Developmental, functional brain imaging and electrophysiological evidence of visual and auditory working memory

Intact function of working memory (WM) is essential for children and adults to cope with every day life. Children with deficits in WM mechanisms have learning difficulties that are often accompanied by behavioral problems. The neural processes subserving WM, and brain structures underlying this system, continue to develop during childhood till adolescence and young adulthood. With functional magnetic resonance imaging (fMRI) it is possible to investigate the organization and development of WM. The present thesis aimed to investigate, using behavioral and neuroimaging methods, whether mnemonic processing of spatial and nonspatial visual information is segregated in the developing and mature human brain. A further aim in this research was to investigate the organization and development of audiospatial and visuospatial information processing in WM. The behavioral results showed that spatial and nonspatial visual WM processing is segregated in the adult brain. The fMRI result in children suggested that memory load related processing of spatial and nonspatial visual information engages common cortical networks, whereas selective attention to either type of stimuli recruits partially segregated areas in the frontal, parietal and occipital cortices. Deactivation mechanisms that are important in the performance of WM tasks in adults are already operational in healthy school-aged children. Electrophysiological evidence suggested segregated mnemonic processing of visual and auditory location information. The results of the development of audiospatial and visuospatial WM demonstrate that WM performance improves with age, suggesting functional maturation of underlying cognitive processes and brain areas. The development of the performance of spatial WM tasks follows a different time course in boys and girls indicating a larger degree of immaturity in the male than female WM systems. Furthermore, the differences in mastering auditory and visual WM tasks may indicate that visual WM reaches functional maturity earlier than the corresponding auditory system. Spatial WM deficits may underlie some learning difficulties and behavioral problems related to impulsivity, difficulties in concentration, and hyperactivity. Alternatively, anxiety or depressive symptoms may affect WM function and the ability to concentrate, being thus the primary cause of poor academic achievement in children.

Task-dependent activations of human auditory cortex during pitch discrimination and pitch memory tasks

"The functional organization of auditory cortex (AC) is still poorly understood. Previous studies suggest segregation of auditory processing streams for spatial and nonspatial information located in the posterior and anterior AC, respectively (Rauschecker and Tian, 2000; Arnott et al., 2004; Lomber and Malhotra, 2008). Furthermore, previous studies have shown that active listening tasks strongly modulate AC activations (Petkov et al., 2004; Fritz et al., 2005; Polley et al., 2006). However, the task dependence of AC activations has not been systematically investigated. In the present study, we applied high-resolution functional magnetic resonance imaging of the AC and adjacent areas to compare activations during pitch discrimination and n-back pitch memory tasks that were varied parametrically in difficulty. We found that anterior AC activations were increased during discrimination but not during memory tasks, while activations in the inferior parietal lobule posterior to the AC were enhanced during memory tasks but not during discrimination. We also found that wide areas of the anterior AC and anterior insula were strongly deactivated during the pitch memory tasks. While these results are consistent with the proposition that the anterior and posterior AC belong to functionally separate auditory processing streams, our results show that this division is present also between tasks using spatially invariant sounds. Together, our results indicate that activations of human AC are strongly dependent on the characteristics of the behavioral task."

Principles of Pitch Organization in Béla Bartók's 'Duke Bluebeard's Castle'

