Aristotle (4th century B.C.E/1925) described eudaimonia as “the good life”, and is today commonly understood as eudaimonic well-being (EWB) within research. Despite the long history, the definitions and operationalizations of EWB are diverse and no coherent description or explanation for the biology of EWB exist. Hence, the present thesis reviews current neuroscientific- and additional biological research on EWB. This review reveals EWB to be most frequently operationalized as psychological well-being (PWB) (Ryff, 2014), and is here used as basis for an attempt to explain the biological and psychological profiles of EWB as high PWB. High PWB was characterized by brain activity linked to the reward circuitry, dorsolateral and left prefrontal cortex (PFC) and grey matter (GM) volume in areas of the brainstem and insular cortex. High PWB was also positively related to lower levels of several harmful biomarkers. The proposed psychological profile of high PWB included the psychological functions goal directed behaviour and emotional control. It is hoped that the proposed profiles will serve as inspiration for further exploration of the biology and psychology of human well-being (WB).

Psychopathy is a severe personality disorder that results in antisocial, manipulative, and callous behavior. The main diagnostic instrument for assessing psychopathy is the Psychopathy Checklist-Revised. This thesis will introduce the psychopathy construct, including what is known as subclinical psychopathy. Subclinical psychopathy refers to individuals who exhibit many of the characteristics of psychopathy, except for some of the more severe antisocial behaviors. This constellation of traits allows the subclinical psychopath to avoid incarceration. The fundamental difference between clinical and subclinical psychopaths is a major question in the field of psychopathy and is the main theme of this thesis. Impaired empathy is one of the key aspects of psychopathy and it may be a significant factor in both clinical and subclinical psychopaths. Subclinical psychopathy may be related to a moderated or altered expression of empathy. Hence, the empathy construct is a secondary concern in this thesis. This thesis has two aims: (a) to argue that the conceptualization of subclinical psychopathy is flawed and needs revision in accordance with less ambiguous criteria; and (b) to present data in support of the hypothesis that subclinical psychopaths have intact, or even enhanced, cognitive capacities in contrast to clinical psychopaths.

What am “I”? To what does the word “I” refer? The Self is a concept that feels intuitively obvious to us, but is nevertheless elusive to describe. Against a backdrop of theoretical speculation, this essay presents a basic exposition of the Self with the aid of recent advances in cognitive neuroscience to address one of its most confounding problems: How does the brain sustain the Self – our sense of bodily identity? What informs the question then is dealt with by providing a frame of reference based on the philosophical theory of mereology to contain the analysis (i.e., the relationship of parts to wholes, and of parts to parts within a whole). In relation to the question “What makes us experience what we are?” the Self is put in a context of a multisensory description – a context in which the center very much fails to hold. Enacting such self-plasticity comes at the cost of explicit boundaries, and is in need of a theoretical and methodological framework – not instead, but of folk-psychological criteria – in determining the nature behind why and how we have the intuition of being a Self.

Testing facilitates memory retention more than studying. The current experiment aimed to investigate neural memory-related processes during repeated testing and studying, thereby contributing to more elaborate theories. 5 participants (aged 19-31) practiced word-pair associates during fMRI through repeated studying (40 pairs) and testing (40 pairs). One week later they returned for a test and the outcome was used to calculate subsequent memory differences during fMRI. Findings included higher subsequent memory difference in left parietal lobe, precuneus and superior frontal gyrus for the test condition, implying more elaborate semantic processing. Also, an interaction effect was found in anterior cingulate cortex, possibly indicating an early beneficial recruitment of memory enhancing functions in the test condition. / Testning förbättrar minnesinlagring mer än studium. Det aktuella experimentet syftade till att undersöka neurala minnesrelaterade processer under upprepad testning och studium, och därmed bidra till mer konkreta teorier. 5 deltagare (i åldern 19-31) tränade ordpar (Swahili-Svenska) i en fMRI-scanner, antingen genom upprepat studium (40 par) eller upprepad testning (40 par). En vecka senare återvände de för ett slutgiltigt test på alla ordpar. Resultatet användes för att beräkna skillnader mellan lyckade och ej lyckade omgångar i fMRI-scannern. Högre skillnader i vänstra inferiora parietalloben, precuneus och superiora frontalgyrus hittades för testning jämfört med studium, vilket kan spegla en djupare semantisk bearbetning. En interaktionseffekt hittades i anteriora cingulate cortex, vilket möjligen indikerar en tidig rekrytering av fördelaktiga minnesfunktioner i test-betingelsen.

