| 1. |
- Nyberg, Lars, et al.
(författare)
-
Striatal dopamine D2 binding is related to frontal BOLD response during updating of long-term memory representations
- 2009
-
Ingår i: NeuroImage. - : Elsevier. - 1053-8119 .- 1095-9572. ; 46:4, s. 1194-1199
-
Tidskriftsartikel (refereegranskat)abstract
- Multi-modal brain imaging was used to examine the relation between individual differences in resting-state striatal dopamine D2 binding and the magnitude of prefrontal BOLD activation during updating of long-term memory (LTM) representations. Increased activity in the left prefrontal cortex was observed when LTM updating was required, and there was a positive correlation between striatal D2 activity and the magnitude of left prefrontal activity during updating. These findings support predictions from neurocomputational models of a relation of dopaminergic neurotransmission to transient cognitive operations and related brain activity.
|
|
| 2. |
- de Frias, Cindy M, et al.
(författare)
-
Catechol O-methyltransferase Val158Met polymorphism is associated with cognitive performance in nondemented adults.
- 2005
-
Ingår i: Journal of cognitive neuroscience. - Cambridge : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 17:7, s. 1018-25
-
Tidskriftsartikel (refereegranskat)abstract
- The catechol O-methyltransferase (COMT) gene is essential in the metabolic degradation of dopamine in the prefrontal cortex. In the present study, we examined the effect of a Val158Met polymorphism in the COMT gene on individual differences and changes in cognition (executive functions and visuospatial ability) in adulthood and old age. The participants were 292 nondemented men (initially aged 35-85 years) from a random sample of the population (i.e., the Betula study) tested at two occasions with a 5-year interval. Confirmatory factor analyses were used to test the underlying structure of three indicators of executive functions (verbal fluency, working memory, and Tower of Hanoi). Associations between COMT, age, executive functioning, and visuospatial (block design) tasks were examined using repeated-measures analyses of variance. Carriers of the Val allele (with higher enzyme activity) compared with carriers of the Met/Met genotype (with low enzyme activity) performed worse on executive functioning and visuospatial tasks. Individuals with the Val/Val genotype declined in executive functioning over the 5-year period, whereas carriers of the Met allele remained stable in performance. An Age x COMT interaction for visuospatial ability located the effect for middle-aged men only. This COMT polymorphism is a plausible candidate gene for executive functioning and fluid intelligence in nondemented middle-aged and older adults.
|
|
| 3. |
- Lind, Johanna, et al.
(författare)
-
Reduced functional brain activity response in cognitively intact apolipoprotein E ε4 carriers
- 2006
-
Ingår i: Brain. - : Oxford University Press. - 0006-8950 .- 1460-2156. ; 129:5, s. 1240-1248
-
Tidskriftsartikel (refereegranskat)abstract
- The apolipoprotein E epsilon4 (APOE epsilon4) is the main known genetic risk factor for Alzheimer's disease. Genetic assessments in combination with other diagnostic tools, such as neuroimaging, have the potential to facilitate early diagnosis. In this large-scale functional MRI (fMRI) study, we have contrasted 30 APOE epsilon4 carriers (age range: 49-74 years; 19 females), of which 10 were homozygous for the epsilon4 allele, and 30 non-carriers with regard to brain activity during a semantic categorization task. Test groups were closely matched for sex, age and education. Critically, both groups were cognitively intact and thus symptom-free of Alzheimer's disease. APOE epsilon4 carriers showed reduced task-related responses in the left inferior parietal cortex, and bilaterally in the anterior cingulate region. A dose-related response was observed in the parietal area such that diminution was most pronounced in homozygous compared with heterozygous carriers. In addition, contrasts of processing novel versus familiar items revealed an abnormal response in the right hippocampus in the APOE epsilon4 group, mainly expressed as diminished sensitivity to the relative novelty of stimuli. Collectively, these findings indicate that genetic risk translates into reduced functional brain activity, in regions pertinent to Alzheimer's disease, well before alterations can be detected at the behavioural level.
|
|
| 4. |
- Lind, Johanna, et al.
