In the Neurocognitive Outcomes of Depression in the Elderly study, researchers have published findings which show a correlation between reduced stressors and subsequent improvement in cognitive scores (n=213). Decreased social interaction was a predictor of cognitive decline and although this could have been due to confounders, the relationship still held after controlling for variables such as depression status. One of the most interesting questions about antidepressants is why they characteristically take many weeks to reach a full beneficial effect. There are a number of studies which suggest that the antidepressants act to increase the number of synapses between neurons in the hippocampus – a region of the brain involved in memory formation. A recent murine study provides evidence that a class of antidepressants – the SSRI’s act in the hippocampus to cause one class of cells known as the granule cells to revert to a more ‘immature’ form which are able to form new synapses more readily.
A Dutch group has assessed psychosocial intervention for Alzheimer’s Disease guidelines across 12 European countries using a standardised protocol. Amongst their findings the researchers concluded that
‘The UK NICE SCIE guideline had the best methodological quality and included the most recommendations for psychosocial interventions‘
and that across Europe special attention is needed in terms of updating guidelines with evidence and implementing these guidelines in service delivery. In a longitudinal study involving subjects with non-amnestic and amnestic mild cognitive impairment (naMCI and aMCI respectively) (n=106) amongst other results researchers found that there was a decline in simple attention in both groups but a decline in divided attention in the aMCI group. The researchers suggest further research to corroborate these findings. Psychological constructs influencing verbal fluency were examined in one study which compared young and older adult healthy controls with people with Alzheimer’s or Parkinson’s Disease. Amongst the researcher’s results they found that processing speed was the strongest correlate of verbal fluency performance and they conclude that
‘the primary role of processing speed in performance suggests that the use of fluency tasks as measures of EF or verbal ability warrants reexamination‘
In an interesting study, researchers used post-mortem and structural MRI data to assess the volume of the hypothalamus in people with Frontotemporal Dementia. They found that the volume of the posterior hypothalamus was significantly reduced in those with behavioural variant Frontotemporal Dementia
There is an open-access article on primate evolution at PLOS Genetics. An international group of researchers have looked at variation in 54 genes in primates in order to produce a more accurate phylogenetic tree.
Phylogenetic Tree from (Perelman P, Johnson WE, Roos C, Seuánez HN, Horvath JE, et al. (2011) A Molecular Phylogeny of Living Primates. PLoS Genet 7(3): e1001342. doi:10.1371/journal.pgen.1001342)
The diversion of human and Chimpanzee lineages is estimated to be between 6 and 7 million years ago from this analysis. There analysis sheds light on some of the earlier and more controversial diversions particularly regarding the New World Primates.
There is also an interesting open-access paper on Neanderthals and fire use in the Proceedings of the National Academy of Sciences here. The researchers looked at a number of sites used by archaic hominids in Europe and found no evidence of fire use by predecessors to the Neanderthals (e.g Homo Heidelbergensis) but repeated fire use by Neanderthals across sites. Although there is evidence of fire use by Homo Erectus at Koobi Fora (estimated at 1.4 million years before present) the evidence here suggests that Neanderthals were consistently using fire and this raises questions about how this consistency was achieved. For instance this may have been achieved through language. A current controversy in the literature centres around whether hominid brain size increased as a result of cooking or preceded this and so this has other implications. Contextualising these findings it’s also interesting to ask if early humans (Homo Sapiens) in Europe learnt their fire making skills from Neanderthals in order to survive in this Ice Age environment.
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