Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that manifests as a developmentally inappropriate pattern of inattention, and hyperactivity or impulsivity. ADHD is a multifactorial disorder with inter alia deficits in selective attention processing. The current diagnosis of ADHD is error-prone as it relies on subjective descriptions and external observations of behavior. Measures that are less reliant on subjective descriptions can enable more accurate and informative diagnoses of ADHD. Wang et al. (2016) have identified two event-related potential (ERP) components, posterior contralateral N2 (N2pc) and distractor positivity (PD) as predictors of ADHD symptom severity in children. N2pc reflects target selection and PD reflects distractor suppression during visual selective attention. The present study aimed to examine how target-evoked N2pc and distractor-evoked PD related to attentional capacity in non-clinical adults. Participants were presented with a visual search paradigm and a self-report scale, the Everyday Life Attention Scale (ELAS). The amplitude of target-evoked N2pc and distractor-evoked PD amplitude was compared to ELAS score in multiple linear regression models. Results displayed that the peak amplitude of target-evoked N2pc was a significant predictor of attentional capacity (as measured with ELAS), while the peak amplitude of distractor-evoked PD was not associated with attentional capacity. Participants with higher attentional capacity (ELAS score) displayed less negative peak amplitudes of target-evoked N2pc. This seems to suggest that target selection, but not distractor suppression in nonclinical adults can predict attentional capacity. However, due to a limited sample size, further research is needed before drawing any major conclusions.

Basal Ganglia are evolutionarily conserved brain nuclei involved in several physiologically important animal behaviors like motor control and reward learning. Striatum, which is the input nuclei of basal ganglia, integrates inputs from several neurons, like cortical and thalamic glutamatergic input and local GABAergic inputs. Several neuromodulators, such as dopamine, accetylcholine and serotonin modulate the functional properties of striatal neurons. Aberrations in the intracellular signaling of these neurons lead to several debilitating neurodegenerative diseases, like Parkinson’s disease. In order to understand these aberrations we should first identify the role of different molecular players in the normal physiology. The long term goal of this research is to understand the molecular mechanisms responsible for the integration of different neuromodulatory signals by striatal medium spiny neurons (MSN). This signal integration is known to play important role in learning. This is manifested via changes in the synaptic weights between different neurons. The group of synpases taken into consideration for the current work is the corticostriatal one, which are synapses between the cortical projection neurons and MSNs. One of the molecular processes of considerable interest is the interaction between dopaminergic and cholinergic inputs. In this thesis I have investigated the interactions between the biochemical cascades triggered by dopaminergic, cholinergic (ACh) and glutamatergic inputs to the striatal MSN. The dopamine induced signaling increases the levels of cAMP in the striatonigral MSNs. The sources of dopamine and acetylcholine are dopaminergic neurons (DAN) from midbrain and tonically active cholinergic interneurons (TAN) of striatum, respectively. A sub-second burst activity in DAN along with a simultaneous pause in TAN is a characteristic effect elicited by a salient stimulus. This, in turn, leads to a dopamine peak and, possibly, an acetylcholine (ACh) dip in striatum. I have looked into the possibility of sensing this ACh dip and the dopamine peak at striatonigral MSNs. These neurons express D1 dopamine receptor (D1R) coupled to Golf and M4 Muscarinic receptor (M4R) coupled to Gi/o . These receptors are expressed significantly in the dendritic spines of these neurons where the Adenylate Cyclase 5 (AC5) is a point of convergence for these two signals. Golf stimulates the production of cAMP by AC5 whereas Gi/o inhibits the Golf mediated cAMP production. I have performed a kinetic-modeling exercise to explore how dopamine and ACh interacts with each other via these receptors and what are the effects on the downstream signaling events. The results of model simulation suggest that the striatonigral MSNs are able to sense the ACh dip via M4R. They integrate the dip with the dopamine peak to activate AC5 synergistically. We also found that the ACh tone may act as a potential noise filter against noisy dopamine signals. The parameters for the G-protein GTPase activity indicate towards an important role of GTPase Activating Proteins (GAPs), like RGS, in this process. Besides this we also hypothesize that M4R may have therapeutic potential. / <p>QC 20140325</p>