(författare)
-
Reduced hippocampal volume in non-demented carriers fo the apolipoprotein E ε4 : Relation to chronological age and recognition memory
- 2006
-
Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 396:1, s. 23-27
-
Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein E ε4 (APOE ε4) is the main known genetic risk factor for Alzheimer's disease (AD). Some previous studies have reported structural brain changes as well as cognitive deficits in non-demented APOE ε4 carriers, but the pattern of results is inconsistent and studies with larger sample sizes have been called for. Here we compared hippocampal volume and recognition–memory performance between AD-symptom-free carriers (N = 30) and non-carriers (N = 30) of the APOE ε4 (age range: 49–79 years). We observed reduced right hippocampal volume in APOE ε4 carriers, and found that the difference was most pronounced before the age of 65. Further, the APOE ε4 carriers made significantly more false alarms in the recognition–memory test, and the number of false alarms correlated significantly with right hippocampus volume. These results indicate that relatively young individuals at genetic risk for AD have smaller hippocampal volume and lower performance on hippocampal-dependent cognitive tasks. A question for the future is whether smaller hippocampal volume represents early-onset hippocampal volume reduction or an inherent trait.
|
|
| 5. |
|
|
| 6. |
- Nilsson, Lars-Göran, et al.
(författare)
-
The influence of APOE status on episodic and semantic memory : data from a population-based study
- 2006
-
Ingår i: Neuropsychology. - Washington : American Psychological Association. - 0894-4105 .- 1931-1559. ; 20:6, s. 645-57
-
Tidskriftsartikel (refereegranskat)abstract
- In a prospective cohort study, the authors demonstrated a more pronounced epsilon4-related deficit for participants 70 years of age and older in tasks assessing episodic recall. Apolipoprotein E (APOE) and age interacted for episodic memory tasks, whereas the interaction for semantic memory tasks was between APOE and test wave. Heterozygotes of epsilon4 between middle-age and young-old participants performed at a higher level than noncarriers of this allele in recall tasks. A dose effect was found such that carriers of 2 epsilon4 alleles failed more profoundly in acquiring and recollecting episodic information than carriers of 1 epsilon4 allele, who in turn failed more than carriers of non-epsilon4 alleles. The pattern of findings observed for older epsilon4 carriers suggests that these individuals have particular difficulty when the executive task demands are high. Several factors (e.g., smaller hippocampal volumes, less effective neural repair mechanisms) may account for these findings. On the basis of the data obtained, the authors argue that analyses of the effect of specific genes in cognition should be accompanied by assessment of performance at a specific level, with due attention to the individual's age.
|
|
| 7. |
- Rönnlund, Michael, et al.
(författare)
-
Stability, Growth, and Decline in Adult Life Span Development of Declarative Memory : Cross-Sectional and Longitudinal Data From a Population-Based Study
- 2005
-
Ingår i: Psychology and Aging. - : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 20:1, s. 3-18
-
Tidskriftsartikel (refereegranskat)abstract
- Five-year changes in episodic and semantic memory were examined in a sample of 829 participants (35-80 years). A cohort-matched sample (N=967) was assessed to control for practice effects. For episodic memory, cross-sectional analyses indicated gradual age-related decrements, whereas the longitudinal data revealed no decrements before age 60, even when practice effects were adjusted for. Longitudinally, semantic memory showed minor increments until age 55, with smaller decrements in old age as compared with episodic memory. Cohort differences in educational attainment appear to account for the discrepancies between cross-sectional and longitudinal data. Collectively, the results show that age trajectories for episodic and semantic memory differ and underscore the need to control for cohort and retest effects in cross-sectional and longitudinal studies, respectively.
|
|
| 8. |
- Andersson, J., et al.
(författare)
-
Worse survival for TP53 (p53)-mutated breast cancer patients receiving adjuvant CMF
- 2005
-
Ingår i: Ann Oncol. - : Elsevier BV. - 0923-7534 .- 1569-8041. ; 16:5, s. 743-8
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: TP53 has been described as a prognostic factor in many malignancies, including breast cancer. Whether it also might be a predictive factor with reference to chemo- and endocrine therapy is more controversial. PATIENTS AND METHODS: We investigated relapse-free (RFS), breast cancer-corrected (BCCS) and overall survival (OS) related to TP53 status in node-positive breast cancer patients that had received polychemotherapy [cyclophosphamide, methotrexate, 5-fluorouracil (CMF)] and/or endocrine therapy (tamoxifen). Sequence analyses of the whole TP53 coding region was performed in 376 patients operated on for primary breast cancer with axillary lymph node metastases between 1984 and 1989 (median follow-up time 84 months). RESULTS: TP53 mutations were found in 105 patients (28%). We found 90 (82%) of the 110 mutations in the more frequently analysed exons 5-8, while the other 20 (18%) were located in exons 3-4 and 9-10, respectively. Univariate analyses showed TP53 to be a significant prognostic factor with regard to RFS, BCCS and OS in patients who received adjuvant CMF. CONCLUSIONS: TP53 mutations might induce resistance to certain modalities of breast cancer therapy. Sequence-determined TP53 mutation was of negative prognostic value in the total patient population and in the CMF treated patients.
