Browsing by master's degree program "Neurotieteen maisteriohjelma"

White matter (WM) structural connectivity alterations have been linked to depression. This study aimed to identify structural connectivity metrics associated with Major depressive disorder (MDD) and predictive of different symptom phenotypes. The study sample included N=29 control and N=86 subjects with MDD who underwent a clinical interview, Mini-International Neuropsychiatric Interview (MINI), and assessment of depression symptoms severity. Using a 3T MRI scanner, diffusion tensor imaging (DTI) was employed to capture WM connectivity markers at baseline. While no distinct differences between control and MDD groups were observed at the whole-brain network level, significant alterations were evident at the node level. Clinical group demonstrated enhanced connectivity, particularly in the DefaultB and LimbicB subsystems, as evidenced by measures such as eigenvector centrality. Furthermore, notable differences were observed in clustering coefficient and local efficiency, predominantly in DefaultB, LimbicB, and VisPeri networks, with MDD patients showing higher connectivity. Analysis of the association between WM structural connectivity measures, both global (e.g. global efficiency) and local (e.g. clustering coefficient) with MDD symptom scores and related symptoms, revealed no significant correlation at the whole-brain level, both at baseline and post-intervention. Distinct patterns were identified when evaluating node-level metrics averaged across networks, which together with group differences, point to MDD patients exhibiting characteristics consistent with regular networks. Hierarchical clustering based on standardized baseline DTI structural connectivity within the clinical cohort revealed three distinct clusters of MDD patients, with the first cluster exhibiting a higher WHO-5 score, indicating a potential association with better well-being. These findings provide insight into MDD-specific brain regions’ structural alterations and underscore the heterogeneity of depression symptom profiles. Further research is needed, including a higher sample size and control for confounding factors.

Women have exhibited higher levels of math anxiety (MA) compared to men. Despite the relationship between MA and sex differences being topic of interest for over twenty years, the focal point has mostly been on the psychological causes. This review investigates the biological underpinnings of the social phobia and identifies numerous possible correlates which could inform future efforts to support students experiencing math anxiety and encourage more females to pursue STEM related careers. Articles that investigated sex differences in the context of MA were selected for the study using PRISMA guidelines. Females were found to experience higher levels of math anxiety compared to males. Age was shown to influence the prevalence of MA between sexes, with sex differences in MA being more infrequent in children and increasing towards adulthood. The findings suggest that a diverse set of biological sex differences related to to brain function, cognition and sex hormones can, in part, explain the higher prevalence of MA among females and age-related deviations. By shedding light on possible biological factors contributing to sex differences in MA, this review represents a valuable step toward a more comprehensive understanding of this complex issue.

Hippocampal place fields play a key role in spatial navigation. New place fields are formed during exploratory behavior through long-term potentiation (LTP) and long-term depression (LTD) of synaptic inputs to place cells located in hippocampal CA1. Recently, a novel form synaptic plasticity termed behavioral time scale plasticity (BTSP) has been demonstrated to occur in CA3–CA1 synapses in vitro. BTSP can potentiate synapses that were active several hundred milliseconds before or after a priming event such as a strong and prolonged somatic depolarization. This plasticity rule could be an important complement to well-established spike timing dependent plasticity (STDP) which associates neuronal inputs with outputs at a time scale less than a few tens of milliseconds. The aim of this thesis was to determine whether high frequency antidromic stimulation can act as a priming event that enables BTSP induction in CA1 pyramidal neurons. The underlying assumption was that antidromic stimulation could prime BTSP via action potential backpropagation. High frequency bursting of CA1 neurons in hippocampal slices was achieved with 100 Hz antidromic stimulation of CA1 axons in the alveus. Schaffer collaterals were stimulated 500 ms before or after CA1 burst firing with intensities that were subthreshold for LTP when unpaired. I found that high frequency firing did not enable LTP induction during either of the two experimental protocols, suggesting that neuronal output alone is insufficient for priming BTSP.