Early-life stress, consisting of several stressors appears to be associated with several impacts on the brain. The impacts of stress seem to be more vulnerable to the developing brain as it undergoes important changes during childhood. This thesis aims to present the association between childhood maltreatment, which is a form of early-life stress, and affected brain regions such as the hippocampus, prefrontal cortex, corpus callosum, and the amygdala. The findings in this thesis demonstrated the left hippocampus to be more vulnerable to the effects of maltreatment, corpus callosum appeared to be gender and maltreatment specific, indicating that the corpus callosum were more vulnerable to neglect in boys whereas in females the structure was more vulnerable to sexual abuse. The prefrontal cortex demonstrated a marked reduction in gray matter, and the amygdala showed increased activation in response to emotional facial expressions. Cognitive deficits as a result of earlylife stress were also discussed, showing that worse intellectual ability and the academic performance had been noted in children with exposure to early-life stress.

The study investigated aspects of self-rated autobiographical memory between young and middle-aged adults, as well as examined sex differences. A Swedish version of a self-rating questionnaire was used online to assess autobiographical memory. The Survey of autobiographical memory assesses autobiographical memory abilities in episodic, semantic, spatial, and future domains. Forty-one healthy volunteers were included. The youngest group (Mage=26), had 70% women and middle-aged adults (Mage=44) had 50 % percent women. The mean age for women was (M= 30, range = 30) and the mean age for men was (M=34, range= 30). Univariate General Linear Model was performed to determine whether there is a significant mean difference between the age-groups and sex, while a repeated-measures multivariate analysis of variance assessed the interaction between age group and memory type. It was hypothesized that there would be no difference between young and middle-aged adults in semantic autobiographical memory, but that episodic autobiographical memory would be rated lower by the middle-aged adults. The two dependent variables were semantic and episodic scores. No significant effects were found for age-group or sex on the total, episodic, and semantic scores. The age-group by memory-type interaction showed that semantic and episodic memories were not rated differently by the two age-groups. One reason for these non-significant outcomes could be the overall small sample sizes. Further elaboration is needed to assess the aspects of self-rated AM changes from young to middle adulthood, including sex differences in the self-assessment since not many studies have addressed such questions. / Studien undersökte aspekter avsjälvskattat självbiografiskt minne mellan unga vuxna och individer i medelåldern samt även könsskillnader. En svensk version av ett självsskattningsfrågeformulär användes online för att undersöka självbiografiskt minne. Frågeformuläret bedömer autobiografiska minnesförmågor inom episodiska, semantiska, rumsliga och framtida domäner. Fyrtio friska deltagare medverkade i undersökningen. Den yngsta gruppen (M ålder=26), hade 70% kvinnor, medan medelålders vuxna (M ålder =44), hade 50% kvinnor. Medelåldern för kvinnor var (M = 30, intervall = 30) och mäns var (M = 34, intervall = 30). Univariata allmänna linjär modeller utfördes för att bestämma om det finns en signifikant genomsnittlig skillnad mellan åldersgrupperna och kön, medan en multivariat variansanalys med upprepade mätningar bedömde interaktionen mellan åldersgrupp ochminnestyp. Det antogs att det inte skulle finnas någon skillnad mellan unga och i det semantiska självbiografiska minnet, men att episodiskt självbiografiskt minne skulle skattas lägre efter medelåldern. De två beroende variablerna var semantiska och episodiska poäng. Inga signifikanta effekter hittades för åldersgrupp eller kön på den totala, episodiska och semantiska poängen. Interaktionen mellan åldersgrupp och minnestyp visade att semantiska och episodiska minnen inte bedömdes annorlunda av de två åldersgrupperna.

