Mental sleep activity and disturbing dreams in the lifespan

Sleep significantly changes across the lifespan, and several studies underline its crucial role in cognitive functioning. Similarly, mental activity during sleep tends to covary with age. This review aims to analyze the characteristics of dreaming and disturbing dreams at dierent age brackets. On the one hand, dreams may be considered an expression of brain maturation and cognitive development, showing relations with memory and visuo-spatial abilities. Some investigations reveal that specific electrophysiological patterns, such as frontal theta oscillations, underlie dreams during sleep, as well as episodic memories in the waking state, both in young and older adults. On the other hand, considering the role of dreaming in emotional processing and regulation, the available literature suggests that mental sleep activity could have a beneficial role when stressful events occur at dierent age ranges. We highlight that nightmares and bad dreams might represent an attempt to cope the adverse events, and the degrees of cognitive-brain maturation could impact on these mechanisms across the lifespan. Future investigations are necessary to clarify these relations. Clinical protocols could be designed to improve cognitive functioning and emotional regulation by modifying the dream contents or the ability to recall/non-recall them

Functional Connectivity of EEG LORETA in Cortical Core Components of the Self and the Default Network (DNt) of the Brain

INTRODUCTION: Recent research exploring cortical functional connectivity defines a default network (DNt) of brain function and activation of a core midline network (CMS) in the processing of self. The electroencephalographic (EEG) activity in these components of the human DNt and CMS is not well understood. METHODS: This study was conducted with 63 participants. Individuals were recorded during eyes-closed (ECB) and eyes-opened (EOB) baselines and active task (AT) conditions (e.g., self-referential, self-image, self-concept, recent symptomology, other face and object processing). We estimated EEG source localization with standardized low resolution electromagnetic tomography (sLORETA). Subjective experience was obtained for baselines and photographic conditions. RESULTS: The ECB resting condition shows higher activity in all frequencies as compared to all other conditions. Likewise, the active tasks show differential effects for increased activity as compared to EOB for each region of interest (ROI) in each frequency domain. CONCLUSION: The data are in agreement with other neuroimaging techniques (fMRI/PET) investigating the DNt of brain function and further shows that the 3-dimensional localization accuracy of LORETA EEG is sufficient for the study of the DNt. In examining both within and between functional core regions there was a higher degree of activity in lower frequency bands during eyes closed; however, this pattern does not extend to all ROIs for all frequency domains. The differences may represent functional connectivity relating to endogenous/exogenous attention states as opposed to the simple concept of “resting” or “non-activity”. Further study of the functional relationships between EEG frequencies within and between regions in the default network and during self-specific processing may prove important to understanding the complex nature of neocortical functional integration

Observing the Functional Maturation of the Female Prefrontal Cortex Using Ventral Hippocampal Stimulation

Adolescence is a time when the brain continues to mature. Specifically the prefrontal cortex (PFC) goes through a process of disinhibition to inhibition as we age. Inputs to this region have a frequency dependent maturation pattern in male rats, but this has not been studied in females. We focused on frequency dependent responses in the medial PFC that are evoked by stimulation to the ventral hippocampus. This was conducted by measuring Local Field Potential responses in the medial PFC via in vivo electrophysiology. We found that stimulating with a 10 Hz train response showed no difference across age groups. In contrast, a 20 Hz train of stimulation revealed an age-dependent shift through increasing suppression of the signal. Finally, a 40 Hz train stimulation evoked suppression in all three age groups, but in different magnitudes. With these established patterns we can compare a normal PFC maturation with factors such as chronic drug use and stress

The cognitive neuroscience of visual working memory

Visual working memory allows us to temporarily maintain and manipulate visual information in order to solve a task. The study of the brain mechanisms underlying this function began more than half a century ago, with Scoville and Milner’s (1957) seminal discoveries with amnesic patients. This timely collection of papers brings together diverse perspectives on the cognitive neuroscience of visual working memory from multiple fields that have traditionally been fairly disjointed: human neuroimaging, electrophysiological, behavioural and animal lesion studies, investigating both the developing and the adult brain