|
|
| 9. |
- Bergdahl, Jan, et al.
(författare)
-
Treatment of chronic stress in employees: Subjective, cognitive, and neural correlates.
- 2005
-
Ingår i: Scandinavian Journal of Psychology. - : Wiley. - 0036-5564 .- 1467-9450. ; 46:5, s. 395-402
-
Tidskriftsartikel (refereegranskat)abstract
- This study reports the effect of an affect-focused intervention program, the Affect School (AS), on stress, psychological symptoms, cognitive functioning and neural activity. Fifty employees in social service and education, with high levels of chronic stress, were randomly divided into a treatment (N=27) and control (N=23) group. Complete sets of data were available in 20 participants in the treatment group and in 17 in the control group. The Percieved Stress Questionnaire assessed stress and the Symptom Chech List-90 psychological symptoms before and after the treatment. Episodic-memory functioning under focussed and divided attention conditions was also assessed. Prior and after the AS, seven participants in the treatment group were studied with fMRI during episodic memory processing. After the AS there was a reduction in stress and psychological symptoms for the treatment group but not in the control group. The controls showed a reduction in episodic memory functioning whereas the performance of the treatment group remained intact. The fMRI scanning indicated a qualitative change in the neural network subserving episodic memory. These preliminary results suggest that the AS is effective on individuals with high stress.
|
|
| 10. |
- Bergdahl, Maud, et al.
(författare)
-
Difference in apolipoprotein E type 4 allele (APOE ɛ4) among dentate and edentulous subjects
- 2008
-
Ingår i: Gerodontology. - : Wiley. - 0734-0664 .- 1741-2358. ; 25:3, s. 179-186
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: To evaluate the frequency of apolipoprotein (APOE) alleles and determine whether APOE type 4 allele (ɛ4) was associated with edentulousness even when certain factors were controlled.Background: The APOE are important in lipid homeostasis, and APOE ɛ4 has been found in many diseases and to have a negative impact on longevity. Tooth loss is more common in ill aged subjects with low income and education.Materials and methods: In a population-based study involving 1860 subjects between 35 and 85 years 1321 dentate (mean age = 54; 54% women, 46% men) and 539 edentulous (mean age = 72; 62% women, 38% men) subjects were studied. Logistic regression was performed with dentate/edentulous as dependent variables and years of education, socio-economic status, social network, stress level, handicap from birth, 23 various diseases and APOE ɛ4 as covariates. Thereafter, APOE ɛ4 frequencies were studied in 342 dentate and 336 edentulous subjects 50–85 years of age. The subjects were matched with regard to age, gender, years of education, living condition, stress level, handicap from birth and 23 various diseases.Results: APOE allele frequency in the total group was ɛ2 = 7.8%, ɛ3 = 76.4% and ɛ4 = 15.8%. Age, living condition, years of education and APOE ɛ4 were significant covariates in edentulous subjects (p ≤ 0.001). APOE ɛ4 in the matched groups revealed significant differences between the dentate group and the edentulous group (χ2 = 5.68; p = 0.017). There was no group effect (F(29,648) = 0.849; p < 0.696; Wilks' lambda = 0.963). In the dentate group, the frequencies of APOE were: ɛ2 = 8.8%, ɛ3 = 77.9% and ɛ4 = 13.3%. Corresponding frequencies of APOE in the edentulous group were: ɛ2 = 6.6%, ɛ3 = 75.4% and ɛ4 = 18.0%.Conclusion: Despite matching both groups with regard to different background factors, the edentulous group had a higher frequency of APOE ɛ4 than the dentate group. Thus, genetic factors might contribute to greater risk in developing complex oral diseases leading to tooth loss or just be an indication that the subjects in our study carrying APOE ɛ4 are more fragile.
|
|
