Publications by authors named "Olafsdottir H"

Background: Myotonic Dystrophy type 1 (DM1) is an autosomal dominant disease with anticipation due to increased number of CTG repeats in the DMPK gene.

Methods: This retrospective, cohort study in Iceland assessed prevalence of DM1, molecular pathology, and patient ascertainment. Data was collected from all major hospitals in Iceland, Medical Director of Health, and independent clinics.

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Autosomal recessive coding variants are well-known causes of rare disorders. We quantified the contribution of these variants to developmental disorders in a large, ancestrally diverse cohort comprising 29,745 trios, of whom 20.4% had genetically inferred non-European ancestries.

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Hippocampal-dependent memory is known to emerge late in ontogeny, and its full development is protracted. Yet the changes in hippocampal neuronal function that underlie this delayed and gradual maturation remain relatively unexplored. To address this gap, we recorded ensembles of CA1 neurons while charting the development of hippocampal-dependent spatial working memory (WM) in rat pups (∼2-4 weeks of age).

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Article Synopsis
  • Human episodic memory starts to show significant development around 2 years old and continues to mature during childhood, as revealed by various behavioral studies.
  • Research on non-human primates and rodents has identified important brain structures and mechanisms related to episodic memory, but collaboration between psychologists and neuroscientists is still limited.
  • This article aims to connect findings from human and non-human studies, addressing key challenges and proposing a flexible research framework to enhance cross-species investigations in episodic memory development.
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Objective: Exposure to adverse childhood experiences (ACEs) is a significant predictor for physical and mental health problems later in life, especially during the perinatal period. Prenatal common mental disorders (PCMDs) are well-established as a risk for obstetric interventions but knowledge on combined effects of multiple psychosocial risk factors is sparse. We aim to examine a comprehensive model of ACEs and PCMDs as risk factors for poor delivery and neonatal outcomes.

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Hierarchical organization of memory is observed in the brains of rats.

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Precisely timed interactions between hippocampal and cortical neurons during replay epochs are thought to support learning. Indeed, research has shown that replay is associated with heightened hippocampal-cortical synchrony. Yet many caveats remain in our understanding.

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A hallmark of biological intelligence is the ability to adaptively draw on past experience to guide behaviour under novel situations. Yet, the neurobiological principles that underlie this form of meta-learning remain relatively unexplored. In this Opinion, we review the existing literature on hippocampal spatial representations and reinforcement learning theory and describe a novel theoretical framework that aims to account for biological meta-learning.

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Background: Complications after esophagectomy are common and the possible increase in postoperative complications associated with neoadjuvant chemoradiotherapy is of concern. The aim of our study was to analyze if the addition of radiotherapy to neoadjuvant chemotherapy increases the incidence and severity of postoperative complications, including evaluation of the relation between radiation doses to the heart and lungs and postoperative complications.

Methods: The study was based on an institutional surgical database for esophageal cancer.

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Background: The globally dominant treatment with curative intent for locally advanced esophageal squamous cell carcinoma (ESCC) is neoadjuvant chemoradiotherapy (nCRT) with subsequent esophagectomy. This multimodal treatment leads to around 60% overall 5-year survival, yet with impaired post-surgical quality of life. Observational studies indicate that curatively intended chemoradiotherapy, so-called definitive chemoradiotherapy (dCRT) followed by surveillance of the primary tumor site and regional lymph node stations and surgery only when needed to ensure local tumor control, may lead to similar survival as nCRT with surgery, but with considerably less impairment of quality of life.

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On 30 January 2020, the disease covid-19 was declared by the World Health Organization to be an international threat to human health and on 11 March 2020, the outbreak was declared a pandemic. The aim of this study was to analyse policy strategies developed by the five Nordic countries during the first 3 months of the pandemic from a health promotion perspective in order to identify Nordic responses to the crisis. Although the Nordic countries have a long tradition of co-operation as well as similar social welfare policies and legislation, each country developed their own strategies towards the crisis.

