Vain muutaman millisekunnin tähden – Tajunnantutkimuksen lähtökohtia mediatajun tutkimukselle

Tutkielmani tarkoituksena on tarkastella tajuntaa mediatajun käsitteen perustana. Tajunta ilmiönä on yhteydessä siihen, miten 2000-luvun mediateknologia kytkeytyy osaksi ihmisen jokapäiväistä todellisuutta. Tutkielmani mediafilosofisena lähtökohtana on oletus, että elokuva viihde- ja taidemuotona syntyi rinnakkain 1900-luvun kokeellisen psykologian kehityksen kanssa. 2000-luvulle siirryttäessä tämä tarkoittaa sitä, että uusi mediateknologia syntyy rinnakkain aikakautensa kokeellisen psykologian kanssa. 2000-luvun kokeellisen psykologian haasteena on ihmisen aivotoiminta ja erityisesti tajunnan ilmiön tutkiminen. Mediatajun käsitteen perustana olevan tajunnan määrittelemiseen pyrin muodostamani Artaud’n hypoteesin avulla. Hypoteesin mukaan elokuva saa aikaan katsojassa neurofysiologisia värähtelyjä prosessissa, jossa kuvan tehtävänä on antaa shokki-isku hermoihin niin, että uusi ajatus syntyy ja lähtee liikkeelle. Tutkimusmenetelmänäni on tajunnantutkimuksen ja kognitiivisen neurotieteen käsitteiden ja tutkimustulosten käyttäminen Artaud’n hypoteesin arvioimiseen. Lähteenä käytän Turun yliopiston kognitiivisen neurotieteen tutkimuskeskuksen julkaisemaa oppikirjaa Mieli ja aivot (2006) ja Antti Revonsuon teosta Inner Presence: Consciousness as a Biological Phenomenon (2006) sekä alan tuoreita tutkimustuloksia. Keskeisenä elokuvateoreettisena päälähteenäni on Noël Carrollin teos Mystifying Movies (1988). Keskeisenä tutkimustuloksena on tajunnan ilmiön monimutkaisuuden hahmottaminen mediatutkimuksen tutkijaa varten. Esimerkiksi mediatutkimukseen sisältyvässä elokuvateoreettisessa keskustelussa on vedetty selvä raja kognitiivisen ja psykoanalyyttisen elokuvateorian välille. Tajunnantutkimuksen tutkimustulokset osoittavat, että rajanveto ei ole yksiselitteistä. Tutkielmani tuo myös esiin mediatajun käsitteen rajaukseen liittyviä mahdollisuuksia, joita voidaan selvittää jatkotutkimuksen avulla. Muodostamani Artaud’n hypoteesi sisältää ajatuksen elokuvan ja laajemmin ottaen taiteen potentiaalista uusien ajatuksien herättäjänä. Tutkielmani osoittaa, että tällä hetkellä tajunnantutkimuksen ja kognitiivisen neurotieteen avulla ei voida paikantaa taiteen herättämiä uuden ajattelun prosesseja. Tässä suhteessa hypoteesin voidaan katsoa kumoutuvan neurotieteen alueella. Tutkimustulokset osoittavat kuitenkin taiteen saavan aikaan aivoaktivaatioita, joten tutkimus ja keskustelu taiteen vaikutuksesta ajatteluun jatkuu.

(1)H NMR determination of beta-N-methylamino-L-alanine (L-BMAA) in environmental and biological samples

A nuclear magnetic resonance ((1)H NMR) method for the determination of beta-N-methylamino-L-alanine (L-BMAA) in environmental aqueous samples was developed and validated. L-BMAA is a neurotoxic modified amino acid that can be produced by cyanobacteria in aqueous environments. This toxin was extracted from samples by means of solid-phase extraction (SPE) and identified and quantified by (1)H NMR without further derivatization steps. The lower limit of quantification (LLOQ) was 5 mu g/mL Good inter and intra-assay precision was also observed (relative standard deviation <8.5%) with the use of 4-nitro-DL-phenylalanine as an internal standard (IS). This method of 1H NMR analysis is not time consuming and can be readily utilized to monitor L-BMAA and confirm its presence in environmental and biological samples. (C) 2008 Elsevier Ltd. All rights reserved.

Threat Simulation- The Function of Dreaming?

