| 1. |
- Kubik, Veit, 1981-, et al.
(author)
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Individual and Combined Effects of Enactment and Testing on Memory for Action Phrases
- 2014
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In: Experimental psychology (Göttingen). - : Hogrefe Publishing Group. - 1618-3169 .- 2190-5142. ; 61:5, s. 347-355
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Journal article (peer-reviewed)abstract
- We investigated the individual and combined effects of enactment and testing on memory for action phrases to address whether bothstudy techniques commonly promote item-specific processing. Participants (N = 112) were divided into four groups (n = 28). They eitherexclusively studied 36 action phrases (e.g., ‘‘lift the glass’’) or both studied and cued-recalled them in four trials. During study trials participantsencoded the action phrases either by motorically performing them, or by reading them aloud, and they took final verb-cued recall tests over 18-min and 1-week retention intervals. A testing effect was demonstrated for action phrases, however, only when they were verbally encoded, andnot when they were enacted. Similarly, enactive (relative to verbal) encoding reduced the rate of forgetting, but only when the action phraseswere exclusively studied, and not when they were also tested. These less-than-additive effects of enactment and testing on the rate of forgetting,as well as on long-term retention, support the notion that both study techniques effectively promote item-specific processing that can only bemarginally increased further by combining them.
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| 2. |
- Furmark, Tomas, et al.
(author)
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Cerebral blood flow changes after treatment of social phobia with the neurokinin-1 antagonist GR205171, citalopram, or placebo.
- 2005
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In: Biol Psychiatry. - : Elsevier. - 0006-3223 .- 1873-2402. ; 58:2, s. 132-42
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Journal article (other academic/artistic)abstract
- BACKGROUND: Evidence is accumulating that pharmacological blockade of the substance P preferring neurokinin-1 (NK1) receptor reduces anxiety. This study compared the effects of an NK1 receptor antagonist, citalopram, and placebo on brain activity and anxiety symptoms in social phobia. METHODS: Thirty-six patients diagnosed with social phobia were treated for 6 weeks with the NK1 antagonist GR205171 (5 mg), citalopram (40 mg), or matching placebo under randomized double-blind conditions. GR205171 was administered for 4 weeks preceded by 2 weeks of placebo. Before and after treatment, regional cerebral blood flow (rCBF) during a stressful public speaking task was assessed using oxygen-15 positron emission tomography. Response rate was determined by the Clinical Global Impression Improvement Scale. RESULTS: Patients improved to a larger extent with the NK1 antagonist (41.7% responders) and citalopram (50% responders), compared with placebo (8.3% responders). Within- and between-group comparisons showed that symptom improvement was paralleled by a significantly reduced rCBF response to public speaking in the rhinal cortex, amygdala, and parahippocampal-hippocampal regions. The rCBF pattern was corroborated in follow-up analyses of responders and subjects showing large state anxiety reduction. CONCLUSIONS: Short-term administration of GR205171 and citalopram alleviated social anxiety. Neurokinin-1 antagonists may act like serotonin reuptake inhibitors by attenuating neural activity in a medial temporal lobe network.
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| 3. |
- Alaerts, Maaike, et al.
(author)
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Support for NRG1 as a Susceptibility Factor for Schizophrenia in a Northern Swedish Isolated Population
- 2009
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In: Archives of General Psychiatry. - : American Medical Association. - 0003-990X .- 1538-3636. ; 66:8, s. 828-837
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Journal article (peer-reviewed)abstract
- Context: Neuregulin 1 (NRG1), a growth factor involved in neurodevelopment, myelination, neurotransmitter receptor expression, and synaptic plasticity, first joined the list of candidate genes for schizophrenia when a 7-marker haplotype at the 5' end of the gene (Hap(ICE)) was shown to be associated with the disorder in the Icelandic population. Since then, more genetic and functional evidence has emerged, which supports a role for NRG1 in the development of schizophrenia.Objective: To determine the contribution of NRG1 to susceptibility for schizophrenia in a northern Swedish isolated population.Design: Detailed linkage disequilibrium (LD)-based patient- control association study. This is the first study to type and analyze the 7 Hap(ICE) markers and a set of 32 HapMap tagging single-nucleotide polymorphisms (SNPs) that represents variants with a minor allele frequency of at least 1% and fully characterizes the LD structure of the 5' part of NRG1.Setting: Outpatient and inpatient hospitals.Participants: A total of 486 unrelated patients with schizophrenia and 514 unrelated control individuals recruited from a northern Swedish isolated population.Main Outcome Measures: Association between markers and disease.Results: Analysis of the Hap(ICE) markers showed the association of a 7-marker and 2-microsatellite haplotype, different from the haplotypes associated in the Icelandic population and overrepresented in northern Swedish control individuals. Subsequently, a more detailed analysis that included all 37 genotyped SNPs was performed by investigating haplotypic association, dependent and independent of LD block structure. We found significant association with 5 SNPs located in the second intron of NRG1 (.007 <= P <= .04). Also, 2-, 3-, and 4-SNP windows that comprise these SNPs were associated (P < 3 x 10(-4)). One protective haplotype (0% vs 1.8%; P < 5 x 10(-5)) and 1 disease risk-causing haplotype (40.4% vs 34.9%, P=.02) were defined.Conclusion: The NRG1 gene contributes to the susceptibility for schizophrenia in the northern Swedish population.
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| 4. |
- Hansson, Patrik, et al.
