Nägemistaju automaatsete protsesside eksperimentaalne uurimine

Väitekirja elektrooniline versioon ei sisalda publikatsiooneVäitekiri keskendub nägemistaju protsesside eksperimentaalsele uurimisele, mis on suuremal või vähemal määral automaatsed. Uurimistöös on kasutatud erinevaid eksperimentaalseid katseparadigmasid ja katsestiimuleid ning nii käitumuslikke- kui ka ajukuvamismeetodeid. Esimesed kolm empiirilist uurimust käsitlevad liikumisinformatsiooni töötlust, mis on evolutsiooni käigus kujunenud üheks olulisemaks baasprotsessiks nägemistajus. Esmalt huvitas meid, kuidas avastatakse liikuva objekti suunamuutusi, kui samal ajal toimub ka taustal liikumine (Uurimus I). Nägemistaju uurijad on pikka aega arvanud, et liikumist arvutatakse alati mõne välise objekti või tausta suhtes. Meie uurimistulemused ei kinnitanud taolise suhtelise liikumise printsiibi paikapidavust ning toetavad pigem seisukohta, et eesmärkobjekti liikumisinformatsiooni töötlus on automaatne protsess, mis tuvastab silma põhjas toimuvaid nihkeid, ja taustal toimuv seda eriti ei mõjuta. Teise uurimuse tulemused (Uurimus II) näitasid, et nägemissüsteem töötleb väga edukalt ka seda liikumisinformatsiooni, millele vaatleja teadlikult tähelepanu ei pööra. See tähendab, et samal ajal, kui inimene on mõne tähelepanu hõlmava tegevusega ametis, suudab tema aju taustal toimuvaid sündmusi automaatselt registreerida. Igapäevaselt on inimese nägemisväljas alati palju erinevaid objekte, millel on erinevad omadused, mistõttu järgmiseks huvitas meid (Uurimus III), kuidas ühe tunnuse (antud juhul värvimuutuse) töötlemist mõjutab mõne teise tunnusega toimuv (antud juhul liikumiskiiruse) muutus. Näitasime, et objekti liikumine parandas sama objekti värvimuutuse avastamist, mis viitab, et nende kahe omaduse töötlemine ajus ei ole päris eraldiseisev protsess. Samuti tähendab taoline tulemus, et hoolimata ühele tunnusele keskendumisest ei suuda inimene ignoreerida teist tähelepanu tõmbavat tunnust (liikumine), mis viitab taas kord automaatsetele töötlusprotsessidele. Neljas uurimus keskendus emotsionaalsete näoväljenduste töötlusele, kuna need kannavad keskkonnas hakkamasaamiseks vajalikke sotsiaalseid signaale, mistõttu on alust arvata, et nende töötlus on kujunenud suuresti automaatseks protsessiks. Näitasime, et emotsiooni väljendavaid nägusid avastati kiiremini ja kergemini kui neutraalse ilmega nägusid ning et vihane nägu tõmbas rohkem tähelepanu kui rõõmus (Uurimus IV). Väitekirja viimane osa puudutab visuaalset lahknevusnegatiivsust (ingl Visual Mismatch Negativity ehk vMMN), mis näitab aju võimet avastada automaatselt erinevusi enda loodud mudelist ümbritseva keskkonna kohta. Selle automaatse erinevuse avastamise mehhanismi uurimisse andsid oma panuse nii Uurimus II kui Uurimus IV, mis mõlemad pakuvad välja tõendusi vMMN tekkimise kohta eri tingimustel ja katseparadigmades ning ka vajalikke metodoloogilisi täiendusi. Uurimus V on esimene kogu siiani ilmunud temaatilist teadustööd hõlmav ülevaateartikkel ja metaanalüüs visuaalsest lahknevusnegatiivsusest psühhiaatriliste ja neuroloogiliste haiguste korral, mis panustab oluliselt visuaalse lahknevusnegatiivsuse valdkonna arengusse.The research presented and discussed in the thesis is an experimental exploration of processes in visual perception, which all display a considerable amount of automaticity. These processes are targeted from different angles using different experimental paradigms and stimuli, and by measuring both behavioural and brain responses. In the first three empirical studies, the focus is on motion detection that is regarded one of the most basic processes shaped by evolution. Study I investigated how motion information of an object is processed in the presence of background motion. Although it is widely believed that no motion can be perceived without establishing a frame of reference with other objects or motion on the background, our results found no support for relative motion principle. This finding speaks in favour of a simple and automatic process of detecting motion, which is largely insensitive to the surrounding context. Study II shows that the visual system is built to automatically process motion information that is outside of our attentional focus. This means that even if we are concentrating on some task, our brain constantly monitors the surrounding environment. Study III addressed the question of what happens when multiple stimulus qualities (motion and colour) are present and varied, which is the everyday reality of our visual input. We showed that velocity facilitated the detection of colour changes, which suggests that processing motion and colour is not entirely isolated. These results also indicate that it is hard to ignore motion information, and processing it is rather automatically initiated. The fourth empirical study focusses on another example of visual input that is processed in a rather automatic way and carries high survival value – emotional expressions. In Study IV, participants detected emotional facial expressions faster and more easily compared with neutral facial expressions, with a tendency towards more automatic attention to angry faces. In addition, we investigated the emergence of visual mismatch negativity (vMMN) that is one of the most objective and efficient methods for analysing automatic processes in the brain. Study II and Study IV proposed several methodological gains for registering this automatic change-detection mechanism. Study V is an important contribution to the vMMN research field as it is the first comprehensive review and meta-analysis of the vMMN studies in psychiatric and neurological disorders

