Browsing by master's degree program "Neurotieteen maisteriohjelma"

Educational technology is advancing rapidly, with VR (virtual reality) emerging as a promising branch of XR (extended reality) technology for educational purposes. Utilizing head-mounted displays (HMD), immersive VR experiences immerse users in a virtual environment, limiting their awareness of the physical world. VR proves valuable in education by complementing traditional teaching methods, offering experiences impossible in the physical realm. Studies indicate enhanced affective factors, understanding, motivation, and memorization among students. In biology education, VR serves as a visual aid, helping students grasp complex biological concepts difficult to visualize from a two-dimensional textbook. It also shows potential in supplementing hands-on activities like laboratory work and anatomical dissections, experiences outside classrooms, and sustainability education. However, challenges persist in VR's educational application, including uncertainty about learning outcomes, health concerns, high costs, and a general lack of expertise in VR design and pedagogical implementation. Educational VR design has thus far lacked a foundation in pedagogy and learning theories. This thesis aims to address this gap by reflecting on the development of a pedagogically meaningful VR experience within sustainability education. Collaborating with the Global Campus project of the University of Helsinki, the thesis introduces a VR experience integrated into the immersive virtual sustainability learning experience, Serendip. The design process involved literature research, user and expert interviews, and consideration of learning theories such as constructivist learning, experiential learning, flow theory, gamification, CTML, SDL, and CLT. Specific aspects of VR design, like immersion levels and prior knowledge of users, were also considered. The thesis's significance lies in pioneering pedagogy-based design for educational VR, particularly addressing complex, abstract, and multidisciplinary subjects. It emphasizes the need for collaboration among pedagogy, content, and VR animation experts in future educational VR design. This work serves as a potential template and inspiration for further research in the field, aiming to refine the integration of pedagogical principles into VR experiences for education.

Pain is a subjective feeling often difficult to interpret or study and thus, pain of those unable to communicate their pain is difficult to recognize. According to the new definition of pain by IASP (Raja et al 2020), verbal description is only one of the many behaviours that can be used to express pain, and the inability to communicate pain does not negate the possibility of experiencing it. This addition to the definition points out that non-human animals, too, even if they cannot express it in words, are capable of both experiencing and communicating pain. Can we as humans interpret a state of pain in an animal in a trustworthy way – and in a manner that would be respectful and non-invasive to the animal? Infrared thermography (IRT) is a technology based on using infrared radiation instead of normal light to form images. These images can be used to quantify the surface temperature of an object with high resolution. The intensity of the radiation emitted by the object being imaged depends on the surface temperature and for this reason thermal imaging enables detecting and measuring changes of surface temperature. Pain and stress might manifest physiologically as activation of the autonomic nervous system, which in turn might result in changes in surface temperatures of the body. These changes might be detectable with a thermal camera. If we could establish a link between certain intricate temperature changes of the head area to certain type of activation of the sympathetic nervous system resulting from pain, thermal imaging could have the potential to detect this. In this study I investigated if there were detectable temperature changes in animal patients before and after a standard examination conducted to each patient admitted to the Wildlife Hospital of Helsinki Zoo, where my data was gathered. Another question was whether the patients that had pain differed in their temperature changes as compared to other patients. The question at the heart of my research was whether there would be a change in peripheral facial temperatures of patients before and after the examination. Another question was whether thermal patterns would be different for pain- and non-pain patients. I found that for some parameters, the temperature differences between pain- and non-pain patients were indeed different, for example the crown temperature of birds seemed to change with examination for patients without pain but not for patients with pain. A more prominent finding was that temperatures decrease across many parameters after an examination as compared to prior to it, across all or many patient groups. My research does not univocally show that thermal imaging could be used to detect pain; rather it affirms the thought that the measurement of changes in peripheral temperatures could be a potential window to non-invasively detect some changes of activation of the sympathetic nervous system in animals.

