Adolescent-specific patterns of behavior and neural activity during social reinforcement learning

Humans are sophisticated social beings. Social cues from others are exceptionally salient, particularly during adolescence. Understanding how adolescents interpret and learn from variable social signals can provide insight into the observed shift in social sensitivity during this period. The current study tested 120 participants between the ages of 8 and 25 years on a social reinforcement learning task where the probability of receiving positive social feedback was parametrically manipulated. Seventy-eight of these participants completed the task during fMRI scanning. Modeling trial-by-trial learning, children and adults showed higher positive learning rates than adolescents, suggesting that adolescents demonstrated less differentiation in their reaction times for peers who provided more positive feedback. Forming expectations about receiving positive social reinforcement correlated with neural activity within the medial prefrontal cortex and ventral striatum across age. Adolescents, unlike children and adults, showed greater insular activity during positive prediction error learning and increased activity in the supplementary motor cortex and the putamen when receiving positive social feedback regardless of the expected outcome, suggesting that peer approval may motivate adolescents towards action. While different amounts of positive social reinforcement enhanced learning in children and adults, all positive social reinforcement equally motivated adolescents. Together, these findings indicate that sensitivity to peer approval during adolescence goes beyond simple reinforcement theory accounts and suggests possible explanations for how peers may motivate adolescent behavior.Psycholog

Euler characteristic surfaces

We study the use of the Euler characteristic for multiparameter topological data analysis. Euler characteristic is a classical, well-understood topological invariant that has appeared in numerous applications, including in the context of random fields. The goal of this paper is to present the extension of using the Euler characteristic in higher-dimensional parameter spaces. While topological data analysis of higher-dimensional parameter spaces using stronger invariants such as homology continues to be the subject of intense research, Euler characteristic is more manageable theoretically and computationally, and this analysis can be seen as an important intermediary step in multi-parameter topological data analysis. We show the usefulness of the techniques using artificially generated examples, and a real-world application of detecting diabetic retinopathy in retinal images

Animal recognition using deep learning

Camera traps are widely used for wildlife monitoring. In this work machine learning based data processing pipeline is assembled for animal detection on the camera trap images focusing on the ungulate species. The typical animal detection challenges are noted, and available solutions are evaluated. As the result of this work, two different deep neural networks Faster R-CNN and RetinaNet were trained, achieving 0.2786 [email protected]:0.05:0.95 and 0.4562 [email protected] on the dataset of interest gathered in the Latvian forest regions during the ”ICT-based wild animal census approach for sustainable wildlife management” project. Additionally, different learning optimization techniques such as data augmentation and oversampling were implemented and assessed

Embarking on the Autonomous Journey: A Strikingly Engineered Car Control System Design

openThis thesis develops an autonomous car control system with Raspberry Pi. Two predictive models are implemented: a convolutional neural network (CNN) using machine learning and an input-based decision tree model using sensor data. The Raspberry Module controls the car hardware and acquires real-time camera data with OpenCV. A dedicated web server and event stream processor process data in real-time using the trained neural network model, facilitating real-time decision-making. Unity and Meta Quest 2 VR set create the VR interface, while a generic DIY kit from Amazon and Raspberry PI provide the car hardware inputs. This research demonstrates the potential of VR in automotive communication, enhancing autonomous car testing and user experience.This thesis develops an autonomous car control system with Raspberry Pi. Two predictive models are implemented: a convolutional neural network (CNN) using machine learning and an input-based decision tree model using sensor data. The Raspberry Module controls the car hardware and acquires real-time camera data with OpenCV. A dedicated web server and event stream processor process data in real-time using the trained neural network model, facilitating real-time decision-making. Unity and Meta Quest 2 VR set create the VR interface, while a generic DIY kit from Amazon and Raspberry PI provide the car hardware inputs. This research demonstrates the potential of VR in automotive communication, enhancing autonomous car testing and user experience