The topic of my doctoral thesis is to demonstrate the usefulness of incorporating tonal and modal elements into a pitch-web square analysis of Béla Bartók's (1881-1945) opera, 'A kékszakállú herceg vára' ('Duke Bluebeard's Castle'). My specific goal is to demonstrate that different musical materials, which exist as foreground melodies or long-term key progressions, are unified by the unordered pitch set {0,1,4}, which becomes prominent in different sections of Bartók's opera. In Bluebeard's Castle, the set {0,1,4} is also found as a subset of several tetrachords: {0,1,4,7}, {0,1,4,8}, and {0,3,4,7}. My claim is that {0,1,4} serves to link music materials between themes, between sections, and also between scenes. This study develops an analytical method, drawn from various theoretical perspectives, for conceiving superposed diatonic spaces within a hybrid pitch-space comprised of diatonic and chromatic features. The integrity of diatonic melodic lines is retained, which allows for a non-reductive understanding of diatonic superposition, without appealing to pitch centers or specifying complete diatonic collections. Through combining various theoretical insights of the Hungarian scholar Ernő Lendvai, and the American theorists Elliott Antokoletz, Paul Wilson and Allen Forte, as well as the composer himself, this study gives a detailed analysis of the opera's pitch material in a way that combines, complements, and expands upon the studies of those scholars. The analyzed pitch sets are represented on Aarre Joutsenvirta's note-web square, which adds a new aspect to the field of Bartók analysis. Keywords: Bartók, Duke Bluebeard's Castle (Op. 11), Ernő Lendvai, axis system, Elliott Antokoletz, intervallic cycles, intervallic cells, Allen Forte, set theory, interval classes, interval vectors, Aarre Joutsenvirta, pitch-web square, pitch-web analysis.

Memory disorders in acute encephalitis : A neuropsychological study

Acute encephalitis is an inflammation of the brain, mostly caused by viral infection. A variety of cognitive symptoms may persist after the acute stage, and neuropsychological assessment is crucial in evaluation of the outcome. The most commonly reported sequelae are memory deficits. The main aims of this study were to investigate the types of memory impairment in various encephalitides, the frequency of global amnesia following encephalitis, and the changes in the deficits during follow-up. Between 1 January 1985 and 31 December 1994, 77 adult patients under the age of 75 with acute encephalitis but without alcohol abuse, or coexisting or previous neurological diseases were consecutively referred for neuropsychological examination at the Department of Neurology, Helsinki University Central Hospital. The aetiology was established in 44/77 (57%) patients; 17 had Herpes simplex virus encephalitis (HSVE). Transient amnesia (TENA) at the acute stage of the disease was found in 70% of patients. Furthermore, similarly to brain trauma, TENA was found to indicate cognitive outcome. The frequency of persisting global amnesia syndrome with both anterograde and retrograde amnesia in all encephalitic patients was 6%. One patient had isolated retrograde amnesia, which is very rare. In HSVE the frequency of global amnesia was 12.5%, which is lower than expected. As a group, HSVE patients were not found to have a homogeneous pattern of amnesia, instead subgroups among all encephalitic patients were observed: some patients had impaired semantic memory, some had difficulty predominantly with executive functions and some suffered from an increased forgetting rate. Herpes zoster encephalitis was found to result in mild memory impairment only, and the qualitative features indicated a subcortical dysfunction. On the whole, the cognitive deficits were predominantly found to diminish during follow-up. Progressive deterioration was often associated with intractable epilepsy. The frequency of dementia was 12.5%. In conclusion, the neuropsychological outcome, especially in HSVE, was more favourable than has previously been reported, possibly due to early acyclovir medication. Memory disorders after encephalitis should not be considered uniform, and the need for neuropsychological rehabilitation should be considered case-by-case