Dreaming is a pure form of phenomenality, created by the brain untouched by external stimulation or behavioral activity, yet including a full range of phenomenal contents. Thus, it has been suggested that the dreaming brain could be used as a model system in a biological research program on consciousness (Revonsuo, 2006). In the present thesis, the philosophical view of biological realism is accepted, and thus, dreaming is considered as a natural biological phenomenon, explainable in naturalistic terms. The major theoretical contribution of the present thesis is that it explores dreaming from a multidisciplinary perspective, integrating information from various fields of science, such as dream research, consciousness research, evolutionary psychology, and cognitive neuroscience. Further, it places dreaming into a multilevel framework, and investigates the constitutive, etiological, and contextual explanations for dreaming. Currently, the only theory offering a full multilevel explanation for dreaming, that is, a theory including constitutive, etiological, and contextual level explanations, is the Threat Simulation Theory (TST) (Revonsuo, 2000a; 2000b). The empirical significance of the present thesis lies in the tests conducted to test this specific theory put forth to explain the form, content, and biological function of dreaming. The first step in the empirical testing of the TST was to define exact criteria for what is a ‘threatening event’ in dreams, and then to develop a detailed and reliable content analysis scale with which it is possible to empirically explore and quantify threatening events in dreams. The second step was to seek answers to the following questions derived from the TST: How frequent threatening events are in dreams? What kind of qualities these events have? How threatening events in dreams relate to the most recently encoded or the most salient memory traces of threatening events experienced in waking life? What are the effects of exposure to severe waking life threat on dreams? The results reveal that threatening events are relatively frequent in dreams, and that the simulated threats are realistic. The most common threats include aggression, are targeted mainly against the dream self, and include simulations of relevant and appropriate defensive actions. Further, real threat experiences activate the threat simulation system in a unique manner, and dream content is modulated by the activation of long term episodic memory traces with highest negative saliency. To sum up, most of the predictions of the TST tested in this thesis received considerable support. The TST presents a strong argument that explains the specific design of dreams as threat simulations. The TST also offers a plausible explanation for why dreaming would have been selected for: because dreaming interacted with the environment in such a way that enhanced fitness of ancestral humans. By referring to a single threat simulation mechanism it furthermore manages to explain a wide variety of dream content data that already exists in the literature, and to predict the overall statistical patterns of threat content in different samples of dreams. The TST and the empirical tests conducted to test the theory are a prime example of what a multidisciplinary approach to mental phenomena can accomplish. Thus far, dreaming seems to have always resided in the periphery of science, never regarded worth to be studied by the mainstream. Nevertheless, when brought to the spotlight, the study of dreaming can greatly benefit from ideas in diverse branches of science. Vice versa, knowledge learned from the study of dreaming can be applied in various disciplines. The main contribution of the present thesis lies in putting dreaming back where it belongs, that is, into the spotlight in the cross-road of various disciplines.

Tietoisuuden arvoituksia

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Concepts and determination of reference values for human biomonitoring of environmental contaminants

Human biomonitoring (HBM) of environmental contaminants plays an important role in estimating exposure and evaluating risk, and thus it has been increasingly applied in the environmental field. The results of HBM must be compared with reference values ( RV). The term ""reference values"" has always been related to the interpretation of clinical laboratory tests. For physicians, RV indicate ""normal values"" or ""limits of normal""; in turn, toxicologists prefer the terms ""background values"" or ""baseline values"" to refer to the presence of contaminants in biological fluids. This discrepancy leads to the discussion concerning which should be the population selected to determine RV. Whereas clinical chemistry employs an altered health state as the main exclusion criterion to select a reference population ( that is, a ""healthy"" population would be selected), in environmental toxicology the exclusion criterion is the abnormal exposure to xenobiotics. Therefore, the choice of population to determine RV is based on the very purpose of the RV to be determined. The present paper discusses the concepts and methodology used to determine RV for biomarkers of chemical environmental contaminants.

The Sense of embodiment in virtual reality

What does it feel like to own, to control, and to be inside a body? The multidimensional nature of this experience together with the continuous presence of one's biological body, render both theoretical and experimental approaches problematic. Nevertheless, exploitation of immersive virtual reality has allowed a reframing of this question to whether it is possible to experience the same sensations towards a virtual body inside an immersive virtual environment as toward the biological body, and if so, to what extent. The current paper addresses these issues by referring to the Sense of Embodiment (SoE). Due to the conceptual confusion around this sense, we provide a working definition which states that SoE consists of three subcomponents: the sense of self-location, the sense of agency, and the sense of body ownership. Under this proposed structure, measures and experimental manipulations reported in the literature are reviewed and related challenges are outlined. Finally, future experimental studies are proposed to overcome those challenges, toward deepening the concept of SoE and enhancing it in virtual applications.

Kognitiivis-neurotieteellistä tajunnanvirtaa

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