| 1. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 2. |
- MacDonald, Stuart W S, et al.
(författare)
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Extrastriatal dopamine D2 receptor binding modulates intraindividual variability in episodic recognition and executive functioning.
- 2009
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Ingår i: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 47:11, s. 2299-2304
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Tidskriftsartikel (refereegranskat)abstract
- Intraindividual variability (IIV) reflects lawful but transient within-person changes in performance. Increased IIV in cognition shares systematic associations with numerous conditions characterized by alterations in dopamine (DA) neuromodulation (e.g., old age, ADHD, schizophrenia, and Parkinson's disease). In a group of normal middle-aged adults, we examined links between PET-derived measures of D2 receptor binding in striatum, orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and hippocampus (HC) and IIV for tasks assessing recognition memory and executive functioning. An index of IIV, the intraindividual standard deviation (ISD), was computed across successful response latency trials for each cognitive outcome. Lower D2 binding in OC, ACC, and HC, but not striatum, was associated with increasing ISDs for the memory and executive measures. Consistent with neurocomputational models, the present findings suggest a role for extrastriatal DA neurotransmission in modulating variability in cognitive functioning.
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| 3. |
- MacDonald, Stuart W S, et al.
(författare)
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Intra-individual variability in behavior : links to brain structure, neurotransmission and neuronal activity.
- 2006
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Ingår i: Trends in Neurosciences. - : Elsevier BV. - 0166-2236. ; 29:8, s. 474-80
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Intra-individual variability reflects a transient, within-person change in behavioral performance. It is a common component of aging-related cognitive decline and the behavioral changes associated with neurodegenerative and other brain-related disorders such as traumatic brain injury and schizophrenia. Behavioral changes within an individual can reflect alterations at a systems or a cellular level in the brain, and monitoring intra-individual variability can therefore provide a warning of underlying pathology. Despite frequent reports of intra-individual variability, there is little synthesis, and no direct examination of the neural underpinnings. Here, we integrate seminal findings from cognitive research across lifespans of individuals, and also neuropsychological and neurobiological findings, to identify key questions and some potential answers, and to set challenges for fostering future research into intra-individual variability.
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| 4. |
- Wahlin, Åke, et al.
(författare)
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How health and biological age influence chronological age and sex differences in cognitive aging: Moderating, mediating, or both?
- 2006
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Ingår i: Psychology and Aging. - : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 21:2, s. 318-332
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Tidskriftsartikel (refereegranskat)abstract
- Much research on cognitive competence in normal older adults has documented age and sex differences. We used cross-sectional data from the Victoria Longitudinal Study (n=386; age 61-95 years) to examine how health and biological age influence age and sex differences in cognitive aging. We found evidence for both moderating and mediating influences. Age differences were moderated by health status, such that the negative effects of age were most pronounced among participants of relatively better health. Sex differences were moderated by health and were pronounced among participants reporting comparatively poorer health. Although health mediated a notable amount of age-related cognitive variation, BioAge mediated considerably more variance, even after statistical control for differences in health. A complex pattern emerged for the mediation of sex differences: whereas BioAge accounted for sex-related variation in cognitive performance, health operated to suppress these differences. Overall, both health and BioAge predicted cognitive variation independently of chronological age.
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