Studies of working memory in interrupted human-computer interaction

Distraction in the workplace is increasingly more common in the information age. Several tasks and sources of information compete for a worker's limited cognitive capacities in human-computer interaction (HCI). In some situations even very brief interruptions can have detrimental effects on memory. Nevertheless, in other situations where persons are continuously interrupted, virtually no interruption costs emerge. This dissertation attempts to reveal the mental conditions and causalities differentiating the two outcomes. The explanation, building on the theory of long-term working memory (LTWM; Ericsson and Kintsch, 1995), focuses on the active, skillful aspects of human cognition that enable the storage of task information beyond the temporary and unstable storage provided by short-term working memory (STWM). Its key postulate is called a retrieval structure an abstract, hierarchical knowledge representation built into long-term memory that can be utilized to encode, update, and retrieve products of cognitive processes carried out during skilled task performance. If certain criteria of practice and task processing are met, LTWM allows for the storage of large representations for long time periods, yet these representations can be accessed with the accuracy, reliability, and speed typical of STWM. The main thesis of the dissertation is that the ability to endure interruptions depends on the efficiency in which LTWM can be recruited for maintaing information. An observational study and a field experiment provide ecological evidence for this thesis. Mobile users were found to be able to carry out heavy interleaving and sequencing of tasks while interacting, and they exhibited several intricate time-sharing strategies to orchestrate interruptions in a way sensitive to both external and internal demands. Interruptions are inevitable, because they arise as natural consequences of the top-down and bottom-up control of multitasking. In this process the function of LTWM is to keep some representations ready for reactivation and others in a more passive state to prevent interference. The psychological reality of the main thesis received confirmatory evidence in a series of laboratory experiments. They indicate that after encoding into LTWM, task representations are safeguarded from interruptions, regardless of their intensity, complexity, or pacing. However, when LTWM cannot be deployed, the problems posed by interference in long-term memory and the limited capacity of the STWM surface. A major contribution of the dissertation is the analysis of when users must resort to poorer maintenance strategies, like temporal cues and STWM-based rehearsal. First, one experiment showed that task orientations can be associated with radically different patterns of retrieval cue encodings. Thus the nature of the processing of the interface determines which features will be available as retrieval cues and which must be maintained by other means. In another study it was demonstrated that if the speed of encoding into LTWM, a skill-dependent parameter, is slower than the processing speed allowed for by the task, interruption costs emerge. Contrary to the predictions of competing theories, these costs turned out to involve intrusions in addition to omissions. Finally, it was learned that in rapid visually oriented interaction, perceptual-procedural expectations guide task resumption, and neither STWM nor LTWM are utilized due to the fact that access is too slow. These findings imply a change in thinking about the design of interfaces. Several novel principles of design are presented, basing on the idea of supporting the deployment of LTWM in the main task.

Oscillatory brain activity in memory disorders

Neuronal oscillations are thought to underlie interactions between distinct brain regions required for normal memory functioning. This study aimed at elucidating the neuronal basis of memory abnormalities in neurodegenerative disorders. Magnetoencephalography (MEG) was used to measure oscillatory brain signals in patients with Alzheimer s disease (AD), a neurodegenerative disease causing progressive cognitive decline, and mild cognitive impairment (MCI), a disorder characterized by mild but clinically significant complaints of memory loss without apparent impairment in other cognitive domains. Furthermore, to help interpret our AD/MCI results and to develop more powerful oscillatory MEG paradigms for clinical memory studies, oscillatory neuronal activity underlying declarative memory, the function which is afflicted first in both AD and MCI, was investigated in a group of healthy subjects. An increased temporal-lobe contribution coinciding with parieto-occipital deficits in oscillatory activity was observed in AD patients: sources in the 6 12.5 Hz range were significantly stronger in the parieto-occipital and significantly weaker in the right temporal region in AD patients, as compared to MCI patients and healthy elderly subjects. Further, the auditory steady-state response, thought to represent both evoked and induced activity, was enhanced in AD patients, as compared to controls, possibly reflecting decreased inhibition in auditory processing and deficits in adaptation to repetitive stimulation with low relevance. Finally, the methodological study revealed that successful declarative encoding and retrieval is associated with increases in occipital gamma and right hemisphere theta power in healthy unmedicated subjects. This result suggests that investigation of neuronal oscillations during cognitive performance could potentially be used to investigate declarative memory deficits in AD patients. Taken together, the present results provide an insight on the role of brain oscillatory activity in memory function and memory disorders.

