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Objectives. Sign languages are perceived and produced by different modalities compared to spoken languages. This has lead to different viewpoints regarding the status of sign languages: are they human languages at all or are they fully comparable to spoken languages? Modality differences have been an interesting topic in the research of the brain mechanisms of sign languages. For spoken languages, the brain mechanisms are mainly based on the left hemisphere and especially on its perisylvian areas. Particularly the role of the left posterior superior temporal sulcus and the left inferior frontal gyrus have been researched. In this review the similarities and differences between the brain mechanisms of sign language and spoken language are discussed based on the current research. Methods. The method of this review was literature review. The studies and books were found from Google Scholar and Helka Finna using, for example, search term sign language brain. Some references for the introduction were searched also from Google. In addition, the suggestion and citation functions were used in Google Scholar, and articles were discovered also by conducting a manual search from the reference lists of the found studies. Results and conclusions. In the studies on the brain mechanisms of sign language it was consistently found that similarly to spoken language, the processing of sign language is mainly based on the left hemisphere and especially on its perisylvian areas. The left inferior frontal gyrus was engaged in production of both spoken and signed languages. In comprehension, the left superior temporal sulcus, the left superior temporal gyrus and the left inferior frontal gyrus were engaged. Results suggested that auditory cortex in the temporal lobe is a constituent part of brain mechanisms despite that sign languages are not perceived auditorily. On the other hand, the relevance of the visuospatial component for the brain mechanisms of sign language was noted in the studies and it was observed that sign language was perceived more bilaterally than spoken language. The more spatial processing was required, the more the activation in the right hemisphere and in the parietal lobes increased. More research is needed about the distinction and overlap of sign language and gesture. Also, the role of the basal ganglia should be studied more in languages of different modalities. The similarities between the brain mechanisms of sign language and spoken language suggest that language is not just a bunch of sensomotor mechanisms but has a deeper neural function in the brain.

Visual working memory is a cognitive system that is responsible of short term storage and manipulation of visual information. Working memory is divided to memorising, storage and recalling of the stimulus. This review concentrates in visual working memory studies that used functional magnetic resonance imaging (fMRI). FMRI is a spatially accurate and is based on changes in the brains blood circulation. The data from fMRI can be analysed with univariate or multivariate methods. These methods answer different research problems because of their different premises. The premise of univariate analysis is that the neural activation in one part of the brain is directly related to its function. In multivariate analysis, the neural activation is approached by observing the activations distribution, which means that different activation distributions in same parts of the brain can be related to different processes. The visual areas of the brain are located in the occipital lobe but, before multivariate analysis, the visual working memory has been associated with prefrontal cortex. After multivariate pattern analysis (MVPA) has increased in popularity the hypothesis, that visual areas have a part in visual working memory, has also generalised. Because of the activation distribution premise, the MVPA is a more sensitive method to analyse fMRI data. Still there have been different results in different MVPA using studies. Different memory tasks might also be partly responsible of different results. A visual working memory task always activates prefrontal and parietal cortices in addition to sensory cortex. Visual cortex seems to have the principal part and prefrontal and parietal cortices take part most likely in executive functions but they can’t be ruled out from storage either.

Depression during adolescence is a significant problem. Depression causes harm to adolescents and it is associated with many negative outcomes, including academic problems, impaired social relationships, substance abuse, mental health problems and suicide. Thus, prevention of adolescent depression is extremely important and many prevention programs have been developed to do so. The purpose of current thesis is to examine the effectiveness and applicability of cognitive-behavioral prevention programs for adolescent depression. Prevention programs are classified into three categories on basis of the populations to whom the interventions are directed. Universal programs are provided to all members of a target population, selective programs are targeted to individuals at elevated risk for depression, and indicative programs are provided to individuals who manifest subclinical depression symptoms. These programs differ in their effectiveness in depression prevention and in their applicability. Universal programs are more applicable and more inexpensive than selective or indicative programs. According to the existing findings, selective and indicative programs seem to be more effective in preventing depression in adolescence than universal programs and selective and indicative programs seem to be as effective. Longer programs and programs that have older adolescents and more female participants, seem to be more effective in preventing depression. The most common limitations of studies so far are the relatively short follow-ups. In future there is a need for longer follow-ups and more longitudinal studies.

Objective. Today almost everyone has access to the internet and thus the incidence of internet-related mental problems has also increased. Youth and young adults in particular are at risk for experiencing these problems because they use the internet more compared to the rest of the population. Loneliness is common among young people and they often gravitate toward the internet to alleviate their feelings of loneliness. This type of internet usage can be problematic, meaning that it is pathological, compulsive and harmful to the user. The objective of this review is to examine the association between loneliness and problematic internet use among youth and young adults. Methods. The studies that were included in this review were as recently published as possible and examined the association between loneliness or related experiences and problematic internet or Facebook use among youth and young adults. Keywords that were used to search for the studies were loneliness, problematic internet use, internet addiction, problematic facebook use, youth and young adults. The search was carried out utilizing the Google Scholar search engine. Results and conclusions. Based on this review there is a positive association of some magnitude between loneliness and problematic internet use. The association is likely bidirectional, meaning that problematic internet use causes feelings of loneliness and feelings of loneliness increase problematic internet use. In the future longitudinal studies are required to form a more thorough understanding of the phenomenon because loneliness and problematic internet use are both phenomena that develop relatively slowly over a long period of time. Problematic internet use as a phenomenon is diverse and appears to be widely connected to mental well-being, so understanding the causes behind it helps healthcare and educational institutions develop services to prevent it and its harmful effects.