Sense of agency (SoA) is defined as the subjective experience of being in control of our own actions. This attribution of control underpins all human action and is a vital aspect of the experience of being human. This systematic review sought to address whether intentional binding (IB), a proxy of SoA, can be found during observation of other-generated actions. This was done by investigating the current state of research in the field. Past studies are inconclusive in regards to what factors play into the formation of SoA and the motivation behind this review was to provide a conclusion regarding IB from observed actions. The studies featured in this review found that the IB effect was present in different procedures and contexts which highlights the flexible nature of SoA. Most importantly, this systematic review concluded that IB can and does occur during the observation of other-generated actions. Furthermore, this review found that social influence has an effect on SoA in both human- and robot-observations. We also found that the IB effect manifests in the absence of voluntary actions but to a lesser degree. However, the magnitude of the IB effect varied across studies where one found IB to be greater during action observation than self-generated actions, whilst another study found a weaker IB effect for action observation. Finally, this review provides a discussion on theories that best explain this phenomena, the neural evidence behind action observation, and what implications the findings could have for SoA as a whole

During adolescence, the brain undergoes significant reorganization due to myelination and synaptic pruning. These changes are associated with risk-taking behaviors and the development of social relationships. Recent advancements in adolescent brain development can potentially enhance strategies for preventing and treating mental health disorders. This systematic review focuses on structural changes in the adolescent brain, specifically emphasizing a decrease in gray matter and an increase in white matter changes. Four longitudinal MRI studies were included in this systematic review to identify changes in brain volume among healthy adolescents with an age range of 10 to 19 years. The results revealed observable changes in gray and white matter volume in various brain regions during this period. A decrease in gray matter was observed in the frontal, temporal, and parietal cortex, and several subcortical regions. Contrary to our expectations, the amygdala displayed an increase in gray matter in early adolescence. We expected this findings to occur in late childhood. The results also indicated that males undergo more significant changes in the brain during this period than females. Considering the Social Process Network (SIPN) and triadic model, changes occurring in the frontal cortex and the amygdala could be linked to social behavior. While the changes in the thalamus, hippocampus, and amygdala may be linked to heightened risk-taking and mental health disorders. Further research is necessary to clarify the relationship between mental health disorders, behaviors, and developmental processes during adolescence.

The purpose of this systematic review is to provide insight into the impact traumatic brain injury (TBI) has on the executive function known as the working memory. TBI is a damage to the brain that occurs when the brain is critically injured to the degree that it impacts several brain regions and functions such as the hippocampus, its surrounding areas, the prefrontal cortex, and the performance of the working memory ability. TBI may occur from bleeding or infraction (stroke), lack of oxygen after cardiac arrest (anoxic brain injury), or diseases such as brain tumours or infections in the brain (encephalitis/meningitis). Working memory is the ability that maintains and manipulates information such as judgment and decision-making. TBI impacts several cognitive and executive functions such as the working memory. The implications that TBI has on working memory is that it relatively decreases the activation and connectivity capacity among the main areas of the working memory network which may result in difficulties of attention and concentration. This review summarises five studies about TBI and working memory that uses different working memory task while examiningwith brain imaging techniques. The studies conclude that TBI has a negative impact on working memory since the ability becomes weak.