Human brain networks of auditory attention and working memory

This thesis examines brain networks involved in auditory attention and auditory working memory using measures of task performance, brain activity, and neuroanatomical connectivity. Auditory orienting and maintenance of attention were compared with visual orienting and maintenance of attention, and top-down controlled attention was compared to bottom-up triggered attention in audition. Moreover, the effects of cognitive load on performance and brain activity were studied using an auditory working memory task. Corbetta and Shulman s (2002) model of visual attention suggests that what is known as the dorsal attention system (intraparietal sulcus/superior parietal lobule, IPS/SPL and frontal eye field, FEF) is involved in the control of top-down controlled attention, whereas what is known as the ventral attention system (temporo-parietal junction, TPJ and areas of the inferior/middle frontal gyrus, IFG/MFG) is involved in bottom-up triggered attention. The present results show that top-down controlled auditory attention also activates IPS/SPL and FEF. Furthermore, in audition, TPJ and IFG/MFG were activated not only by bottom-up triggered attention, but also by top-down controlled attention. In addition, the posterior cerebellum and thalamus were activated by top-down controlled attention shifts and the ventromedial prefrontal cortex (VMPFC) was activated by to-be-ignored, but attention-catching salient changes in auditory input streams. VMPFC may be involved in the evaluation of environmental events causing the bottom-up triggered engagement of attention. Auditory working memory activated a brain network that largely overlapped with the one activated by top-down controlled attention. The present results also provide further evidence of the role of the cerebellum in cognitive processing: During auditory working memory tasks, both activity in the posterior cerebellum (the crus I/II) and reaction speed increased when the cognitive load increased. Based on the present results and earlier theories on the role of the cerebellum in cognitive processing, the function of the posterior cerebellum in cognitive tasks may be related to the optimization of response speed.

Boundaries in Action : An Activity-theoretical Study of Development, Learning, and Change in Health Care Organization for Patients with Multiple and Chronic Illnesses

This study examines boundaries in health care organizations. Boundaries are sometimes considered things to be avoided in everyday living. This study suggests that boundaries can be important temporally and spatially emerging locations of development, learning, and change in inter-organizational activity. Boundaries can act as mediators of cultural and social formations and practices. The data of the study was gathered in an intervention project during the years 2000-2002 in Helsinki in which the care of 26 patients with multiple and chronic illnesses was improved. The project used the Change Laboratory method that represents a research assisted method for developing work. The research questions of the study are: (1) What are the boundary dynamics of development, learning, and change in health care for patients with multiple and chronic illnesses? (2) How do individual patients experience boundaries in their health care? (3) How are the boundaries of health care constructed and reconstructed in social interaction? (4) What are the dynamics of boundary crossing in the experimentation with the new tools and new practice? The methodology of the study, the ethnography of the multi-organizational field of activity, draws on cultural-historical activity theory and anthropological methods. The ethnographic fieldwork involves multiple research techniques and a collaborative strategy for raising research data. The data of this study consists of observations, interviews, transcribed intervention sessions, and patients' health documents. According to the findings, the care of patients with multiple and chronic illnesses emerges as fragmented by divisions of a patient and professionals, specialties of medicine and levels of health care organization. These boundaries have a historical origin in the Finnish health care system. As an implication of these boundaries, patients frequently experience uncertainty and neglect in their care. However, the boundaries of a single patient were transformed in the Change Laboratory discussions among patients, professionals and researchers. In these discussions, the questioning of the prevailing boundaries was triggered by the observation of gaps in inter-organizational care. Transformation of the prevailing boundaries was achieved in implementation of the collaborative care agreement tool and the practice of negotiated care. However, the new tool and practice did not expand into general use during the project. The study identifies two complementary models for the development of health care organization in Finland. The 'care package model', which is based on productivity and process models adopted from engineering and the 'model of negotiated care', which is based on co-configuration and the public good.

The Neurofibromatosis 2 tumor suppressor merlin in cytoskeleton organization and cell cycle regulation

