Functional imaging of peripheral vision and dorsal stream function in the human cerebral cortex

Visual information processing in brain proceeds in both serial and parallel fashion throughout various functionally distinct hierarchically organised cortical areas. Feedforward signals from retina and hierarchically lower cortical levels are the major activators of visual neurons, but top-down and feedback signals from higher level cortical areas have a modulating effect on neural processing. My work concentrates on visual encoding in hierarchically low level cortical visual areas in human brain and examines neural processing especially in cortical representation of visual field periphery. I use magnetoencephalography and functional magnetic resonance imaging to measure neuromagnetic and hemodynamic responses during visual stimulation and oculomotor and cognitive tasks from healthy volunteers. My thesis comprises six publications. Visual cortex forms a great challenge for modeling of neuromagnetic sources. My work shows that a priori information of source locations are needed for modeling of neuromagnetic sources in visual cortex. In addition, my work examines other potential confounding factors in vision studies such as light scatter inside the eye which may result in erroneous responses in cortex outside the representation of stimulated region, and eye movements and attention. I mapped cortical representations of peripheral visual field and identified a putative human homologue of functional area V6 of the macaque in the posterior bank of parieto-occipital sulcus. My work shows that human V6 activates during eye-movements and that it responds to visual motion at short latencies. These findings suggest that human V6, like its monkey homologue, is related to fast processing of visual stimuli and visually guided movements. I demonstrate that peripheral vision is functionally related to eye-movements and connected to rapid stream of functional areas that process visual motion. In addition, my work shows two different forms of top-down modulation of neural processing in the hierachically lowest cortical levels; one that is related to dorsal stream activation and may reflect motor processing or resetting signals that prepare visual cortex for change in the environment and another local signal enhancement at the attended region that reflects local feed-back signal and may perceptionally increase the stimulus saliency.

Reduced visual function and its association with physical functioning in the Finnish adult population : Prevalence, causes, and need for eye care services

The purpose of this study was to estimate the prevalence and distribution of reduced visual acuity, major chronic eye diseases, and subsequent need for eye care services in the Finnish adult population comprising persons aged 30 years and older. In addition, we analyzed the effect of decreased vision on functioning and need for assistance using the World Health Organization’s (WHO) International Classification of Functioning, Disability, and Health (ICF) as a framework. The study was based on the Health 2000 health examination survey, a nationally representative population-based comprehensive survey of health and functional capacity carried out in 2000 to 2001 in Finland. The study sample representing the Finnish population aged 30 years and older was drawn by a two-stage stratified cluster sampling. The Health 2000 survey included a home interview and a comprehensive health examination conducted at a nearby screening center. If the invited participants did not attend, an abridged examination was conducted at home or in an institution. Based on our finding in participants, the great majority (96%) of Finnish adults had at least moderate visual acuity (VA ≥ 0.5) with current refraction correction, if any. However, in the age group 75–84 years the prevalence decreased to 81%, and after 85 years to 46%. In the population aged 30 years and older, the prevalence of habitual visual impairment (VA ≤ 0.25) was 1.6%, and 0.5% were blind (VA < 0.1). The prevalence of visual impairment increased significantly with age (p < 0.001), and after the age of 65 years the increase was sharp. Visual impairment was equally common for both sexes (OR 1.20, 95% CI 0.82 – 1.74). Based on self-reported and/or register-based data, the estimated total prevalences of cataract, glaucoma, age-related maculopathy (ARM), and diabetic retinopathy (DR) in the study population were 10%, 5%, 4%, and 1%, respectively. The prevalence of all of these chronic eye diseases increased with age (p < 0.001). Cataract and glaucoma were more common in women than in men (OR 1.55, 95% CI 1.26 – 1.91 and OR 1.57, 95% CI 1.24 – 1.98, respectively). The most prevalent eye diseases in people with visual impairment (VA ≤ 0.25) were ARM (37%), unoperated cataract (27%), glaucoma (22%), and DR (7%). One-half (58%) of visually impaired people had had a vision examination during the past five years, and 79% had received some vision rehabilitation services, mainly in the form of spectacles (70%). Only one-third (31%) had received formal low vision rehabilitation (i.e., fitting of low vision aids, receiving patient education, training for orientation and mobility, training for activities of daily living (ADL), or consultation with a social worker). People with low vision (VA 0.1 – 0.25) were less likely to have received formal low vision rehabilitation, magnifying glasses, or other low vision aids than blind people (VA < 0.1). Furthermore, low cognitive capacity and living in an institution were associated with limited use of vision rehabilitation services. Of the visually impaired living in the community, 71% reported a need for assistance and 24% had an unmet need for assistance in everyday activities. Prevalence of ADL, instrumental activities of daily living (IADL), and mobility increased with decreasing VA (p < 0.001). Visually impaired persons (VA ≤ 0.25) were four times more likely to have ADL disabilities than those with good VA (VA ≥ 0.8) after adjustment for sociodemographic and behavioral factors and chronic conditions (OR 4.36, 95% CI 2.44 – 7.78). Limitations in IADL and measured mobility were five times as likely (OR 4.82, 95% CI 2.38 – 9.76 and OR 5.37, 95% CI 2.44 – 7.78, respectively) and self-reported mobility limitations were three times as likely (OR 3.07, 95% CI 1.67 – 9.63) as in persons with good VA. The high prevalence of age-related eye diseases and subsequent visual impairment in the fastest growing segment of the population will result in a substantial increase in the demand for eye care services in the future. Many of the visually impaired, especially older persons with decreased cognitive capacity or living in an institution, have not had a recent vision examination and lack adequate low vision rehabilitation. This highlights the need for regular evaluation of visual function in the elderly and an active dissemination of information about rehabilitation services. Decreased VA is strongly associated with functional limitations, and even a slight decrease in VA was found to be associated with limited functioning. Thus, continuous efforts are needed to identify and treat eye diseases to maintain patients’ quality of life and to alleviate the social and economic burden of serious eye diseases.