Kas see on sama mis too? Hinnangukatse eesti keele demonstratiivpronoomenite ja demonstratiivadverbidega

Eesti keeles on kaks demonstratiivpronoomenite süsteemi: üheliikmeline, kus kasutatakse demonstratiivpronoomenit seedistantsneutraalselt, ja kaheliikmeline, kus see viitab kõneleja lähedal ning too kaugel olevale referendile. Mõlemas süsteemis lisatakse demonstratiivpronoomenile sageli demonstratiivadverb (nt see siin). Süsteemi valik näib olevat seotud keelekõneleja päritoluga – Lõuna-Eesti päritolu kõnelejad kasutavad kaheliikmelist, Põhja-Eesti päritolu üheliikmelist süsteemi. Uurimuses keskendume kahe demonstratiiviga fraasidele (nt see siin), püstitades kaks küsimust. Esiteks, milline on keelekõnelejate enda arvamus selle kohta, milliseid demonstratiive millises ruumilises olukorras nad kasutaksid. Teiseks, kas see, kuidas keelekõneleja arvab end demonstratiive sisaldavaid lauseid kasutavat kattub vastavate lausete tõlgendamisega samas olukorras. Viisime läbi hinnangukatse, mille tulemusi võrdleme varem avaldatud tõlgenduskatse tulemustega. Mõlema katse andmed koguti järjestikuselt ning samadelt katseisikutelt. Hinnangukatse näitas, et lõunaeestlased hindasid too’d sisaldavate lausete ütlemist tõenäolisemaks kui põhjaeestlased. See’d sisaldavate lausete puhul päritolu hinnanguid ei eristanud. Sarnaselt tõlgenduskatsega osutus ka hinnangukatses oluliseks referendi kaugus, kuid visuaalne esilduvus andis erinevaid tulemusi, viidates kauguse teguri kesksusele ning esilduvuse perifeersusele demonstratiivide tähenduses. Abstract. Maria Reile, Kristiina Averin, Nele Põldver: Does see ‘this’ equal too ‘that’? Rating task with Estonian demonstrative pronouns and demonstrative adverbs. Estonian employs two demonstrative pronoun systems – a one-way system (used in North Estonia) where the demonstrative pronoun see is distance neutral, and a two-way system (in South Estonia) where see is the proximal and too the distal demonstrative pronoun. In both systems, demonstrative adverbs are often added to demonstrative pronouns, forming two-demonstrative phrases (e.g., see siin). We conducted a rating study to investigate these phrases, asking which demonstratives the speakers would use in which spatial settings. In addition, we compared these results with a previously published interpretation study to see whether the speakers’ opinions to use or not use certain demonstratives match their interpretations of these demonstratives. The rating study showed that South Estonians would use the demonstrative too more likely as compared to North Estonians while origin had no effect on using the demonstrative see. Both experiments showed a similar effect of distance on demonstrative use, but not visual salience

Eesti lapsevanemate uskumused laste plaanilise vaktsineerimise kohta ja vaktsineerimiskäitumist mõjutavad tegurid: internetiküsitluse tulemused