Neurofibromatosis 2 (NF2) is a dominantly inherited disorder, which predisposes to multiple tumours of the nervous system, typically schwannomas and meningiomas. Biallelic inactivation of the NF2 gene occurs both in sporadic and NF2-related schwannomas and in most meningiomas. The NF2 gene product merlin (or schwannomin) is structurally related to the ERM proteins, ezrin, radixin and moesin, which act as molecular linkers between the actin cytoskeleton and the plasma membrane. Merlin is a tumor suppressor that participates in cell cycle regulation. Merlin s phosphorylation status appears to be associated with its tumour suppressor activity, i.e. non-phosphorylated merlin functions as a tumour suppressor, whereas protein phosphorylation results in loss of functional activity. This thesis study was initiated to investigate merlin s role as a tumor suppressor and growth inhibitor. These studies show, that like many other tumor suppressors, also merlin is targeted to the nucleus at some stages of the cell cycle. Merlin s nuclear localization is regulated by cell cycle phase, contact inhibition and adhesion. In addition, a potential nuclear binding partner for merlin was identified, Human Enhancer of Invasion 10 (HEI10), a cyclin B interacting protein. Many tumor suppressors interact with microtubules and this thesis work shows that also merlin colocalizes with microtubules in mitotic structures. Merlin binds microtubules directly, and increases their polymerization in vitro and in vivo. In addition, primary mouse Schwann cells lacking merlin displays disturbed microtubule cytoskeleton. Fourth part of this thesis work began from the notion that PKA phosphorylates an unidentified site from the merlin N-terminus. Our studies show that serine 10 is a target for PKA and modulation of this residue regulates cytoskeletal organization, lamellipodia formation and cell migration. In summary, this thesis work shows that merlin s role is much more versatile than previously thought. It has a yet unidentified role in the nucleus and it participates in the regulation of both microtubules and the actin cytoskeleton. These studies have led to a better understanding of this enigmatic tumor suppressor, which eventually will aid in the design of specific drugs for the NF2 disease.

Middleware for Mobile Sensing Applications in Urban Environments

Sensor networks represent an attractive tool to observe the physical world. Networks of tiny sensors can be used to detect a fire in a forest, to monitor the level of pollution in a river, or to check on the structural integrity of a bridge. Application-specific deployments of static-sensor networks have been widely investigated. Commonly, these networks involve a centralized data-collection point and no sharing of data outside the organization that owns it. Although this approach can accommodate many application scenarios, it significantly deviates from the pervasive computing vision of ubiquitous sensing where user applications seamlessly access anytime, anywhere data produced by sensors embedded in the surroundings. With the ubiquity and ever-increasing capabilities of mobile devices, urban environments can help give substance to the ubiquitous sensing vision through Urbanets, spontaneously created urban networks. Urbanets consist of mobile multi-sensor devices, such as smart phones and vehicular systems, public sensor networks deployed by municipalities, and individual sensors incorporated in buildings, roads, or daily artifacts. My thesis is that "multi-sensor mobile devices can be successfully programmed to become the underpinning elements of an open, infrastructure-less, distributed sensing platform that can bring sensor data out of their traditional close-loop networks into everyday urban applications". Urbanets can support a variety of services ranging from emergency and surveillance to tourist guidance and entertainment. For instance, cars can be used to provide traffic information services to alert drivers to upcoming traffic jams, and phones to provide shopping recommender services to inform users of special offers at the mall. Urbanets cannot be programmed using traditional distributed computing models, which assume underlying networks with functionally homogeneous nodes, stable configurations, and known delays. Conversely, Urbanets have functionally heterogeneous nodes, volatile configurations, and unknown delays. Instead, solutions developed for sensor networks and mobile ad hoc networks can be leveraged to provide novel architectures that address Urbanet-specific requirements, while providing useful abstractions that hide the network complexity from the programmer. This dissertation presents two middleware architectures that can support mobile sensing applications in Urbanets. Contory offers a declarative programming model that views Urbanets as a distributed sensor database and exposes an SQL-like interface to developers. Context-aware Migratory Services provides a client-server paradigm, where services are capable of migrating to different nodes in the network in order to maintain a continuous and semantically correct interaction with clients. Compared to previous approaches to supporting mobile sensing urban applications, our architectures are entirely distributed and do not assume constant availability of Internet connectivity. In addition, they allow on-demand collection of sensor data with the accuracy and at the frequency required by every application. These architectures have been implemented in Java and tested on smart phones. They have proved successful in supporting several prototype applications and experimental results obtained in ad hoc networks of phones have demonstrated their feasibility with reasonable performance in terms of latency, memory, and energy consumption.