Morphological features are considered as markers of microglial functionality, and they show regional heterogeneity in the brain. Recently the sleep-wake cycle was shown to affect microglial morphology in mice and correlate with cortical sleep slow wave activity (SWA). Microglial sizes and ramification increased during the dark period and decreased during the light period in cerebral areas associated with SWA, suggesting that neuronal activation could be affecting microglial morphology through SWA. I studied microglia in the hindbrain areas with and without functional connection to SWA to further investigate the association between SWA and alterations in morphology, and to investigate if there are differences in microglial morphology and their diurnal alterations in brain regions other than those commonly investigated. I examined three hindbrain areas (cerebellar cortex (CC), deep cerebellar nucleus (DCN) and medial vestibular nucleus (MVN)) and somatosensory cortex (SC) of mice (n=15) at two timepoints: 6 hours after the light onset (high SWA) and offset (low SWA). My aims were to answer if there are morphological differences in microglia between 1) the four brain areas at both timepoints and 2) between the two timepoints in each brain area. My hypotheses were that CC and DCN which have functional connections to cortical SWA, would show similar diurnal morphology alterations as demonstrated in the cerebral areas, and MVN that has no known cortical SWA connection, would lack significant alterations. As microglia are heterogenous throughout brain, I expected microglia to differ between different brain areas, especially the hindbrain and the SC. I found that microglial morphologies significantly differed between the hindbrain and the cortex, while the hindbrain areas were more similar in morphology. Moreover, the brain areas demonstrated diurnal morphology alterations of microglia with varying extent: CC and DCN microglial morphology did not correlate with SWA as clearly as SC did, and interestingly, morphological features of MVN microglia showed a pattern opposite to other areas, microglia being larger during the light period than the dark period. These results highlight the importance of the diurnal time to microglial morphology and the heterogeneity of microglia between different brain regions.

Microglia, the resident macrophage-like glial cells of the central nervous system (CNS), form the first line of defense against pathogens in the brain, and regulate both innate and adaptive immunity. Any abnormalities in their microenvironment lead to microglial activation, characterized by alterations in their gene expression, morphology, and functional behavior. Once activated, microglia respond to CNS injury and inflammation by, e.g., migrating to the site of damage, releasing pro-inflammatory cytokines, as well as phagocyting cell debris and pathogens. Prolonged activation of microglia expressing pro-inflammatory phenotypes can lead to exacerbated CNS damage. Hence, limiting CNS inflammation by stimulating microglial polarization towards their pro-resolving phenotypes would be of great clinical relevance. The research of our laboratory focuses on CNS injury and repair, as well as finding novel therapies for ischemic stroke. Specialized pro-resolving mediators (SPMs) derived from essential fatty acids have been proposed to offer a potential therapeutic approach for ischemic stroke via promoting resolution of post-stroke inflammation. Previous studies have revealed the ability of SPMs to induce a transformation of macrophages, the immune cells strongly resembling microglia, towards their anti-inflammatory phenotypes. The aim of this study was therefore to assess whether SPMs have similar effects on BV2 microglia, specifically on their lipopolysaccharide (LPS)-induced production of pro-inflammatory cytokines, tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6). In addition to assessing the cytokine levels, our aim was to determine the optimal conditions for studying the effects of SPMs on microglial migration. In the present study, the levels of TNF-α and IL-6 were determined by specific ELISAs, and the transwell assay was used to measure microglial migration. Resolvins E1 (RvE1) and D1 (RvD1), as well as protectin D1 (PD1) and 15-epimer of lipoxin A4 (15-epi-LXA4) were all associated with decreased levels of TNF-α and IL-6, with RvE1 having the most potential as a resolving agent. In addition, we observed that serum starvation notably decreases the release of IL-6 and affects microglial migration. Overall, our results support the idea that SPMs could provide a novel therapeutic strategy for stroke therapy as they contribute to the resolution of CNS inflammation.