A novel approach towards electrode openings for flexible neural implants

Der anhaltente technologische Fortschritt, lässt sich auch im medizinischen Bereich feststellen und führt zu einem wachsenden Markt für mikro-medizinische Implantate, die simultan neurologische Signale detektieren, wie auch das umliegende Gewebe stimulieren können. Als Beispiel für elektrisch aktive Implantate in der medizinischen Anwendung sind Retina- Implantate und Gehirnimplantate zu nennen. Während Erstere die degenerierte Retina des menschlichen Auges ersetzen und so Augenlicht wiederherstellen, stimulieren Letztere das menschliche Gehirn von Parkinson-Patienten und unterdrücken erfolgreich den resultierenden Tremor. Im Gegensatz zu herkömmlichen medizinisch elektrisch aktiven Implantate wie dem Cochlea- Implantat oder Herzschrittmachern, sind moderne neurologische Implantate nicht von einem starren Keramik- oder Metallgehäuse umgeben, aus dem lediglich die Elektroden herausgeführt werden. Stattdessen verweilt die Elektronik bei modernen Implantaten neben den Elektrodenöffnungen auf einem flexiblen Substrat und ist dennoch hermetisch gegenüber dem Gewebe abgeschirmt, während die Elektroden geöffnet bleiben und so ein elektrischer Kontakt zum Gewebe hergestellt wird. Als flexible, biokompatible und biostabile Materialien haben sich Parylen und Polyimid durchgesetzt. Beide sind allerdings wasserdampfdurchlässig, was negative Effekte wie Korrosion und Lagenablösung zur Folge hat. Durch Einbringen von Metalllagen in die Passivierung soll eine Wasserdampfundurchlässigkeit garantiert werden. Diese Metalllagen sind an den Elektrodenöffnungen exponiert und können dort zu Kurzschlüssen führen. Gleichzeitig ist die Elektrodenseitenwand selbst ungeschützt gegenüber negativen Effekten wie Korrosion und Lagendelamination. Daher wurde eine Möglichkeit der Elektrodenseitenwandpassivierung entwickelt und ist in dieser Arbeit vorgestellt. Dazu wurden sowohl nicht-flexible wie auch flexible polyimid-basierte Testsubstrate mikrotechnologisch unter Verwendung von Reinraumtechnologie und Verfahren der physikalischen Gasphasenabscheidung entwickelt und hergestellt. Ein Multilayer, bestehend aus Titan und Gold wurde als Leiterbahnmaterial gewählt, um die Haftung der Leiterbahnen an das umgebende passivierende Polyimid herzustellen. Die Elektrodenöffnungen wurden per reaktivem Ionenstrahlätzen, sowie Ionendünnung realisiert. Neben der Herstellung neuartiger Substrate wurden auch zwei Messaufbauten entwickelt, angefertigt, validiert und zu einem komplett automatisierten Messstand kombiniert. Die erste Messanordnung kann (Leck-) Ströme in der Größenordnung von 1 ∙ 10−12 A über mehrere Kanäle hinweg detektieren. Der zweite Messaufbau simuliert kleinste flüssigkeits-induzierte mechanische Bewegungen auf flexible Substrate, wie sie auch im menschlichen Körper auftreten. Aber auch Materialtests bis an die Grenzen der flexiblen Substrate sind möglich. Durch die Kombination beider Aufbauten ist eine komplett autonome elektrische Analyse flexibler Substrate möglich, während sie parallel mechanisch definiert belastet werden. Zum Zeitpunkt dieser Arbeit existiert keine vergleichbare Messanordnung. Atomlagenabscheidung wurde genutzt, um dünne Titandioxid Schichten herzustellen, die ausgiebig auf ihre elektrischen Eigenschaften wie auch Schichtbegebenheit getestet wurden. Die Biokompatibilität von diesen Schichten ist bekannt und viele Arbeitsgruppen haben eine Steigerung der Biostabilität von Substraten durch die Nutzung dieser bestätigt. Nach Prüfung aller Voraussetzungen wurden Elektrodenseitenwände hergestellter Substrate mit Titandioxid passiviert und analysiert. Die Steigerung der Biostabilität von elektrisch aktiven, flexiblen, Implantat-ähnlichen Substraten durch die Passivierung der Elektrodenseitenwand wird in dieser Arbeit zusammen mit einigen Anwendungen der neuartigen Passivierung vorgestellt

2012 Abstract Booklet

Complete Schedule of Events for the 14th Annual Undergraduate Research Symposium at Minnesota State University, Mankato

Development of Molecular Contrast-enhanced Imaging for Optical Coherence Tomography

