor for morbidities such as hypertension and stroke. Identifying the impact of mild hypoxia on functional brain metabolism in the healthy human brain is a crucial step for understanding basics aspects of cerebral bioenergetics and its relationship with the neurovascular system. In this thesis we evaluate the impact of reduced oxygen availability in the neurovascular and metabolic coupling of the healthy human brain. Two studies were performed in the presence of mild hypoxia, with 80 to 85% arterial blood oxygen saturation, and normoxia as the control condition. The first study utilized functional Magnetic Resonance Imaging techniques (fMRI) at 3T to characterize the vascular response to visual stimulation in 9 subjects. The second study aimed at characterizing the neurochemical profile of the human brain and quantifying the stimulus-induced metabolic changes as measured by fMRS at 7T in 11 subjects. The fMRI data showed significant reductions in the recruited cortical areas during mild hypoxia, although activated areas in all three imaging modalities showed responses with similar amplitude of blood flow and volume from normoxia. In addition, the variation of oxygen consumption due to stimulation was smaller during mild hypoxia. These findings could potentially suggest decreased neuronal recruitment, although a new decoupling between neuronal activity and vascular response (i.e. similar neuronal recruitment with different vascular response) could not be discarded. The fMRS study showed similar stimulus-induced glutamate and lactate changes during both gas conditions. However, significant concentration differences were observed in aspartate, glutamate and glutamine during rest conditions. Finally, the combination of the data from the two studies herein presented suggests that mild hypoxia does not result in reduced neuronal recruitment despite the altered vascular response, as shown by the similar glutamate and lactate stimulus-induced responses, known to be strong markers of increased neuronal activity. However, there are evidences that support altered neurovascular coupling and metabolic concentrations during reduced oxygen availability at rest. Further analysis will be necessary to elucidate how the new steady state concentrations of aspartate, glutamate and glutamine could be linked to physiological mechanism that potentially alters the neurovascular response.
6
Bungert, Andreas. "TMS combined with fMRI". Thesis, University of Nottingham, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546548.
Testo completo
7
Bischoff, Matthias [Verfasser]. "Neurofunctional correlates of audiovisual binding in fMRI, EEG and EEG-guided fMRI / Matthias Bischoff". Gießen : Universitätsbibliothek, 2014. http://d-nb.info/1068589051/34.
Testo completo
8
Soldati, Nicola. "Novel data-driven analysis methods for real-time fMRI and simultaneous EEG-fMRI neuroimaging". Doctoral thesis, University of Trento, 2012. http://eprints-phd.biblio.unitn.it/842/1/Soldati_PhD_thesis.pdf.
Testo completoAbstract (sommario):
Real-time neuroscience can be described as the use of neuroimaging techniques to extract and evaluate brain activations during their ongoing development. The possibility to track these activations opens the doors to new research modalities as well as practical applications in both clinical and everyday life. Moreover, the combination of different neuroimaging techniques, i.e. multimodality, may reduce several limitations present in each single technique. Due to the intrinsic difficulties of real-time experiments, in order to fully exploit their potentialities, advanced signal processing algorithms are needed. In particular, since brain activations are free to evolve in
an unpredictable way, data-driven algorithms have the potentials of being more suitable than model-driven ones. In fact, for example, in neurofeedback experiments brain activation tends to change its properties due to training or task eects thus evidencing the need for adaptive algorithms.
Blind Source Separation (BSS) methods, and in particular Independent Component Analysis (ICA) algorithms, are naturally suitable to such kind of conditions. Nonetheless, their applicability in this framework needs further investigations.
The goals of the present thesis are: i) to develop a working real-time set up for performing experiments; ii) to investigate different state of the art ICA algorithms with the aim of identifying the most suitable (along with their optimal parameters), to be adopted in a real-time MRI environment; iii) to investigate novel ICA-based methods for performing real-time MRI neuroimaging; iv) to investigate novel methods to perform data fusion between EEG and fMRI data acquired simultaneously.
The core of this thesis is organized around four "experiments", each one addressing one of these specic aims. The main results can be summarized as follows.
Experiment 1: a data analysis software has been implemented along with the hardware acquisition set-up for performing real-time fMRI. The set-up has been developed with the aim of having a framework into which it would be possible to test and run the novel methods proposed to perform real-time
fMRI.
Experiment 2: to select the more suitable ICA algorithm to be implemented in the system, we investigated theoretically and compared empirically the performance of 14 different ICA algorithms systematically sampling different growing window lengths, model order as well as a priori conditions
(none, spatial or temporal). Performance is evaluated by computing the spatial and temporal correlation to a target component of brain activation as well as computation time. Four algorithms are identied as best performing without prior information (constrained ICA, fastICA, jade-opac
and evd), with their corresponding parameter choices. Both spatial and temporal priors are found to almost double the similarity to the target at not computation costs for the constrained ICA method.
Experiment 3: the results and the suggested parameters choices from experiment 2 were implemented to monitor ongoing activity in a sliding-window approach to investigate different ways in which ICA-derived a priori information could be used to monitor a target independent component: i)
back-projection of constant spatial information derived from a functional localizer, ii) dynamic use of temporal , iii) spatial, or both iv) spatial-temporal ICA constrained data. The methods were evaluated based on spatial and/or temporal correlation with the target IC component monitored, computation time and intrinsic stochastic variability of the algorithms. The results show that the back-projection method offers the highest performance both in terms of time course reconstruction and speed. This method is very fast and effective as far as the monitored IC has a strong and well defined behavior, since it relies on an accurate description of the spatial behavior.
The dynamic methods oer comparable performances at cost of higher computational time. In particular the spatio-temporal method performs comparably in terms of computational time to back-projection, offering more variable performances in terms of reconstruction of spatial maps and time courses.
Experiment 4: finally, Higher Order Partial Least Square based method combined with ICA is proposed and investigated to integrate EEG-fMRI data acquired simultaneously. This method showed to be promising, although more experiments are needed.
9
Drobnjak, Ivana. "FMRI simulator : development and applications". Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444904.
Testo completo
10
De, Luca Marilena. "Low frequency signals in FMRI". Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418562.
Testo completo
11
Zwaag, Wietske van der. "Techniques for high-performance fMRI". Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436813.
Testo completo
12
Ou, Wanmei. "fMRI detection with spatial regularization". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33856.
Testo completoAbstract (sommario):
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 99-102).
Functional Magnetic Resonant Imaging (fMRI) is a non-invasive imaging technique used to study the brain. Neuroscientists have developed various algorithms to determine which voxels of the images are active. Most of these algorithms, operating on the signal of each voxel separately, are referred to as the voxel-by-voxel detectors. Among those voxel-by-voxel detectors, paired T-test and General Linear Model (GLM) are the most popular. The Mutual Information (MI) based detector has recently been introduced. It is interesting to compare these three detectors' modeling assumptions, as well as their performance, in order to understand their advantages and shortcomings. Due to the low signal-to-noise ratio (SNR), the voxel-by-voxel detectors usually result in fragmented activation pattern, which is not in agreement with our understanding of brain activation. The biological models of brain activation suggest that adjacent locations of the brain tend to be in the same activation state. We take advantage of these models and apply a Markov Random Field (MRF) spatial prior to the statistics provided by the voxel-by-voxel algorithms. MRF has been shown to be able to overcome the effect of over-smoothing, which is the major drawback of the conventional spatial regularization models such as the Gaussian smoothing model.
(cont.) We adopt Mean Field, a variational algorithm, to estimate the MRF solution. We show that Mean Field can provide reasonable approximation compared with the exact solver in the case of binary MRFs, while reducing the computations by one to two orders of magnitude in our simulated and real data sets. In addition, unlike the exact solver, it can handle multiple-state MRFs. Inspired by atlas-based segmentation, we further refine the spatial regularization process by incorporating anatomical information, such as segmentation results from Magnetic Resonance Imaging (MRI), into the MRF prior. The extended MRF model encodes both tissue type and activation state. To our knowledge, our approach is the first spatial smoothing method that utilizes anatomical information without cortical surface extraction. To evaluate the smoothing models, we performed ROC and confusion matrix analysis on synthetic data. We also evaluate them by studying their ability to recover activation from significantly shorter time course using real data. Including anatomical information improves detection accuracy for both the Gaussian-smoothing-based detector and the MRF-based detector. The Gaussian-smoothing model provides poor results if we are interested in both positive and negative activation regions in the brain.
