Wyniki wyszukiwania - Biblioteka Nauki

1

Inside bold - why neuronal activity modulates MR signal?

100%

Bogorodzki P.

Acta Neurobiologiae Experimentalis

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2009

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tom 69

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nr 3

EN

Although fMRI methods are well recognized as a powerful tool in neuroimaging, they still suffer from lack of repeatable quantitative measures of effect studied, especially in disease group studies, where pathologically changed brain morphologies or distortions caused by head movement arise. In such cases where typical statistical parametric mapping (SPM) approach based on general linear model (GLM) modeling fails, additional methods, giving complementary measures to standard statistical maps SPM may comprise an alternative approach. This subject covers two basic methodologies, which will be presented in this presentation: (1) A novel technique called Mean Regional Response (MRR) uses features derived from time-intensity curves in anatomically or functionally defi ned regions of interest (ROIs). Resulting features can be used for higher level analysis, like ANOVA or highlight differences between groups of subjects allowing inference about group separation; (2) Structural Equation Modeling (SEM) technique is focused on the extraction of connections between the active regions. Although SEM still do not allow arbitrary connection patterns, its use allows determination of time varying and bi-directional, asymmetric connections for groups of interest (patient vs. controls etc.). A methodological basics of BOLD modeling, which can be considered as a basis for most detection and classifi cation methods, will be presented and illustrated with author’s fMRI studies

2

Zastosowanie metod tomograficznych do badania dynamiki procesów fizjologicznych

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Bogorodzki P.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2011

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tom z. 176

3-118

PL

Niniejsza praca zawiera podsumowanie prac autora w dziedzinie zastosowania tomografii do badań in vivo procesów fizjologicznych, zachodzących w organizmie człowieka. Referując większość zagadnień, będących przedmiotem niniejszej pracy, autor skupia uwagę na przestrzenno-czasowych (4D) protokołach obrazowania, nazywanych obrazowaniem dynamicznym. W pracy opisano i zdefiniowano podstawowe pojęcia związane z dynamicznym obrazowaniem w tomografii komputerowej (KT) i w obrazowaniu techniką rezonansu magnetycznego (MRI), omówiono zastosowania tomografii dynamicznej do obrazowania ukrwienia mózgowego oraz obrazowania in vivo stężenia we krwi naturalnego środka cieniującego, jakim jest odtleniona hemoglobina (dHB). Technika ta, nazywana czynnościowym rezonansem magnetycznym, umożliwia badania procesów mózgowych człowieka. W pracy przedstwiono opis metodyki eksperymentów dynamicznych oraz przykłady aparatury i oprogramowania, wykorzystywanego przez autora w pracach badawczych dotyczących tych technik.

EN

The paper summarizes the autor's work in the area of 'in-vivo' imaging of physiological processes in living humans using spatial-temporal (4D) scanning protocols, known as dynamic imaging. The introductory chapter defines data structures ised in computed tomography (CT) and magnetic resonance imaging (MRI) dynamic scanning protocols. These data are used in applications described in the next chapter : perfusion imaging and 'in-vivo' monitoring of deoxy-hemoglobin (dHB) concentration in blood. This technique, known as functional magnetic resonance imaging (fMRI), allows to infer information about regional neuronal activity in the human brain. The paper also describes methodological aspects of dynamic imaging experiments and example instrumentation setups used by the author in his research work in this field.

3

Obrazowanie czynności mózgu techniką rezonansu magnetycznego

100%

Bogorodzki P.

Przegląd Elektrotechniczny

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2009

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tom R. 85, nr 9

40-45

PL

W artykule przedstawiono podstawy obrazowania czynności mózgu metodą Jądrowego Rezonansu Magnetycznego. Obejmuje to następujące aspekty tej techniki: historię odkrycia sygnału BOLD (ang. blood oxygenation level dependent), sposoby jego detekcji, metody prezentacji map czynościowych oraz pomocnicza aparatura stosowana do stymulacji wybranych obszarów korowych mózgu.