Taust. Vaktsiiniga välditavate haiguste üldine vähenemine on tinginud rahvastikus leviva kahtluse suurenemise lapse vaktsineerimise vajaduse suhtes. Tõenduspõhised andmed Eesti lapsevanemate arusaamade kohta seoses vaktsineerimisega puuduvad. Eesmärk. Selgitada Eesti lapsevanemate vaktsineerimiskäitumist ja uskumusi seoses plaanilise vaktsineerimisega ning seda mõjutavaid tegureid. Metoodika. Kasutati veebipõhist ankeetküsitlust (8. novembrist 7. detsembrini 2017). Valimi moodustas 1557 lapsevanemat, kelle noorim laps oli noorem kui 5aastane. Ankeedi tulemuste põhjal jaotati uuritavad vaktsineerijateks (72,3%), kahtlejateks (11,9%) ja mittevaktsineerijateks (15,8%). Nende vaktsinatsioonikäitumise mõjurite selgitamiseks kasutati logistilist regressioonanalüüsi. Uskumusi hinnati 5astmelisel Likerti skaalal. Tulemused. Oma last vaktsineerida on suurem šanss 25–34aastastel, võrreldes vanematega kui 35 aastat, ja väiksema sissetulekuga lapsevanematel. Kahtlejad on pigem üle 35aastased kui 25–34aastased. Mittevaktsineerijatel on rohkem kui 1 laps, samuti on mitttevaktsineerijad suuremapalgalised. Arvamused vaktsineerimise, selle olulisuse ja efektiivsuse kohta erinesid kõikides rühmades. Enim usuti, et vaktsineerimine kaitseb haiguste eest (78,7%; vaktsineerijad 96,4%; kahtlejad 65,1%; mittevaktsineerijad 8,1%), ja vaktsiiniga välditavaid haigusi peeti raskeks (74,3%; vastavalt 90,9%; 62,4%; 7,3%). Kahtlejad ja mittevaktsineerijad usaldasid vähem kui vaktsineerijad nii tervishoidu kui ka sellega seotud institutsioone, näiteks peab arstide soovitusi usaldusväärseks 71,7% (vastavalt 89,3% vaktsineerijatest, 46,8% kahtlejatest ja 9,8% mittevaktsineerijatest) ja Terviseameti soovitusi 67,6% (vastavalt 86,7% vaktsineerijatest, 39,8% kahtlejatest ja 1,6% mittevaktsineerijatest) vanematest. Järeldused. Uuring näitab, et lapsevanemad kahtlevad vaktsiinide ohutuses ja vajalikkuses. Et vältida vaktsineerimisest keeldumise trendi suurenemist, tuleks suurendada usaldust vaktsineerimise suhtes

Psycho-social factors associated with mental resilience in the Corona lockdown.

The SARS-CoV-2 pandemic is not only a threat to physical health but is also having severe impacts on mental health. Although increases in stress-related symptomatology and other adverse psycho-social outcomes, as well as their most important risk factors have been described, hardly anything is known about potential protective factors. Resilience refers to the maintenance of mental health despite adversity. To gain mechanistic insights about the relationship between described psycho-social resilience factors and resilience specifically in the current crisis, we assessed resilience factors, exposure to Corona crisis-specific and general stressors, as well as internalizing symptoms in a cross-sectional online survey conducted in 24 languages during the most intense phase of the lockdown in Europe (22 March to 19 April) in a convenience sample of N = 15,970 adults. Resilience, as an outcome, was conceptualized as good mental health despite stressor exposure and measured as the inverse residual between actual and predicted symptom total score. Preregistered hypotheses (osf.io/r6btn) were tested with multiple regression models and mediation analyses. Results confirmed our primary hypothesis that positive appraisal style (PAS) is positively associated with resilience (p < 0.0001). The resilience factor PAS also partly mediated the positive association between perceived social support and resilience, and its association with resilience was in turn partly mediated by the ability to easily recover from stress (both p < 0.0001). In comparison with other resilience factors, good stress response recovery and positive appraisal specifically of the consequences of the Corona crisis were the strongest factors. Preregistered exploratory subgroup analyses (osf.io/thka9) showed that all tested resilience factors generalize across major socio-demographic categories. This research identifies modifiable protective factors that can be targeted by public mental health efforts in this and in future pandemics