Early life stress (ELS) has been associated with the development of psychiatric disorders such as anxiety and depression later in life. The central hypothesis is that these disorders are caused by a malfunctioning of the serotonin system and serotonin (5-HT) produced in the dorsal raphe nucleus (DRN). The DRN is anatomically connected to the medial prefrontal cortex (mPFC), especially to the infra- and prelimbic cortex, where 5-HT modulates behaviors such as impulsivity and cognitive flexibility. The DRN and mPFC mediate with low-frequency network oscillations, which are indicative of the state of the network and its funtional connectivity, as disturbances in these network oscillations have been connected to neuropsychiatric disorders. The aim of the thesis is to investigate whether and how ELS can influence the local field potential (LFP) activity of the mPFC and DRN and the functional connectivity of the DRN and mPFC. This is researched by characterizing and comparing the LFP activity recorded in the DRN, where 5-HTergic neurons are located, and in layer 5 of the infralimbic area of the mPFC. To accomplish these aims, a well-established animal model of early-life stress, the limited bedding and nesting model (LBN), was used. The model causes fragmented maternal care due to the stress of the dam, which in turn leads to the stress of the pups. Simultaneous multi-site recordings of LFP and multi-unit activity (MUA) within DRN and mPFC were performed in vivo during postnatal days (PND) 10-11 from control and LBN pups to characterize the network activity of these two brain areas and then investigate possible changes in their functional connectivity. The efficacy of the LBN model was determined by the observed decreased weight gain of LBN animals compared to controls. From the data, the LFP activity of the DRN and mPFC were characterized. The activity was characterized as power spectrum, wavelet spectrum, and MUA with DRN showing discontinuous activity with low signal-to-noise ratio and low frequency theta oscillations (4-12 Hz), while mPFC showed almost continuous activity with higher signal-to-noise ratio and developing gamma oscillations (20-50 Hz). The power of LFP signal of the areas was not found to be affected by ELS. To investigate if the coupling by synchrony between DRN and mPFC networks is altered by ELS, I analyzed wavelet coherence by computing coherence values between LFP signals in DRN and mPFC in a control and ELS for frequencies from 1 to 50Hz. The functional connectivity was affected by ELS. Statistically significant changes were observed in wavelet coherence in the lower frequencies of 1-2.8 Hz between the control and LBN treatment, suggesting impaired synchronization between DRN and mPFC at 1-2.8Hz frequency range immediately after ELS exposure at PND 10-11 mice. Caveats of the study were low signal-to-noise ratio of the recordings, the small group size of LBN animals (n=5) as well as the uneven sex distribution (male n=11, female n=3) which prevented the sex-based comparison of the effects of ELS. The thesis examines postnatal LFP brain activity in the DRN and mPFC and the functional connectivity between these brain areas. The results of the thesis show that ELS exposure is able to influence the functional connectivity of these two brain regions. The results support previous findings, which have found alterations in the functional connectivity of the neural networks underlying neuropsychiatric disorders in adulthood. The findings of this thesis suggest that ELS could affect the functional connectivity of a developing network and thus increase the risk of the development of neuropsychiatric disorders. Further studies are needed with larger group size, even gender balance, and better signal-to-noise ratio of recordings.

An increasing number of people are diagnosed with depression. One possible reason for the development of depression is faulty wiring and information processing in certain neural networks (network hypothesis) in the central nervous system. It has been shown that antidepressant drugs (ADs) can induce a juvenile-like plasticity state in the brain (iPlasticity) comparable to the plastic state of critical periods during development. iPlasticity enables the rewiring of neuronal networks in combination with environmental stimuli. At the molecular level, the binding of brain-derived neurotrophic factor (BDNF) to its high-affinity receptor tropomyosin kinase receptor B (TRKB) leads to TRKB dimerization and activation, triggering a downstream signalling cascade promoting brain plasticity. Activation of the TRKB signalling cascade is triggered by neuronal activity as well as AD treatment. Recent findings demonstrate that classical as well as rapid-onset ADs bind directly to the transmembrane domain of TRKB, leading to increased translocation of intracellularly stored TRKB to the plasma membrane and enhanced BDNF binding. Cholesterol, a sterol lipid known to regulate TRKB signalling, has been found to ensure optimal TRKB-BDNF signalling by changing the TRKB dimers’ relative orientation when altering the membrane thickness. A point mutation of TRKB tyrosine 433 to phenylalanine (TRKB.Y433F) has been found to hinder TRKB dimerization. Molecular dynamic simulations reveal that other membrane lipids are likely to participate in AD binding to TRKB. The aim of this thesis was to investigate whether lipid and drug compound treatments affect TRKB dimerization in Neuro2A cells expressing TRKB. Furthermore, we assessed whether the Y433F mutation modulates TRKB dimerization in such treatments. Protein fragment complementation assay (PCA) was used as in vitro protein-protein interaction assay to quantify dimerization of overexpressed TRKB carrying two split luciferase reporter proteins. Additionally, to avoid variability caused by transient transfection and be able to test large compound libraries, the establishment of a stably TRKB-expressing N2A cell line was initiated. The results show that lipid compounds, such as Allopregnanolone, as well as ADs, such as Imipramine and (2R,6R)-Hydroxynorketamine, increased TRKB dimerization in vitro in a dose-dependent manner within 40 minutes. The increase was more pronounced in the TRKB WT-expressing cells. This indicates that the compounds tested here may be directly interacting with TRKB, facilitating dimerization. Moreover, data seem to confirm previous research on the less effective TRKB.Y433F mutation. While stable expression of TRKB carrying one of the luciferase reporter proteins was successfully achieved in a monoclonal cell line, the amount of protein expressed seems to require further optimization before utilising it for PCA. In conclusion, lipid and AD treatments can induce an increase in TRKB dimerization in a dose-dependent fashion. Further investigations are needed to determine where the compounds bind and by which mechanisms they exert their effects on TRKB. Furthermore, the work on the stable cell line will be completed to avoid variability of transient transfection in the future.

