Browsing by Subject "motoriikka"

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  • Lappi, Otto (2016)
    Understanding the brain's capacity to encode complex visual information from a scene and to transform it into a coherent perception of 3D space and into well-coordinated motor commands are among the outstanding questions in the study of integrative brain function. Eye movement methodologies have allowed us to begin addressing these questions in increasingly naturalistic tasks, where eye and body movements are ubiquitous and, therefore, the applicability of most traditional neuroscience methods restricted. This review explores foundational issues in (1) how oculomotor and motor control in lab experiments extrapolates into more complex settings and (2) how real-world gaze behavior in turn decomposes into more elementary eye movement patterns. We review the received typology of oculomotor patterns in laboratory tasks, and how they map onto naturalistic gaze behavior (or not). We discuss the multiple coordinate systems needed to represent visual gaze strategies, how the choice of reference frame affects the description of eye movements, and the related but conceptually distinct issue of coordinate transformations between internal representations within the brain.
  • Virtanen, Hennariikka (Helsingfors universitet, 2006)
    The aim of this work was to study what kind of working grips people use to knit in Finland and decide if one grip is superior to others. I investigated how knitters have adopted their grips and how they experience their knitting. I also explored whether it is possible to change one's grip. To provide a theoretical basis for the research I observed knitting in terms of culture, skill and ergonomics. The first part of the study material comprised video recordings of the grips of 95 knitters together with background information collected via a questionnaire during the education of craft teachers at the University of Helsinki in spring 2004, 2005 and 2006. Using the data obtained I focused on three knitters, whose grip of the knitting needles clearly differed from the ergonomically good grip. In addition to them I interviewed one student, who had changed over to more ergonomic way of knitting after participating in the first part of this study. In this respect my study is a several events' case study. In order to analyse my data I used both qualitative and quantitative content analysis methods to complement each other. Most of my research participants had learned to knit in first years of elementary school or comprehensive school. Almost everyone had adopted the basics of knitting by imitating, and many of them had corrected "incorrect" positions from verbal instructions. Through practice the imitated position had gradually become the style unique to each knitter. The findings showed that students' background in knitting is quite varied due to the diverse level of craft teaching. This is reflected in their knitting grips and their interest in knitting. Students do not think that there is one right working grip. The most important thing is that working seems as fluent and relaxed as possible, at which point knitting is easy and flows freely. They often consider their own style so pleasing and well-functioning that they do not think there could be any room for improvement. This study pointed out that, while it is possible to change a knitter's working grip, there is a bigger challenge in acknowledging weaknesses in one's know how. According to the results of my research, the most common working grip among Finnish knitters' corresponds with the grip that has been described as ergonomically good. Over one third of all participants knitted this way. Hands keep the knitting firmly but without tension. The forefinger that guides the yarn from the ball rests gently against the knitting needle, and the yarn goes in front of the first joint of the forefinger. The position of the hands and loops is the same as in the ergonomically good grip, i.e. the fingertips of both hands and the loops are near the tips of the knitting needles, so that the fingers only have to move small distances. When knitters purl and plain, they commonly pick up the yarn from the back of the knitting needle in the same way as when knitting. While researching the common features of working grips I have learned what abnormal grips are like. Although I recognized many different ways to knit, all the peculiar grips were modifications of the continental way of knitting. The results of this study give a clear picture of those points knitters should focus their attention on in order to gain a good hold of the needles.
  • Rantala, Aleksi (Helsingin yliopisto, 2017)
    Objective: There is known to be a strong connection between hand movements and speech in humans. This has emerged for example in experiments where subjects pronounce syllables and simultaneously move their arm either towards or away from their body. The subjects produce both the hand movement and the pronunciation of syllables the fastest when the direction of the movement and the syllable are congruent. The original explanation for this was that the sounds that are congruent with the push movement, like [i] and [t], are made by pushing the tongue forward as well. Likewise, the sounds that are congruent with the pull movement, like [a] and [k], are made by a pull movement of the tongue. The objective of this study is to take a more precise look at this so-called direction-sound effect. The aim is to examine whether the effect is really caused by the overlap of the motor representations of hand and tongue, like it was originally interpreted, or if it is caused by some properties of sounds other than their horizontal movement direction. Methods: The direction-sound effect was studied in five experiments. In each experiment the subjects were presented with two different syllables, from which the other was supposed to be congruent with push hand movements and the other with pull hand movements. The subjects read each syllable out loud and performed simultaneously either a push or pull movement with a joystick according to the colour of the syllable. Experiments 1 and 2 tested whether the direction-sound effect emerges with consonants. Experiments 3, 4, and 5 tested whether the effect emerges when the vowels differ in one of their properties. In experiment 3 the vowels differed in openness, in experiment 4 they differed in frontness, and in experiment 5 in roundedness. 19-20 subjects participated in each experiment. Results and conclusions. In experiments 3 and 4 the syllables pronounced by the subjects, and the direction of their hand movement, had a statistically significant interaction to the reaction times of both the hand movements and the pronunciation of the syllables. There was not a similar interaction in experiments 1, 2, or 5. According to the results, vowels [ø] and [i] are congruent with the push hand movement and vowels [o] ja [æ] with the pull hand movement. The direction-sound effect does not seem to emerge with consonants but only with vowels. With vowels the effect seems to emerge when the vowels differ in their frontness and possibly in openness, but not when they differ in roundedness. The results bring more knowledge about how the speech movements of different parts of the mouth are represented when pronouncing vowels and consonants. The results also shed more light on previous speculations about which kind of sounds are universally associated with words referring to different directions across different languages.
  • Tapanainen, Tuukka (Helsingfors universitet, 2017)
    The α5 subunit of nicotinic acetylcholine receptors forms functional receptors with other subunits as a structural subunit. It affects the structural and functional properties of the nicotinic receptor by increasing calcium permeability and accelerating desensitization. In the mammalian brain, the α5 mRNA is widely expressed, mostly in substantia nigra pars compacta, ventral tegmental area and interpeduncular nucleus. Its protein has been identified in various distinct brain areas, such as striatum, cortex and medial habenula. In the dorsal striatum partaking in motor functions, the α5 subunit modulates the release of dopamine, thus it is believed to have an impact on motor function. In the experimental part of the thesis mice lacking the α5 subunit were injected unilaterally with neurotoxin 6-hydroxydopamine (6-OHDA) in the striatum. The purpose was to determine the importance of the subunit with regard to the lesion extent and motor function. The motor functions of α5-deficient and wild type control mice were assessed in amphetamine- and apomorphine-induced rotametry. After the tests the mice were euthanized and their substantia nigra and striatal brain samples were collected for further analysis. The number of dopamine cells in the medial and dorsal tier of substantia nigra were determined, so as to quantify the extent of the lesions and to explain the research group's previous finding about the α5-deficient mice spinning less ipsilaterally in amphetamine induced rotametry. The α5-deficient mice were found to turn less ipsilaterally compared to the control mice in the amphetamine-induced rotametry and in the apomorphine-induced rotametry, first less contralaterally and subsequently more contralaterally than the control mice. The results of male mice, that were less in number, were excluded from the results as the difference between genders was significant in the wild type mice in the amphetamine-induced rotametry. There was no significant difference in the number of remaining dopamine cells between the genotypes after the lesioning in either of the areas of interest. However, the wild type mice tended to have less cells remaining in the medial tier of the substantia nigra. The observed differences between the genotypes in the rotametries could be accounted by differences in the amount of dopamine released from striatal neurons or differences in striatal dopamine receptor quantities or function. The results support the hypothesis about the contribution of the α5 subunit containing acetylcholine nicotinic receptors in motor function.