Spontaneous and voluntary movements of infants effectively reflect the developmental integrity of brain networks. When it comes to the research of motor development, the use of intelligent technology has shown to provide objective, automated, and scalable methods for movement assessment. In addition to intelligent technology, research on the usage of surveys – in this case parental surveys – has looked at the untapped potential that parental viewpoint. Guardians have a unique and holistic image of the child’s development, thus data from parental surveys could be used to further help us to assess infant’s development. For this study, I studied how the parents’ time estimate on the positions their child spends time in holds up against the machine-learning based data obtained with the smart jumpsuit. Using the data acquired from the smart jumpsuit during the recordings, we can see the amount of time the child spends in each position. Aim was to study the relationship between these variables and gain further understanding on the utilization of parental perspective in the assessment of motor development. Data was collected from 19 video recordings and videos were annotated with Anvil video annotation software for child’s posture and movements, and the annotations were used for training a machine learning-based classifier of the smart jumpsuit. Only data regarding postures was extracted for further analysis. Parental surveys were carried alongside of recordings. In the survey of parental estimate, we asked the parent to assess how much time the child spends in a specific posture. Positions which the survey focused on were prone, supine, side, sitting, crawling, and standing. Data from the recordings as well as data from parental surveys were visualized with radar plots. In addition, correlation was visualized in a linear regression. Positions which had both correlation of higher than 0.5 and a significant p-value were sitting (p < .001**), crawl posture (p < .05*), standing (p < .001**), and supine (p < .05*). Results suggested that parents were successfully assess the time spent in following postures: sitting, crawling, standing, and supine. This indicates that parents have a holistic understanding of their child’s motor development, and the knowledge could be useful in the overall assessment of development, especially when it comes to children with developmental delay. The parent’s ability to accurately assess a child’s motor development helps the parent support the child’s development.

Intersectins (ITSNs) are important scaffold and adaptor proteins that play an important role in various cellular processes such as endocytosis. Although we know a lot about their function, there is little information on the regulation of these proteins. On the other hand, microRNAs have been shown to have an extensive function in regulating numerous genes in animals and their dysfunction is credited for down regulation of many proteins. In this study, I demonstrate that microRNAs are potential regulators of ITSNs in HEK293 cells and human neuronal cell cultures. In this study, I cloned 3’UTRs of different isoforms of intersectins (ITSNs) and microRNAs to the expression vectors to express them in cells. I then transfected HEK293T or neuronal stem cell line (HEL47.2) with the constructed vectors and used various methods to analyse the effect of microRNAs on the expression of ITSNs. The main methods I used were dual-luciferase assay, reverse transcription quantitative PCR and western blotting, human neuronal stem cell culturing and lentiviral transduction. My results demonstrate that there were two microRNAs that stood out from other and had a significant downregulation of ITSNs mRNA levels in HEK293T cells. Those were miR-124 and miR-19. However, in the human neuronal cell line I did not observe a significant alteration of the ITSNs transcript level. Additionally, I suggest that the given microRNAs regulate protein levels by promoting the decay of the ITSN transcripts. However, more studies are needed to show a stronger causative effect of microRNAs on ITSNs. Subsequent studies should also look at how multiple microRNAs can influence gene expression cooperatively.