The present thesis explores how personality traits are connected to academic achievement. First, a theoretical discussion on the neurobiological basis of different personality traits is presented, where variance in brain- activity, volume and chemistry describes possible differences in personality. Traits previously linked to academic achievement is also described in terms of neurobiology. This is followed by an empirical investigation of the connection between personality traits and academic achievement. Previous research suggest the Big Five (Costa & McCrae, 1992a) personality traits of conscientiousness, order and self-discipline to be positively associated with academic achievement. Also, similar suggestions have been put forward concerning the Values in Action (VIA-IS; Peterson & Seligman, 2004) character strengths of love of learning, self-regulation and persistence and academic achievement. 90 students in a medium sized Swedish senior high school completed the two personality inventories and their grades were collected. Positive correlations were found for the personality traits conscientiousness, order, and self-discipline and for the character strengths persistence, love of learning, perspective and open-mindedness. The results partly supported the hypotheses as well as extended the knowledge about what factors contribute to academic achievement. Discussion of the results and suggestions for further research concludes the thesis. Keywords: personality trait, character strength, neurobiology, academic achievement, BFI, VIA-IS

Humans express complex moral behaviour, from altruism to antisocial acts. The investigationof the neural and cognitive mechanisms underlying our moral minds is of profoundimportance for understanding these behaviours. By reviewing recent findings in cognitive andmoral neuroscience, along with other relevant areas of research, the current study aims to: (1)Investigate the neural correlates of moral intuition and moral reasoning, and see how thesetwo systems relate to moral judgement and moral behaviour. (2) Examine how the moralintuitive system and the moral reasoning system relate to one another. Neuroscientificevidence suggests that these two systems are supported by different areas in the brain. Whiletheir relationship is argued to be both sequential, integrative and competitive, evidenceindicates that the moral reasoning system primarily functions as a post hoc rationalization ofour intuitive-driven judgements and behaviours. While our moral intuitive system motivateskin altruism, both moral intuition and moral reasoning serve to uphold reciprocal altruism.

Due to abnormal functioning of the brain’s reward and prediction system patients with schizophrenia spectrum disorders are thought to assign salience to non-relevant objects and events and to form context-inappropriate associations. The brain’s ventral striatum is critical in the formation of associations, and aberrant associations are believed to create delusional content during psychosis. The study wanted to examine the neural response, particularly in the ventral striatum, combined with subjective reports as patients learn associations in an aversive Pavlovian conditioning paradigm. The stimuli were randomized and involved circles of different colors. The conditioned stimuli (CS+) was followed by an unconditioned stimuli (US), consisting of an unpleasant sound, in 50% of events. The unconditioned (CS-) stimuli was followed by a low, not unpleasant sound in 50% of events. The degree of striatal activation was thought to be associated with the severity of patient’s illness. Functional magnetic resonance imaging (fMRI) blood-oxygen-level dependent (BOLD) responses were examined in eleven unmedicated non-institutionalized patients with schizophrenia spectrum disorders and 15 matched healthy controls. No significant within group differences in neural or subjective response to the [CS+ > CS-] contrast were found. No significant associations between severity of illness and degree of striatal activation in response to CS+ or CS- were found. Significant differences in neural activation for the [CS+ > CS-] contrast were found in the ventral striatum, the right inferor frontal gyrus, and the right angular gyrus, with patients exhibiting stronger activation compared to controls. The results and implications are discussed along with suggestions for future research.

Anxiety is the most commonly reported mental health problem among adolescents. Still, many adolescents in need of treatment are not detected and the clinical characteristics and etiological pathways of adolescent anxiety are under-researched topics. This thesis examined the clinical utility of the Swedish versions of the Spence Children’s Anxiety Scale (SCAS) and the clinical characteristics of multiple anxiety disorders among psychiatrically referred adolescents, and the influence of parenting and oxytocin gene (OXT) variants on anxiety among adolescents in the general population.  Studies employed cross-sectional and longitudinal designs and were based on questionnaire, interview, and genotype data. Support for the reliability and validity of both SCAS and SCAS-P was obtained. The overall ability to predict anxiety among referred adolescents ranged from fair to excellent for both scales.  Among adolescents psychiatrically referred for any reason, the prevalence of any anxiety disorder was 46%. Homotypic comorbidity was observed in 43%, and heterotypic comorbidity in 91%. Early adolescent anxiety influenced homotypic anxiety in late adolescence independent of parental rejection and control. The mediating role of parenting was small with indirect effect sizes no larger than one-tenth the size of direct effects, irrespective of the informant on parenting behavior. Significant interaction effects with positive and negative parenting were observed for OXT variants rs4813625 and rs2770378 in relation to social anxiety. The nature of the interactions was in line with the differential susceptibility framework for rs4813625, whereas for rs2770378, results indicated a diathesis–stress type of interaction. The findings suggest that psychiatrically referred adolescents with anxiety disorders are best characterized as a highly complex patient group and call attention to the necessity of structured assessment. For this purpose, this thesis provides evidence for the clinical utility of the SCAS; routine utilization of this questionnaire can improve detection of adolescents in need of anxiety treatment. Findings of this theses further suggest that the influence of positive and negative parenting behaviors on anxiety may be of greater importance among some adolescents than others, depending on individual differences in sensitivity to parenting. The etiology of anxiety among adolescents may therefore involve differential susceptibility effects of the interplay between genes and parenting behaviors.