Syfte: Syftet med litteraturstudien var att undersöka förekomsten av muskuloskeletala besvär, vilka faktorer som orsakar dessa samt vilka kroppsdelar som drabbar kliniskt verksamma tandhygienister. Metod: Studiens design var en litteraturstudie baserad på tidigare forskning av 14 vetenskapliga artiklar som hittades i databaserna CIHNAL, MEDELINE och DOSS. Artiklarna som inkluderades i denna litteraturstudie var mellan åren 2012–2022. Utvalda artiklar är kvalitetsgranskade för att säkerställa hög kvalité och de besvarade studiens syfte. Resultat:  Muskuloskeletala besvär drabbade i genomsnitt 80% av tandhygienisterna från alla studier. Faktorer som kan leda till muskuloskeletala besvär inkluderade arbetsrelaterade faktorer såsom arbetstid, arbetsbelastning och arbetsställning. Individuella faktorer som kön, ålder, fysisk kondition och tidigare skador. Psykosociala faktorer som stressnivå, arbetsplatsmiljö och socialt stöd. Mer än hälften av tandhygienisterna upplevde besvär i flera kroppsdelar samtidigt. Kroppsdelarna som drabbades var nacken (67%), axlar (54%), ryggen (46%), Händer/Handleder (44%), armbågar (20%) höften (17%) knäna (12%) och fötter (12%) Slutsats: Det finns tydliga resultat att muskuloskeletala besvär är ett stort problem för tandhygienister. Det bör uppmärksammas i arbete för en god arbetsmiljö. Mer forskning och mer utbildningsprogram inom ergonomi behövs för att kunna förebygga muskuloskeletala besvär bland tandhygienister som jobbar kliniskt i framtiden. / Aim: The aim of the literature study was to investigate the prevalence of musculoskeletal disorders, which factors cause these, and which body parts affect clinically active dental hygienists. Method: The study design was a literature review based on previous research of 14 scientific articles found in the databases CIHNAL, MEDELINE and DOSS. The articles included in this literature review were between the years 2012–2022. Selected articles are quality reviewed. Results: Musculoskeletal disorders affected an average of 80% of dental hygienists from all studies. The factors where work-related such as working hours, workload and working posture. Individual factors such as gender, age, physical fitness and previous injuries. Psychosocial factors such as stress level, workplace environment and social support. More than half of the dental hygienists experienced problems in several body parts at the same time. The body parts affected were the neck (67%), shoulders (54%), the back (46%), hands/wrists (44%), elbows (20%), the hip (17%), the knees (12%) and the feet (12%) Conclusion: Musculoskeletal disorders are a major problem for dental hygienists. This should be considered in the work for a good working environment. More research and more educational programs in ergonomics are needed to prevent musculoskeletal disorders among dental hygienists who work clinically in the future.

To understand more about the neural underpinnings for leading and following is the driving force behind this thesis. To do so, there is a need to study leading and following on a basic level. For study I, an fMRI study of neuronal reactivity during leading and following, a minimal model was developed to study leader and follower behavior in a standardized way. This model uses finger tapping of rhythms representing the core of the interactions during leading and following. Participants are invited to both lead and follow, and no expertise is expected. The status difference between the leader and follower is not a part of the model. Data collection is made in Japan, and most of the analyses are carried out in Sweden. In study II the Swedish Universities Scales of Personality is translated from Swedish to Japanese. Personality can be described as a crucial feature in a person’s social and emotional functioning; they are relatively stable over the course of a lifetime. Three dimensions representing personality facets probably relevant for leading and following are emotional stability, extraversion, and agreeableness. Study II resulted in SSPJ-11 with eleven reliable personality scales representing theses three facets relevant for leading and following. Study I presented an effective model to investigate leading and following during fMRI scanning. This model can be used with other designs for further brain imaging and behavior studies. From Study I, it became clear that the neuronal reactivation for leading and following largely overlap, with some specific differences in insular, temporal, and cerebellar reactivity. These results could be a first step towards a revealing the crucial components of neuro reactivations for leading and following.

Attention deficit hyperactivity disorder is one of the most common neurodevelopmental disorders, affecting around 7% of the worldwide population in their everyday life. It has been suggested that individuals with ADHD differ in gray matter volume from typically developing controls. However, findings on in which brain areas these differences are located, as well as how gray matter volume is affected by stimulant medication, remain inconclusive. Therefore, this systematic review aimed to investigate any potential differences in gray matter volume in medication-naïve individuals with ADHD compared to controls, focusing on studies using voxel-based morphometry applied to MRI-imaging data A keyword search in the databases Web of Science, Scopus and Medline EBSCO resulted in 349 studies, of which seven met the inclusion criteria and were included in the review. The results included a total of 169 participants diagnosed with ADHD and 148 typically developing controls. Findings suggested decreased cerebellar gray matter volume, potential gender-wise volume differences in the anterior cingulate cortex, and a decrease in caudate gray matter volume, specifically in adults with ADHD. Some limitations include small sample sizes, possible effects of age on gray matter volume, and the overall heterogeneous nature of the disorder. The present review agrees that individuals with ADHD exhibit differences in gray matter volume, but also highlights the importance of expanding research on medication-naïve subjects, to be able to draw more robust scientific conclusions about the neural correlates of ADHD in the future.