EN

Paper presents an introduction to functional Magnetic Resonance Imaging (fMRI) methodology. This covers the following aspects of fMRI methodology: an historic overview of BOLD (ang. blood oxygenation level dependent) discovery, BOLD detection, mapping techniques used in FMRI and supporting fMRI instrumentation used for region of interest (ROI) stimulation of human brain cortex.

4

Obrazowanie parametryczne z wykorzystaniem dynamicznych badań tomograficznych

51%

Bogorodzki P. , Wolak T. , Orzechowski M. , Piątkowski A.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2001

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tom z. 130

73-89

PL

W niniejszym artykule przedstawiono metodę tworzenia obrazu czynnościowego z serii czasowej obrazów tomograficznych (CT, MRI). Obraz parametryczny wyliczany jest za pomocą modelu otrzymanego z referencyjnego obszaru mózgu z zastosowaniem analizy korelacyjnej. Przyjęcie takiego sposobu postępowania umożliwia wyeliminowanie najbardziej zawodnego i czasochłonnego etapu tworzenia obrazu czynnościowego, jakim jest procedura aproksymacyjna.

EN

Parametric images can be obtained from CT or MRI modalities through a special sequential scanning after the injection of a contrast medium. This kind of examination, called dynamic study, forms an image sequence that monitors the first pass transit of injected boluses of the contrast agents, through an organ of interest. The new proposed method applies correlation and discrimination analysis to each concentration-time curve instead of fitting them to any a priori and arbitrary tracer kinetic model. We have previously shown that temporal correlation methods can be used to analyse functional images of the brain, kidney and heart (Bogorodzki, 1996, Lo 1996).

5

Functional dissociation within the reward system in humans

45%

Jednorog K. , Szatkowska I. , Marchewka A. , Wolak T. , Bogorodzki P.

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nr 3

6

Neuroanatomical correlates of fast forward training: an fMR1 study

45%

Lewandowska M. , Piatkowska-Janko E. , Bogorodzki P. , Wolak T. , Szelag E.

Acta Neurobiologiae Experimentalis

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2009

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tom 69

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nr 3

EN

Using fMRI we tested brain activations involved in temporal processing following Fast ForWord (FFW) training in 11 young volunteers. They performed the Temporal Order Judgment task in two sessions: before and after the training. The task was to report the order of two sounds presented in rapid succession. Each pair consisted of a short (10-ms) and a long (50-ms) sound separated by Inter-Stimulus-Intervals of 160 ms (easy condition), 60 ms (medium) and 10 ms (diffi cult). FFW training was applied for ca. 8 weeks with four 1-hour sessions per week. The brain activations during particular conditions (“before vs. after” and “after vs. before”) the training were compared using paired sample t-tests from SPM5. ‘Before vs. after’ comparisons resulted in the following activations: (1) easy condition – left cerebellum, (2) medium condition – cerebellum and insula bilaterally, left thalamus and putamen and moreover, bilaterally selected areas of the temporal, frontal and parietal lobes, (3) diffi cult condition – left insula and the left temporal, frontal and parietal gyri. “After vs. before” comparisons showed no signifi cant differences for each condition, thus, indicating no increase of activation “after” than “before” the training. These results support the involvement of above structures in timing and suggest decreased brain activation in timing tasks following FFW training. We thank Scientifi c Learning for the opportunity to use FFW grant MSHE no.: 1082/P01/2006/31.

7

Comparison of purely scattering finite difference method for the two-dimensional TM wave with the analytical solution

32%

Domański G. , Konarzewski B. , Kurjata R. , Zaremba K. , Marzec J. , Ziembicki M. , Rychter A. , Piątkowska-Janko E. , Bogorodzki P.

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2018

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tom Vol. 59, nr 12

78--83

EN

This paper presents a comparison of purely scattering method of the finite-difference time-domain with the analytical solution for the case of two-dimensional TM wave and the object in the form of a cylinder made either from an ideal conductor or a dielectric material. The total scattering cross-section of the electromagnetic wave is calculated without transition from the near field to the far field. A simple algorithm for calculating wave power distributed on the control surface is presented. The dependence of the relative error of the scattering efficiency factor in the function of the number of iterations is shown for various values of scattering object diameter to wavelength ratios. The influence of relative dielectric constant of cylinder material on scattering efficiency coefficient is examined.