Any image can be described in terms of its statistics (i.e. quantitative parameters calculated from the image, for example RMS-contrast, the skewness of image brightness distribution, and slope constant of an average amplitude spectrum). It was previously shown that insect and vertebrate visual systems are optimised to the statistics common among natural scenes. However, the exact mechanisms of this process are still unclear and need further investigation. This thesis presents the results of examining links between some image statistics and visual responses in humans and hoverflies. It was found that while image statistics do not play the main role when hoverflies (Eristalis tenax and Episyrphus balteatus) chose what flowers to feed on, there is a link between hoverfly (Episyrphus balteatus) active behaviours and image statistics. There is a significant difference in the slope constant of the average amplitude spectrum, RMS contrast and skewness of brightness distribution between photos of areas where hoverflies were hovering or flying. These photos were also used to create a prediction model of hoverfly behaviour. After model validation, it was concluded that photos of both the ground and the surround should be used for best prediction of behaviour. The best predictor was skewness of image brightness distribution. By using a trackball setup, the optomotor response in walking hoverflies (Eristalis tenax) was found to be influenced by the slope constant of an average amplitude spectrum.  Intracellular recording showed that the higher-order neuron cSIFE (The centrifugal stationary inhibited flicker excited) in the hoverfly (Eristalis tenax) lobula plate was inhibited by a range of natural scenes and that this inhibition was strongest in a response to visual stimuli with the slope constant of an average amplitude spectrum of 1, which is the typical value for natural environments.  Based on the results of psychophysics study in human subjects it was found that sleep deprivation affects human perception of naturalistic slope constants differently for different image categories (“food” and “real world scenes”). These results help provide a better understanding of the link between visual processes and the spatial statistics of natural scenes.

Malignant gliomas grow infiltrative in the brain and can therefore not be completely removed by neurosurgical means. However, for an optimized oncological treatment it has proven useful to resect as much as possible of tumor. The identification of the tumor in the marginal zone is difficult but crucial. Studies have shown that visualization of the specific enhancement of 5-aminolevulinic acid(5-ALA) in the tumor can help to maximize the resection. The Department of Biomedical Engineering, Linköping University, has developed an optical hand-held probe (HHP) to identify tumor tissue with a high sensitivity by means of fluorescence spectroscopy. The technical design and the optical properties of the probe were gradually developed in a standard neurosurgical setting during resection of malignant gliomas. The device could easily be implemented in the operating room, meeting all requirements in terms of sterile handling and without interference of any kind with other equipment. The integration of the device in a navigation system and its use in combination with a blue light surgical microscope were simple. Measurements in 27 operations during resection of malignant gliomas were compared to results from biopsies from the same tumor locations. The equipment was tested as a stand-alone device (n = 180), integrated in a navigation system or in combination with the blue light microscope (n = 190). A ratiocal culated from the measurements enabled objective and comparable values for different tissue types, in correspondence with the findings from the histopathological examinations and in accordance with the navigation system as well as with the surgical microscope.The marginal zone was explored and tumor fluorescence could be identified beyond the fluorescence as seen through the microscope. A higher sensitivity of the HHP was confirmed; the specificity was lower. The combined use of the HHP with a navigation system and with asurgical microscope was beneficial. / Maligna hjärntumörer växer infiltrerande i hjärnan och kan därförinte helt avlägsnas genom kirurgiska operationer. För en optimerad behandling har det emellertid visat sig vara av värde att avlägsna såmycket som möjligt av tumörvävnaden. Identifiering av tumören i gränszonen är mycket svårt, men avgörande. Studier har visat att visualisering av den specifika laddningen av 5-aminolevulinsyra (5-ALA) i tumören kan bidra till att maximera resektionen. Institutionen för Medicinsk Teknik (IMT) på Linköpings universitet,har utvecklat en liten handhållen optisk prob (HHP) för att identifiera tumörvävnad med hög känslighet med hjälp avfluorescens-spektroskopi. Den tekniska konstruktionen och de optiska egenskaperna hos proben utvecklades stegvis genom testning i flera neurokirurgiska operationer för resektion av maligna gliom. Utrustningen uppfyllde alla krav när det gällde steril hantering i operationssalen och kunde användas utan störningar av något slag med annan operationsutrustning. Integreringen i ett navigerings-system och användningen i kombination med ett kirurgiskt mikroskop för fluorescens-styrd kirurgi var oproblematiska. Mätningar under 27 operationer vid resektion av maligna gliom jämfördes med resultat från biopsier från samma tumörtagningsställen. Utrustningen testades såväl som en fristående enhet (n = 180) och som integrerad i ett navigationssystem eller i kombination med mikroskopet (n =190). En särskild kvot beräknad ur mätningarna möjliggjorde objektiva och jämförbara värden för olika vävnader, i överensstämmelse med resultaten från de vävnadspatologiska undersökningarna och i överensstämmelse med navigationssystemet såväl som med det kirurgiska mikroskopet. Tumörernas gränszon undersöktes och tumörfluorescens kunde identifieras bortom fluorescensen som mikroskopet visade. En högre känslighet hos HHP bekräftades; specificiteten var lägre. Den kombinerade användningen av HHP med ett navigationssystem och med ett kirurgiskt mikroskop visade sig vara fördelaktig.