Alpha and gamma-band oscillations in MEG-data: networks, function and development

Die Adoleszenz, d.h. die Reifungsphase des Jugendlichen zum Erwachsenen, stellt einen zentralen Abschnitt in der menschlichen Entwicklung dar, der mit tief greifenden emotionalen und kognitiven Veränderungen verbunden ist. Neure Studien (Bunge et al., 2002; Durston et al., 2002; Casey et al., 2005; Crone et al., 2006; Bunge and Wright, 2007) machen deutlich, dass sich die funktionelle Architektur des Gehirns während der Adoleszenz grundlegend verändert und dass diese Veränderungen mit der Reifung höherer kognitiven Funktionen in der Adoleszenz assoziiert sein könnten. Messungen des Gehirn-Volumens mit Hilfe der Magnet-Resonanz-Tomographie (MRT) zum Beispiel zeigen eine nicht-lineare Reduktion der grauen und eine Zunahme der weißen Substanz während der Adoleszenz (Giedd et al., 1999; Sowell et al., 1999, 2003). Des weiteren treten in dieser Zeit Veränderungen in exzitatorischen und inhibitorischen Neurotransmitter-Systemen auf (Tseng and O’Donnell, 2005; Hashimoto et al., 2009). Zusammen deuten diese Ergebnisse darauf hin, dass während der Adoleszenz ein Umbau der kortikalen Netzwerke stattfindet, der wichtige Konsequenzen für die Reifung neuronaler Oszillationen haben könnte. Im Anschluss an eine Einführung im Kapitel 2, fasst Kapitel 3 der vorliegenden Dissertation die Vorbefunde bezüglich entwicklungsbedingter Veränderungen in der Amplitude, Frequenz und Synchronisation neuronaler Oszillationen zusammen und diskutiert den Zusammenhang zwischen der Entwicklung neuronaler Oszillationen und der Reifung höhere kognitiver Funktionen während der Adoleszenz. Ebenso werden die anatomischen und physiologischen Mechanismen, die diesen Veränderungen möglicherweise zu Grunde liegen könnten, theoretisch vorgestellt. Die in Kapitel 4-6 vorgestellten eigenen empirischen Arbeiten untersuchen neuronale Oszillationen mit Hilfe der Magnetoencephalographie (MEG), um die Frequenzbänder und die funktionellen Netzwerke zu charakterisieren, die mit höheren kognitiven Prozessen und deren Entwicklung in der Adoleszenz assoziiert sind. Hierzu wurden drei Experimente durchgeführt, bei denen MEG-Aktivität während der Bearbeitung einer Arbeitsgedächtnisaufgabe und im Ruhezustand aufgezeichnet wurde. Die Ergebnisse dieser Experimente zeigen, dass Alpha Oszillationen und Gamma-Band Aktivität sowohl task-abhängig als auch im Ruhezustand gemeinsam auftreten. Darüber hinaus ergänzen die vorliegenden Untersuchungen Vorarbeiten, indem sie eine Wechselwirkung zwischen beiden Frequenzbändern aufgezeigt wird, die als ein Mechanismus für das gezielte Weiterleiten von Informationen dienen könnte. Die in Kapitel 6 vorgestellten Entwicklungsdaten weisen weiterhin darauf, dass in der Adoleszenz späte Veränderungen im Alpha und Gamma-Band stattfinden und dass diese Veränderungen involviert sind in die Entwicklung der Arbeitsgedächtnis-Kapazität und die Entwicklung der Fähigkeit, Distraktoren zu inhibieren. Abschliessend werden in Kapitel 7, die in dieser Dissertation vorgestellten Arbeiten, aus einer übergeordneten Perspektive im Gesamtzusammenhang diskutiert

The Relationship Between Adverse Childhood Experiences, Acute Stress, and Working Memory