Biological imaging techniques that are able to detect a contrast-enhanced signal from the target molecules have been widely applied to various techniques in the imaging field. The complex biological environment provides numerous and more efficient pathways along which the chromophores (light absorber) may release its energy. This energy can provide not only morphological information, but also specific molecular information such as a biochemical map of a sample. All diseases correlate with both morphological and biochemical changes. Optical coherence tomography (OCT) system is one of the biological imaging techniques. OCT has widely been applied to many medical/clinical fields, giving benefit from a penetration depth of a few millimeters while maintaining a spatial resolution on the order of a micron. Unfortunately, OCT lacks the straightforward functional molecular imaging extensions available for other technologies, e.g. confocal fluorescence microscopy and fluorescence diffuse optical tomography. This is largely because incoherent processes such as fluorescence emission and Raman scattering are not readily detectable with low coherence interferometry that is the central technique that underlies all OCT systems. Despite a drawback of molecular imaging with OCT, it is highly desirable to measure not only morphological, but also molecular information from either endogenous or exogenous molecules. In order to overcome the limitation of molecular contrast imaging for OCT, our group has been researched the hybrid OCT imaging technique and a new exogenous contrast agent. Our contrast-enhanced imaging technique integrates OCT with a well-researched and well-established technique: two-colored pump-probe absorption spectroscopy. Our novel imaging technique is called Pump-Probe OCT (PPOCT). Based upon current successful results, molecular imaging with OCT potentially gives us the ability to identify pathologies. In order to expand the capacity of PPOCT, this dissertation focuses on development of molecular contrast-enhanced imaging for optical coherence tomography (OCT). In the first phase of the research, we developed and optimized for sensitivity a two-color ground state recovery Pump-Probe Optical Coherence Tomography (gsrPPOCT) system and signal algorithm to measure the contrast-enhanced signal of endogenous and exogenous contrast agents such as Hemoglobin (Hb) and Methylene blue (MB) from in vivo samples. Depending on the absorption peak of a target molecule, the pump light sources for PPOCT used 532nm Q-switched laser or 663nm diode laser. Based on different experimental application, Ti:sapp or SLD of 830nm center wavelength were utilized. The PPCOT system was firstly used to image Hb of in vivo vasulature in a Xenopus laevis as the endogenous contrast agent and a larval stage zebrafish using MB as the exogenous contrast agent via transient changes in light absorption. Their morphological in addition to molecular specific information from a live animal was described. The incorporation of a pump laser in an otherwise typical spectrometer based OCT system is sufficient to enable molecular imaging with PPOCT. In the second phase of this research, based on endoscopic molecular contrast-enhanced applications for OCT, we invented an ultra-wideband lensless fiber optic rotary joint based on co-aligning two optical fibers has excellent performance (~0.38 dB insertion loss). The developed rotary joint can cover a wavelength range of at least 355- 1360 nm with single mode, multimode, and double clad fibers with rotational velocities up to 8800 rpm (146 Hz). In the third phase of this research, we developed and manufactured a microencapsulated methylene blue (MB) contrast agent for PPOCT. The poly lactic coglycolic acid (PLGA) microspheres loaded with MB offer several advantages over bare MB. The microsphere encapsulation improves the PPOCT signal both by enhancing the scattering and preventing the reduction of MB to leucomethylene blue. The surface of the microsphere can readily be functionalized to enable active targeting of the contrast agent without modifying the excited state dynamics of MB that enable PPOCT imaging. Both MB and PLGA are used clinically. PLGA is FDA approved and used in drug delivery and tissue engineering applications. 2.5 µm diameter microspheres were synthesized with an inner core containing 0.01% (w/v) aqueous MB. As an initial demonstration the MB microspheres were imaged in a 100 µm diameter capillary tube submerged in a 1% intralipid emulsion. By varying the oxygen concentration both 0% and 21%, we observed he lifetime of excited triple state using time-resolved Pump-Probe spectroscopy and also the relative phase shift between the pump and probe is a reliable indicator of the oxygen concentration. Furthermore, these results are in good agreement with our theoretical predictions. This development opens up the possibility of using MB for 3-D oxygen sensing with PPOCT

Development of Molecular Contrast-enhanced Imaging for Optical Coherence Tomography