(cont.) Furthermore, the anatomically guided MRF-based detector improves the detection quality compared with the anatomically guided Gaussian-smoothing-based detector for standard fMRI in standard SNR quality.
by Wanmei Ou.
S.M.
13
Tijssen, Hendrikus N. "Novel methods for brainstem FMRI". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:ed8e4c4f-5152-44e4-936f-ccf6092d904b.
Testo completoAbstract (sommario):
The brainstem plays a crucial role in a great number of vital functions such as respiratory regulation, visual reflexes, and the perception of pain. The small size and close proximity of the nuclei requires high-resolution functional magnetic resonance imaging (FMRI). However, brainstem FMRI using conventional gradient-echo echo-planar imaging (GRE-EPI) techniques is challenging due to the increased signal dropout and geometric distortions in the brainstem. The primary aim of the work presented in this thesis was to investigate alternative methods for brainstem FMRI in order to overcome some of the challenges associated with single-shot GRE-EPI techniques. Towards this goal 3D segmented sequences were explored, which have the advantage that the size of the geometric distortions is not proportional to the resolution at which is scanned. In particular, two sequences were investigated: balanced steady-state free-precession (bSSFP) and spoiled gradient echo (SPGR). First, a set of experiments was conducted, in which each experiment aimed to isolate a limited range of sequence properties in order to characterize and assess the potential of the candidate sequences. It was found that bSSFP has better noise characteristics compared to GRE-EPI when applied with a 2D acquisition, but when 3D readouts were used the signal instabilities increased dramatically. Based on these findings, experiments that investigate the influence of multishot acquisitions on signal instabilities caused by physiological noise were performed. The signal instabilities were found to mainly originate from regions of CSF and blood and were highly correlated to the cardiac cycle. Several correction methods were explored and one method was identified to be implemented in vivo. A novel method that allows real-time cardiac synchronization of the k-space acquisition was developed. The developed methods used a custom parallel imaging reconstruction to allow for acquisition with a fixed volume frame rate, which is desirable for FMRI purposes. The method was found to reduce the signal instabilities in 3D SPGR and bSSFP significantly. A comprehensive assessment of two currently available retrospective correction techniques was conducted and their practicalities were compared. Recommendations are made to improve the robustness of the investigated correction methods. A novel optimization method was implemented, which was developed to determine the optimal regressor set for retrospective corrections. The method can be applied to image based as well as k-space based methods.
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Manczak, Tiago. "Estimulador galvânico vestibular para fMRI". Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/406.
Testo completoAbstract (sommario):
Este trabalho apresenta o desenvolvimento de um estimulador galvânico vestibular para ser usado em experimentos de imageamento por ressonância magnética funcional (fMRI). Em experiências de fMRI é necessário a produção de estímulos somatossensoriais no paciente. Os estímulos devem ser sincronizados com a sequência de pulsos da fMRI. O estimulador foi dividido em circuitos analógicos (colocados dentro da sala do magneto) e circuitos digitais (sala de comando do sistema de MRI). A comunicação entre os circuitos é feita através de fibra óptica. Experimentos de fMRI realizados com voluntários demonstraram que o estimulador proposto é capaz de manter a sincronização com sistema de fMRI e pode ser usado para localizar as áreas do cérebro que são ativados pelo sistema vestibular.This work presents the development of a galvanic vestibular stimulator to be used in functional magnetic resonance imaging experiments (fMRI). In fMRI experiments it is required the production of somatosensory stimuli in the patient must be sincronized with the fMRI pulse sequence. The stimulator circuits were divided in analog circuits (placed within the magnet room) and digital circuits (placed in the MRI command room). The communication between the circuits is made through optical fiber. fMRI experiments performed with volunteers demonstrated that the proposed stimulator is able to keep the sincronization with the MRI system and can be used to locate the brain areas that are activated by the vestibular system.
15
Nováková, Marie. "Mapování pohybových artefaktů ve fMRI". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220039.
Testo completoAbstract (sommario):
This thesis summarizes a theory of magnetic resonance and the method of functional magnetic resonance. It is focused on the influence of motion artifacts and image preprocessing methods, especially realign. It deals with the possibility of using movement parameters obtained in the process of alignment of functional scans to create maps that show the expression of motion artifacts. In this thesis, three different methods were designed, implemented a tested. These methods lead to the creation of probability, power and statistical group maps showing areas typically affected by movement artifacts.
16
Rocchi, Federico. "Chemogenetic modulation of fMRI connectivity". Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/335219.
Testo completoAbstract (sommario):
Resting-state fMRI (rsfMRI) has been widely used to map intrinsic brain network organization of the human brain both in health and in pathological conditions. However, the neural underpinnings and dynamic rules governing brain-wide rsfMRI coupling remain unclear. Filling this knowledge gap is of crucial importance, given our current inability to decode and reverse-engineer clinical signatures of aberrant connectivity into interpretable neurophysiological events that can help understand or diagnose brain disorders. Toward this goal, here we combined chemogenetics, rsfMRI, and in vivo electrophysiology in the mouse to investigate how regional manipulations of brain activity (i.e. neural inhibition, or excitation) causally contribute to whole-brain fMRI network organization. In a first set of proof of concept investigations, we empirically probed the widely held notion that neural inhibition of a cortical node would result in reduced fMRI coupling of the silenced area and its long-range terminals. Surprisingly, we found that chronic inhibition of the mouse medial prefrontal cortex (PFC) via viral overexpression of a potassium channel paradoxically increased fMRI connectivity between the inhibited area and its direct thalamo-cortical targets. Notably, acute chemogenetic inhibition of the PFC reproduced analogous patterns of fMRI overconnectivity. Using in vivo electrophysiology, we found that chemogenetic inhibition of the PFC enhances low frequency (0.1 - 4 Hz) oscillatory power via suppression of neural firing not phase-locked to slow rhythms, resulting in increased slow and δ band coherence between areas that exhibit fMRI overconnectivity. These results provide causal evidence that cortical inactivation can counterintuitively increase fMRI connectivity via enhanced, less-localized slow oscillatory processes, with important implications for neural modeling and interpretation of fMRI overconnectivity in brain disorders.
Importantly, our observation that neural inhibition of the PFC results in fMRI overconnectivity allowed us to predict that neural activation of the same area might produce opposite results, i.e. fMRI underconnectivity and neural desynchronization. To test this hypothesis, we used chemogenetics to increase local excitatory-inhibitory (E/I) balance in the PFC. As predicted, chemogenetic stimulation of CamkII-expressing neurons, or inhibition of fast-spiking parvalbumin-expressing neurons, produced similar rsfMRI signatures of rsfMRI underconnectivity. Both manipulations produced analogous electrophysiological signatures characterized by increased firing activity and a robust LFP power shift towards higher (i.e. γ) frequencies, effectively reversing the corresponding neural signature observed in DREADD inhibition studies. Importantly, the same E/I affecting perturbations were also associated with socio-communicative deficits in behaving mice hence underscoring the behavioral relevance of the employed manipulations. These results show that excitatory/inhibitory balance critically biases brain-wide fMRI coupling, pointing at a possible unifying mechanistic link between E/I imbalance and rsfMRI connectivity disruption in developmental disorders. More broadly, these investigations reveal a set of fundamental rules linking regional brain activity to macroscale functional connectivity, offering opportunities to physiologically interpret rsfMRI signatures of functional dysconnectivity in human brain disorders.
17
Yildirim, Funda. "Localization Facial Symmetry Perception Through Fmri". Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615040/index.pdf.