Kalvojännitteen syntyyn ja sen muutoksiin liittyvät prosessit mielletään usein haastaviksi aiheiksi oppia ja opettaa. Aiheen opetuksesta ja oppimisesta lukiossa ei juurikaan ole tehty tutkimusta, mutta aiemmat tutkimukset yliopisto-opiskelijoilla ovat osoittaneet, että haasteita esiintyy erityisesti lepokalvojännitteen muodostumisen ymmärtämisessä. Aihetta käsitellään suomalaisissa lukiossa pääasiassa ihmisen biologian kontekstissa vapaavalintaisella kurssilla 4 (LOPS 2015) tai 5 (LOPS 2019) ja aihe onkin yksi ihmisen biologian kurssin keskeisistä sisällöistä oppia ja ymmärtää. Kalvojännitteen synty ja sen muutokset on kuvattu suomenkielisissä lukion biologian oppikirjoissa usein yksinkertais-tetusti ja ajoittain virheellisesti. Tämä saattaa johtaa virhekäsitysten syntymiseen, jolloin opiskeltavaa aihetta ei opita riittävällä tasolla. Siksi tämän maisterintutkielman tavoitteena on selvittää, miten solukalvon sähköistä aktiivisuutta opetetaan suomenkielisissä lukioissa ja millaisia virhekäsityksiä opiskelijoilla aiheesta esiintyy. Näiden tulosten pohjal-ta luodaan kehittämistuotos eli opetusmateriaali biologian aineenopettajien käyttöön, jolla voidaan tukea solukalvon sähköisen aktiivisuuden opetusta ja oppimista. Tutkimusmenetelmänä tutkimuksessa käytettiin kehittämistutkimusta, jossa yhdisteltiin teoreettisen ja empiirisen ongelma-analyysin periaatteita. Teoreettisen ongelma-analyysin kautta pyrittiin kartoittamaan lukio-opetuksen kannalta solukalvon sähköiseen toimintaan liittyvät keskeisimmät seikat, joihin monet virhekäsitykset liittyvät, sekä tarkastelemaan niitä eri näkökulmista. Tämä toteutettiin aiemman tutkimuskirjallisuuden avulla. Empiirisessä ongelma-analyysissä tarkasteltiin sekä lukion biologian oppikirjoja (N=3) että kevään 2021 biologian ylioppilaskoevastauksia (N=400) hermosolun aktiopotentiaalin kulkuun liittyen. Molempia aineistoja analysoitiin laadullisen sisällönanalyysin periaatteiden mukaisesti. Teoreettisesta ja empiirisestä ongelma-analyysistä saatujen tulosten perusteella kehitettiin opetusmateriaalin ensimmäinen versio. Opetusmateriaali luetutettiin läpi maisterintutkielman ohjaajilla ja opetusmateriaalia kehitettiin heiltä saatujen kommenttien perusteella. Jatkokehittämisen tuloksena syntyi opetusmateriaalin toinen ja virallinen versio. Tutkimuksen tulokset osoittivat, että solukalvon sähköinen aktiivisuus on haastava aihe sekä opetuksen että oppimi-sen näkökulmasta. Lukion biologian oppikirjoissa esiintyi epätarkkoja kohtia solukalvon sähköiseen aktiivisuuteen liit-tyen ja nämä epätarkkuudet näkyivät opiskelijoiden ylioppilaskokeen vastauksissa yleisinä virhekäsityksinä. Erityisesti esiin nousi virheellinen käsitys natrium-kaliumpumpun ioneja ”palauttavasta” vaikutuksesta aktiopotentiaalin jälkeen. Toinen yleinen virhekäsitys oli, että uusi aktiopotentiaali on mahdollinen vasta kun kalvojännite on hyperpolarisaation jälkeen palautunut lepotilaan. Tulosten perusteella voidaan todeta, että ainakin osa opiskelijoiden virhekäsityksistä on lähtöisin oppikirjoista eikä näitä virhekäsityksiä ole pystytty korjaamaan opettajan toimesta opetustilanteessa. Ylioppi-laskokeessa tehtävään vastanneista opiskelijoista 11,3 % ei osannut vastata tehtävän ensimmäiseen kysymykseen ollenkaan. Vastauksista, joissa opiskelija oli vähintään välttävällä tasolla onnistunut vastaamaan kysymykseen (N=381), 92,4 % sisälsi yhden tai useamman virhekäsityksen. Virhekäsitysten karsimiseksi paras keino on estää niiden syntyminen. Siksi tämän tutkimuksen perusteella voidaan todeta, että lukion uuden opetussuunnitelman biologian oppikirjat tulisi päivittää sellaisiksi, että virheellistä käsitystä ei pääse syntymään. Tämä ei kuitenkaan pelkästään riitä, vaan myös lukion biologian opettajien tulisi luopua vanhoista opetusdioistaan ja varmistaa, että he opettavat aihetta nykytiedon valossa oikein. Tässä apuna toimii tämän tutkimuksen osana kehitetty opetusmateriaali solukalvon sähköisestä aktiivisuudesta hermosolun aktiopotentiaalin kontekstissa. Jotta opetusmateriaalin toimivuutta ja opiskelijoiden käsitteellistä muutosta voidaan arvioida, jatkotutkimukset ai-heesta ovat tarpeellisia.

Parkinsonin tauti on maailman yleisin hermorappeumaa aiheuttava liikehäiriösairaus. Taudin ilmaantuvuus- ja esiintyvyysluvut ovat jatkuvassa nousussa, mitä väestön ikääntyminen ei yksin selitä. Taudin patologisia löydöksiä ovat alfasynukleiinin kertyminen ja vääränlaisesta laskostumisesta johtuva aggregaatio, Lewy neuriittien ja kappaleiden kertyminen sekä dopaminergisten hermosolujen solukato mustatumakkeesta. Taudin pidemmälle edenneille vaiheille on tyypillistä vaikea toimintakyvyttömyys ja elinajanodotteen lasku. Nykyiset hoitomuodot niin Parkinsonin taudille, kuin muillekin hermorappeumasairauksille ovat ainoastaan oireita lievittäviä. Onnistuneeseen lääkekehitykseen vaaditaan parannusta eläinmallien validiteetin jokaisella alatasolla. Parkinsonin taudin käytössä olevissa prekliinisissä eläinmalleissa on huono ilmivaliditeetti monien potilailla tehtyjen patologisten löydösten puuttuessa. Tässä tutkielmassa esitän uudenlaisen SynFib rottamallin Parkinsonin tautiin. Eksogeenisesti valmistettuja ihmisen alfasynukleiinifibrillejä injisoitiin yhdessä alfasynukleiinia ekspressoivien virusvektoreiden kanssa mustatumakkeeseen. Injektio aiheutti intensiivisen ja etenevän alfasynukleiinista johtuvan patologian ja merkittävän dopaminergisen soluvaurion. Taudin etenemistä seurattiin pitkittäistutkimuksessa positroniemissiotomografialla ja toiminnallisia puutteita arvioitiin synapsitiheydessä, inflammaatiossa ja dopaminergisessa järjestelmässä 16 viikon ajan. Havaitsin aivokudoksen tulehduksen ja dopaminergisen ipsilateraalisen soluvaurion lisääntyneen merkittävästi. Kahden viikon kohdalla synapsitiheys oli merkittävästi vähentynyt ipsilateraalisesti ja taudin leviäminen kontralateraaliselle puolelle oli alkanut.

