While dreaming, one lacks the understanding that what is experienced is self-generated hallucinatory contents of consciousness. However, during dreaming there is a rare state called lucid dreaming. The minimal requirement for a dream to be considered lucid is that one is self-aware that one is currently sleeping. If self-awareness is the minimal criterion for lucid dreaming, that would entail the activation of those brain areas and networks typically related to self-referential processing. Further, lucid dreaming often entails the ability to exert volition over dream content. This thesis is a systematic review of the neural correlates of lucid dreaming and investigates the potential overlap of the neural correlates of lucid dreaming and volition. Only peer-reviewed original empirical articles that used healthy adults as participants were included. Thus, five studies were found. Two of the studies used functional magnetic resonance imaging (fMRI), two used electroencephalography (EEG), and one used both EEG and fMRI. This thesis found that the precuneus and left parietal lobe, which are brain areas related to self-referential processing, have increased activity during lucid dreaming compared to non-lucid dreaming. Also, the dorsolateral prefrontal cortex (DLPFC) has increased functional connectivity in people who are more likely to experience lucid dreaming. DLPFC has been associated with metacognitive functions, which includes volition.There also seems to be an overlap in brain regions activated in volition compared to lucid dreaming; these areas include the parietal cortex, supplementary motor area, and anteriorprefrontal cortex.

The human relationship with mortality has been widely studied in psychology research, with an extensive record suggesting that death-related stimuli impact behavior, even without conscious awareness. Yet, little is known about the underlying brain activity. In this systematic review, we aimed to examine whether there is something distinctive about the neural processing of death-related stimuli. We conducted a literature search to find studies where participants had been presented with death-related vs. other negatively valenced stimuli while undergoing functional brain imaging scanning. Seven functional magnetic resonance imaging (fMRI) studies with a total of 204 participants adhered to our criteria. Five of six studies that used whole-brain analysis found that unpleasant stimuli consistently elicited increased insular activity, but only when it was unrelated to mortality. This suggests a difference between the neural processing of death and other threats. We discuss possible interpretations and speculate that it is related to the insula’s role in sense of self and assessment of threat. Further research is needed to determine whether this marker is robust and what its function and consequences may be. A better understanding of how individuals process death-related information promises deeper insight into the human relationship with mortality. Bringing to light the nature of this relationship has significant implications for individuals and society, not least for mental health interventions and end-of-life care.

Access to nature has been shown to positively impact human health and well-being, reducing stress, anxiety, and depression while increasing relaxation. The Biophilia hypothesis suggests that even brief interactions with natural settings can have beneficial effects, emphasizing the evolutionary importance of our connection with nature and its potential as a tool for health promotion. The aim of this systematic review is to investigate the brain activity during indirect and direct exposure to nature and urban environments. The search was done in Web of Science and MEDLINE EBSCO and 8 articles were identified to fulfill the inclusion criteria, based on,among others, the neuroimaging technique and mode of exposure to nature stimuli. Exposure to nature increases alpha power in the brain, with studies showing increased activity in variousregions such as the left and right prefrontal cortex. Additionally, specific brain regions, like the right orbitofrontal cortex and the right prefrontal cortex, exhibit lower oxy-Hb concentrations when viewing nature compared to urban environments. In sum, exposure to nature elicits changes in brain activity, particularly in alpha wave patterns and oxy-Hb concentrations. The findings support the integration of nature into urban design, highlighting its potential tobenefit public health and well-being, though further research is needed to explore long-term effects and potential applications in healthcare.

Functional connectivity measures have become one of the most common biomarkers when correlating brain activity to task and resting states post treatment. Mindfulness based stress reduction (MBSR) and cognitive behavioral therapy (CBT) are two well established forms of therapies treating clinical populations worldwide today. Although there are several studies that have investigated the neural correlations of these therapy forms individually, no systematic review has compared them side by side, to identify potential similarities and differences in functional connectivity. This systematic review attempts to shed light on how functional connectivity is altered during resting state after completed treatment, by reviewing a total of 4 CBT and 4 MBSR studies containing 337 participants. The results point to possible differences in resting state functional connectivity (rsFC) concerning the insula and similarities involving the cingulate cortex and other parts of the DMN. The insula has been suggested to be involved in the creation of motivation and the integration of bodily sensations and feelings. Furthermore, emotional reactions to personally valued behaviors and the retrieving of episodic memories is associated with the function of the cingulate cortex. These changes in rsFC might relate to the theoretical underpinnings of CBT and MBSR. However, more compelling research needs to be conducted before drawing conclusions on how these therapeutic approaches can alter rsFC and improve psychological health among individuals suffering from clinical conditions.

The ventromedial prefrontal cortex (vmPFC) has been suggested to be of great importance for moral decision-making. It has been suggested that during moral decision-making, lesions to the vmPFC increases what researchers term “utilitarian” decision-making. This systematic review summarizes four peer-reviewed studies that were filtered and selected from the databases Web of Science, Scopus and Medline EBSCO. The studies selected compared participants with vmPFC lesions to controls during moral decision-making. One study tested moral evaluation through moral transgressions and distractions. Two studies tested moral responses during personal, impersonal and non-moral dilemmas. One study tested whether direct involvement in a dilemma alters the utilitarian response. The overall results all point towards the vmPFC being directly involved in moral decision-making and that higher rates of utilitarian decision-making were shown in patients with vmPFC lesions compared to controls.