4-Methylmethcathinone (Mephedrone) is one of the the most prevalent synthetic cathinones that bears close structural similarity to amphetamines. Like other stimulants, mephedrone is often used with alcohol (ethanol). In animal studies ethanol has been observed to potentiate the neurotoxicity of amphetamine-type stimulants, and same has been observed when mephedrone and alcohol is combined. The long-term effects of mephedrone have still remained largely elusive. The aim of this thesis is to study the effects of mephedrone, methamphetamine, and ethanol on dendritic spine density and morphology in the hippocampus, nucleus accumbens and caudate putamen, and compare the spine densities with changes in brain activation observed in manganese-enhanced magnetic resonance imaging (MEMRI). Dendritic spines are small membranous protrusions on dendrites that act as the post-synaptic sites for most of the excitatory synapses. Amphetamine and methamphetamine have been shown to affect the density and morphology of the spines. The goal of this thesis was to investigate the long-term effect of binge-like (two times a day, four consecutive days) stimulant treatment on dendritic spines using Golgi-stained rat brain sections. The brains of 48 male Wistar rats were imaged using AxioImager Z2 microscope and the number and the size of the spines was analyzed using Reconstruct software. In this thesis no effect on dendritic spines was observed in the hippocampus and nucleus accumbens in animals treated with mephedrone, methamphetamine, ethanol or combination of them. In the caudate putamen significant increase in the total density of dendritic spines and in the density of filopodia-like spines was observed in mephedrone-treated animals. Other treatments showed no observable effect. These results were conflicting with previous studies where amphetamine-type stimulants have been shown to increase the spine density in the nucleus accumbens and the hippocampus and increase the density of branched spines. In the caudate putamen methamphetamine has been observed to decrease the spine density. There was no correlation between spine densities and brain activation observed in MEMRI. To my best knowledge this is the first time when the effect of mephedrone on dendritic spines has been studied. It is possible that the treatment regimen used here was not strong enough to produce marked long-term changes on dendritic spines. It is also possible, that mephedrone is not as neurotoxic as other amphetamine-type stimulants, which may explain why the effects remained limited and conflicting. More research is still required to establish the long-term structural effects of mephedrone.