Consumers and the conceptual and practical appropriation of functional foods

Taking the appropriation of objects as a theoretical starting point, this study makes a distinction between a conceptual and practical level of adopting new objects and products in everyday life. The study applies the concept of appropriation in social food research and examines consumers appropriation of functional foods, i.e., foods developed to improve health and well-being or reduce the risk of disease beyond the usual nutritional effects of foods. The study uses the concept of appropriation to understand the adoption and the process of making functional foods our own . First, the study focuses on the conceptual appropriation by analysing consumers interpretations and opinions on functional foods. Second, it analyses the use of functional foods and examines the role of sociodemographic and food- and health-related background factors in the use of functional foods. Both quantitative and qualitative data were used in the study. Altogether 1210 Finns representative of the population took part in a survey carried out in 2002 as computer-assisted telephone interviews (CATI). The survey examined the acceptability and use of functional foods in Finland. In 2004, eight focus group discussions were organised for 45 users and non-users of cholesterol-lowering spreads. The qualitative study focused on consumers interpretative perspectives on healthy eating and functional foods. The findings are reported in four original articles and a summary article. The results show that the appropriation of functional foods is a multifaceted phenomenon. The conceptual appropriation is related to consumers interpretations of functional foods in the context of healthy foods and healthy eating; their trust in the products, their manufacturers, research and control; and the relationship of functional foods and the ideal of natural foods. The analysis of the practical appropriation of four different types of foods marketed as functional showed that there are sociodemographic differences between users and non-users of the products, but more importantly, the differences are related to consumers food- and health-related views and practices. Consumers ways of appropriating functional foods in the conceptual and practical sense take shape in a complex web of ideas and everyday practices concerning food, health and eating as a whole. The results also indicate that the conceptual and practical appropriation are not necessarily uniform or coherent processes. Consumers interpret healthy eating and functional foods from a variety of perspectives and there is a multiplicity of rationales of using functional foods. Appropriation embraces many opposing dimensions simultaneously: good experiences and doubts, approval and criticism, expectations and things taken for granted.

Functional and work disability and treatment received by patients with major depressive disorder