Neural Oscillations at large-scale local and global neural synchrony levels can be detected at the scalp using electroencephalography. This neural activity presents itself in a varied range of frequencies referred to as ‘Brain Waves’. These frequency bands have cognitive significance and have been implicated in several neural functions due to its important role in communicating with functionally-similar but spatially-distinct brain regions. Frontal Asymmetry is the difference in activity between the right and left hemispheres in frontal areas of the brain recorded via EEG and is seen to be a strong indicator of emotional states. Specifically, approach and withdrawal motivation which have been associated with positive and negative emotions respectively. Using a combination of behavioural and physiological methods in measuring preference and responses gives us an accurate representation of the participant responses. In this study, three tests were conducted during a continuous EEG recording. Test 1: The implication of inducing a positive mood before the onset of stimulus line-up and the extent of its effect on emotions and alpha asymmetry is not extensively studied. In this test, we employed the use of an instrumental soundscape for one experimental group before beginning the stimulus presentation to test this effect against a ‘silent’ control group. Test 2: This test aims to compare the participants’ physiological measures (EEG) and behavioural self-reports to audio advertisement stimuli consisting of different categories of music: ‘Brand music’ vs. ‘Campaign’ music or ‘No music’ Controls. Test 3: There is ambiguity in research regarding how frontal alpha asymmetry as measured by EEG and self-report preferences might change with changing the format of the advertisement to: only Audio, Audiovisual and Silent videos. There has been contradictory evidence regarding the impact of music on an individual’s emotions and consequent memory and decision-making. This thesis delves into these questions through the post-study behavioural test and simple binary choice paradigm that measure the above-mentioned in relation with the stimuli presented to participants. Our results did not show a significant difference in frontal asymmetry in the stimulus presentation across the three tests conducted during EEG recording. The behavioural data however indicated significant preference in behavioural self-report ratings for Brand Music- associated stimuli in Test 2 and for Audiovisual advertisement stimuli in Test 3. Results also revealed a significant correlation between ratings given to a stimulus and post-study memorability. The final binary choice paradigm test indicated higher preference to products related to stimulus presentation (‘advertised’ brand) vs similar products not related to the presented stimulus (‘non-advertised’ brand). We anticipate that these results will further help us understand and predict general preferences that can help companies, government policy-makers and the general public be more aware and better equipped to manage their valuable resources of money, time, attention and memory.

Meningeal lymphatic vessels (mLVs), a recent functionally characterized structure in the meninges, contribute to the clearance of macromolecules, immune cells and metabolic waste from the central nervous system to peripheral lymph nodes. Having been identified as a route of clearance, there is a focus on understanding their role in neurological disease pathology. Here we consider their function in the pathology of traumatic brain injury (TBI) particularly in blood solute clearance, lesion progression and neuroinflammatory response. We use a transgenic model of mLV developmental dysfunction, K14-VEGFR3-Ig, to analyze the progression and severity of a controlled cortical impact (CCI) injury. We show that in mice lacking mLVs there are a higher percentage of microglia cells in an activated state in the hippocampus whereas the progression of hematoma and lesion size does not differ from wild type. Our results suggest that at two months post injury, meningeal lymphatics could be functionally important in modulating microglia activation, which is associated with chronic inflammation.

Efficient processing of auditory information begins to emerge early in human ontogeny and establishes foundations for learning language from speech exposure. Here we show that repeated exposure to spoken words causes in neonatal brain attenuated neural responses that are linked to language skills at the age of 24 months. In the study, 75 newborn infants were exposed to repeated presentation of two spoken disyllabic pseudowords. During the word exposure, event-related potentials to presented pseudowords were measured with electroencephalography. The study provides three kinds of findings regarding neonatal brain dynamics and repetitive word exposure. Firstly, the results show that continuous exposure to spoken pseudowords modulates neonatal brain activity and can lead to attenuation of neural responses. This neural suppression likely reflects neonates’ early capacity to recognize spoken words and form neural representations of the stimuli through repetition. Secondly, the attenuated neural responses were bound to the presentation of the first syllable and did not occur after presentation of the second syllable. Thirdly, occurrence of neonatal neural suppression was associated with better expressive language skills later, at the age of 2 years. Altogether, the results provide preliminary evidence that neonatal brain responses to word repetition can be utilized to indicate efficiency of learning language from speech exposure and later state of language development.