Biological imaging techniques that are able to detect a contrast-enhanced signal from the target molecules have been widely applied to various techniques in the imaging field. The complex biological environment provides numerous and more efficient pathways along which the chromophores (light absorber) may release its energy. This energy can provide not only morphological information, but also specific molecular information such as a biochemical map of a sample. All diseases correlate with both morphological and biochemical changes. Optical coherence tomography (OCT) system is one of the biological imaging techniques. OCT has widely been applied to many medical/clinical fields, giving benefit from a penetration depth of a few millimeters while maintaining a spatial resolution on the order of a micron. Unfortunately, OCT lacks the straightforward functional molecular imaging extensions available for other technologies, e.g. confocal fluorescence microscopy and fluorescence diffuse optical tomography. This is largely because incoherent processes such as fluorescence emission and Raman scattering are not readily detectable with low coherence interferometry that is the central technique that underlies all OCT systems. Despite a drawback of molecular imaging with OCT, it is highly desirable to measure not only morphological, but also molecular information from either endogenous or exogenous molecules. In order to overcome the limitation of molecular contrast imaging for OCT, our group has been researched the hybrid OCT imaging technique and a new exogenous contrast agent. Our contrast-enhanced imaging technique integrates OCT with a well-researched and well-established technique: two-colored pump-probe absorption spectroscopy. Our novel imaging technique is called Pump-Probe OCT (PPOCT). Based upon current successful results, molecular imaging with OCT potentially gives us the ability to identify pathologies. In order to expand the capacity of PPOCT, this dissertation focuses on development of molecular contrast-enhanced imaging for optical coherence tomography (OCT). In the first phase of the research, we developed and optimized for sensitivity a two-color ground state recovery Pump-Probe Optical Coherence Tomography (gsrPPOCT) system and signal algorithm to measure the contrast-enhanced signal of endogenous and exogenous contrast agents such as Hemoglobin (Hb) and Methylene blue (MB) from in vivo samples. Depending on the absorption peak of a target molecule, the pump light sources for PPOCT used 532nm Q-switched laser or 663nm diode laser. Based on different experimental application, Ti:sapp or SLD of 830nm center wavelength were utilized. The PPCOT system was firstly used to image Hb of in vivo vasulature in a Xenopus laevis as the endogenous contrast agent and a larval stage zebrafish using MB as the exogenous contrast agent via transient changes in light absorption. Their morphological in addition to molecular specific information from a live animal was described. The incorporation of a pump laser in an otherwise typical spectrometer based OCT system is sufficient to enable molecular imaging with PPOCT. In the second phase of this research, based on endoscopic molecular contrast-enhanced applications for OCT, we invented an ultra-wideband lensless fiber optic rotary joint based on co-aligning two optical fibers has excellent performance (~0.38 dB insertion loss). The developed rotary joint can cover a wavelength range of at least 355- 1360 nm with single mode, multimode, and double clad fibers with rotational velocities up to 8800 rpm (146 Hz). In the third phase of this research, we developed and manufactured a microencapsulated methylene blue (MB) contrast agent for PPOCT. The poly lactic coglycolic acid (PLGA) microspheres loaded with MB offer several advantages over bare MB. The microsphere encapsulation improves the PPOCT signal both by enhancing the scattering and preventing the reduction of MB to leucomethylene blue. The surface of the microsphere can readily be functionalized to enable active targeting of the contrast agent without modifying the excited state dynamics of MB that enable PPOCT imaging. Both MB and PLGA are used clinically. PLGA is FDA approved and used in drug delivery and tissue engineering applications. 2.5 µm diameter microspheres were synthesized with an inner core containing 0.01% (w/v) aqueous MB. As an initial demonstration the MB microspheres were imaged in a 100 µm diameter capillary tube submerged in a 1% intralipid emulsion. By varying the oxygen concentration both 0% and 21%, we observed he lifetime of excited triple state using time-resolved Pump-Probe spectroscopy and also the relative phase shift between the pump and probe is a reliable indicator of the oxygen concentration. Furthermore, these results are in good agreement with our theoretical predictions. This development opens up the possibility of using MB for 3-D oxygen sensing with PPOCT

Early Cortical Thickness Change after Mild Traumatic Brain Injury following Motor Vehicle Collision

In a motor vehicle collision (MVC), survivors often receive mild traumatic brain injuries (mTBI). Although there have been some reports of early white matter changes after an mTBI, much less is known about early cortical structural changes. To investigate early cortical changes within a few days after an MVC, we compared cortical thickness of mTBI survivors with non-mTBI survivors, then reexamined cortical thickness in the same survivors 3 months later. MVC survivors were categorized as mTBI or non-mTBI based on concussive symptoms documented in emergency departments (EDs). Cortical thickness was measured from MRI images using FreeSurfer within a few days and again at 3 months after MVC. Post-traumatic stress symptoms and physical conditions were also assessed. Compared with the non-mTBI group (n=23), the mTBI group (n=21) had thicker cortex in the left rostral middle frontal (rMFG) and right precuneus gyri, but thinner cortex in the left posterior middle temporal gyrus at 7.2±3.1 days after MVC. After 3 months, cortical thickness had decreased in left rMFG in the mTBI group but not in the non-mTBI group. The cortical thickness of the right precuneus region in the initial scans was positively correlated with acute traumatic stress symptoms for all survivors and with the number of reduced activity days for mTBI survivors who completed the follow-up. The preliminary results suggest that alterations in cortical thickness may occur at an early stage of mTBI and that frontal cortex structure may change dynamically over the initial 3 months after mTBI.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140167/1/neu.2014.3492.pd

2013 Abstract Booklet

Complete Schedule of Events for the 15th Annual Undergraduate Research Symposium at Minnesota State University, Mankato