PL

Artykuł przedstawia porównanie czysto rozproszeniowej metody różnic skończonych z rozwiązaniem analitycznym dla przypadku dwuwymiarowej fali TM i obiektu w postaci cylindra wykonanego z idealnego przewodnika lub dielektryka. Całkowity przekrój dla fali elektromagnetycznej obliczono bez przejścia z pola bliskiego na dalekie. Przedstawiono prosty algorytm obliczania rozkładu mocy fali na powierzchni kontrolnej. Zależność błędu względnego wydajności rozpraszania w funkcji liczby iteracji została przedstawiona dla różnych wartości stosunku średnicy obiektu rozpraszającego do długości fali. Zbadano wpływ względnej przenikalności dielektrycznej materiału cylindra na współczynnik wydajności rozpraszania.

8

Laboratorium hiperpolaryzowanych środków cieniujących NMR : tomografia MR hiperpolaryzowanych środków cieniujących

32%

Obrębski W. , Piątkowska-Janko E. , Sawionek B. , Orzeł J. , Kossowski B. , Werys K. , Szczepankowski M. , Tor P. , Bogorodzki P.

Elektronika : konstrukcje, technologie, zastosowania

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2015

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tom Vol. 56, nr 7

7-11

PL

Artykuł przedstawia laboratorium technik rezonansu magnetycznego (NMR) w którym prowadzone są badania magnetyzacji układów spinowych, w szczególności badania mechanizmów indukowania i utrzymywania wysokich stopni polaryzacji spinowej zwanej hiperpolaryzacją i dotyczy próbek stałych (13C, 29Si) czy gazowych (3He, 129Xe), która pozwala na wzmocnienie ich sygnału jądrowego rezonansu magnetycznego o cztery rzędy wielkości.

EN

This paper presents a magnetic resonance laboratory (NMR) where magnetization of spin systems is studied, in particular development of robust strategies for inducing and maintaining a high nuclear spin polarization levels called hyperpolarization either solid (13C, 29Si) or gaseous (3He, 129Xe)samples. Sample hyperpolarization gains its nuclear magnetic resonance signal in four orders of magnitude giving enormous sensitivity enhancement in NMR and MRI.

9

Sprzęt i oprogramowanie do obrazowania czynności mózgu techniką rezonansu magnetycznego

32%

Bogorodzki P. , Piątkowska-Janko E. , Orzechowski M. , Kurjata R. , Obrębski W. , Kołaszewski Ł. , Wagner M. , Wolak T.

Elektronika : konstrukcje, technologie, zastosowania

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2008

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tom Vol. 49, nr 4

128-135

PL

Opisano aparaturę i oprogramowanie przeznaczone do badań czynnościowych fMRI, opracowane w ramach realizacji projektu badawczego Ministerstwa Nauki i Szkolnictwa Wyższego oraz prac inżynierskich i magisterskich studentów Wydziału Elektroniki i Technik Informacyjnych (specjalność Elektronika i Informatyka w Medycynie).

EN

This paper describes software and hardware tools designed for brain studies with the aid of functional Magnetic Resonance Imaging (fMRI). Presented work was supported by the grant from Polish Science and Education Ministry and realized during Master's degree courses at the Faculty of Electronics and Information Technology (specialization: electronics and informatics in medicine).

10

Badania czynnościowe mózgu jako metoda diagnostyki przedoperacyjnej u chorych operowanych z powodu padaczki opornej na leczenie farmakologiczne

26%

Wolak T. , Szymańska O. , Soluch P. , Szeszkowski W. , Kurjata R. , Orzechowski M. , Bogorodzki P. , Piątkowska-Janko E. , Marchel A. , Rysz A. , Majkowska-Zwolińska B.