Classic psychedelic substances, such as lysergic acid diethylamide and the active compound in magic mushrooms, psilocybin, are being studied again in a renaissance of psychedelic research. Psychedelic substances have profound effects on perception, emotion, and cognition, as well as the capacity to induce mystical-type experiences and ego-dissolution. Recent clinical studies indicate that these substances have positive effects on patient populations and healthy participants, both acutely and long-term. Neuroimaging studies show that psychedelics alter neural integration, by the disintegration of normally stable resting state networks, and increasing network connectivity between normally anticorrelated networks. This thesis will review the phenomenological characteristics of the psychedelic-induced altered state of consciousness, the therapeutic potential of the psychedelic-induced altered state of consciousness, and neuroimaging studies on the psychedelic state. Two theoretical accounts are compared on the brain basis of psychedelic-induced altered state of consciousness. From the recent research on psychedelics a novel theory of conscious states has evolved, the entropic brain theory. This theory will be compared to the integrated information theory, a well-established theory of consciousness within cognitive neuroscience.

Why do you experience yourself as a continuous self? This is a central question when regarding the self and it has two kinds of answers: either there is something like an ego inside you which is the entity perceiving all your experiences (the ego theory-view), or there is no such thing as a self or an ego and you are just a collection of different perceptions (the bundle theory-view). There are many different components all contributing to the concept of self as a whole leading to different neuroscientific ways of measuring it and some researchers are arguing for the nonexistence of a unified self-system within the brain. The aim of this thesis is to review how neuroscientific findings might contribute to the philosophical debate about the nature of self. The thesis starts off by reviewing the different concepts and components with which the self is typically described, both in philosophy and in the empirical research field of neuroscience. Then follows a presentation of three important aspects of self-awareness – first-person perspective, self-reflection, and interoception – and their specific associated brain areas (namely, the medial prefrontal cortex, the posterior and anterior cingulate cortices, and insula). The purpose here is to examine how the self is approached in these studies. After this the thesis explores to what extent neuroscience supports the bundle theory-view, with a focus on reviewing the different brain networks involved in the processing of self. In conclusion, the thesis suggests that the literature reviewed provides neuroscientific support for the bundle theory-view that there is no unified self located in the brain, mostly because of the dissimilar neural activations associated with different self-related processes. In other words, the bundle theory seems to be correct despite the experienced feeling you have of being a continuous and unified self.

The facial width-to-height ratio (fWHR) is a measure of the cheekbone width divided by the height of the face from the upper lip to the brows. The metric is hypothesised to have evolved as an intra-sexual competition mechanism in males, where large fWHRs are thought to signal both threat and aggression. The fWHR is suggested to subtly resemble angry facial expressions, which, in turn, also signal threat. The late positive potential (LPP) and the vertex positive potential (VPP) are two event-related potentials (ERPs) especially sensitive to emotional content. Studies have also found that viewing angry compared to neutral facial expressions elicit a stronger response on the LPP. However, no study has tested how responses to the fWHR and angry facial expressions elicit changes in the LPP or VPP. In this study, participants firstly rated how threatening faces were with either low or high fWHRs with neutral or angry facial expressions. Secondly, EEG-activity was recorded during a picture-viewing task of the same faces. In the first task, participants rated the faces with angry facial expressions as more threatening compared to all other faces, regardless of fWHR, although the high fWHRs were rated as more threatening than the low fWHRs. In the second task, LPP and VPP mean amplitudes were significantly higher for the angry, high fWHR face compared to all other faces tested. This suggests that an additive effect of both angry facial expressions and high fWHRs together creates the highest threat level in both subjective ratings as well as in ERP mean amplitudes. Further ERP research is needed on the relationship between fWHRs and anger to establish how the two features work both separately and together.

In daily life there are numerous experiences and events that divert people's attention and cause stress, which may be linked with aspects of ill-being and lowered well-being. Mindfulness meditation may alleviate such issues. Mindfulness can be summarized as a form of awareness and attention in the present that is characterized by an open-minded and non-judgemental perspective, and meditation as a group of practices that engage many of the same processes and may involve mindfulness. There is evidence that both mindfulness and mindfulness meditation are associated with activity in brain regions relating to, for example, attention, emotion-regulation, and bodily awareness. Consequently, mindfulness meditation was hypothesized in the present study to improve attention as measured by the Attention Network Test, and decrease negative affect as measured by the Positive and Negative Affect Schedule when compared to a control condition. The mindfulness meditation instructions employed were largely based on the work of Kabat-Zinn (1982). 14 participants were recruited to the study, and 7 of them completed the experiment. 3 participants were randomized to the experimental group, and 4 to the control group. Results were largely contrary to the hypotheses, with only executive attention having statistical significance (p < .05) and supporting one hypothesis. Although effect sizes were on average large for the variables of the study, the small sample size may have limited the power and increased the risk for type-II errors.

This thesis combines phenomenological and neuroscientific research to elucidate the effects of psychedelic agents on the human brain, mind and psychological well-being. Psychoactive plants have been used for thousands of years for ceremonial and ritual purposes. Psychedelics are psychoactive substances that affect cognitive processes and alter perception, thoughts, and mood. Illegalization of psychedelics in the 1960s rendered them impossible to study empirically but in the last couple of decades, relaxed legal restrictions regarding research purposes, renewed interest in the effects of psychedelic drugs and new brain imaging techniques have started to reveal the possibilities of these mind-altering substances. Psychedelics mainly affect the serotonin receptor 5-HT2A which in turn affect the functioning of largescale cortical areas by changing cerebral blood flow, alpha oscillations, and functional connectivity. These cortical changes not only induce immediate alterations in perception and cognition but have been shown to have positive effects in therapeutic interventions for depression, anxiety, and addiction, and also positively affect well-being in general. Although the pharmacology and neurobiology of psychedelics are still poorly understood, the potential benefits justify empirical research on psychedelics in humans.