News – Page 13

July 17, 2019Reconfigurable MRI technology for low-SAR imaging of deep brain stimulation at 3T: Application in bilateral leads, fully-implanted systems, and surgically modified lead trajectories

Our PhD student Ehsan Kazemivalipour and Prof.Ergin Atalar have published a paper ”Reconfigurable MRI technology for low-SAR imaging of deep brain stimulation at 3T: Application in bilateral leads, fully-implanted systems, and surgically modified lead trajectories” with their collaborators Boris Keil, Alireza Vali, Sunder Rajan, Behzad Elahi, Lawrence L. Wald, Joshua Rosenow, Julie Pilitsis nad Laleh Golestanirad.

Abstract:

Patients with deep brain stimulation devices highly benefit from postoperative MRI exams, however MRI is not readily accessible to these patients due to safety risks associated with RF heating of the implants. Recently we introduced a patient-adjustable reconfigurable coil technology that substantially reduced local SAR at tips of single isolated DBS leads during MRI at 1.5 T in 9 realistic patient models. This contribution extends our work to higher fields by demonstrating the feasibility of scaling the technology to 3T and assessing its performance in patients with bilateral leads as well as fully implanted systems. We developed patient-derived models of bilateral DBS leads and fully implanted DBS systems from postoperative CT images of 13 patients and performed finite element simulations to calculate SAR amplification at electrode contacts during MRI with a reconfigurable rotating coil at 3T. Compared to a conventional quadrature body coil, the reconfigurable coil system reduced the SAR on average by 83% for unilateral leads and by 59% for bilateral leads. A simple surgical modification in trajectory of implanted leads was demonstrated to increase the SAR reduction efficiency of the rotating coil to >90% in a patient with a fully implanted bilateral DBS system. Thermal analysis of temperature-rise around electrode contacts during typical brain exams showed a 15-fold heating reduction using the rotating coil, generating <1°C temperature rise during ∼4-min imaging with high-SAR sequences where a conventional CP coil generated >10°C temperature rise in the tissue for the same flip angle.

Kazemivalipour, E., Keil, B., Vali, A., Rajan, S., Elahi, B.,
Atalar, E., … Golestanirad, L. (2019). Reconfigurable MRI technology for
low-SAR imaging of deep brain stimulation at 3T: Application in bilateral
leads, fully-implanted systems, and surgically modified lead trajectories, NeuroImage. http://doi.org/10.1016/j.neuroimage.2019.05.015

July 17, 2019Cortical processes underlying the effects of static sound timing on perceived visual speed

At UMRAM, our post-doc alumni Utku Kaya and faculty member Ass.Prof. Hulusi Kafaligonul published a paper titled “Cortical processes underlying the effects of static sound timing on perceived visual speed” in NeuroImage on 1 Oct 2019. …

July 16, 2019Distinct representations in occipito-temporal, parietal, and premotor cortex during action perception revealed by fMRI and computational modeling

UMRAM, Psychology and Neuroscience faculty Dr. Burcu Ayşen Ürgen has published a paper titled "Distinct representations in occipito-temporal, parietal, and premotor cortex during action perception revealed by fMRI and computational modeling" in Neuropsychologia. Her collaborators in the project…

UMRAM, Psychology and Neuroscience faculty Dr. Burcu Ayşen Ürgen has published a paper titled “Distinct representations in occipito-temporal, parietal, and premotor cortex during action perception revealed by fMRI and computational modeling” in Neuropsychologia. Her collaborators in the project include Dr. Ayse P. Saygin from UC San Diego and Dr. Selen Pehlivan from TED University. The project investigates visual action representations in the human brain using fMRI and computational modeling.

Abstract:

Visual processing of actions is supported by a network consisting of occipito-temporal, parietal, and premotor regions in the human brain, known as the Action Observation Network (AON). In the present study, we investigate what aspects of visually perceived actions are represented in this network using fMRI and computational modeling. Human subjects performed an action perception task during scanning. We characterized the different aspects of the stimuli starting from purely visual properties such as form and motion to higher-aspects such as intention using computer vision and categorical modeling. We then linked the models of the stimuli to the three nodes of the AON with representational similarity analysis. Our results show that different nodes of the network represent different aspects of actions. While occipito-temporal cortex performs visual analysis of actions by means of integrating form and motion information, parietal cortex builds on these visual representations and transforms them into more abstract and semantic representations coding target of the action, action type and intention. Taken together, these results shed light on the neuro-computational mechanisms that support visual perception of actions and provide support that AON is a hierarchical system in which increasing levels of the cortex code increasingly complex features.