(author)
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Adult age differences in the realism of confidence judgments : Overconfidence, format dependence, and cognitive predictors
- 2008
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In: Psychology and Aging. - : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 23:3, s. 531-544
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Journal article (peer-reviewed)abstract
- Realistic confidence judgments are essential to everyday functioning, but few studies have addressed the issue of age differences in overconfidence. Therefore, the authors examined this issue with probability judgment and intuitive confidence intervals in a sample of 122 healthy adults (ages: 35-40, 55-60, 70-75 years). In line with predictions based on the naïve sampling model (P. Juslin, A. Winman, & P. Hansson, 2007), substantial format dependence was observed, with extreme overconfidence when confidence was expressed as an intuitive confidence interval but not when confidence was expressed as a probability judgment. Moreover, an age-related increase in overconfidence was selectively observed when confidence was expressed as intuitive confidence intervals. Structural equation modeling indicated that the age-related increases in overconfidence were mediated by a general cognitive ability factor that may reflect executive processes. Finally, the results indicated that part of the negative influence of increased age on general ability may be compensated for by an age-related increase in domain-relevant knowledge.
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| 5. |
- Kask, Kristiina, et al.
(author)
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Allopregnanolone impairs episodic memory in healthy women
- 2008
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In: Psychopharmacology. - : Springer Science and Business Media LLC. - 0033-3158 .- 1432-2072. ; 199:2, s. 161-168
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Journal article (peer-reviewed)abstract
- Allopregnanolone is an endogenous neuroactive steroid that, through its binding to the γ-aminobutyric acid (GABA) A receptor, has GABA-active properties. Animal studies indicate that allopregnanolone administration results in diminished learning and memory impairment. The aim of the current study was to investigate the effect of intravenously administered allopregnanolone on episodic memory, semantic memory, and working memory in healthy women. Twenty-eight healthy women were included in the study. The participants were scheduled for the memory tests twice in the follicular phase. During the test sessions, an intravenous allopregnanolone and placebo infusion were administered in a double-blinded, randomized order at intervals of 48 h. Before and 10 min after the allopregnanolone/placebo injections, memory tasks were performed. The study demonstrated that allopregnanolone impaired episodic memory in healthy women. There was a significant difference between pre- and postallopregnanolone injection episodic memory scores (p < 0.05), whereas there was no change in episodic memory performance following the placebo injections. There was also a significant difference between allopregnanolone and placebo postinjection episodic memory scores (p < 0.05). There were no effects of allopregnanolone on the semantic memory task or working memory task. Intravenous allopregnanolone impairs episodic memory in healthy women, but there is a high degree of individual variability.
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| 6. |
- Moens, Lotte N, et al.
(author)
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Sequencing of DISC1 Pathway Genes Reveals Increased Burden of Rare Missense Variants in Schizophrenia Patients from a Northern Swedish Population
- 2011
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:8, s. e23450-
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Journal article (peer-reviewed)abstract
- In recent years, DISC1 has emerged as one of the most credible and best supported candidate genes for schizophrenia and related neuropsychiatric disorders. Furthermore, increasing evidence - both genetic and functional - indicates that many of its protein interaction partners are also involved in the development of these diseases. In this study, we applied a pooled sample 454 sequencing strategy, to explore the contribution of genetic variation in DISC1 and 10 of its interaction partners (ATF5, Grb2, FEZ1, LIS-1, PDE4B, NDE1, NDEL1, TRAF3IP1, YWHAE, and ZNF365) to schizophrenia susceptibility in an isolated northern Swedish population. Mutation burden analysis of the identified variants in a population of 486 SZ patients and 514 control individuals, revealed that non-synonymous rare variants with a MAF<0.01 were significantly more present in patients compared to controls (8.64% versus 4.7%, P = 0.018), providing further evidence for the involvement of DISC1 and some of its interaction partners in psychiatric disorders. This increased burden of rare missense variants was even more striking in a subgroup of early onset patients (12.9% versus 4.7%, P = 0.0004), highlighting the importance of studying subgroups of patients and identifying endophenotypes. Upon investigation of the potential functional effects associated with the identified missense variants, we found that similar to 90% of these variants reside in intrinsically disordered protein regions. The observed increase in mutation burden in patients provides further support for the role of the DISC1 pathway in schizophrenia. Furthermore, this study presents the first evidence supporting the involvement of mutations within intrinsically disordered protein regions in the pathogenesis of psychiatric disorders. As many important biological functions depend directly on the disordered state, alteration of this disorder in key pathways may represent an intriguing new disease mechanism for schizophrenia and related neuropsychiatric diseases. Further research into this unexplored domain will be required to elucidate the role of the identified variants in schizophrenia etiology.
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| 7. |
- Wikgren, Mikael, 1981-, et al.
(author)
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Shorter telomere length is linked to brain atrophy and white matter hyperintensities
- 2014
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In: Age and Ageing. - : Oxford University Press (OUP). - 0002-0729 .- 1468-2834. ; 43:2, s. 212-217
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Journal article (peer-reviewed)abstract
- Background: leukocyte telomere length (TL) is considered a marker of biological aging. Several studies have investigated the link between leukocyte TL and aging-associated functional attributes of the brain, but no prior study has investigated whether TL can be linked to brain atrophy and white matter hyperintensities (WMHs); two prominent structural manifestations of brain aging. Methods: we investigated whether leukocyte TL was related to brain atrophy and WMHs in a sample of 102 non-demented individuals aged 64-75 years. Results: shorter TL was related to greater degree of subcortical atrophy (beta = -0.217, P = 0.034), but not to cortical atrophy. Furthermore, TL was 371 bp shorter (P = 0.041) in participants exhibiting subcortical WMHs, and 552 bp shorter (P = 0.009) in older participants exhibiting periventricular WMHs. Conclusion: this study provides the first evidence of leukocyte TL being associated with cerebral subcortical atrophy and WMHs, lending further support to the concept of TL as a marker of biological aging, and in particular that of the aging brain.
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