Testo completoAbstract (sommario):
Humans are extremely sensitive and accurate about detecting the amount of symmetry that a face possesses. However perception of facial symmetry has not been investigated in terms of its neural correlates yet. In this thesis, we investigated localization of facial symmetry perception in the brain through the use of the fMR-adaptation method. In this method, marginally active neuronal populations can be detected by presenting faces with varying symmetry. By standardizing all aspects of the faces such as illumination, pose and contrast, we manipulated only the amount of fluctuating asymmetry in the face images. Previous studies have shown that a specific area, lateral occipital complex (LOC) exhibits sensitivity to orientation and position changes to faces and other objects. We observed that facial symmetry activation is specifically localized within the LOC boundaries. Within the LOC, we found that previously defined areas namely LO1 and LO2 are both responsive to manipulations of facial symmetry. We also tested our fMR-adaptation paradigm on non-face images, generated by scrambling the face stimuli used in our experiments. We replicated earlier results which demonstrated that LO1 and LO2 are activated in detecting differences between symmetric versus asymmetric patches. This suggests that although facial symmetry perception is not processed by a function specific area of the LOC, it uses main resources allocated for the object recognition system in an efficient manner. To the best of our knowledge, our study is the first to investigate face symmetry perception through fMR-adaptation.
18
Bai, Ping Truong Young K. Smith Richard L. "Temporal-spatial modeling for fMRI data". Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1481.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Apr. 25, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Statistics and Operations Research." Discipline: Statistics and Operations Research; Department/School: Statistics and Operations Research.
19
Woolrich, Mark. "Model-based approaches to FMRI analysis". Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249485.
Testo completo
20
Plumpton, Catrin Oliver. "Classifier ensembles for streaming fMRI data". Thesis, Bangor University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540419.
Testo completo
21
Rollings, David T. "EEG-fMRI in epilepsy and sleep". Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7287/.
Testo completoAbstract (sommario):
This thesis used simultaneous electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) to investigate both epilepsy and sleep. Initially, EEG-fMRI was used in a cohort of patients with complex epilepsy referred from a tertiary epilepsy clinic for both pre-surgical evaluation and diagnostic reasons. The results suggest a limited utility of EEG-fMRI in the epilepsy clinic with a very complex patient group. Following on, investigation of early blood oxygen level dependent (BOLD) signal changes in a group of patients with focal epilepsy demonstrated potentially meaningful BOLD changes occurring six seconds prior to interictal epileptiform discharges, and modelling less than this six seconds can result in overlap of the haemodynamic response function used to model BOLD changes. The same analysis was used to model endogenously occurring sleep paroxysms; K-complexes (KCs), vertex sharp waves (VSWs) and sleep spindles (SSs), finding early BOLD signal changes with SSs in group data. Finally, KCs and VSWs were investigated in more detail in a group of participants under both sleep deprived and non-deprived conditions, demonstrating an increase in overall activation for both KCs and VSWs following sleep deprivation. Overall, we find early BOLD changes are not restricted to pathological events and sleep deprivation can enhance BOLD responses.
22
Rülander, Britta Angela. "Galvanic vestibular stimulator for fMRI research". Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/1843.
Testo completoAbstract (sommario):
CAPESThis master thesis presents the further development of a galvanic vestibular stimulator for use in fMRI examinations developed in a previous thesis (MANCZAK, 2012). This thesis amends the GVS by circuits to measure feedback values and implements the stimulation circuit with digital components, such as a microcontroller and flyback integrated circuits. The microcontroller is used in order to control the current source and process the measured values. The communication between the PC, which allows user interaction through a graphical user interface, and the microcontroller is implemented through optical communication, which is defined by a communication protocol specification. The digital circuitry is designed to be placed within the MRI room, meeting the requirements imposed by strong magnetic fields and radio frequency pulses. The underlying hypothesis of the thesis is that the device can be placed within the MRI room without having a negative impact on the MRI image quality. Laboratory tests without the MRI confirmed the correct design of the galvanic vestibular stimulator.
23
Zeledon, Lostalo Emilia Maria. "FMRI IMAGE REGISTRATION USING DEEP LEARNING". OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2641.
Testo completoAbstract (sommario):
fMRI imaging is considered key on the understanding of the brain and the mind, for this reason has been the subject of tremendous research connecting different disciplines. The intrinsic complexity of this 4-D type of data processing and analysis has been approached with every single computational perspective, lately increasing the trend to include artificial intelligence. One step critical on the fMRI pipeline is image registration. A model of Deep Networks based on Fully Convolutional Neural Networks, spatial transformation neural networks with a self-learning strategy was proposed for the implementation of a Fully deformable model image registration algorithm. Publicly available fMRI datasets with images from real-life subjects were used for training, testing and validating the model. The model performance was measured in comparison with ANTs deformable registration method with good results suggesting that Deep Learning can be used successfully for the development of the field using the basic strategy of studying the brain using the brain-self strategies.
24
McEvoy, Bradley Wright. "Spatial Bayesian variable selection and fMRI". Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1709046681&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Testo completo
25
Perez, Carlos Arturo. "Discovering causal relationships from fMRI data". [Pensacola, Fla.] : University of West Florida, 2009. http://purl.fcla.edu/fcla/etd/WFE0000189.
Testo completoAbstract (sommario):
Thesis (M.S.)--University of West Florida, 2009.Submitted to the Dept. of Computer Science. Title from title page of source document. Document formatted into pages; contains 90 pages. Includes bibliographical references.
26
Bartoň, Marek. "Dekonvoluce hemodynamické odezvy z dat fMRI". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219259.
Testo completoAbstract (sommario):
This paper deals with the variability of HRF, which may have crucial impact on outcomes of fMRI neuronal activation detection in some cases. There are three methods described - averaging, regression deconvolution and biconjugate gradient method - which provide HRF shape estimation. In frame of simulations regression method, which uses B-spline curves of 4-th order for window length of 30 s, was chosen as the most robust method. Deconvolution estimates was used as HRF models for classic analyse of fMRI data, concretely visual oddball paradigm, via general linear model. Enlargement of localizated areas was observed and after expert consultation with scientific employees from neurology clinic, outcomes was evaluated as relevant. Furthermore Matlab application, which provides confortable observation of HRF variability among brain areas, was made.
27
Gathers, Ann D. "DEVELOPMENTAL FMRI STUDY: FACE AND OBJECT RECOGNITION". Lexington, Ky. : [University of Kentucky Libraries], 2005. http://lib.uky.edu/ETD/ukyanne2005d00276/etd.pdf.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Kentucky, 2005.Title from document title page (viewed on November 4, 2005). Document formatted into pages; contains xi, 152 p. : ill. Includes abstract and vita. Includes bibliographical references (p. 134-148).
28
Tuan, August Saul. "fMRI representation of transient onsets and adaptation". Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3214711.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of California, San Diego, 2006.Title from first page of PDF file (viewed June 30, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 86-92).
29
Keinänen, T. (Tuija). "Infra-slow fluctuations in simultaneous EEG-fMRI". Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526213880.