This study is one part of a collaborative depression research project, the Vantaa Depression Study (VDS), involving the Department of Mental and Alcohol Research of the National Public Health Institute, Helsinki, and the Department of Psychiatry of the Peijas Medical Care District (PMCD), Vantaa, Finland. The VDS includes two parts, a record-based study consisting of 803 patients, and a prospective, naturalistic cohort study of 269 patients. Both studies include secondary-level care psychiatric out- and inpatients with a new episode of major depressive disorder (MDD). Data for the record-based part of the study came from a computerised patient database incorporating all outpatient visits as well as treatment periods at the inpatient unit. We included all patients aged 20 to 59 years old who had been assigned a clinical diagnosis of depressive episode or recurrent depressive disorder according to the International Classification of Diseases, 10th edition (ICD-10) criteria and who had at least one outpatient visit or day as an inpatient in the PMCD during the study period January 1, 1996, to December 31, 1996. All those with an earlier diagnosis of schizophrenia, other non-affective psychosis, or bipolar disorder were excluded. Patients treated in the somatic departments of Peijas Hospital and those who had consulted but not received treatment from the psychiatric consultation services were excluded. The study sample comprised 290 male and 513 female patients. All their psychiatric records were reviewed and each patient completed a structured form with 57 items. The treatment provided was reviewed up to the end of the depression episode or to the end of 1997. Most (84%) of the patients received antidepressants, including a minority (11%) on treatment with clearly subtherapeutic low doses. During the treatment period the depressed patients investigated averaged only a few visits to psychiatrists (median two visits), but more to other health professionals (median seven). One-fifth of both genders were inpatients, with a mean of nearly two inpatient treatment periods during the overall treatment period investigated. The median length of a hospital stay was 2 weeks. Use of antidepressants was quite conservative: The first antidepressant had been switched to another compound in only about one-fifth (22%) of patients, and only two patients had received up to five antidepressant trials. Only 7% of those prescribed any antidepressant received two antidepressants simultaneously. None of the patients was prescribed any other augmentation medication. Refusing antidepressant treatment was the most common explanation for receiving no antidepressants. During the treatment period, 19% of those not already receiving a disability pension were granted one due to psychiatric illness. These patients were nearly nine years older than those not pensioned. They were also more severely ill, made significantly more visits to professionals and received significantly more concomitant medications (hypnotics, anxiolytics, and neuroleptics) than did those receiving no pension. In the prospective part of the VDS, 806 adult patients were screened (aged 20-59 years) in the PMCD for a possible new episode of DSM-IV MDD. Of these, 542 patients were interviewed face-to-face with the WHO Schedules for Clinical Assessment in Neuropsychiatry (SCAN), Version 2.0. Exclusion criteria were the same as in the record-based part of the VDS. Of these, 542 269 patients fulfiled the criteria of DSM-IV MDE. This study investigated factors associated with patients' functional disability, social adjustment, and work disability (being on sick-leave or being granted a disability pension). In the beginning of the treatment the most important single factor associated with overall social and functional disability was found to be severity of depression, but older age and personality disorders also significantly contributed. Total duration and severity of depression, phobic disorders, alcoholism, and personality disorders all independently contributed to poor social adjustment. Of those who were employed, almost half (43%) were on sick-leave. Besides severity and number of episodes of depression, female gender and age over 50 years strongly and independently predicted being on sick-leave. Factors influencing social and occupational disability and social adjustment among patients with MDD were studied prospectively during an 18-month follow-up period. Patients' functional disability and social adjustment were alleviated during the follow-up concurrently with recovery from depression. The current level of functioning and social adjustment of a patient with depression was predicted by severity of depression, recurrence before baseline and during follow-up, lack of full remission, and time spent depressed. Comorbid psychiatric disorders, personality traits (neuroticism), and perceived social support also had a significant influence. During the 18-month follow-up period, of the 269, 13 (5%) patients switched to bipolar disorder, and 58 (20%) dropped out. Of the 198, 186 (94%) patients were at baseline not pensioned, and they were investigated. Of them, 21 were granted a disability pension during the follow-up. Those who received a pension were significantly older, more seldom had vocational education, and were more often on sick-leave than those not pensioned, but did not differ with regard to any other sociodemographic or clinical factors. Patients with MDD received mostly adequate antidepressant treatment, but problems existed in treatment intensity and monitoring. It is challenging to find those at greatest risk for disability and to provide them adequate and efficacious treatment. This includes great challenges to the whole society to provide sufficient resources.

Social and material deprivation among youth in Finland : causes, consequences, and coping.