Urgen, B. A., Pehlivan, S., & Saygin, A. P. (2019). Distinct representations in occipito-temporal, parietal, and premotor cortex during action perception revealed by fMRI and computational modeling. Neuropsychologia, 127, 35–47. http://doi.org/10.1016/j.neuropsychologia.2019.02.006

March 28, 2019IEEE BILKENT GRC 2019, Best Oral Presentation Award : Ehsan Kazemivalipour

March 18, 2019Farewell Party for Emine Karabulut

Our beloved employee Emine Karabulut has just left from UMRAM. She was working as an administrative project assistant in UMRAM since 2018. She has had succesful work since a year. We would like…

March 6, 2019SEMINAR at UMRAM: Maria Veldhuizen

Dr. Maria Veldhuizen conducted a seminar at UMRAM/Aysel Sabuncu Research Center on March 6, 2019. Maria Veldhuizen was trained as a psychophysicist in taste, smell and flavor perception, both during her PhD…

Dr. Maria Veldhuizen conducted a seminar at UMRAM/Aysel Sabuncu Research Center on March 6, 2019.

Maria Veldhuizen was trained as a psychophysicist in taste, smell and flavor perception, both during her PhD with Dr. Jan Kroeze at Utrecht University in the Netherlands and post-doctoral fellowship with Dr.

Lawrence Marks at The John B. Pierce Laboratory and Yale School of Medicine in New Haven, Connecticut, USA. Since joining Dr. Dana Small’s lab in 2006, in the department of Psychiatry at Yale School of Medicine , she has combined these skills with neuroimaging of chemosensory perception in humans using fMRI and advanced computational techniques such as network modeling and pattern analysis. She is interested in gustatory encoding, integration of taste and smell, and development of flavor preferences. One focus has been on how the human brain achieves attention to taste and how taste cortex interacts with other cortical areas under attention. She has also worked on the neural commonalities of sweet taste and sweet odors. Lastly she is specifically interested in understanding how the appreciation of a flavor develops by association with calories and interactions with metabolism in humans. Her future ambitions include employing non-invasive neuro-modulation as an intervention in obesity and writing a children’s book on taste and smell perception.

Here her talk’s abstract:

Food cues previously paired with calories become liked and facilitate the identification of reliable energy sources. Post-ingestive signals related to nutrient metabolism are thought to be the primary drivers of this reinforcement, however, the identity of the physiological signals regulating this remain elusive. In a series of neuroimaging and indirect calorimetry human studies, we examine the relative roles of caloric load and perceived sweetness in driving metabolic, perceptual, gastric and brain responses to sugared beverages. We demonstrate a non-linear association between caloric load, metabolic response, and reinforcement potency, which is driven in part by the extent to which sweetness is proportional to caloric load. Altered metabolism may lead to weight-gain over time. Thus these results suggest we need to carefully consider the desirability of adjusting the fidelity between sweetness and calories in beverages.

February 27, 2019Seminar at UMRAM: Prof. Dr. Kamil Uğurbil

Prof. Dr. Kamil Uğurbil conducted a seminar at UMRAM/Aysel Sabuncu Brain Research Center on February 22, 2019.

He is a professor from University of Minessota and he is also director of Center for Magnetic Resonance Research. The title of the seminar was ‘Pushing to High Magnetic Fields in Pursuit of Understanding Human Brain Function’.

Here is his biography;
Kamil Ugurbil currently holds the McKnight Presidential Endowed Chair Professorship in Radiology, Neurosciences, and Medicine and is the Director of the Center for Magnetic Resonance Research (CMRR) at the University of Minnesota. Prof. Ugurbil was educated at Robert Academy, Istanbul (high school) and Columbia University, New York, N.Y. After completing his B.A. and Ph.D. degrees in physics, and chemical physics, respectively, at Columbia, he joined AT&T Bell Laboratories in 1977, and subsequently returned to Columbia as a faculty member in 1979. He was recruited to the University of Minnesota in 1982 where his research in magnetic resonance led to the evolution of his laboratory into an interdepartmental and interdisciplinary research center, the CMRR.