Testo completoAbstract (sommario):
Abstract Brain activity fluctuations occur in multiple spatial and temporal scales. Functional magnetic resonance imaging (fMRI) has shown that infra slow fluctuations (ISF) of blood oxygen level-dependent signal (BOLD) are organized into well-defined areas called resting state networks (RSN). ISFs have also been detected in full-band EEG (fbEEG) data and in recent years, many have combined these two modalities to enable more accurate measurements of brain fluctuations. In simultaneous EEG-fMRI measurements the ISFs of BOLD signal have been found to be correlated with amplitude envelopes of faster electrophysiological data, suggesting the same underlying neuronal dynamics. Also direct correlations have been found in task related studies but not previously in resting state studies. Understanding the relation between EEG and BOLD signal in resting state might prove beneficial in the research of baseline activity fluctuations of the brain. Functional connectivity (FC) of the RSNs has been found to vary in different tasks and in some diseases, but also in resting state in healthy people. Despite numerous studies, no clear cause for these variations has yet been found. To research these open questions we performed simultaneous fbEEG-fMRI studies. The measurements from both modalities were analyzed with independent component analysis to improve the comparability of these results. Correlation analysis revealed that the EEG ISFs correlate with BOLD signal both temporally and spatially. These correlations showed spatiotemporal variability that was related to the strength of RSN functional connectivity. These results indicate that the ISFs of EEG and BOLD reflect a common source of fluctuations. The understanding of the correlations between ISFs in EEG and fMRI BOLD signals gives basic information of brain dynamics and of the variables that affect it. A better understanding of the background of brain activity helps in the development of more effective treatments for various neurological diseases as the knowledge of the mechanisms behind them grows. The ability to measure RSN activity with EEG more accurately can help in the development of new methods for early diagnosis of diseasesTiivistelmä Aivojen toiminta vaihtelee monissa avaruudellisissa ja ajallisissa mittakaavoissa. Toiminnallisissa magneettikuvauksissa (TMK) on havaittu, että veren happipitoisuudesta riippuvan (engl. BOLD) signaalin erittäin hitaat vaihtelut ovat järjestäytyneet hyvin määriteltyihin alueisiin, joita kutsutaan lepotilahermoverkostoiksi. Erittäin hitaita vaihteluita on havaittu myös täysikaistaisesta aivosähkökäyrästä (fbEEG). Viime vuosina nämä kaksi menetelmää on usein yhdistetty tarkemman mittaustuloksen aikaansaamiseksi. Samanaikaisissa EEG-TMK-mittauksissa BOLD signaalin erittäin hitaiden vaihteluiden on huomattu korreloivan nopeampien elektrofysiologisten värähtelyjen amplitudien verhokäyrien kanssa, mikä viittaa samaan perustana olevaan neuraaliseen dynamiikkaan. Myös suoria korrelaatioita on löydetty tehtäviin liittyvissä tutkimuksissa, mutta ei aiemmin lepotilatutkimuksissa. Lepotilan EEG:n ja BOLD-signaalin suhteen ymmärrys voi osoittautua hyödylliseksi aivojen perustilan aktiivisuuden vaihteluiden tutkimisessa. Hermoverkostojen toiminnallisen liittyvyyden on todettu huojuvan tietyissä tehtävissä ja joissain sairauksissa, mutta myös lepotilassa terveillä henkilöillä. Runsaasta tutkimuksesta huolimatta ei liittyvyyden huojunnalle ole vielä löytynyt selkeää aiheuttajaa. Näiden avoimien kysymysten tutkimiseksi suoritimme yhdenaikaisia fbEEG-TMK-mittauksia. Kummankin modaliteetin mittaustuloksia analysoitiin itsenäisten komponenttien analyysillä tulosten vertailtavuuden parantamiseksi. Korrelaatioanalyysit osoittivat, että EEG:n erittäin hitaat vaihtelut korreloivat ajallisesti ja avaruudellisesti TMK:n BOLD-signaalin kanssa. Näissä korrelaatioissa esiintyi sekä paikkaan että aikaan liittyvää huojuntaa, joka oli yhteydessä lepotilahermoverkostojen toiminnallisen liittyvyyden vahvuuteen. Nämä tulokset viittaavat siihen, että samat tekijät tuottavat EEG:n ja TMK:n BOLD-signaalien hitaat vaihtelut. EEG:n ja TMK:n signaalien erittäin hitaiden vaihteluiden välisen korrelaation ymmärtäminen antaa perustason tietoa aivojen toiminnan dynamiikasta sekä siihen vaikuttavista tekijöistä. Parempi ymmärrys aivotoiminnan taustoista auttaa kehittämään tehokkaampia hoitoja neurologisiin sairauksiin, kun tieto mekanismeista niiden takana tarkentuu. Mahdollisuus mitata lepotilahermoverkostojen toimintaa EEG:llä aiempaa tarkemmin voi auttaa kehittämään uusia menetelmiä sairauksien varhaiseen diagnostiikkaan
30
Liu, Aiping. "Brain connectivity network modeling using fMRI signals". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58126.
Testo completoAbstract (sommario):
Functional magnetic resonance imaging (fMRI) is one of the most popular non-invasive neuroimaging technologies, which examines human brain at relatively good spatial resolution in both normal and disease states. In addition to the investigation of local neural activity in isolated brain regions, brain connectivity estimated from fMRI has provided a system-level view of brain functions. Despite recent progress on brain connectivity inference, there are still several challenges. Specifically, this thesis focuses on developing novel brain connectivity modeling approaches that can deal with particular challenges of real biomedical applications, including group pattern extraction from a population, false discovery rate control, incorporation of prior knowledge and time-varying brain connectivity network modeling. First, we propose a multi-subject, exploratory brain connectivity modeling approach that allows incorporation of prior knowledge of connectivity and determination of the dominant brain connectivity patterns among a group of subjects. Furthermore, to integrate the genetic information at the population level, a framework for genetically-informed group brain connectivity modeling is developed. We then focus on estimating the time-varying brain connectivity networks. The temporal dynamics of brain connectivity assess the brain in the additional temporal dimension and provide a new perspective to the understanding of brain functions. In this thesis, we develop a sticky weighted time-varying model to investigate the time-dependent brain connectivity networks. As the brain must strike a balance between stability and flexibility, purely assuming that brain connectivity is static or dynamic may be unrealistic. We therefore further propose making joint inference of time-invariant connections and time-varying coupling patterns by employing a multitask learning model. The above proposed methods have been applied to real fMRI data sets, and the disease induced changes on the brain connectivity networks have been observed. The brain connectivity study is able to provide deeper insights into neurological diseases, complementing the traditional symptom-based diagnostic methods. Results reported in this thesis suggest that brain connectivity patterns may serve as potential disease biomarkers in Parkinson's Disease.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
31
Hollinger, Avrum. "Design of fMRI-compatible electronic musical interfaces". Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116045.
Testo completoAbstract (sommario):
The designs of two functional magnetic resonance imaging-compatible electronic interfaces for use in neuropsychological studies involving musical tasks are presented. The devices, a two-button response box in the form of a computer mouse and a piano keyboard, were designed for rhythmic tapping and piano performance tasks, respectively. In order to correlate changes in neural activation acquired through magnetic resonance imaging (MRI) with task performance, the electronic collection of behavioural data, such as the timing of button or key presses was required. These behavioural measures were captured electronically and communicated to a host computer for synchronization with feedback, stimuli, and the MRI scanner itself. As well, data was logged for offline analysis. Due to the intense and volatile electromagnetic fields, most commercially-available electronic interfaces do not function properly and can even pose a serious safety hazard within the MRI scanner environment. Therefore these custom-designed interfaces were free of ferromagnetic parts and all electronic components were relegated to the control room outside of the scanner environment. Acquisition of button and key presses was accomplished using fibre optic sensors, which are immune to electromagnetic interference. The devices performed successfully within the scanner, and MRI scans showed no image artifacts caused by the prototypes. Sensing of key and button transition velocity was sufficient after extensive calibration. Next generation prototypes are planned and will implement more robust and tighter tolerance manufacturing, improved sensing techniques, the acquisition of isometric forces, and an auto-calibration scheme.
32
Mullinger, Karen Julia. "Simultaneous EEG and fMRI at high fields". Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/14142/.
Testo completoAbstract (sommario):
The work described in this thesis involves an investigation of the implementation and application of simultaneous EEG and fMRI. The two techniques arc complementary, with EEG providing excellent temporal resolution and fMRI having good spatial resolution. Combined EEG/fMRI thus forms a powerful tool for neuroscience studies. In initial work, methods for improving the removal of the gradient and pulse artefacts, which are induced in EEG traces recorded during concurrent MRI, have been developed. Subsequently, the effects of the EEG hardware on MR images were investigated. This involved acquiring a series of scans to identify the sources of B0- and B1 inhomogeneities and the extent to which these affect EPI data. The adverse effects on data quality of combining EEG and fMRI increase with field strength. Consequently, EEG-fMRI at 7T is particularly challenging, although a number of advantages make its implementation desirable. Safety tests were performed which showed the presence of the EEG system caused a negligible increase in RF heating effects during scanning at 7T. After elimination of a number of noise sources, the first simultaneous EEG-fMRI experiments at 7T using commercially available equipment were performed. Concurrent EEG/fMRI at 3T was then used to investigate the correlation between the BOLD (blood oxygenation level dependent) response measured during visual stimulation and both the preceding alpha power and the strength of the driven, electrical response. In considering the correlation of the range of variation of the alpha power and BOLD response, a trend emerged which allowed tentative conclusions to be drawn. Variation of the BOLD and driven response with the frequency of visual stimulation relative to a subject's individual alpha frequency (IAF) was also investigated. A significant increase in the driven response, accompanied by a decrease in the BOLD response was observed in visual cortex when it was driven at the IAF.