Rukous on perintöä suvusta sukuun : Ikääntyneet ja uskonto vuosituhannen vaihteen Suomessa

"Prayer, a heritage from generation to generation" The elderly and religion in Finland at the turn of the 21st century The strong demographic changes in Europe mean that research on the elderly is highly needed, and also from the viewpoint of their resources and opportunities. Further, it is important to determine, how the elderly could find a meaningful place as members of the chain of generations in our rapidly changing society. The aim of this study was to find out how the elderly build and perceive their place in the society through religious texts. The study was based on religious texts written by elderly people in the study groups of the Finnish pensioners organization Pension Union (Eläkeliitto). These 943 short prayers, poems, and aphorisms were collected during the Tree of Life (Elämänpuu) project in 1998-1999 and were then analysed applying qualitative content analysis and grounded theory methodology. The social construction of aging and the view of communication as a collective signifying process were used as the mainstays of the research perspective. The themes brought forward by the elderly writers were grouped around three key themes: the self, the world and religion. In this examination religion with its forms of expression appeared to be deeply rooted to each of these themes and thus seems a vital part of the elderly writers' culture. In connection with the theme of the self, the religious forms of expression provided a means of building a coherent and culturally accepted self-image which is further supported by positive views of personal history and current life situation. In relation to the world theme, the elderly writers stressed the importance of close social relationships and at the same time expressed anxiety with regard to the changing world. Concerning the theme of religion, the religious forms of expression were first and foremost used in building and creating a sense of personal safety and a belief in the future. The study suggests that skill in the use of religious language enable the elderly to cope with equivocal life events and cognitive dissonance. At the social level the religious forms of expression seemed to connect the writers to the Finnish linguistic culture and identity, as well as to the collective memory, where religion plays a central part. By using religious language the elderly both exploit and maintain these considerable social resources. The key result of the study is that the elderly were found to have a significant and separate role in the continuity and well-being of society. Bound to the religious tradition, the elderly seem to carry significant information as regards the identity of the Finnish people, information which is essentially passed on to future generations. By sustaining traditions and thus the collective identity, they perform a uniquely productive task and their life experience could be seen as a particular type of capital in the society. This result also raises a grave question: Will the elderly of the future be able to undertake this task that so profoundly requires religious literacy?

Memory Meanders : Place, Home and Commemoration in an Ex-Rhodesian Diaspora Community

Memory Meanders is an ethnographic analysis of a postcolonial migrant community, white former Rhodesians, who have emigrated from Zimbabwe to South Africa after Zimbabwe s independence in 1980. An estimated 100 000 whites left the country during the first years of independence. Majority of these emigrants settled in South Africa. In recent years President Mugabe s land redistribution program has inflicted forced expulsions and violence against white farmers and black farm workers, and instigated a new wave of emigration. Concerning the study of Southern Africa, my research is therefore very topical. In recent years there has been a growing concern to study postcolonialism as it unfolds in the lived realities of actual postcolonies. A rising interest has also been cast on colonial cultures and white colonials within complex power relationships. My research offers insight to these discussions by investigating the ways in which the colonial past affects and effects in the present activities and ideas of former colonials. The study also takes part in discussing fundamental questions concerning how diaspora communities socially construct their place in the world in relation to the place left behind, to their current places of dwelling and to the community in dispersal. In spite of Rhodesia s incontestable ending, it is held close by social practices; by thoughts and talks, by material displays, and by webs of meaningful relationships. Such social memory practices, I suggest, are fundamental to how the community understands itself. The vantage points from which I examine how the ex-Rhodesians reminisce about Rhodesia concern ideas and practices related to place, home and commemoration. I first focus on the processes of symbolic investment that go into understanding place and landscape in Rhodesia and ask how the once dwelled-in places, iconic landscapes and experiences within places are reminisced about in diaspora. Secondly, I examine how home both as a mundanely organized sphere of everyday lives and as an idea of belonging is culturally configured, and analyze how and if homes travel in diaspora. In the final ethnographic section I focus on commemorative practices. I first analyze how food and culturally specific festive occasions of commensality are connected to social and sensual memory, considering the unique ways in which food acts as a mnemonic trigger in a diaspora community. The second example concerns the celebration of a centenary of Rhodesia in 1990. Through this case I describe how the mnemonic power of commemoration rests on the fact that culturally meaningful experiences are bodily re-enacted. I show how habitual memory connected to performance is one example of how memory gets passed-on in non-textual ways.