The work that introduced magnetic resonance imaging of neuronal activity in the human brain (known as fMRI) was accomplished independently and simultaneously in two laboratories, one of which was Ugurbil’s in CMRR. Since then, his primary focus has been the development and application of methods capable of obtaining high resolution and high accuracy functional and anatomical information in the human brain, targeting spatial scales ranging from the whole brain to elementary neuronal ensembles exemplified by cortical columns and layers. This body of work has culminated in unique accomplishments, such as the first time functional mapping of orientation columns in the human primary visual cortex, and involved the development of extensive new instrumentation and image acquisition approaches, including the introduction and development of ultrahigh magnetic fields (7 Tesla and higher) for functional and anatomical imaging and highly accelerated functional brain imaging. This body of work was recognized by several awards and honors including:
IEEE Medal for Innovations in Healthcare Technology
Koç Award
Richard Ernst Lecture and Gold Medal
Election to the National Academy of Medicine
Election to the American Academy of Arts and Sciences (USA)
Election to the National Academy of Inventors (USA)
Membership in NIH Working Group on Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative
Honorary Doctorate (Doctorate Honoris Causa), University of Maastricht, Netherlands
Honorary Doctorate (Doctorate Honoris Causa), University of Utrecht, Netherlands
Gold Medal, International Society of Magnetic Resonance in Medicine (ISMRM)
Co-Principal Investigator, Human Connectome Project (http://humanconnectome.org/)
Membership in National Institute of Mental Health (NIMH), Board of Scientific Advisors
Irma T. Hirschl Career Scientist Award
Hammett Award for Original and Distinguished Research
Columbia University, Graduate Faculties Alumni Scholar

February 12, 2019PRESENTATIONS from UMRAM and BILKENT UNIVERSITY RESEARCHERS: ISMRM 27TH ANNUAL MEETING & EXHIBITION

February 12, 2019ERGIN ATALAR and KADER K. OGUZ ARE in the COMMITTEE: AMPC (Annual Meeting Program Committee)

February 11, 2019Farewell Party for Utku Kaya

UMRAM had a farewell party for Dr. Utku Kaya. Utku has been a researcher at UMRAM since 2014 and he mainly worked on the multisensory nature of human motion perception by performing EEG experiments.…

February 10, 2019Seminar at UMRAM: Dr. Adema Ribic

Dr. Adema Ribic conducted a seminar at UMRAM/Aysel Sabuncu Brain Reserch Center on January 31, 2019. She is a researcher from Tufts University School of Medicine, Department of Neuroscience. The title of the seminar was “Synaptic Brakes on Neuroplasticity: Mechanism of Critical Period Closure in Visual Cortex”.

Abstract: Connections between nerve cells in the brain, termed synapses, are formed using precise genetic programming and are remodeled with experience throughout lifetime. Synaptic remodeling is a highly regulated process, prominent in the developing, young brain when plasticity is high. Brain plasticity in mammals tapers off in adulthood, paralleling the maturation of inhibitory neurotransmission and a steady increase in the expression of nerve growth inhibitors. The goal of my research is to identify mechanisms that act at the synapse to direct synaptic remodeling and plasticity. My recent research demonstrated a key role of Synaptic Cell Adhesion Molecule 1 (SynCAM 1/Cadm1) in maturation and plasticity of visual cortex. SynCAM 1 is a synaptic organizer that selectively controls development of subcortical, thalamic inputs onto Parvalbumin (PV+) inhibitory interneurons in the visual cortex. Loss of SynCAM 1 in PV+ interneurons retards the maturation of cortical inhibition and mice deficient in SynCAM 1 show increased visual plasticity at all ages, indicating that synaptic adhesion directs brain maturation. Even a brief loss of SynCAM 1 in PV+ interneurons upregulates plasticity in the adult brain, suggesting that plasticity is actively restricted through SynCAM 1 in adults. These results identify a synaptic locus for closure of developmental windows of plasticity, as well as a new synaptic factor that restricts adult plasticity.

About the speaker: Dr. Ribic received her PhD in Molecular Biology and Neuroscience from the University of Göttingen in Germany. She has done a postdoctoral fellowship at Yale University and is currently a Research Associate at Tufts. She has published in journals such as the Journal of Neuroscience, Journal of Comparative Neurology, and Behavioral Brain Research among others.

February 4, 2019UMRAM Opens Its Doors to High School Students.

UMRAM opens its doors to high school students. Student of TED Ankara College Foundation Schools, Burcu Gülşah Alıcı has spent her semester vacation at UMRAM as our guest to get to know…