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Insects are part of the diet of over 2 billion people worldwide; however, insects have not been popular in Europe, neither as food nor as a feed ingredient. This has been changing in recent years, due to increased knowledge regarding the nutritional benefits, the need for novel protein production and the low environmental impact of insects compared to conventional protein production. The purpose of this study is to give an overview of the most popular insects farmed in Europe, yellow mealworm, , and black soldier fly (BSF), , together with the main obstacles and risks.

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Neuronal "replay," in which place cell firing during rest recapitulates recently experienced trajectories, is thought to mediate the transmission of information from hippocampus to neocortex, but the mechanism for this transmission is unknown. Here, we show that replay uses a phase code to represent spatial trajectories by the phase of firing relative to the 150- to 250-Hz "ripple" oscillations that accompany replay events. This phase code is analogous to the theta phase precession of place cell firing during navigation, in which place cells fire at progressively earlier phases of the 6- to 12-Hz theta oscillation as their place field is traversed, providing information about self-location that is additional to the rate code and a necessary precursor of replay.

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Background: Common symptoms of oesophageal cancer are dysphagia, pain, and bleeding. These symptoms can be relieved with palliative radiotherapy. The aim of this study was to analyse the outcome of two different palliative radiotherapy schedules.

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There are rich structures in off-task neural activity which are hypothesized to reflect fundamental computations across a broad spectrum of cognitive functions. Here, we develop an analysis toolkit - temporal delayed linear modelling (TDLM) - for analysing such activity. TDLM is a domain-general method for finding neural sequences that respect a pre-specified transition graph.

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Objective: Evaluate adults referred to a national ADHD clinic, by comparing those diagnosed with those who were not, and those who screened negative and to evaluate changes among those diagnosed at follow-up.

Method: Data obtained from 531 patients' medical records (49.7% males).

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In this issue of Neuron, McKenzie et al. (2021) test the degree to which pre-existing biases in hippocampal circuits constrict the encoding of new information via artificial induction of place cell remapping. Their results suggest that the hippocampal spatial map encodes new information via pre-existing latent place fields.

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Introduction: Limited evidence suggests that the presence of a prehospital physician improves survival from cardiac arrest. A retrospective study is undertaken to examine this question. In Reykjavik, Iceland, prehospital physicians on ambulances were replaced by emergency medical technicians (EMTs) in 2007.

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Purpose: The survival of esophageal and gastric cancer patients treated with chemotherapy is rarely assessed outside of clinical trials. Therefore, we compared the effectiveness of various curative or palliative chemotherapy regimens on the survival of esophageal and gastric cancer patients in a "real world" clinical setting.

Methods: We identified a cohort of 966 incident esophageal and gastric cancer patients in Stockholm/Gotland County (a low-risk Western population) during 2008-2013.

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Most cortical synapses are local and excitatory. Local recurrent circuits could implement amplification, allowing pattern completion and other computations. Cortical circuits contain subnetworks that consist of neurons with similar receptive fields and increased connectivity relative to the network average.

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Background: Attention deficit hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder among children but symptoms may persist into adulthood. At Landspitali - the National University Hospital an interdisciplinary unit is responsible for ADHD-diagnosis and for commencing treatment of adult ADHD. The aim of this study is to evaluate the effectiveness of pharmaceu-tical treatment provided by the unit and the effects of psychiatric comorbidities.

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Introduction: Although perinatal distress is acknowledged as a burdening condition for pregnant women, its effects on pregnancy are not well known. This study was conducted to increase knowledge regarding the effects of distress on pregnancy-related problems. The study also assessed women's need for sick leave and increased prenatal care due to distress, and the effects of weak social support and dissatisfaction with their partner relationships.

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Place cells in the mammalian hippocampus signal self-location with sparse spatially stable firing fields. Based on observation of place cell activity it is possible to accurately decode an animal's location. The precision of this decoding sets a lower bound for the amount of information that the hippocampal population conveys about the location of the animal.

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Objective: To evaluate the psychometric properties of the Icelandic version of the Edinburgh Postnatal Depression Scale (EPDS) when used prenatal, explore the dimensionality of the scale and describe its effectiveness in identifying depression.

Design: A sample of Icelandic women filled in the EPDS at week 16 gestation, week 24 and week 36. If screened positive in week 16 they were asked to attend a psychiatric diagnostic interview 2-4 weeks later.

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