News in Brief
The authors of a paper using data from the prospective DESCRIPA case-control study found evidence that the characteristic CSF biomarkers of Alzheimer’s Disease increased risk of progression up to 27-fold relative to controls. More details can be found here. Preliminary evidence from one study found that Donepezil was associated with a reduction in progression to Alzheimer’s Disease in people with MCI and depression compared to the control group. The control group took either placebo and Vitamin E and the same effect was not found in people with MCI without depression. Images have been captured of neuronal synapses forming with the involvement of a protein – Neuroligin. A recent potentially important finding is that the response of glial cells is reduced in Alzheimer’s Disease and if this is so it could play a role in the degenerative process. This study did however have a small sample size and the findings are in opposition to the main theory proposing an immune response triggered by the Beta Amyloid plaque. It will be interesting to see the results of larger replication studies. A new protein found in the brain – hypoxia upregulated mitochondrial movement regulator (HUMMR) has been associated with the movement of the mitochondria within cells under conditions of hypoxia. The positioning is suggested to play a role in the removal of calcium ions from the intracellular environment under such conditions and there may be a role in hypoxia secondary to stroke (although further research is needed). Diffraction enhanced imaging has been used to image finer anatomical detail in brains in vivo although the synchotron produced radiation is not viable for clinical use, the researchers state that it establishes the principle of using imaging to obtain highly detailed in vivo images of Alzheimer’s Disease related plaques.
A meta-analysis of 14 studies examining aetiology of depression found that variations in the serotonin transporter gene were not associated with an increased risk of depression (This is also covered over by the Neurocritic). An Australian study provided further evidence that depression significantly contributes to quality of life measures if people have concurrent somatic and medical conditions but also that dysthymia more significantly impacted on these quality of life measures. There was evidence of a correlation between dopamine metabolism and reduced grey matter density in people with fibromyalgia compared to controls in a small case-control study. There have been similar studies of this type before, but this 5-year follow-up study of 1238 older adults provided evidence that having a purpose in life was associated with a 50% reduction in mortality. An interesting nurse-led study characterised qualitative aspects of relationships and other changes that occur in people after they have developed a stroke and more information can be found here.
One study provided evidence that naming objects may play a role in their perception. In this study people learnt how to group a novel class of object (designed for the study) based on similarities or name the objects. The latter group were better able to process new examples of these objects incorporating all of the features of this object much like one would with a face. More details are available here.
From an evolutionary perspective there were a number of interesting findings that may be relevant to complex human phenomenon such as sleep. Thus in one study it was found that queen fire ants can sleep up to 9 hours a day whilst worker ants have small naps of up to a minute through the day suggesting a possible role for genetics in sleep patterns (although environmental cues may possibly play a role particularly as a recent study showed that ants respond to high pitched sounds which may be mimicked by other species and can produce marked behavioural responses). In another study it was found that rats were able to manage risk/reward so as to optimise reward in a task analogous to the Iowa gambling task. A study has recently provided preliminary evidence that paternal investment of resources (using a relevant outcome measure) is associated with the genetic similarity of the child.
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