Background: Social and material deprivation is associated with poor health, decreased subjective well-being, and limited opportunities for personal development. To date, little is known about the lived experiences of Finnish low-income youths and the general purpose of this study is to fill this gap. Despite the extensive research on socioeconomic income disparities, only a few scholars have addressed the question of how low socioeconomic position is experienced by disadvantaged people themselves. Little is known about the everyday social processes that lead to decreased well-being of economically and socially disadvantaged citizens. Data: The study is based on the data of 65 autobiographical essays written by Finnish low-income youths aged 14-29 (M=23.51, SD=3.95). The research data were originally collected in a Finnish nationwide writing contest “Arkipäivän kokemuksia köyhyydestä” [Everyday Experiences of Poverty] between June and September of 2006. The contest was partaken by 850 Finnish writers. Methods and key concepts: Autobiographical narratives (N=65) of low-income youths were analyzed based on grounded theory methodology (GTM). The analysis was not built on specific pre-conceived categorizations; it was guided by the paradigm model and so-called “sensitizing concepts”. The concepts this study utilized were based on the research literature on socioeconomic inequalities, resilience, and coping. Socioeconomic inequalities refer to unequal distribution of resources, such as income, social status, and health, between social groups. The concept of resilience refers to an individual’s capacity to cope despite existing risk factors and conditions that are harmful to health and well-being. Coping strategies can be understood as ways by which a person tries to cope with psychological stress in a situation where internal or externals demands exceed one’s resources. The ways to cope are cognitive or behavioral efforts by which individual tries to relieve the stress and gain new resources. Lack of material and social resources is associated with increased exposure to health-related stressors during the life-course. Aims: The first aim of this study is to illustrate how youths with low socioeconomic status perceive the causes and consequences of their social and material deprivation. The second aim is to describe what kind of coping strategies youths employ to cope in their everyday life. The third aim is to build an integrative conceptual framework based on the relationships between causes, consequences, and individual coping strategies associated with deprivation. The analysis was carried out through systematic coding and orderly treatment of the data based on the grounded theory methodology. Results: Finnish low-income youths attributed the primary causes of deprivation to their family background, current socioeconomic status, sudden life changes, and contextual factors. Material and social deprivation was associated with various kinds of negative psychological, social, and material consequences. Youths used a variety of coping strategies that were identified as psychological, social, material, and functional-behavioral. Finally, a conceptual framework was formulated to link the findings together. In the discussion, the results were compared and contrasted to the existing research literature. The main references of the study were: Coping: Aldwin (2007); Lazarus & Folkman (1984); Hobfoll (1989, 2001, 2002). Deprivation: Larivaara, Isola, & Mikkonen (2007); Lister (2004); Townsend (1987); Raphael (2007). Health inequalities: Dahlgren & Whitehead (2007); Lynch. et al. (2000); Marmot & Wilkinson (2006); WHO (2008). Methods: Charmaz (2006); Flick (2009); Strauss & Corbin (1990). Resilience: Cutuli & Masten (2009); Luthar (2006).

Linguistic and perceptual processing of communicative cues in Asperger Syndrome

Asperger Syndrome (AS) belongs to autism spectrum disorders where both verbal and non-verbal communication difficulties are at the core of the impairment. Social communication requires a complex use of affective, linguistic-cognitive and perceptual processes. In the four studies included in the current thesis, some of the linguistic and perceptual factors that are important for face-to-face communication were studied using behavioural methods. In all four studies the results obtained from individuals with AS were compared with typically developed age, gender and IQ matched controls. First, the language skills of school-aged children were characterized in detail with standardized tests that measured different aspects of receptive and expressive language (Study I). The children with AS were found to be worse than the controls in following complex verbal instructions. Next, the visual perception of facial expressions of emotion with varying degrees of visual detail was examined (Study II). Adults with AS were found to have impaired recognition of facial expressions on the basis of very low spatial frequencies which are important for processing global information. Following that, multisensory perception was investigated by looking at audiovisual speech perception (Studies III and IV). Adults with AS were found to perceive audiovisual speech qualitatively differently from typically developed adults, although both groups were equally accurate in recognizing auditory and visual speech presented alone. Finally, the effect of attention on audiovisual speech perception was studied by registering eye gaze behaviour (Study III) and by studying the voluntary control of visual attention (Study IV). The groups did not differ in eye gaze behaviour or in the voluntary control of visual attention. The results of the study series demonstrate that many factors underpinning face-to-face social communication are atypical in AS. In contrast with previous assumptions about intact language abilities, the current results show that children with AS have difficulties in understanding complex verbal instructions. Furthermore, the study makes clear that deviations in the perception of global features in faces expressing emotions as well as in the multisensory perception of speech are likely to harm face-to-face social communication.