33
He, Jiabao. "Functional brain imaging with fMRI and MEG". Thesis, University of Nottingham, 2005. http://eprints.nottingham.ac.uk/12371/.
Testo completoAbstract (sommario):
The work described in this thesis was performed by the author, except where indicated. All the studies were accomplished on the 3 Tesla system within the Magnetic Resonance Centre at the University of Nottingham, and the Wellcome Trust MEG Laboratory at the Aston University during the period between October 1999 and June 2005. Functional Magnetic Resonance Imaging (fMRI) and Magnetoencephalography (MEG) are two promising brain function research modalities, sensitive to the hemodynamic and electrophysiological responses respectively during brain activites. The feasibility of joint employment of both modalities was examined in both spatial and temporal domains. A somatosensory tactile stimulus was adopted to induce simple functional reaction. It was shown that a reasonable spatial correspondence between fMRI and MEG can be established. Attempts were made on MEG recordings to extract suitable aspects for temporal features matching fMRI with a method reflecting the physical principles. It was shown that the this method is capable of exposing the nature of neural electric activities, although further development is required to perfect the strategy.
34
Balcı, Serdar Kemal. "Classification of whole brain fMRI activation patterns". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45854.
Testo completoAbstract (sommario):
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (p. 59-62).
Functional magnetic resonance imaging (fMRI) is an imaging technology which is primarily used to perform brain activation studies by measuring neural activity in the brain. It is an interesting question whether patterns of activity in the brain as measured by fMRI can be used to predict the cognitive state of a subject. Researchers successfully employed a discriminative approach by training classifiers on fMRI data to predict the mental state of a subject from distributed activation patterns in the brain. In this thesis, we investigate the utility of feature selection methods in improving the prediction accuracy of classifiers trained on functional neuroimaging data. We explore the use of classification methods in the context of an event related functional neuroimaging experiment where participants viewed images of scenes and predicted whether they would remember each scene in a post-scan recognition-memory test. We view the application of our tool to this memory encoding task as a step toward the development of tools that will enhance human learning. We train support vector machines on functional data to predict participants' performance in the recognition test and compare the classifier's performance with participants' subjective predictions. We show that the classifier achieves better than random predictions and the average accuracy is close to that of the subject's own prediction. Our classification method consists of feature extraction, feature selection and classification parts.
(cont.) We employ a feature extraction method based on the general linear model. We use the t-test and an SVM-based feature ranking method for feature selection. We train a weighted linear support vector machine, which imposes different penalties for misclassification of samples in different groups. We validate our tool on a simple motor task where we demonstrate an average prediction accuracy of over 90%. We show that feature selection significantly improves the classification accuracy compared to training the classifier on all features. In addition, the comparison of the results between the motor and the memory encoding task indicates that the classifier performance depends significantly on the complexity of the mental process of interest.
by Serdar Kemal Balcı.
S.M.
35
Sander, Christin Y. (Christin Yen-Ming). "Simultaneous PET/fMRI for imaging neuroreceptor dynamics". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/93832.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 147-158).
Whole-brain neuroimaging is a key technique for studying brain function and connectivity. Recent advances in combining two imaging modalities - magnetic resonance imaging (MRI) and positron emission tomography (PET) - into one integrated scanner, have created the opportunity to explore the underlying neurochemistry of brain function in more detail. Imaging these dynamics plays an important role for understanding drug action and function of neurochemical pathways in the brain and is crucial, yet largely unexplored, for creating and evaluating treatment of neurological and psychiatric disorders. In this thesis, we first address technological challenges in simultaneous PET/MRI by designing, building and evaluating PET compatible MR probes for brain imaging, which enable highly sensitive dual modality imaging. We then develop simultaneous imaging methods with PET and functional MRI to assess and validate relationships between receptor occupancy and changes in brain activity due to pharmacological challenges targeting the dopamine system. Our results indicate that dopamine receptor occupancies and vascular responses are correlated in anatomical space and with pharmacological dose. Moreover, the temporal dynamics of the signals show that a direct neurovascular coupling between receptor occupancy and hemodynamics exists and that a temporal divergence between PET and fMRI can be used to investigate previously unexplored neurochemical parameters and adaptation mechanisms in vivo. Overall, our findings provide insight into dopaminergic receptor dynamics and their effects on high-level brain function, paving a way to address receptor-specific brain dysfunction effectively.
by Christin Y. Sander.
Ph. D.
36
Tobón, Gabriel Andres. "Spatial alignment of functional regions in fMRI". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66810.
Testo completoAbstract (sommario):
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 49-50).
An essential step for discovering a common structure in brain activation regions from multi-subject fMRI data is the ability to find spatial correspondences across subjects. This has proven to be a challenging problem due to the lack of a ground truth and variability in anatomical brain structure, functional activation, and spatial locations of functional regions. Standard methods rely on the correspondences given by anatomical registration to a common space, but fail to account for spatial variability of the functional regions relative to anatomy. We develop a clustering method that relies on the alignment of both the anatomical structure and the functional landmarks. The method is shown to improve over standard group analysis techniques that rely on anatomical alignment only. The validation of our method confirms that peaks of activation exhibit consistent spatial structure. Furthermore, our work creates a framework for future testing of different metrics for similarity of brain activation regions across subjects.
by Gabriel Andres Tobón.
M.Eng.
37
Habes, Isabelle. "Real-time fMRI-based neurofeedback in depression". Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/59751/.
Testo completoAbstract (sommario):
Depression is one of the leading causes of disability worldwide. Currently available treatment methods are not always effective in improving depression. There is thus a pressing need for the development of novel treatment methods. Neurofeedback training can potentially alleviate symptoms of depression. By providing depressed patients with feedback about the ongoing processes in their brain via functional magnetic resonance imaging (fMRI), patients can be trained to increase the activation in positive emotion processing areas by engaging in positive imagery. The advantages of this method are that it is non-invasive, offers an individually tailored approach without any side-effects and has the capability to target the neurobiological and cognitive pathways putatively mediating depression. The main aim of this thesis was to elaborate on pilot findings that fMRI-neurofeedback has potential as an add-on treatment tool for depression (Linden et al., 2012). In doing so, this thesis does not focus on confirming that fMRI-neurofeedback can improve symptoms of depression as the dataset employed here is part of a larger dataset of a currently still running clinical trial. Instead this work investigated the feasibility of a control group receiving feedback from a scene processing area and assessed whether fMRI-neurofeedback can indeed affect emotion processing areas that function abnormally in depression and enhance perceived self-efficacy. Sixteen moderately to severely depressed patients took part in a course of five neurofeedback training sessions in which all patients learned to up-regulate the activation in their individually localised target areas. The patients that had received feedback from a positive emotion area influenced the activity in a wider emotion regulation network than just their target area. Additionally, the acquisition of self-regulation skills significantly improved scores on a self-efficacy scale. These findings confirmed the ability of neurofeedback to target biological and cognitive pathways putatively mediating depression.
38
Talasu, Dharneesh. "Efficient fMRI Analysis and Clustering on GPUs". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322077186.
Testo completo
39
McGregor, Keith Matthew. "Negative BOLD and aging an fMRI study /". [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0013860.