Visual mismatch negativity (vMMN): A review and meta-analysis of studies in psychiatric and neurological disorders

The visual mismatch negativity (vMMN) response is an event-related potential (ERP) component, which is automatically elicited by events that violate predictions based on prior events. VMMN experiments use visual stimulus repetition to induce predictions, and vMMN is obtained by subtracting the response to rare unpredicted stimuli from those to frequent stimuli. One increasingly popular interpretation of the mismatch response postulates that vMMN, similar to its auditory counterpart (aMMN), represents a prediction error response generated by cortical mechanisms forming probabilistic representations of sensory signals. Here we discuss the physiological and theoretical basis of vMMN and review thirty-three studies from the emerging field of its clinical applications, presenting a meta-analysis of findings in schizophrenia, mood disorders, substance abuse, neurodegenerative disorders, developmental disorders, deafness, panic disorder and hypertension. Furthermore, we include reports on aging and maturation as they bear upon many clinically relevant conditions. Surveying the literature we found that vMMN is altered in several clinical populations which is in line with aMMN findings. An important potential advantage of vMMN however is that it allows the investigation of deficits in predictive processing in cognitive domains which rely primarily on visual information; a principal sensory modality and thus of vital importance in environmental information processing and response, and a modality which arguably may be more sensitive to some pathological changes. However, due to the relative infancy of research in vMMN compared to aMMN in clinical populations its potential for clinical application is not yet fully appreciated. The aim of this review and meta-analysis therefore is to present, in a detailed systematic manner, the findings from clinically-based vMMN studies, to discuss their potential impact and application, to raise awareness of this measure and to improve our understanding of disease upon fundamental aspects of visual information processing

Perceptual asymmetries and auditory processing of Estonian quantities

Similar to visual perception, auditory perception also has a clearly described “pop-out” effect, where an element with some extra feature is easier to detect among elements without an extra feature. This phenomenon is better known as auditory perceptual asymmetry. We investigated such asymmetry between shorter or longer duration, and level or falling of pitch, of linguistic stimuli that carry a meaning in one language (Estonian), but not in another (Russian). For the mismatch negativity (MMN) experiment, we created four different types of stimuli by modifying the duration of the first vowel [ɑ] (170, 290 ms) and pitch contour (level vs. falling pitch) of the stimuli words (‘SATA’, ‘SAKI’). The stimuli were synthesized from Estonian words (‘SATA’, ‘SAKI’) and follow the Estonian language three-way quantity system, which incorporates tonal features (falling pitch contour) together with temporal patterns. This made the meaning of the word dependent on the combination of both features and allows us to compare the relative contribution of duration and pitch contour in discrimination of language stimuli in the brain via MMN generation. The participants of the experiment were 12 Russian native speakers with little or no experience in Estonian and living in Estonia short-term, and 12 Estonian native speakers (age 18-27 years). We found that participants’ perception of the linguistic stimuli differed according to their native language, confirming that the meaning of the word interferes with the early automatic processing of phonological features and thus illustrating the effect of language background on language perception and also on auditory asymmetry. The GAMM and ANOVA analysis of the reversed design results showed that the deviant with longer duration among shorter standards elicited a MMN response with greater amplitude than the short deviant among long standards, while changes in pitch contour (falling vs. level pitch) produced neither strong MMN or asymmetry. Our results align with those of previous studies (Jaramillo et al., 2000), and contribute to the growing body of knowledge supporting auditory perceptual asymmetry

Subjectively different emotional schematic faces not automatically discriminated from the brain’s bioelectrical responses

The present study investigates how the brain automatically discriminates emotional schematic faces, as indicated by the mismatch responses, and how reliable these brain responses are. Thirty-three healthy volunteers participated in the vMMN EEG experiment with four experimental sets differing from each other by the type of standard (object with scrambled face features) and the type of deviants (Angry, Happy and Neutral schematic faces) presented. Conscious subjective evaluations of valence, arousal and attention catching of the same stimuli showed clear differentiation of emotional expressions. Deviant faces elicited rather similar vMMN at frontal and occipital sites. Bayesian analyses suggest that vMMN does not differ between angry and happy faces. Neutral faces, however, did not yield statistically significant vMMN at occipital leads. Pearson’s correlation and intra-class correlation analyses showed that the brain’s reactions to the stimuli were highly stable within individuals across the experimental sets, whereas the mismatch responses were much more variable