Epigenetics is the study of changes in gene function without affecting the DNA sequence. Epigenetics studies the effects of the environment and behavior on the genome. Researchers have been able to detect several epigenetic modifications such as –DNA methylation, histone acetylation, and microRNA-associated gene silencing. Changes in the epigenome are essential for proper cell function and normal development and can also be induced by environmental factors. Stress is defined as a biological response to physiological and psychological demands which can affect cellular homeostasis. Factors such as prenatal life stress can affect gene function without directly altering the DNA nucleotide sequence. Elevated levels of stress can immobilize with the ability to impair cognitive function. There is evidence that suggests the involvement of epigenetic regulation in disorders such as addiction, depression, schizophrenia, and cognitive dysfunction. Therefore, this systematic review discusses recent findings of the role of epigenetics in prenatal exposure to stress. To achieve this, the thesis will cover different subtopics from genetics, neurobiology, and diseases, neuroscience, biological psychiatry, life sciences, medicine, behavioral brain research, biochemistry & molecular biology, as well as neuroendocrinology. Research questions are 1) Is there an association between epigenetics and prenatal stress? 2) What kind of mechanisms have been found? 3) What kind of techniques have been used in the identification of potential epigenetic mechanisms? What genes are associated with these epigenetic changes?. This study followed the "The Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA) guideline checklist. Eligibility criteria and search terms where be selected and documented to offer the widest range of articles covering the subjects of this study. A literature search was done using PubMed/Medline, Google scholar, and gray literature. The last sample comprised 59 articles. Data were extracted so that the participants, intervention, comparisons, and outcomes were included. The literature search conducted in this systematic review identified a few findings. First is that the majority of animal and human studies found a significant or moderate association between epigenetics and prenatal stress. Second, DNA methylation is the most studied epigenetic mechanism in maternal exposure to stress Third, genome-wide studies were more common in human studies than in animals and the most widely used method used is Infinium HumanMethylation450 Bead Chip. However, the common methods used in human and animal studies are most likely because of the small sample size and causation cannot be determined. Finally, NR3C1 and FKBP5 genes were the most studied in human studies where they showed the strongest association between prenatal stress and epigenetic modifications. While in animal studies, the most studied genes were Bdnf and Dnmt1 as they showed a significant methylation level after maternal prenatal stress exposure. In conclusion, maternal prenatal stress could trigger epigenetic alterations in neonates in both animals and humans. This holistic review detailed and evaluated locus-specific and studies exploring current knowledge about associations between maternal prenatal stress and epigenetic changes.

Each year many new-borns are at risk for long-term developmental deficits due to adverse perinatal events. Early gross motor abilities have been shown to link with cognitive development and studying infant motor behaviour may provide means to assess global neurodevelopment. This thesis aims to explore a potential association between early gross motor abilities recorded at infancy with a multi-sensor wearable jumpsuit MAIJU and later neurocognitive development assessed at two years of age. The study sample (N=26) consisted of healthy full-term infants and those with prematurity or perinatal asphyxia. Spontaneous motor activity was recorded at home with the jumpsuit. Machine learning methods were used to quantitate the time infants spent in different postures and estimate the maturity of their motor abilities, which were compared to cognitive development at two years of age with correlational- and regression analyses. There was a positive trend between early motor abilities and later cognitive development. Specifically, standing posture explained the association, such that infants who spent more time standing had better cognitive abilities at two years of age. Standing may support cognitive development by increasing opportunities for visual and manual exploration and learning. Shared neuronal circuitries for motor and cognitive functions and faster neuronal maturation may also underlie the association. The current study supports the creation of future studies with larger sample sizes to establish the potential for the use of postural and movement information obtained from wearable jumpsuit MAIJU to assess the variability of neurocognitive development of at risk and typical infants with potential goal to identify future cognitive deficits at early stage.

Histamine receptors are known to be expressed throughout the peripheral nervous system and are involved in regulating the gut and immune system. The gut-brain axis, which consists of bidirectional signaling between the central nervous system and gastrointestinal tract, links gut functions to emotional and cognitive controls in the brain. Many animal models are known to express histamine receptors in their gut and brain tissue which can be altered by a compromised gut-brain axis like stress. Histamine receptors also play an important role in many gastric and intestinal disorders. However, the precise expression pattern of histamine receptors in zebrafish gut tissue is unknown, as is whether their expression levels also change with stress. Here, I show that zebrafish gut contains several histamine receptors, but their role involving stress within the gut remains unknown. I found that histamine receptors hrh1 and hrh3 as well as the enzyme that synthesizes histamine, histidine decarboxylase (hdc), are expressed in zebrafish gut and brain in wildtype and hdc knockout adult zebrafish using in situ hybridization. Stress induction on wildtype male zebrafish through chronic social defeat and analysis of histamine receptor and hdc mRNA levels using quantitative real time PCR showed no differences in subordinate, dominate, or control fish. However, it did provide quantitative data that hrh1, hrh2, and hdc mRNA expresses in the adult gut. My results demonstrate the first data to suggest histamine receptors are expressed in zebrafish gut, and that even though stress can alter the gut-brain axis, it may not do so through the regulation of these receptors.