Testo completo
40
Orff, Henry John. "Neurobiology of insomnia as measured with FMRI". Diss., [La Jolla] : [San Diego] : University of California, San Diego ; San Diego State University, 2010. http://wwwlib.umi.com/cr/ucsd/fullcit?p3389700.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2010.Title from first page of PDF file (viewed February 17, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 81-86).
41
Štens, Radovan. "Analýza obrazových dat funkční magnetické rezonance (fMRI)". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-375489.
Testo completoAbstract (sommario):
Master's thesis focuses on processing fMRI data, which are mapping blood oxygenation level dependence in a state of brain activity. Usable and necessarily preprocessing tech- niques of the data, together with two main analysis approaches are introduced. The area of univariate methods, especially general linear model and multivariate principal or independent component analysis is explained. Practical application of the methods involved on the real fMRI data set is implemented. Relevant results as well as theirs mutual possible comparison is presented.
42
Lee, Woogul. "Neural substrates of intrinsic motivation: fMRI studies". Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/2738.
Testo completoAbstract (sommario):
Numerous social and educational psychologists propose that intrinsic motivation generated by personal interests and spontaneous satisfactions is qualitatively different from extrinsic types of motivation generated by external compensations and also that intrinsic motivation is more beneficial to learning than extrinsic types of motivation. However, in the field of neuroscience, intrinsic motivation has been little studied while extrinsic types of motivation (e.g., incentive motivation) have been thoroughly studied. The purpose of the present studies was to expand the neural understanding of motivation to include intrinsic motivational processes. To do so, a series of three event-related functional magnetic resonance imaging (fMRI) studies were conducted. Study 1 and Study 2 compared the neural activities when participants decided to act for intrinsic reasons (i.e., self-determined volitional and agentic behavior) versus when they decided to act for extrinsic reasons (i.e., non-self-determined volitional and agentic behavior). Both studies showed that the anterior insular cortex, known to be related to a sense of agency, was more activated during self-determined behavior associated with intrinsic reasons for acting while the posterior parietal regions (e.g., posterior cingulate cortex, angular gyrus), known to be related to a sense of a loss of agency, were more activated during non-self-determined behavior associated with extrinsic reasons for acting. These findings confirm the existence of neural-based intrinsic motivational processes, differentiate intrinsic motivation from incentive motivation, and document the important neural activities which function for generating self-determined agentic action. Study 3 examined these same neural activities as participants engaged in interesting and uninteresting versions of two experimental tasks. Results confirmed the results of the earlier two studies, as the anterior insular cortex was more recruited when participants performed the interesting, but not the uninteresting, version of the tasks. Results also extended the findings from Studies 1 and 2 in an important way in that the ventral striatum, a well-known brain region for reward processing, was more activated when participants performed the interesting, but not the uninteresting, version of the experimental tasks. These findings suggest that intrinsic motivation is generated based on the feeling of intrinsic need satisfaction (from anterior insular cortex activations) and the feeling of reward (from ventral striatum activations). Overall, the present research established three new findings: (1) the neural bases of intrinsic motivation lies largely in increased anterior insular cortical activities; (2) when people made decisions about self-determined intrinsically-motivated behavior, they show enhanced insular cortical activities and suppressed posterior parietal cortical activities; and (3) when people engaged in actual self-determined intrinsically-motivated behavior, they show enhanced insular cortical and ventral striatal activities. In establishing these new findings, the paper introduces a new area of study for motivational neuroscience--namely, intrinsic motivation.
43
Andrade, Katia Cristine. "Dinâmica da alteração perfusional induzida por estado de apnéia utilizando fMRI". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-20042010-100103/.
Testo completoAbstract (sommario):
O mecanismo de contraste mais utilizado em imagens funcionais por ressonância magnética (functional Magnetic Resonance Imaging, fMRI), também conhecido por sinal BOLD (Blood Oxygenation Level Dependent) mede indiretamente a atividade neural, sendo sensível a mudanças no fluxo cerebral sangüíneo (Cerebral Blood Flow, CBF), na taxa cerebral metabólica do oxigênio (Cerebral Metabolic Rate of Oxygen, CMRO2) e no volume cerebral sanguíneo (Cerebral Blood Volume, CBV) e, em princípio, ele pode ser utilizado para mapear perfusão cerebral. Desse modo, o objetivo principal deste trabalho foi investigar, quantitativamente, alterações perfusionais no cérebro humano mapeadas pelas mudanças do sinal BOLD em resposta à indução transitória do estado de apnéia. Para isso, imagens por ressonância magnética foram obtidas através de um scanner de 1.5 T Siemens (Magneton Vision) com seqüências do tipo EPI-BOLD. Nesta pesquisa, foi analisada a influência da duração da apnéia no sinal BOLD. Observou-se, também, a diferença ocasionada no sinal em duas situações: apnéia iniciando-se após a inspiração ou após a expiração. Além disso, foi estudada a propagação deste sinal BOLD pelas diferentes regiões cerebrais. Por último, fazendo uso deste sinal BOLD, construiu-se mapas para obter informações a respeito do volume cerebral sangüíneo. Pelos dados obtidos, foi possível analisar o comportamento do sinal BOLD quando na presença de diferentes PaO2 e PaCO2. Observaram-se, também, diferenças regionais na sensibilidade do sinal BOLD ocasionada pelo estado de apnéia induzido. Essa diferença pode estar relacionada à reatividade das artérias que irrigam cada região ou ao volume sangüíneo basal dessas artérias. Além disso, foi possível obter informações a respeito das características temporais da mudança do CBF para diferentes regiões do cérebro em resposta a hipercapnia. Também, foi feita a identificação de áreas corticais responsáveis pelo controle voluntário da respiração. Por fim, os mapas de B-CBV obtidos utilizando o contraste BOLD em resposta à apnéia foram capazes de refletir o volume sangüíneo local, embora, estudos para análise dos outros parâmetros que influenciam o sinal devam ser realizados.The BOLD (Blood Oxygenation Level Dependent) signal, is the most used contrast mechanism of the so called functional Magnetic Resonance Imaging (fMRI). Although it indirectly measures neuronal activity, its response is directly related to cerebral blood flow (CBF), Cerebral Metabolic Rate of Oxygen (CMRO2) and Cerebral Blood Volume (CBV) and can be, in principle, used to map cerebral perfusion. Thus, the main purpose of this study was to investigate, quantitatively, some aspects of perfusional alterations in the human brain. These changes were mapped by changes in the BOLD signal as a result of a global and uniform stimulation: hypercapnia induced by breath holding paradigms. Magnetic resonance images were acquired in a 1.5 T scanner (Siemens, Magneton Vision) with EPI-BOLD fMRI sequences. It was analyzed the BOLD dependency on breath holding duration and differences on the BOLD signal due the employed breath holding techniques: breath holding after expiration or after inspiration. The regional variability of the BOLD signal propagation was also studied. Moreover, the signal was used to construct maps based on CBV information. It was possible to gain information about the BOLD signal behavior that respond to PaO2 and PaCO2 alterations. Besides, it was demonstrated its regional variations sensibility, which can be correlated with arterial reactivity or the rest CBV of this arteries. It was also possible acquire information about the temporal characteristics of CBF changes induced by hypercapnia across brain regions as well as the identification of cortical areas that were responsible to the voluntary breathing. Finally, the B-CBV maps that used the BOLD con-trast were able to reflect CBV information, although, it is necessary the study of other parameters that can influence the signal.
44
Peres, André Salles Cunha. "Implementação de um sistema de localização espacial de regiões cerebrais em tempo real para aplicação de TMS por co-registro com fMRI". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-21052009-151939/.