PROCESSING OF LANGUAGE SPECIFIC STIMULI AMONG ESTONIAN AND RUSSIAN NATIVE SPEAKERS: AN EEG STUDY

We studied how linguistic and non-linguistic auditory input is recognized and distinguished by the brain among native and language naïve speakers, and how that might influence the ability to process changes in duration and pitch. 12 Estonian and 12 Russian (with little experience in Estonian) native speakers took part in an MMN experiment using quantity contrast stimuli with changes in pitch and duration. Estonian is a quantity language with a complex and typologically rare three-way contrast while Russian does not exhibit the linguistic quantity category. Two different linguistic stimulus sets (‘SATA’, ‘SAKI’) and one pure tone stimulus set were used. Stimuli differed from each other by the duration of the first vowel [ɑ] (110, 170, 290 ms) and pitch change (level vs falling tone). The sine wave stimulus elicited a more persistent MMN wave with larger amplitude in both language groups, while linguistic stimuli elicited a more pronounced MMN response among the Estonian native speakers. Among the Russian native speakers, the only considerable MMN response for linguistic stimuli was elicited by a clear durational change; while the Estonian native speakers had an MMN response to pitch changes as well. This study is the first ERP study to support previous behavioral findings showing that native Estonian speakers used both durational and pitch cues to discriminate quantities while Russian native speakers used mainly durational cue, while also pointing out some possible limitations and directions for future research

Native Language Background Affects the Perception of Duration and Pitch

Estonian is a quantity language where both a primary duration cue and a secondary pitch cue exist, whereas Chinese is a tonal language that features a dominant use of pitch. Native speakers of both languages (63 Estonian and 61 Chinese participants) participated in a mismatch negativity (MMN) experiment where stimuli in both languages and their non-linguistic equivalents (i.e., pure tones) were discriminated in terms of duration change, pitch change, and duration plus pitch change. The MMN experiment was followed by a behavioral discrimination experiment where non-native stimuli were presented. Chinese participants showed right lateralized MMNs and, behaviorally, a low discrimination accuracy to the duration change in the Estonian stimuli and their non-linguistic equivalents, suggesting that they perceived duration as acoustic information without linguistic meaning. While no group difference was found in perceiving the pitch change in the Estonian stimuli, Chinese participants showed larger MMNs and a higher accuracy than Estonian participants to the pitch change in the Chinese stimuli, suggesting a relatively better pitch discrimination ability than Estonian participants. Estonian participants showed larger MMNs than Chinese participants to the pure tones that resembled the Estonian stimuli containing both duration and pitch changes, suggesting that linguistically-relevant cues can influence the processing of non-linguistic stimuli. Our results indicate that long-term familiarity with specific sound features in one’s native language affects the perception of duration and pitch and that such an effect is not specific to the language domain

Musicality Effect on the Perception of Duration and Pitch in Language: A Cross-linguistic Study

This study adopts a cross-linguistic perspective and investigates how musical expertise affects the perception of duration and pitch in language. Native Chinese (N=44) and Estonians (N=46), each group subdivided into musicians and non-musicians, participated in a mismatch negativity (MMN) experiment where they passively listened to both Chinese and Estonian stimuli, followed by an attentive behavioral experiment where they discriminated the stimuli in the non-native language (i.e., Chinese to Estonian participants and Estonian to Chinese participants). In both experiments, stimuli of duration change, pitch change, and duration plus pitch change were discriminated. We found higher behavioral sensitivity among Chinese musicians than non-musicians in perceiving the duration change in Estonian and higher behavioral sensitivity among Estonian musicians than non-musicians in perceiving all types of changes in Chinese, but no corresponding musicality effect was found in the MMN results, which suggests a more salient musicality effect on foreign language processing when attention is required. Secondly, Chinese musicians did not outperform non-musicians in attentively discriminating the pitch-related stimuli in Estonian, suggesting that musical expertise can be overridden by tonal language experience when perceiving foreign linguistic pitch, especially when an attentive discrimination task is administered. Thirdly, we found larger MMN among Chinese and Estonian musicians than their non-musician counterparts in perceiving the largest deviant (i.e., duration plus pitch) in their native language, demonstrating a positive musicality effect in native language processing