Working memory (WM) is a crucial component of cognitive function that affects learning, reasoning, and problem solving, all of which are important for daily functioning. Therefore, addressing factors that can impact working memory, such as stress, are incredibly relevant to understanding WM efficiency. WM is an important component of higher order cognitive function and high WM capacity has been shown to be important for academic and occupational performance. Thus, understanding the relationship between stress-related factors and WM could aid in identifying strategies to mitigate the deleterious effects of stress on working memory. Although some previous research has indicated a negative impact of acute stress on WM, other research has indicated no impact or even a positive impact of stress on WM. As the relationship between acute stress and WM is mixed, examining other stress-related factors may provide further insight into the relationship. The current study examines how adverse childhood experiences (ACEs) and acute stress influence WM, and how frontal theta and alpha activity are affected by WM task demands. Participants completed a working memory task while their EEG was recorded. Participants then completed the PANAS to assess their current emotional state. Following the PANAS, participants viewed a stressful or neutral video as an acute stress induction, followed by a second PANAS to ensure effectiveness of stress induction. Participants then completed the WM task a second time. Finally, the participants completed the ACEs questionnaire. Bayesian linear mixed effects models were used to examine the relationships between ACEs, acute stress, WM, and frontal theta and alpha frequencies. Findings suggest there is not enough evidence to support a relationship between acute stress, ACEs, WM, and WM-related theta and alpha. While the current study did not reveal a relationship, future research should explore how acute stress and exposure to specific stressors during childhood could explain individual differences in WM

The two-component model of memory development, and its potential implications for educational settings

We recently introduced a two-component model of the mechanisms underlying age differences in memory functioning across the lifespan. According to this model, memory performance is based on associative and strategic components. The associative component is relatively mature by middle childhood, whereas the strategic component shows a maturational lag and continues to develop until young adulthood. Focusing on work from our own lab, we review studies from the domains of episodic and working memory informed by this model, and discuss their potential implications for educational settings. The episodic memory studies uncover the latent potential of the associative component in childhood by documenting children's ability to greatly improve their memory performance following mnemonic instruction and training. The studies on working memory also point to an immature strategic component in children whose operation is enhanced under supportive conditions. Educational settings may aim at fostering the interplay between associative and strategic components. We explore possible routes towards this goal by linking our findings to recent trends in research on instructional design

Cortical and Psychological Mechanisms of Visceral Pain

Objective: Dysmenorrhea is an incapacitating type of visceral pain that affects numerous menstruating women and is defined by painful menstrual cramps and often occurs in the absence of pelvic pathology. Women with dysmenorrhea have reported higher sensitivity to experimental pain, and vulnerability to pain sensitivity may be a primary risk factor for developing chronic pelvic pain for women with dysmenorrhea. Cross-organ sensitization (COS), or the theory that uterine inflammation during menstruation can contribute to chronic pelvic pain by generating neurogenic inflammation in other organs, may be a primary mechanism associated with pelvic pain in women with dysmenorrhea. Dysmenorrhea sufferers with cross-organ sensitization (D+COS), compared to those without COS, are theorized to experience higher rates of chronic visceral pain and are more susceptible to experimentally-induced pain. The implications of long-term pain sensitivity have been theorized to increase susceptibility to other chronic, visceral pain conditions, and these conditions are associated with higher rates of depression and other mood disorders. Frontal activity during pain has been linked to attentional processing, with both the right and left dorsolateral prefrontal cortices (dlPFC) negatively correlated with intensity perception and unpleasantness. However, most visceral pain research has focused on gastrointestinal disorders, making it important to identify pain mechanisms in women with dysmenorrhea. Since dysmenorrhea, depression, and somatization are associated with abnormalities in frontal cingulate networks, and given the emerging evidence supporting an association between affect and pain, it is necessary to account for the potential effects on regional brain function that may be associated with co-occurring psychological symptoms in individuals experiencing dysmenorrhea. The results of the present study provide evidence that psychological symptoms and brain activity predict increased levels of visceral pain, specifically for women with dysmenorrhea and cross-organ sensitization (COS). Results showed that somatization, depression, and frontal beta activity account for a significant amount of variance, yet somatization is the only significant link between women suffering from D+COS and bladder pain. Thus, based on these results, somatization emerged as the candidate risk factor for developing chronic pelvic pain, and somatic symptoms should be considered a primary target for prevention and intervention strategies