Testo completoAbstract (sommario):
Nos últimos 20 anos tivemos um grande avanço na neurociência e nas técnicas de avaliação do sistema nervoso em humanos em uma tentativa inicial de compreensão de seu funcionamento. Colaboram com esse avanço técnicas como a eletroencefalografia (EEG), tomografia com-putadorizada (CT), tomografia por emissão de pósitron (PET), ressonância magnética funcional (fMRI), que geram mapas estatísticos de atividade cerebral, e a estimulação magnética transcrania-na (TMS), que se utiliza de pulsos de campo magnético, intensos e rápidos, de forma que a taxa de variação do fluxo magnético possa produzir uma estimulação cortical. No entanto a técnica de TMS ainda hoje utiliza parâmetros subjetivos para a determinação de um centro responsável por uma determinada atividade estimulada, os quais não possibilitam lo-calizar com precisão a região do córtex cerebral que está sendo estimulada por um pulso magnético. No intuito de eliminar essa subjetividade e estimularmos com precisão os centros de ativi-dade esse trabalho realiza um estudo do co-registro das técnicas de TMS e fMRI através de um neu-ronavegador que possibilita encontrar estruturas cerebrais sob uma determinada posição do escalpo. Inicialmente o estimulador foi caracterizado e um mapa de intensidade de campo magnético produ-zido pela bobina em forma de oito ou butterfly foi realizado por diferentes métodos. Em seguida um neuronavegador foi desenvolvido que permite fazer uma superposição das imagens de fMRI com o padrão de campos magnéticos produzido pela bobina. Pode-se variar a posição da bobina e observarem-se as regiões que provavelmente serão estimuladas pelo campo magnético. Com isso pode-se aperfeiçoar a estimulação. Para verificar a eficiência desse método estimulou-se o córtex motor de um grupo de 10 voluntários assintomáticos. O estímulo foi monitorado através de um eletromiógrafo posicionado no músculo abdutor do polegar da mão. Os resultados indicam que com o uso da neuronavegação foi possível estimular a região motora esperada em 100% dos voluntários estudados.In the last 20 years we witnessed a great advance in neurosciences and evaluation techniques as an initial attempt for understanding of working principles of the human central nervous system Techniques such as electroencephalography (EEG), positron emission tomography (EEG), functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) have produced grate advances in the understanding of human cerebral nervous system. fMRI generates statistical maps of the cerebral activity and TMS uses intense and fast magnetic pulses to produce a high rate magnetic flux variation to produce cortical electrical stimulation. However, even today TMS uses subjective parameters to establish an area responsible for a certain stimulated activity, that does not allow the precise cortical localization of the cortex area being stimulated by the magnetic pulse. Aiming to overcome this subjectiveness to more precisely stimulate the activity center this work investigates the use of a co-register method based on TMS and fMRI through the use of a neuronavigator that allows the location of brain structures below a certain scalp position. Initially the TMS was characterized and a map of the magnetic field intensity produced by the eight shaped or butterfly coils was determined by different methods. After this step a neuronavigator was devel-oped allowing a superposition of the magnetic field pattern with the fMRI images. The coil position can be varied and the possible stimulated regions can be visualized. This integration of information is expected to improve the TMS accuracy. To verify the efficacy of this method the motor cortex of 10 asymptomatic volunteers were stimulated. The stimulus was monitored with an electromyogram acquired in the hand thumb abductor muscle. The results shown that with the neuronavigation it was possible to stimulate the desired motor region in all the volunteers studied.
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Pastorello, Bruno Fraccini. "Em busca da região epileptiforme em pacientes com epilepsia do lobo temporal: métodos alternativos baseados em fMRI e EEG-fMRI". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-26102011-135335/.
Testo completoAbstract (sommario):
A epilepsia do lobo temporal (ELT) é a forma mais comum de epilepsia e a mais resistente ao tratamento medicamentoso. Existem diversos tipos de drogas anti-epilépticas usadas no controle das crises. Entretanto, em alguns casos, esse tipo de tratamento não é eficaz e a cirurgia para remoção da zona epileptogênica (ZE) pode ser uma alternativa recomendada. A ZE é definida como aquela onde as crises são originadas. Trata-se de um conceito teórico e, atualmente, não existem técnicas capazes de delimitá-la precisamente. Na prática, exames de EEG, vídeo-EEG, MEG, SPECT, PET e diversas técnicas de MRI, em especial as funcionais, têm sido usados para mapear zonas relacionadas à ZE. Contudo, em alguns casos, os resultados permanecem não convergentes e a determinação da ZE inconclusiva. Desse modo, é evidente a importância do surgimento de novas metodologias para auxiliar a localização da ZE. Assim, pois, o objetivo deste trabalho foi desenvolver dois métodos para a avaliação da ZE, ambos baseados na imagem funcional por ressonância magnética. No primeiro, investigamos possíveis alterações da resposta hemodinâmica (HRF) quando da modulação da pressão parcial de CO2. Para tanto, fizemos um estudo sobre 22 pacientes com ELT e 10 voluntários assintomáticos modulando a pressão parcial de CO2 sanguíneo cerebral por um protocolo de manobra de pausa respiratória e outro de inalação passiva de CO2/ar. Os resultados mostram que o tempo de onset da HRF tende a ser maior e a amplitude da HRF tende a ser menor em áreas do lobo temporal de pacientes com ELT quando comparados com os dados de voluntários assintomáticos. Além disso, os resultados mostram mapas de onset individuais coincidentes com exames de SPECT ictal. O segundo estudo foi baseado em medidas de EEG-fMRI simultâneo. Neste, avaliamos a relação entres as potências dos ritmos cerebrais alfa e teta (EEG) e o contraste BOLD (fMRI) de 41 pacientes com ELT e 7 voluntários assintomáticos em estado de repouso. A análise da banda alfa mostrou correlações negativas nos lobos occipital, parietal e frontal tanto nos voluntários quanto nos pacientes com ELT. As correlações positivas nos voluntários foram dispersas e variáveis em ambos hemisférios cerebrais. Por outro lado, encontramos forte correlação positiva no tálamo e ínsula dos pacientes com ELT. Na análise da banda teta observamos correlações positivas bilaterais nos giros pré e pós central de voluntários. Ainda, foram observados clusters no cíngulo anterior, tálamo, ínsula, putamen, em regiões parietais superior, frontais e giros temporais. Também, utilizamos um cálculo de índice de lateralização (IL) no lobo temporal em confrontos entre pacientes com ELT à direita, pacientes com ELT à esquerda e voluntários assintomáticos. Verificamos que os ILs, utilizando os clusters obtidos nas análises em teta, foram coincidentes com o diagnóstico clínico prévio da localização da ZE em todas as análises dos grupos de pacientes com ELT à direita, e na maioria do grupo de pacientes com ELT à esquerda. De forma geral, verificamos que o método de hipercapnia se mostrou ferramenta interessante na localização da ZE comprovada pelos coincidentes achados pela avaliação de SPECT. Inferimos que o maior tempo de onset e menor amplitude da HRF observadas nos pacientes em relação a voluntários possam estar relacionados a um stress vascular devido à recorrência de crises. Já o método de ritmicidade alfa e teta proposto parece promissor para ser usado na determinação da lateralização da ZE em pacientes com ELT.Temporal lobe epilepsy (TLE) is the most common and resistant form of epilepsy to anti-epileptic drug. There are several types of anti-epileptic drugs used in seizure control. However, in some cases drug treatment is not effective and surgery to remove the epileptogenic zone (EZ) is a recommended alternative. EZ is a theoretical concept and there are many techniques that have been applied to enclose it precisely. In practice, EEG, video-EEG, MEG, SPECT, PET and various MRI techniques, especially functional MRI (fMRI), have been used to map areas related to EZ. However, in some cases, the results remain non-convergent and the EZ, undefined. Therefore, the use of new methodologies to assist the location of EZ have been proposed. Herein, our goal was to develop two methods for assessing the EZ. The first one was designed to access changes in the hemodynamic response (HRF) of the EZ in response to hypercapnia. 22 patients with TLE and 10 normal volunteers were evaluated by modulating the partial pressure of CO2 during the acquisition of fMRI in a breathing holding and a passive inhalation CO2/air protocols. The results show increased onset times and decreased amplitude of the HRF in the temporal lobe of TLE patients compared with asymptomatic volunteers. Moreover, most patients had onset maps coincident with ictal SPECT localizations. The second proposed study was based on simultaneous EEG-fMRI acquisitions. The relationship between powers of alpha and theta bands (EEG) and BOLD contrast (fMRI) was investigated in 41 TLE patients and 7 healthy controls. Alpha band results show a consistent negative correlation in the occipital, parietal and frontal lobes both in controls and TLE patients. In addition, controls show disperse positive correlations in both hemispheres. On the other hand, TLE patients presented strong positive correlations in the thalamus and insula. Theta band analysis, in controls, primarily show positive correlations in bilateral pre-and post-central gyri. In patients, robust positive correlations were observed in the anterior cingulate gyrus, thalamus, insula, putamen, superior parietal, frontal and temporal gyri. Moreover, the lateralization index (LI) indicates a coincidence between the side of the EZ evaluated by clinical diagnosis and clusters detected in the theta band. In conclusion, the hipercapnia study showed to be an interesting tool in locating EZ and the results are similar to SPECT findings. The longer onset and lower amplitude of the HRF observed in patients may be related to a vascular stress due to the recurrence of seizures. Furthermore, alpha and theta rhythms may be a promising tool to be used in determining the lateralization of EZ in patients with TLE.