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tom z. 157

19-25

EN

For patients with pharmacoresistant epilepsy only surgieal intervention is an effeetive solution. To prevent unnecessary damage of important regions of the brain, there is a need for mapping of funetional organization of cerebral cortex. In cIinical practiec together with neuropsyehological evaluation an invasive techniques are used: intraoperative cortex mapping using electrieal stimulation and Wada test. In this work, usefulness of fMRI in preoperative planning for those patients was assessed. In cooperation with group of neuropsyehologists five patients were studied. A group of tests was prepared eonsisting of phonetie and semantic fIueney for Broea mapping and a group of motoric tests. All experiments were performed on two seanners for repeatability assessment. For each patient individual maps of active regions were eaculated using SPM2 package and self made tools. For verification of results cIinical evaluation methods were used: Wada test comparison, comparison with intraoperative stimulation and spatial relations between lesions and functional regions. Three of five patients had surgical intervention. None of them presented any degradation in most endangered function - verbal for 2 patients and motoric in one case. All patients will be examined after 6 months. At current stage of study a cIinical protocol is being designed for routine use.

11

The neural correlates of specific executive dysfunctions in Parkinson’s disease

26%

Gawrys L. , Falkiewicz M. , Pilacinski A. , Riegel M. , Piatkowska-Janko E. , Bogorodzki P. , Wolak T. , Andrysiak R. , Krolicki L. , Kulinski R. , Koziorowski D. , Janik P. , Rymarczyk K. , Grabowska A. , Kaczmarek L. , Szatkowska I.

Acta Neurobiologiae Experimentalis

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2014

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tom 74

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nr 4

EN

Several functional neuroimaging studies in patients with Parkinson's disease (PD) have suggested that changes in the fronto-parietal-striatal networks are associated with deficits in executive functioning. However, executive functions (EF) are multifaceted and include three dissociable components: working memory, response inhibition, and task-switching. This study investigated which component of executive functioning is most strongly associated with fronto-parietal-striatal efficiency in PD. PD patients (with and without executive dysfunction), and age-matched healthy subjects, completed a battery of cognitive tests previously shown to discriminate among the three EF components. Principal component analysis conducted on the selected cognitive test variables yielded three expected EF components. The component scores were used in regression analysis to assess the relationship between the EF efficiency and blood oxygenation level-dependent (BOLD) signal related to performing the n-back, an experimental task that draws upon multiple components of executive functioning: working memory, response inhibition, and task-switching. We found distinct neural correlates of specific executive dysfunctions in patients with PD. However, all of them seem to be associated with fronto-parietal-striatal efficiency.

12

Parkinson's disease leads to distorted interaction of episodic and working memory systems

26%

Gawrys L. , Szatkowska L. , Pilacinski A. , Piatkowska-Janko E. , Bogorodzki P. , Wolak T. , Friedman A. , Sienkiewicz J. , Koziorowski D. , Janik P. , Jamrozik Z. , Krolicki L. , Andrysiak R. , Kulinski R. , Kaczmarek L.

Acta Neurobiologiae Experimentalis

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2009

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tom 69

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nr 3

EN

Patients with Parkinson’s disease (PD) exhibit impairments in executive function and working memory. As opposed to motor symptoms of the disease the physiological origins of cognitive defi cits are not well understood. The aim of the present study was to delineate mechanisms of cognitive impairment in PD using blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI). Twenty-two patient and 10 matched control subjects accomplished Wisconsin Card Sorting Test (WCST) – standard clinical measure of executive function and then underwent fMRI during performance of the N-Back working memory task.The correlation analysis comparing BOLD signal intensity changes with number of categories achieved in WCST revealed a signifi cant positive correlation within supramarginal gyrus, inferior parietal gyrus, middle and inferior frontal gyrus and caudate nucleus. Signifi cant negative correlations with executive impairment were observed within fusiform and parahippocampal gyrus, as well as enthorhinal and perirhinal cortex. These results suggest that cognitive impairment in PD may origin in consequence of distorted interaction between episodic and working memory systems.