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Conner, Ian Patrick. "fMRI studies of amblyopia pediatric and adult perspectives /". Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4077.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--West Virginia University, 2005.Title from document title page. Document formatted into pages; contains xi, 199 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.
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Leung, Tsan-chiu. "An fMRI study of conceptual combination in Chinese". Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B3105870X.
Testo completo
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Glomb, Katharina. "Spatio-temporal dynamics of human fMRI resting rate". Doctoral thesis, Universitat Pompeu Fabra, 2017. http://hdl.handle.net/10803/402438.
Testo completoAbstract (sommario):
Spontaneous brain activity, measured under the absence of any overt task, has been investigated under the label of “resting state” for about 20 years with rising interest. While it was known since the beginnings of modern electrophysiology that the brain exhibits spontaneous fluctuations also during rest, the discovery, in 1995, that these fluctuations possess a robust spatio-temporal structure had a profound impact on how we understand and investigate brain activity. In this dissertation, we characterize the spatio-temporal dynamics of resting state on a macroscopic level using fMRI recordings from humans and combining novel data analysis tools with theoretical models on the level of the whole brain. We demonstrate the presence of common patterns of functional connectivity, known as resting state networks (RSNs), that evolve in time in both empirical and model data. We show that spontaneous fluctuations and their statistics are determined by the structure of the brain network and its dynamics.La actividad cerebral espontánea, o actividad de reposo, es aquella que uno puede registrar cuando el cerebro no está involucrado en ninguna tarea impuesta del exterior (tal como sería la presentación de un estímulo). El estudio de la actividad de reposo ha conocido un interés creciente durante los últimos 20 años. Si bien las fluctuaciones en la actividad de reposo eran conocidas desde los inicios de la electrofisiología moderna, el descubrimiento, en 1995, de que estas fluctuaciones muestran patrones espaciotemporales robustos ha tenido un impacto profundo en la manera de entender e investigar la actividad del cerebro. En esta disertación caracterizamos la dinámica espaciotemporal de la actividad de reposo a nivel macroscópico usando registros de fMRI en humanos y combinando nuevas herramientas de análisis y modelos teóricos del cerebro a gran escala. Observamos patrones comunes de conectividad funcional evolviendo en el tiempo tanto en los datos empíricos como en las simulaciones. Demostramos que las fluctuaciones de reposo y su estadística son determinadas por la estructura de la red cerebral y su dinámica.
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Koc, Seyma. "Categorical Effect Studied Through Fmri In Color Perception". Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614802/index.pdf.
Testo completoAbstract (sommario):
It is widely accepted that color is perceived categorically. Categorical perception of color can be defined as the tendency to discriminate colors that are from different categories easier, quicker and more accurately than colors that are from the same category. The present study investigated whether brain activity patterns verifies the concept of categorical color perception, an instantiation of top-down influences on low-level perception. Participants performed a color discrimination task on color pairs. Three categories of color pairs are defined in the green-blue region as follows. One of the pairs was specified as cross-category pair by choosing one color from green side of the green-blue boundary and the other color from blue side. The other two pairs were featured as within-category pairs by choosing two shades of green for within-green pair and two shades of blue for within-blue pair. Crucially, the pairs varied only in hue dimension and the physical distance between each of three pairs was set to 10 degrees in CIE LCh space. Pairs on the screen are displayed adjacently or with gaps in between, to further investigate the effect of space in color discrimination. Correct responses, reaction times and fMRI BOLD signals are recorded. Behavioral findings yielded a decrementing pattern from green to blue region challenging the prediction of categorical perception argument that performance is better at green-blue boundary than both within green and blue regions. Behavioral findings also indicated that adjacent display of colors facilitated color discrimination when compared to display of colors with spatial gaps. Brain activity patterns indicated that separate neural processes might underlie these distinct behavioral differences. Although standardized with respect to the color metric, the three categories of our experiment might have involved differences with respect to difficulty levels and memory requirements. Brain activity differences reported in the within-green condition versus cross-category condition are focused on Frontal Eye Fields and Fusiform Gyrus, which is seem to be modulated by Frontal Eye Field activityincreased activation in these regions is related to enhanced visual performance and higher scores, which is consistent with significantly better performance in within-green discrimination than cross-category discrimination. For the same contrast, Parahippocampal Gyrus and Precuneus activations suggest better visual recall and behavioral improvement due to more efficient maintenance in spatial working memory for within-green discrimination than cross-category discrimination. Brain activity differences reported in the within-blue condition versus cross-category condition is focused on Superior Temporal Gyrus, which is involved in color discrimination having the role of color memory. When within-green and within-blue conditions are compared, there was differential activation in the Fusiform Gyrus, and this is the only brain activity which might be attributed to a categorical effect. This comparison also yielded activity in Medial Frontal and Superior Frontal regions concerning more confident perceptual decisions and improved performance on within-green discrimination than within-blue discrimination. In addition, spatial separation of stimuli entailed more cognitive resources to color discrimination than adjacent stimuli as suggested by Cuneus and Lingual Gyrus activations. Overall, to the best of our knowledge our study is the first to investigate the neural framework for color perception, which revealed that color perception might involve several complex sub-processes that activate memory and attention.
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Allievi, Alessandro. "Robot-assisted fMRI assessment of early brain development". Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/34342.
Testo completoAbstract (sommario):
Preterm birth can interfere with the intra-uterine mechanisms driving cerebral development during the third trimester of gestation and often results in severe neuro-developmental impairments. Characterizing normal/abnormal patterns of early brain maturation could be fundamental in devising and guiding early therapeutic strategies aimed at improving clinical outcome by exploiting the enhanced early neuroplasticity. Over the last decade the morphology and structure of the developing human brain has been vastly characterized; however the concurrent maturation of brain function is still poorly understood. Task-dependent fMRI studies of the preterm brain can directly probe the emergence of fundamental neuroscientific notions and also provide clinicians with much needed early diagnostic and prognostic information. To date, task-fMRI studies of the preterm population have however been hampered by methodological challenges leading to inconsistent and contradictory results. In this thesis I present a modular and flexible system to provide clinicians and researchers with a simple and reliable solution to deliver computer-controlled stimulation patterns to preterm infants during task-fMRI experiments. The system is primarily aimed at studying the developing sensori-motor system as preterm infants are often affected by neuro-motor dysfunctions such as cerebral palsy. Wrist and ankle robotic stimulators were developed and firstly used to study the emerging somatosensory 'homunculus'. The wrist robotic stimulator was then used to characterize the development of the sensori-motor system throughout the mid-to-late preterm period. An instrumented pacifier system was also developed to explore the potential sensorimotor modulation of early sucking activity; however, despite its clear potential to be employed in future fMRI studies, results have not yet been obtained on preterm infants. Functional difficulties associated with prematurity are likely to extend to multi-sensory integration, and the olfactory system currently remains under-investigated despite its clear developmental importance. A custom olfactometer was developed and used to assess its early functionality.